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2016/2017 > BIOL 319 Part II > Flashcards

BIOL 319 Part II Flashcards

1
Q

differences in predator interactions in sandy shore relative to rocky

A
  • have to dig/work to get prey
  • less restricted by tides
  • more partial predation
  • seasonal predator intensity
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2
Q

why are predators less restricted by tides in sandy/muddy shore

A

more terrestrial predators (marine predators restricted by submersion)

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3
Q

seasonal predator intensity, soft sediment shore

A

migratory birds

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4
Q

sandy shore infauna predator defense

A
  • differential burrowing depth
  • differential shell thickness
  • anti-predator chemicals
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5
Q

bottom-up and top-down predation in sandy shore

A

top-down typically terrestrial like birds

bottom-up typically marine predators - fish, crabs etc

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6
Q

burrowing benefit

A

hidden

well-defended

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7
Q

sandy shore defense trade-off

A

thin shell bivalves burrow deeper

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8
Q

sandy shore anti-predator chemicals

A

polychaetes

bromide-containing aromatic compounds

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9
Q

infaunal organisms and predators

A
  • infauna typically well protected
  • infauna can suffer high mortality due to seasonal predator intensity
  • more abundant species suffer highest depletion rates
  • predators are specialized to infauna
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10
Q

disturbances in soft shore environment

A
  • physical

- biological

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11
Q

biological disturbance in soft shore environment

A
  • predators

- bioturbation

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12
Q

physical disturbance, soft shore environment

A

waves

  • sediment
  • exposure
  • shelter
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13
Q

waves and sediment

A

impact sediment size, sorting, distribution, permeability, porosity, penetrability

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14
Q

waves and exposure

A

high energy, small sediment size, sandy shore

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15
Q

waves and shelter

A

low energy, more impacted by tides than waves, small size sediment, clay/mudflat

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16
Q

sediment diameter vs water velocity

A

increasing to asymptote (log x)

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17
Q

wave impact on beach sediment

A

longshore transport

tides

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18
Q

wave exposed, sandy beach infauna

A

dominated by long-lived suspension feeders; bivalves, clams

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19
Q

sheltered, muddy beach

A

dominated by short-lived deposit feeders; worms/polychaetes

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20
Q

why are bivalves more common in sandy beach

A

suspension feeders - access to currents in sand, and can get clogged by fine particles in mud

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21
Q

why worms more abundant in muddy beaches

A

fragile; like calm, sheltered environment

deposit feeders - more OM in mud

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22
Q

bioturbation increases

A
  • habitat complexity
  • sediment oxygen
  • sediment sorting
  • sediment stickiness
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23
Q

impact of bioturbation on other organisms

A

commensalism

amensalim

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24
Q

commensalism

A

other species benefit from the activities of bioturbater

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25
Q

example of commensalism

A

mussels sheltering the beach for cockles

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26
Q

supply side ecology soft sediment principles

A
  • infauna have larvae
  • larvae are delivered by currents (depend on wave exposure)
  • variable settlement strategies
  • adults are mobile (unlike rocky shore)
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27
Q

water table

A
  • natural level of water content

- approximately at the tide line

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28
Q

above water table

A

very little water in sediments

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29
Q

changes in water table

A

water line moves up/down during day due to tide/currents

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30
Q

suspension feeders favour

A

high energy, coarser sediments

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31
Q

amensalism

A

other species suffers from the activities of bioturbators

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32
Q

amensalism example

A

lugworms exclude other burrowing organisms

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33
Q

why do deposit-feeders decrease growth of suspension feeders

A

sediment reworking re-suspends particles and clogs the filtering organs

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34
Q

Importance of larval settlement in sandy shore relative to rocky

A

not as important in sandy because they can move

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35
Q

sandy shore zonation hypotheses

A
  • no zonation
  • two zones only (Brown’s)
  • three zones (Dahl’s)
  • four zones (Salvant’s)
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36
Q

sandy shore zonation

A
  • abiotic factors only
  • wetness–dryness gradient
  • disturbance
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37
Q

retention zone

A

where water goes in to sediment but doesn’t stay - waves crash, water enters, water percolates down to water table

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38
Q

supralittoral zone

A
  • highest part of beach
  • dry vast majority of time
  • air breathing organisms, insects
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39
Q

littoral zone

A
  • ‘true intertidal’ zone
  • sometimes dry some wet
  • mixed species
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40
Q

deposit feeders favour

A

low energy, finer sediments

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41
Q

sublittoral zone

A

lowest intertidal zone

  • mostly wet
  • lots of infauna
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42
Q

Brown’s zonation hypothesis

A

2 zones: air breathers vs water breathers

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43
Q

Dahl’s zonation hypothesis

A

3 zones: sub-terrestrial fringe, midlittoral, sublittoral fringe

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44
Q

salivates zonation hypothesis

A

drying, retention, resurgence, saturation

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45
Q

beach types that impact zonation

A
  • dissipative beach
  • intermediate beach
  • reflective beach
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46
Q

dissipative beach

A
  • gentle slope (flat)
  • wave break before hitting beach, sheltered
  • generally wetter, finer sed
  • less pronounced wetness gradient
  • shallower RPD
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47
Q

reflective beach

A
  • steep slope
  • waves break on beach - exposed
  • intertidal dryer, sediment bigger
  • wetness gradient more pronounced
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48
Q

zonation in soft sediments

A
  • 2-4 zone depending on beach
  • always dry and wet zones, middle ones change
  • slope is important
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49
Q

true kelp

A
  • (Order Laminaria) brown algae
  • large, brown subtidal seaweed
  • very strong holdfast
  • form dense NA forests
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50
Q

kelp zones with depth

A

top of water column = canopy
middle = understory
benthos = algal turf

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51
Q

kelp zones with distance from shore

A

inshore
kelp canopy
offshore

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52
Q

what is “brown algae”

A

mixed photosynthetic pigments (chl a and chl c)

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53
Q

Seaweed morphology pars

A

holdfast + stipe = thallus
float
blades/fronds

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54
Q

characteristics of reflective beach

A
  • large particles
  • large physical gradient, flow, moisture
  • low chemical gradient
  • large importance of waves
  • low importance of tides
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55
Q

pneumatocyst

A

seaweed float

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56
Q

seaweed difference from terrestrial/vascular plants

A

seaweed lack ‘true’ leaves, stems, roots, not plants

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57
Q

seaweed blade structures

A

flat, high SA:V, concentrated w/ chl, maximize nutrient absorption

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58
Q

characteristics of dissipative beach

A
  • small particle size
  • low physical gradient
  • large chemical gradient (O2, Eh)
  • low importance of waves
  • high importance of tides
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59
Q

kelp as photosynthesizers

A
  • very highly productive
  • entire body photosynthesizes
  • grow fast and large
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60
Q

pneumatocyst structure and function

A
  • air/gas filled balls
  • grape-volleyball size
  • keep blades close to surface
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61
Q

why do pneumatocysts want to keep the blades close to the surface

A

they have the highest concentration of chl - keep close to sunlight for max production

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62
Q

pneumatocyst gases

A

O2, CO2, CO

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63
Q

stipe

A
  • strong, flexible, “stem”
  • absorbs shock
  • photosynthesizes
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64
Q

holdfast

A

“roots”

  • anchor
  • don’t absorb nutrients
  • may secrete glue-like substance
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65
Q

thallus

A

whole body

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66
Q

convergence in kelp

A

species evolved to have kelp-like morphology can behave in same way and provide similar fn’s to kelp

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67
Q

divergence in kelp

A

species that specialize in different regions may have different morpholgy

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68
Q

divergence examples

A

canopy kelp - long, tall, rise up to 45m
stipulate kelp - only rise ca 2m
prostrate kelp - drape seafloor

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69
Q

canopy kelps

A

-fronds on surface
-giant kelps
-

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70
Q

understory kelp

A
  • fronds erect or close to bottom
  • middle zone
  • stipe dominant
  • highest diversity
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71
Q

algal turf zone

A
  • short clump, filaments, encrusting
  • non-kelp algae
  • abundant red algae
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72
Q

inshore kelp zone

A

feather-boa, laminaria

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73
Q

canopy conditions

A
  • most light
  • most wave action
  • not stable environment
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74
Q

understory conditions

A
  • less light
  • less wave action
  • highest diversity
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75
Q

why is understory so high in diversity

A
  • stipes = area for attachment
  • area between fish to swim
  • calm environment
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76
Q

algal turf conditions

A
  • least light
  • little-no wave influence
  • holdfasts = attachment areas, niche space
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77
Q

why red algae in algal turf?

A

low light chl

flat to maximize absorption

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78
Q

organisms associated with understory

A

stipes: tube-forming polychaetes, byrzoans, sessile organisms
- crustacean feeders
- plankton feeders
- concentrate larvae

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79
Q

kelp crustacean feeders

A

surf perches

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80
Q

kelp plankton feeders

A

topsmelt

blue rockfish

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81
Q

organisms associated with algal turf

A

holdfast: small inverts, brittle stars, polychaetes, urchins, crabs
- herbivores
- carnivores

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82
Q

algal turf herbivores

A
  • adult rockfish

- kelp bass

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83
Q

algal turf carnivores

A

california sheephead - eat crabs, urchins

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84
Q

distribution of kelp forests

A
  • restricted

- concentrated in mid-high lats., upwelling zones

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85
Q

kelp forest restrictions

A
  • hard substrate for attachment
  • coastal zone for sunlight
  • cool Ts, heat sensitive
  • high DIN for high productivity
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86
Q

why aren’t kelp forests in tropics

A
  • too hot

- too nutrient poor

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87
Q

why aren’t kelp forests in polar regions

A
  • growing season too short
  • light limitations
  • ice scouring
  • too harsh of conditions
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88
Q

kelp distribution is closer to tropics than might be expected, why?

A

predominant current direction (S in N, N in S) upwells cool nutrient rich waters and stretches distribution

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89
Q

Kelp importance

A
  • high PP, carbon sequestration
  • provide food, shelter for many species
  • buffer, protect coasts against waves, storms
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90
Q

causes of kelp deforestation

A
  • physical condition anomalies
  • sea urchins
  • storms
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91
Q

El Niño deforestation

A
  • more storms, warmer, less nutrient, removal of predators, release herbivores
  • upwelling reduced, reversed -warm nutrient poor water - not good for kelp
  • kelp often recover from these events
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92
Q

urchin deforestation

A
  • urchins normally passively feed on drift kelp

- when drift limited, urchins experience food limitation - feeding behaviour changes - become destructive

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93
Q

drift kelp

A

free-floating kelp detritus

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94
Q

urchin feeding behaviour change

A
  • actively feed on holdfast
  • aggregate in big groups
  • move through forest as one super kelp eater
  • urchin feeding “front”
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95
Q

kelp forest with low urchin density

A

mix of kelp + other turf algae

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96
Q

kelp forest with high urchin density

A

-kelp deforested
crustose
-coralline algae replaces all other species = “urchin barren”

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97
Q

urchin barrens and kelp recovery

A

less likely to recover from this type of deforestation b/c crustose coralline algae prevent kelp from re-rooting

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98
Q

Controls on kelp urchins in W NAtl

A
  • single tier (prostrate)
  • simple food web
  • strong interactions
  • cod extirpation – phase shift to urchin barren – return to kelp forest
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99
Q

Controls on kelp urchins in Aleutians, Alska

A
  • simple food web but multi-tiered
  • intermediate diversity
  • european settlement– phase shift– switched back and forth after that
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100
Q

Controls on kelp urchins in Southern California

A
  • multi-tier kelp (3 zones)
  • complex food web
  • high diversity
  • urchin barrens/kelp forests flicker back and forth, short duration
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101
Q

What happened to kelp forests in Alaska

A

otters nearly extirpated– urchins grow out of control (trophic cascade)– otter pop’s recover, urchins under control– kelp recovers – then phase shift again!

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102
Q

what caused the second phase shift in Alaska

A

-increased number of orca kills – reduced otter pop. – trophic cascade again by apex predator this time– 4 level trophic cascade

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103
Q

why did orcas start eating more otters

A
  • possibly because their food source is declining (seals)

- possibly b/c geographical distribution is changing

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104
Q

What happened to kelp forest in N Atl

A

decline in cod allowed urchins to take over– phase shift – urchin fisheries opened – kelp forests re-established
-cod functionally equivalent to sea otters – trigger same trophic cascade

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105
Q

impacts of cod collapse in Nova Scotia (relative to Maine)

A

following initial phase change from cod collapse – multiple cycles of urchin disease – several phase shifts

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106
Q

lessons from phase shift studies

A
  • humans are good at triggering phase shifts
  • anything that can control urchin populations can trigger the phase shift
  • phase shifts can lead to new species interactions
  • even in similar regions can have unique triggers/interactions (Maine vs Canada)
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107
Q

new interaction following kelp phase shift, N Atl

A

kelp recover - encourage crabs to migrate into kelp bed– crabs feed on urchin larvae and diseased adults – prevent urchin recruitment

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108
Q

Details of kelp forest phase shift in Southern California

A
  • more predators, species
  • delayed phase shifts (otters removed 150-200ya)
  • other predators fed on urchins – human settlement –functionally equiv. species all under pressure now
  • other predators buffered the system from change, provided insurance
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109
Q

phase shift

A

switch between steady states

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110
Q

threshold

A

energy required to switch between steady states

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111
Q

when do phase shifts reverse

A
  • when they reach their threshold

- urchin density is a threshold for urchin barren phase

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112
Q

threshold to shift to kelp forest

A

variable - reducing urchin density not always enough

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113
Q

continuous phase shift

A

“linear”
-path same backwards and forwards
to switch from one system occurs at the same threshold as switching back (e.g. the same urchin density)

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114
Q

the points at which a threshold is reached and phase change occurs

A

tipping point

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115
Q

kelp forest hysteresis cause by

A

feedback mechanisms stabilize the phases

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116
Q

kelp state feedbacks

A

lots of kelp = lots of detritus = lower urchin migration and grazing = lots of kelp
+kelp - +whiplash – -urchin grazing – +kelp
+kelp – +predator abundance – +urchin mortality – +kelp
+kelp – + spore production – +kelp

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117
Q

barren state feedbacks

A

barren – +urchin fertilization – +recruitment – barren
barren – +settlement facilitation – +recruitment – barren
barren – -detritus – -destructive grazing – kelp recruitment – barren
barren – -detritus – -urchin migration – barren
barren – -predator abundance – -barren state

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118
Q

discontinuous phase shift

A

“non-linear”
switching from one state requires a different threshold than switching back (e.g. lower urchin density to switch back to kelp than to switch to barren)
-harder to predict, reverse

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119
Q

another name for discontinuous shift

A

hysteresis = delay

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120
Q

biggest threats to kelp forest ecosystems

A
  • loss of biodiversity
  • climate change
  • any interference that reduces kelp forest health
  • any interference that increases urchin health / destructive behaviour
  • nutrient loading and water quality
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121
Q

kelp conservation strategies

A
  • maintain biodiv.
  • water quality
  • restoration
  • maintain healthy kelp
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122
Q

how to maintain biodiversity

A

predator recovery
MPAs
responsibly fishery practices

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123
Q

how to maintain water quality

A

sewage and waste management

runoff management

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124
Q

marine foundation species that have evolved from terrestrial ancestors

A 
seagrass (meadows)
mangrove (forests)
salt marshes
convergence, similar adaptations 
-I will call these SMS ecosystems
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125
Q

SMS ecosystems have lots in common with

A

mudflats

the plants root in soft sediment ecosystems

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126
Q

first plant life

A

precambrian

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127
Q

evolution of land plants

A

Silurian

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128
Q

evolution of plants from phytoplankton to seagrass

A

phytoplankton- red algae -brown algae- green algae- land plants- mangroves- sea grasses

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129
Q

adaptations for dealing with life in seawater

A
  • make photosynthesis more efficient
  • stability in soft sediment
  • deal with anoxic waterlogged sediment
  • remove/exclude excess salt
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130
Q

why do marine terrestrial plants need to make photosynthesis more efficient

A
  • gas exchange difficult in seawater
  • light attenuation with depth
  • more energy required for life in seawater
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131
Q

why does life require more energy in seawater

A

need to oxygenate roots -need to photosynthesize more to maintain same growth levels

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132
Q

SMS species commonalities

A
  • have above-ground (leaves) and below-ground (roots) components (very different than kelp)
  • provide surfaces for epifauna
  • interact with infauna
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133
Q

SMS sediments share characteristics w/ soft shore ecosystems

A
  • waterlogged sediment (b/c its mud)
  • anoxia with depth (RPD)
  • similar “chemical layering” as shore sediment
  • processed (bioturbated) by a variety of organisms
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134
Q

seagrass

A
  • vascular, flowering plant
  • monocots
  • angiosperms
  • not true grasses
  • form large meadows (single or multiple species)
  • subtidal
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135
Q

evolution of marine angiosperms

A

Cretaceous

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136
Q

subtidal

A
  • below mean low tide

- normally covered by water at all tide levels

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137
Q

seagrass distribution

A
  • widely distributed in temperature, tropical coastal systems
  • narrow depth restrictions
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138
Q

what determines distribution of seagrass

A
  • substrate
  • light
  • UV
  • desiccation
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139
Q

substrate and seagrass

A
  • majority require soft substrate
  • too much sediment buries them
  • not found in rocky substrates
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140
Q

light and seagrass

A
  • very high light requirement (photosynthesis inefficient in seawater)
  • lower distribution limits set by light availability
  • upper limit may be set by UV
  • restricted by turbidity (upwelling zones too turbid)
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141
Q

seagrass diversity

A
  • ca. 60 species worldwide
  • difficult to classify, lots of plasticity
  • higher diversity in tropics than temperature latitudes
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142
Q

common seagrass genera in North America

A
  • Thalassia: turtle grass, warmer regions, manatees, Florida-Texas
  • Zostera: eelgrass, widely distributed along both coasts
  • Phyllospadix: on both sides of NP, only genus that attaches to rocks
  • Halodule: fresher (lower S) sandy areas, upper eastuaries
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143
Q

seagrass morphology

A

laminate leaf blades, leaf sheath, rhizome, node, simple root

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144
Q

seagrass leaf blade

A
  • strap-like
  • grow from sheath
  • number, height of leaves varies between species
  • up to 1m
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145
Q

seagrass rhizome

A

rooting structure that each plant attaches to, connects plant clones together

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146
Q

seagrass above-ground:below-ground biomass

A

ca. 50:50

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147
Q

seagrass leaf length

A

0.5 cm - 5m

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148
Q

variability in seagrass leaves

A

-many shapes and sizes
-single species can have large variability - plasticity
oblong, longitudinal, serrated, folded, cross veined, etc

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149
Q

variability in seagrass roots

A

simple, branched, hairy

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150
Q

importance of seagrass characteristics/ morphologies

A
  • some forms can’t grow as densely as others
  • SA/shape import for organism attachment, feeding
  • bushy roots stabilize sediment more
  • some forms take more energy to grow resulting in trade-offs
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151
Q

seagrass marine adaptations

A

rhizome - mechanical support, vegetative growth
leaf shape - thin, flexible in high E env.
leaf sheath - provides protection in high E env.
lacunar system - transport O2 below ground to oxygenate roots (depresses RPD)

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152
Q

seagrass reproduction

A
  • sexual rare and inefficient

- vegetative growth (cloning) common but still slow

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153
Q

seagrass sexual reproduction

A
  • mostly dioecious
  • hydophilous pollination
  • flower seasonally w/ high spring tide
  • 10% of meadow flowers at a time
  • dispersal limited, most seeds drop within m’s of parent
  • less than 0.00001 probability seedings become new adult
  • still important for genetic diversity
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154
Q

seagrass asexual reproduction

A
  • rhizomes extend and release new shoots
  • recolonization not fast or efficient
  • old clone persist
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155
Q

importance of seagrass reproduction

A
  • inefficient = long time to recover from disturbance

- low sexual reproduction = low resilience

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156
Q

genotypic diversity =

A
  • lower vulnerability to disturbance, disease
  • more productive, abundant
  • increased abundance, diversity of epifauna
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157
Q

seagrass foodweb

A 
PP- seagrass, algae
Epiphytes and fouling animals 
Grazers: meso, macro
Suspension feeders: bivalves
Shredders, deposit feeders: shrimp, crabs
Predators: meso, macro
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158
Q

fouling animals

A

live on seagrass

e.g. sponges, bivalves

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159
Q

seagrass mesograzers

A

small inverts

  • limpets, amphipods, etc.
  • consume algal epiphytes not seagrass unless left unchecked
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160
Q

seagrass macropredators

A

sharks (primarily prey on fish)

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161
Q

seagrass mesopredators

A

medium carnivorous fish

primarily feed on mesograzers

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162
Q

why so many diverse relationships in seagrass

A

shelter- predators, waves
habitat - attachment sites
food - seagrass, algae, larvae, detritus

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163
Q

epiphytic community in seagrass

A
  • important and diverse
  • rhodophyta (red algae)
  • chlorophyta (green algae)
  • phaeophyta (brown algae)
  • bacillariophyceae (diatoms)
  • older seagrass = more diverse
  • 26 species of algae found on 1 species of seagrass
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164
Q

seagrass macrograzers

A

sea cows

turtes

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165
Q

epiphytic algae impact on seagrass community

A
  • inhibit light, nutrient uptake for seagrass

- nutritious food source for other organisms: higher N:C, easier to digest, no cellulose or lignin, more fatty acids

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166
Q

eating seagrass

A

tough, high in cellulose

  • mostly consumed as detritus (microbial breakdown)
  • some organisms specialized to consume (sea cow)
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167
Q

urchin impacts on seagrass

A
  • live in coral reef (keep them clean)

- leave reef at night to graze on surrounding grasses = reef halo

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168
Q

Green turtle macrograzer

A
  • endangered
  • young are omnivores
  • older turtles increasingly herbivorous, seagrass specialists
  • long guts w/ specialized enzymes to digest
  • selective feeders
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169
Q

green turtle selective feeding

A

‘gardeners’

  • feed on young plants
  • physiological selection: more nutritious, easier to digest
  • biological selection: stimulates growth of new plants
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170
Q

why green turtles are endangered

A
  • human exploitation
  • sensitive to land use change, pollution (because of nesting)
  • loss of habitat
  • accidental kills (bycatch, impacts)
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171
Q

sea cow macrograzers

A
  • Order Sirenia (4 species)
  • most species feed on marine and fresh plants
  • Dugong seagrass specialist
  • only herbivorous marine mammal
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172
Q

Dugong dugon

A
  • Indo-Pacific
  • feed in large herds, leave feeding trail
  • massive guts >30m
  • selective feeding
  • vulnerable
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173
Q

Dugong selective feeding

A

‘cultivation feeders’

  • prefer Halophila (high N, low fibre)
  • pioneer species, grazing it stimulates growth or preferred food
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174
Q

surprising species in seagrass meadows

A

bivalves! (not often found in soft sediments)

-in the sediment and on seagrass blades

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175
Q

seagrass bivalve

A

Pinna nobilis - endemic to mediterranean seagrass

  • gigantic, up to 4ft
  • fast growth, fragile shell
  • possibly mutualistic w/ seagrass
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176
Q

Pinna nobilis mutualism

A
  • seagrass provide food, protection

- bivalves filter water (make it clear)

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177
Q

seagrass burrowers and shredders

A
  • shrimp, crab, feed on seagrass
  • some target detritus, others fresh leaves
  • some transport detritus into burrows
  • rework sediment
  • cause bare patches in meadow - open space
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178
Q

ecological processes in seagrass communities

A
  • bottom-up forces control diversity, abundance, distribution
  • top-down forces control community structure
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179
Q

bottom-up seagrass forces

A

-light
-nutrients
-substrate
seagrasses only distributed and abundant where they factors are

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180
Q

top-down forces in seagrass meadow

A
  • mesograzers (if unchecked)
  • urchins can cause bare patches
  • macrograzers alter composition/abundance
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181
Q

what happens to seagrass community if a mesograzer predator is excluded

A
  • mesograzers increase
  • reduce algae
  • could be positive - more sunlight, nutrients for seagrass
  • could eventually run out of algae and feed on seagrass
  • could be positive or negative
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182
Q

what happens to seagrass community if predator of small fouling animals is removed

A
  • increased fouling animals
  • decrease in seagrass
  • negative impact
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183
Q

mesograzer vs fouling animals

A

-mesograzers feed on photosynthesizes
attached to seagrass
-fouling animals are attached to seagrass and aren’t photsyn.

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184
Q

effect to seagrass community if urchin predators are removed

A
  • increase in urchins
  • decrease in seagrass
  • negative impact
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185
Q

mutualistic grazer model, seagrass community

A
  • small inverts. feed on algae (mesograzersm algae)
  • algae outcompete seagrass is left unchecked
  • small inverts. keep seagrass healthy if controlled by predators
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186
Q

top-down linear seagrass trophic cascade

A

+large predators – (-)small predators — +algae grazers — algae — seagrasses

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187
Q

real trophic cascade in seagrass

A
  • much more complex
  • depend on which organisms are targeted
  • not always intuitive
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188
Q

ecology of fear

A

non-consumptive trophic cascade

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189
Q

example of non-consumptive trophic cascade

A

-wolf reintroduction in Yellowstone

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190
Q

importance of seagrass ecosystem

A
  • increase habitat complexity
  • highly productive, CO2 sink, high levels of biodiversity
  • provide food
  • structural stability, protect shoreline from erosion, waves
  • filter pathogens, environmental cleaners
  • provide ecosystem services
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191
Q

seagrass habitat complexity

A
  • above and below ground
  • new niches
  • protection
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192
Q

seagrasses provide food for

A

endangered marine animals

  • seahorses
  • sharks
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193
Q

seagrass losses

A
  • 15% lost from 93-2003; 2-5% per year
  • 74 species of concern, mostly fish
  • foundation species in decline
  • organisms that live in seagrass in decline
  • water quality in decline
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194
Q

threats to seagrass meadow

A
  • human alterations - eutrophication, fishing, land use change
  • human recreation - habitat fragmentation
  • invasive species (algae)
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195
Q

eutrophication and seagrasses

A
  • increased nutrient supply (N, P)
  • increased algal growth and take over
  • seagrass sensitive to nutrient loading
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196
Q

why is eutrophication better for algae

A
  • at high nutrient level seagrass saturates, can’t grow any faster
  • algae continue to increase and restrict light
  • outcompete seagrass
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197
Q

Valentine and Duffy hypothesized state shifts in seagrass

A

seagrass dominated – algae dominated
low efficiency small predator -overfishing- high efficiency
high abundance mesograzer -pollution- low abundance
low algal biomass -eutrophication- high algal biomass

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198
Q

seagrass overfishing example

A
  • 90% decline of cod in sweden (overfishing) – mesopredators increased – mesograzes decreased – algae increased – seagrass decreased
  • 4 level trophic cascade
  • overfishing caused seagrass smothering, exacerbated by nutrient pollution
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199
Q

boat propeller scars in seagrass

A 
-anchors, moorings, propellers
uproot seagrass
fragmentation
increased patchiness
long time to recover (inefficient reproduction)
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200
Q

studying seagrass processes

A

ASU - artificial seagrass units

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201
Q

major factors affecting seagrass structure

A

abiotic conditions
herbivory
clonal reproduction
hydrodynamics physical disturbance

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202
Q

community impacts from seagrass

A 
water flow
particle deposition
associated species abundance and diversity 
resource availability
predation success
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203
Q

seagrass fragmentation

A
  • reduces overall area
  • isolates organisms from main population
  • edge effects
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204
Q

examples of edge effects

A
  • predators more successful on edge (prey can’t hide)

- changes to sediment profile, water physics

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205
Q

reported invasive species increasing due to

A
  • ability to detect

- higher transportation of invasives

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206
Q

Caulerpa taxifolia

A
  • invasive algae
  • decorative aquarium algae
  • one of worlds 100 worst invasive species
  • very hardy, likes polluted water, high UV, fast growing, toxic chemicals - grazing resistance
  • outcompetes seagrasses, invades damaged beds
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207
Q

invasive algae in Mediterranean

A

introduced in 1980s (possible from ocean institute), almost completely replaced seagrass

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208
Q

climate change and seagrass

A
  • T ∆ has negative effect b/c many species live at their limits (foundation species sensitive to T)
  • +T = declines in health, changes in species composition
  • changes top-down control, rate of consumption
  • herbivores may increase activity (metabolic increase w/ T)
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209
Q

effect of temperature on interaction strength, seagrass

A
  • depends on species
  • strength and direction variable
  • hard to predict
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210
Q

strategies to protect seagrass

A 
MPAs, remove/restrict boating
prevent invasives- promote harvest, regulate ballast water, aquaria trade
fishing regulations
education, promotion, communication
climate change, pollution
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211
Q

name for a mangrove forest

A

mangal (entire forest)

mangrove (single tree)

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212
Q

mangrove importance

A
  • biodiversity
  • trap sediment, increase water quality outside mangal
  • provide shoreline stabilization and protection
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213
Q

what are mangals

A
  • tropical, saline, intertidal/estuarine forest
  • trees w/ exposed rooting structures in soft sed
  • turbid, organic-rich water
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214
Q

mangrove distribution

A

strictly tropical
30ºS - 30ºN
temperatures greater than 20ºC

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215
Q

types of mangal habitats

A
  • riverine
  • tide-dominated
  • basin mangroves
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216
Q

Riverine (estuary) mangals

A

-often river deltas
-large salinity variation
-common in Asia
-seasonal variability high from rainy season
stress = S variability

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217
Q

Tide-dominated (open ocean) mangal

A

-coastal front habitat
-stable salinities, strong tidal cycle
-unstable morphology due to coastal erosion
stress = tide variability

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218
Q

basin mangroves (sheltered system)

A

-inland/fringing mangroves
-little change in tide, no wave action
-often higher S than others (evaporation)
stress = high S

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219
Q

mangal plants

A
  • true mangroves

- mangrove associates

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220
Q

mangrove associates

A
  • widely distributed trees/plants
  • not restricted to mangal
  • peripheral species
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221
Q

true mangroves

A
  • adaptations to life in ocean
  • 50+ species, 20 genera, 16 families
  • up to 16 independent convergent evolution events
  • evolved in Cretaceous
  • all flowering trees
  • viviparous
  • prop roots
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222
Q

majority of mangrove belong to which families

A

Avicennicaceae (white mangroves)

Rhizophoracea (red mangroves)

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223
Q

most diverse mangals

A

Indo-Pacific

Pacific mangroves much more diverse than All

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224
Q

viviparous trees

A

seeds germinate on parent plant, drop into rooting structures as fully fledged embryos

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225
Q

mangrove challenges

A
  • water-logged sed, frequent inundation of saline water
  • salinity either variable or high
  • highly anoxic sed
  • nutrient poor water
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226
Q

whats the problem with water-logged sediment

A

problems for gas exchange
nutrient absorption
stability

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227
Q

prop roots

A

support, nutrient uptake, breathing

-massive surface area

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228
Q

mangrove root parts

A

pneumatophore
lenticels
aerenchyma
-all to help roots ‘breathe’

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229
Q

pneumatophore, mangrove root

A

vertical root structure for air exchange

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230
Q

lentils, mangrove root

A

tiny pores for air exchange

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231
Q

mangrove salt tolerance

A
  • filter at uptake (roots)
  • storage
  • secrete
  • dilute
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232
Q

salt storage, mangrove

A
  • specialized vacuoles in specific tissues

eg. bark, stem root

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233
Q

salt secretion, mangrove

A

specialized salt gland
leaves or roots
occasionally shed leaves to remove accumulated salt

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234
Q

aerenchyma, mangrove root

A

tissue for air exchange

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235
Q

salt dilution, mangrove

A

with succulent leaves

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236
Q

succulent

A

thickened and fleshy, usually to retain water in arid climates or soil conditions

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237
Q

why is it challenging for a plant to live in saline water

A
  • osmosis – fighting water loss

- inhibits transpiration

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238
Q

transpiration

A

water transport from roots to leaves to cool them down`

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239
Q

regulating water loss, mangroves

A
  • close stomata
  • regulate leaf orientation (angle to maximize light, minimize water loss)
  • some species increase root biomass w/ increased S
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240
Q

why are mangrove roots so shallow

A
  • estuarine surface water typically less saline than deeper

- mangrove roots shallow and horizontal to maximize freshwater absorption

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241
Q

mangrove reproduction

A
  • vivapary: seed germinates on parent
  • trees pollinated by insects or animals
  • seeds germinate into propagules and drop in ocean
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242
Q

young mangrove propagule

A

hypocotyl

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243
Q

what is a propagule

A

A structure able to give rise to a new plant

ex. seed, spore, part of vegetative body capable of independent growth

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244
Q

animals that pollinate mangroves

A

bats

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245
Q

propagule dispersal depends on

A
  • tides

- seed shape

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246
Q

tidal impact on mangrove propagule

A
  • dispersal
  • saline water, high tide = propagule afloat, dispersal away from parent
  • fresh water, low tide = propagule sinks and immediately roots
  • note that dropping times may vary and be coordinated w/ tides
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247
Q

seed shape impact on mangrove

A

dart-shaped drops down into mud

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248
Q

mangrove propagule success dependent on

A
  • environmental conditions (especially light)

- predation

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249
Q

mangrove propagule predation

A
  • predators like grapsid crabs feed on seeds

- faster the mangrove roots the more likely it escapes predation

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250
Q

most common mangrove species

A
  • Red Mangrove (eg. Rhizophora)
  • Black mangrove (e.g.. Avicennia)
  • White mangrove (Laguncularia racemosa)
  • named for bark colour
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251
Q

flowering in the common mangroves

A

red - all year, max in spring/summer
black- spring/ summer
white - spring/summer

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252
Q

propagule shape in common mangroves

A

red - cigar, green bean
black - oblong/elliptical, lima bean
white - flattened, pea green, sunflower seed

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253
Q

propagule length in common mangroves

A

red - 15cm
black - 2-3cm
white - less than 0.5 cm

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254
Q

types of mangrove roots

A

prop-root
peg-root
knee-root

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255
Q

prop-root

A
  • looks like arches above ground

- look like mini upside-down trees underground, branching, setose = nutritive roots

256
Q

peg-root

A
  • look like many spikes above ground = peg root
  • single, linear, bristled nutritive roots on peg root below ground
  • ‘hairy’ roots below peg root = anchoring roots
257
Q

mangal biodiversity

A
  • mix of marine and terrestrial organisms
  • numerous infauna phyla
  • epifauna on/amongst roots
  • epiphytes on trunks, branches
  • many insects
258
Q

studying mangal fish provides

A

examples of evolution in extreme environment - anoxic, sulphidic (euxinic)

259
Q

Rivals marmoratus

A
  • mangrove forest fish
  • detects H2S and leaps out of water
  • also leaps to avoid predation
  • generalized response to avoiding stress
260
Q

degree of vivipary in common mangroves

A

red - extensive while on tree
black - intermediate
white - semi-viviparous, germinate during dispersal

261
Q

root establishment time in common mangroves

A

red - 15 days
black - 7 days
white - 5 days

262
Q

knee-root

A

-‘knees’ (small bumps) above ground = site of secondary root development

263
Q

unique fish evolution in mangroves

A
  • Rivulus
  • mudskipper
  • four-eyed fish
264
Q

mudskipper

A
  • bimodal respiration

- “walking”

265
Q

four-eyed fish

A

Anableps anableps

  • eyes split in two - half emerged, 1/2 submerged
  • separate genes to control each half
  • each 1/2 adapted uniquely for vision in air or turbid water
266
Q

why are mangals poorly studied

A
  • difficult conditions: heat, humidity, turbid water, difficult to get around
  • risks: mosquitos (dengue, malaria), predators (snakes, alligators), politically unsafe
267
Q

area of research focus in mangals

A
  • zonation
  • basic ecology
  • role as nurseries (fish, shrimp)
  • response to threats
268
Q

basic ecological research in mangals

A
  • role of ecosystem engineers

- island biogeography

269
Q

zonation in mangals

A
  • some clear zonation, some mixed
  • environmental stress opposite to rocky/sandy shore (landward less stress)
  • hypothesized to be environmental stress driven
270
Q

mangal zonation most common in

A

areas of high

  • tidal variability
  • salinity variability
271
Q

mangal zones

A
  • terrestrial
  • intermediate
  • fringing
272
Q

mangal terrestrial zone

A
  • true terrestrial plants, mangrove associates

- poor tolerance for low O2, high S

273
Q

mangal intermediate zone

A
  • black/white mangroves (no prop roots)
  • least tolerant of salt
  • more tolerant of low O2
  • many pneumatophores
274
Q

mangal fringing zone

A 
red mangroves (prop roots)
-most highly tolerant of salt water
275
Q

mangal zonation hypotheses, zonation driven by:

A
  • tidal propagule sorting
  • physical condition tolerance
  • others: competition, sediment characteristics
276
Q

mangal zonation, tidal propagule sorting

A
  • lighter propagules stranded in upper shores

- heavier propagule carried to edges

277
Q

IBT

A

-diversity depends on distance from parent population and island size

278
Q

The Mangrove Experiment

A
  • founding IBT experiments
  • naturally fragmented mangrove ‘islands’
  • fumugated
  • monitor
279
Q

The Mangrove Experiment results

A
  • islands closer to source population recovered faster

- also teaches us about meta community ecology - community connectedness

280
Q

grapsid crabs

A
  • ecosystem engineers
  • build burrows
  • increase O2 penetration
  • decrease sulfide accumulation
281
Q

Mangrove dual stable isotope study

A
  • C, N ratio analyses on PPers

- find mangrove detritus primary food source of juvenile prawns w/i habitat

282
Q

mangrove isotopic signature

A

∂13C depleted - (ca. -30 - -26)

∂15N depleted (ca. 2-8)

283
Q

river sediment isotopic signature

A

∂13C depleted - (-28 - -24)

∂15N enriched - (18 - 10)

284
Q

eating mangrove leaves

A
  • unplalatable
  • high C:N, high salt - unprofitable resource
  • Grapsid crab shred leaves encouraging microbial degradation and store in burrows to give degradation time
285
Q

other food sources within mangal

A
  • some species (fiddler crab) rely heavily on algae (odd b/c low in mangal)
  • mangal may concentrate other food sources or provide protected env’t to feed in
286
Q

removal of grapsids in mangroves

A
  • increased sediment anoxia, sulfide, ammonium concentrations
  • decreased # trees
287
Q

mangal ecological interaction study summary

A
  • isotopes useful to study forest interactions

- good evidence that organisms use mangal for food as well as shelter

288
Q

threats to mangrove forests

A
  • land use change (especially shrimp farming)
  • climate change (sea level rise, range shift, T shift)
  • lack of knowledge
289
Q

mangrove degradation

A

UN: 20% of worlds mangrove forests lost 1980-2005

total losses - 30-40%

290
Q

shrimp farming

A
  • commonly on edge of mangal
  • uproot trees to make pens
  • high waste, disease, destruction
  • pens last 1-5yrs then move on to new spot
  • lots of illegal farming
  • don’t clean up after
291
Q

mangrove forest vs shrimp farm value

A

-mangal 8-10 higher value than shrimp farm

292
Q

mangal ecosystem goods and services

A
  • forest products
  • fishery
  • storm protection
293
Q

mangrove rehabitation

A
  • replanting has low success rate especially in converted lands
  • restored forest lower complexity, effectiveness
  • burden of restoration falls on small poor communities
294
Q

restoration effort

A
  • often very ineffective

- conservation is a better way to spend time/money

295
Q

sea level rise and mangroves

A
  • more salt water inundation = more stress to higher zones

- more water logging

296
Q

mangrove distribution shift due to climate change

A
  • poleward in response to lower # extreme cold events -threshold response
  • further inland due to sea level rise
297
Q

how will disappearance of manuals affect biodiversity

A
  • reduced habitat complexity likely to reduce biodiversity, abundance
  • may result in cascades
  • likely impact fisheries
  • difficult to predict
298
Q

What are salt marshes

A
  • coastal ecosystem
  • flowering grasses, sedges, rushes, rooted in soft sed
  • terrestrial plants
  • complex topography
  • not uniform, interconnected patches
299
Q

salt marsh distribution

A
  • mid to high lats
  • coastal zones
  • take over from mangroves
  • can be displaced from mangrove distribution shift
300
Q

iconic salt marsh plant genus

A

Spartina (cordgrass)

  • looks similar to seagrass
  • restricted sexual reproduction
301
Q

Spartina morphology

A
  • aboveground stem and leaves

- below ground rhizomes

302
Q

Spartina rhizomes

A
  • take up nutrients
  • connect clonal pant members
  • provide structure and support
  • asexual reproduction
303
Q

Spartina sexual reproduction

A
  • flowers

- seeds and flowers grazed by many animals limiting reproduction

304
Q

Spartina rhizome protection

A

allow sediment buildup in marsh, supports/protects against disturbance/erosion

305
Q

salt marsh impacts on environment

A
  • trap OM (peat) – very anoxic (more than other environments)
  • fuel bacterial respiration = more anoxic
  • change patterns of sediment deposition
306
Q

salt marsh OM

A

4-20% of sediment mass

307
Q

salt marsh adaptations

A
  • roots, leaves, stems highly vascularized with aerenchyma

- salt glands

308
Q

aerenchyma

A
  • air channels
  • support O2 movement between above/below ground structures
  • prevent anoxia in roots
309
Q

spartina salt glands

A

exudate salt from leaves, stems

310
Q

salt marsh formation

A
  • start as mudflat
  • seeds, ‘raftings’ arrive at mudflat
  • new plants root in mud
  • vegetative growth
  • community builds up and up and up
311
Q

new group of salt marsh plants in mudflat

A

baffle

-barrier, trap sediment and peat, build-up ecosystem

312
Q

“rafting”

A

piece of rhizome w/ shoot

313
Q

salt marsh ecosystem engineers

A
  • one of most extreme forms
  • completely change ecosystem, dramatic effect
  • alter physical and chemical composition
314
Q

salt marsh impact on sediment deposition

A
  • create heterogeneous landscape

- considerable depth variations

315
Q

salt marsh heterogeneous landscape

A
  • bare patches
  • various channels
  • -saltwater trapping in lagoons/puddles
316
Q

salt marsh bare patches

A
  • created by floating wrack accumulation
  • smother existing grass = bare patch formation
  • evaporation = salt pan (salty and hard to colonize)
317
Q

floating wrack

A
  • detritus

e. g. dead Spartina

318
Q

salt marsh ecology

A
  • very well studied, especially E USA
  • diverse communities and complex habitat-many microhabitats
  • many ecological lessons learned here
319
Q

salt marsh ecological interactions well studied

A
  • facilitation
  • competition
  • grazing
  • role of detritus
  • upwelling hypothesis
  • role of predators
320
Q

salt marsh mussels

A

semi-infaunal (Geukensia demissa)

  • abyssal threads attached to sed grain
  • breathe air
  • help trap sed. to build up marsh
  • supply marsh w/ N-rich material
321
Q

salt marsh crabs

A

fiddler crab

  • aerates sediment, introduces oxygen – helps plants
  • shredding increases fungi growth
322
Q

salt marsh fungi

A
  • mycorhizae
  • associated w/ plant roots
  • allow plants to gather more nutrients
323
Q

other salt marsh members

A
  • gastropods (grazing snails)
  • inverts
  • deposit feeders (oligochaetes, polychates)
  • predatory crabs (non-fiddlers)
  • juvenile fish (nursery)
  • birds, rodents
324
Q

differences in salt marsh diversity

A

generally more diversity on E coast NA (less human impact)

325
Q

salt marsh facilitation

A
  • salt marsh plants are foundation species
  • create stable habitat for other organisms
  • provide shelter from stress, predators
  • trap food, OM
326
Q

detrimental foundation species interactions

A

Spartina build up sed (+ for many organisms) but exude some sed. organisms (like lugworms)

327
Q

Lugworm vs Spartina

A
  • both ecosystem engineers
  • lugworm can’t burrow in Spartina zone b/c dense rhizomes
  • Spartina does not succeed if lugworms burrow
328
Q

biomechanical warfare paper (lugworms, Spartina)

A
  • success depends on who got there first
  • seeding spartina in lugworm habitat not succesful
  • transporting lugworms to spartina habitat not successful
  • negative ecosystem engineer interaction
  • lugworms protect mudflat
329
Q

salt marsh zonation

A
  • environmental stress, competition

- some have clear zonation, some mixed

330
Q

controls on salt marsh zonation - what areas are more stressful

A
  • opposite to intertidal patterns
  • lower intertidal more stressful
  • competition more important in upper intertidal
331
Q

sheltered beach salt marsh zonation

A

-multiple distinct zones of adjacent foundation species

332
Q

wave exposed beach salt marsh zonation

A

single zone containing nested foundation species

333
Q

why does zonation depend on wave action in salt marsh

A
  • environmental stress prevent single species dominance
  • hardiest species colonizes but does not grow quickly, leaving space
  • less hardy species takes advantage of buffering from species 1
334
Q

broader implications of salt marsh zonation

A

-should translate to any system w/ multiple foundation species

335
Q

menge-sutherland w/ facilitation

A

associational defenses (high in low stress) lowers predation

336
Q

why is salt marsh zonation unique relative to our other ecosystems

A

b/c it is foundation species zonation - not just zonation of a species - zonation of entire community

337
Q

salt marsh grazing

A
  • tough, rich in cellulose, loaded w/ Si, anti-grazing compounds
  • not important source of food, few grazers
  • seeds, flowers tasty -limits dispersal
338
Q

Spartina grazers

A
  • Littoraria (periwinkles)

- grasshoppers, aphids

339
Q

Littoraria

A

radula scrapes materials off plant, attach to plant by glue-like mucus

340
Q

latitudinal differences in salt marsh grazing

A
  • in NA grazing intensity increases from N –> S

- causing salt marsh plants to be less palatable in S

341
Q

why are there latitudinal effects on grazing

A
  • more grazers in the S

- diversity higher in tropical latitudes

342
Q

problems associated with latitudinal grazing differences

A

-if South species transplanted to North can be problematic (no natural grazer)

343
Q

salt marsh POM

A
  • Spartina leaves turn brown, senesce, fall into water (deciduous)
  • microbial decomp.
  • detritus also food source for other organisms (oligochaetes)
344
Q

salt marsh detritus importance to other ecosystems

A
  • outwelling hypothesis
  • mostly rejected now
  • most SM detritus consumed w/i marsh
  • can generate DON that fuels PP in other areas
345
Q

Spartina - Littoraria trophic cascade

A

snail- scrape plant - feeding scar - infection sites for plants
—blue crabs – (-)snail – +plant health

346
Q

exclude blue crabs from salt marsh

A

= more snails = more infected Spartina

347
Q

implications of Spartina/Littoraria interaction

A
  • snails facilitate fungal growth (bad fungi)

- blue crabs decimated by fisheries = major impact on salt marsh

348
Q

salt marsh importance

A
  • high PP, biodiversity
  • nursery
  • shore line stabilization, erosion prevention
  • nutrient filtering
  • sediment trap
349
Q

salt marsh losses

A
  • 92% of NA SMs lost in 200 years

- largest impact is LUC

350
Q

salt marsh threats

A
  • sea level rise (saline inundation)
  • coastal squeeze
  • filling, erosion
  • eutrophication
351
Q

expected sea level rise

352
Q

coastal squeeze

A
  • coast moving inland from sea level rise

- humans moving coastward

353
Q

salt marsh filling

A

many marshes are filled in to create shoreline development - reduces shoreline stability, filtering, increased toxic metal concentration in ocean

354
Q

impact of reduced salt marsh filtering capacity

A

increased toxic metal concentration in ocean

355
Q

eutrophication and salt marsh

A
  • shifts competitive ability from short plant w/ extensive rhizome to taller
  • increase palatability of plant and grazing
356
Q

Spartina invasion

A

-high tolerance, fast vegetative growth = competitive superiority
-‘sterile’ plants sometimes transplanted to rebuild habitat, stabilize shores
-if any reproductive species get in can wreak havoc on ecosystem
-Wa, Or, NZ, Aust,
puget sound

357
Q

spartina and puget sound

A
  • destroying oyster industry
  • crowding out habitat for shellfish, fish, birds, juveniles
  • taken over 15,000 acres of Wilapa Bay
358
Q

Spartina growth rate

A

ca 17% / year

359
Q

estuary overview

A
  • diverse collection of habitats (encompass sandy/rocky shores, mudflats, marshes, etc)
  • incredibly productive, vital for range of animals
  • among most degraded habitats on planet
  • huge variabilities
360
Q

how do we define and classify estuaries

A
  • salinity
  • geomorphology
  • sediment patterns
  • oxygen
361
Q

types of estuaries based on geomorphology

A
  • glacial fjord estuary
  • coastal plain estuary (drowned river valley)
  • bar-build estuary
  • tectonic estuary
362
Q

geomorphology

A

stude of landforms and the processes that shape them`

363
Q

Glacial fjord estuary

A

-common around BC, chile, norway, NZ
-glacier cut U-shaped valley
-long, deep, straight sided, rocky-bottomed
common in higher lats., mt’s
-shallow sill at mouth restricting exchange, circulation

364
Q

Costal plain estuary

A
  • Chesapeake Bay
  • formed from sea level rise after last ice age flooding river valleys
  • funnel-shaped, shallow 30m, river runoff sediments, mud bottom, extensive mudflats
  • temperate lats, low sed discharge
365
Q

sea level change due to changes in volume of wter

A

eustatic (always global)

366
Q

bar-built estuary

A
  • E US, Fl, tropics
  • created by offshore deposits forming barrier across bay/inlet w/ river flow
  • barrier restricts flow of water in
  • commonly tropical
  • extensive lagoons
367
Q

glacial ford geomorphology

A
  • boulders, large rocks

- steep sided

368
Q

drowned river valley geomorphology

A

lots of soft sediments

369
Q

bar-built estuary geomorphology

A

calm bay w/ soft sed.

370
Q

bar-built estuary habitats

A
  • seagrass meadow
  • mangroves
  • mudflats
371
Q

glacial ford habitat

A

-rocky intertidal epifauna

372
Q

estuary tidal classification

A

microtidal estuary (less than 2m tidal range)
mesotidal estuary (2-4m)
macro tidal estuary (4-6m)
hyper tidal estuary (greater than 6m)

373
Q

why estuaries have large tidal ranges

A

topography (constrain water flow)

374
Q

drowned river valley habitats

A
  • mudflats
  • seagrass meadows
  • mangroves
  • salt marshes
375
Q

estuary definition

A

-where a river meets the ocean

376
Q

estuary limits

A

-difficult to define, change based on perspective, time
Upper: where tidal influence begins in the river, noticeable tidal movement
Lower: where river ‘plume’ ends; complex, subjective

377
Q

estuary freshwater/seawater

A
  • determines longitudinal/ vertical salinity variability

- entire world S range seen w/i estuary

378
Q

estuary geomorphology

A

determines shape of estuary, habitat availability

379
Q

estuary tidal range

A

determines emersion/submersion times

380
Q

longitudinal salinity gradient

A

river -estuary: oligohaline
mid-estuary: mescaline, polyhaline
ocean: euhaline

381
Q

oligohaline

382
Q

mesohaline

383
Q

vertical salinity gradient in estuary with large freshwater input

A
  • S low at surface from freshwater input
  • increases through estuary (halocline)
  • high and stable S at depth
384
Q

vertical salinity gradient in lagoon or area with high evaporation

A
  • high S at surface
  • shorter, shallower, reversed halocline
  • relatively stable at depth
385
Q

estuary classification based on salinity gradient

A
  • salt-wedge
  • partially-mixed
  • well-mixed
386
Q

daily salinity change, estuary

A

tidal cycle

-as tide rises saline waters move closer to mouth

387
Q

estuary salinity variability

A

varies in: space, seasons, day

388
Q

polyhaline

389
Q

how do organisms deal with salinity variability

A
  • osmoconformity
  • osmoregulation
  • stenohaline
390
Q

osmoconformity

A
  • maintain internal solutes equal to medium
  • eg. inverts
  • most tolerant to S ∆’s
391
Q

Euhaline

A

ca. 30 PSU

low variability

392
Q

river-driven estuaries have max flow in

393
Q

osmoregulation

A
  • regulate/maintina internal salt levels
  • eg. some fish, inverts
  • intermediate ∆S tolerance
394
Q

rain driven estuary system, max flow

395
Q

5-18 PSU S zone in estuary

A

Polyhaline

396
Q

∆S and climate change, estuary

A

changes to snow packs and rain inputs will alter ∆S’s

397
Q

stenohaline

A
  • limited salinity tolerance
  • many fish, verts
  • cannot tolerate large fluctuations
398
Q

estuary sediments

A
  • rivers (terrestrial)
  • tides, currents (marine)
  • meet at lowest E
  • large particles drop out = sorting
  • plume is fine muds, clays
  • mid-esutary fine sed rich in OM
399
Q

what do you typically find around mid-estuary

A

mudflats!

-only fine sediments remain

400
Q

effect of sediment transport on benthic organisms

A
  • creation, stability of habitats
  • water clarity
  • food availability
401
Q

sediment transport and water clarity in an estuary

A
  • high sed input = reduced clarity
  • clog up filter feeders
  • limit light for P
  • OM-rich seds fuel bacterial resp., deplete O2, provide food
402
Q

estuaries and geological age

A
  • generally young, majority since last glacial retreat (ca. 20,000ya)
  • tropical younger than temperate
  • much less time to accumulate diversity than other marine ecosystems
  • also ephemeral systems (on geo. timescales)
403
Q

organisms that can tolerate salinity fluctuations

A

Euryhaline

404
Q

why are estuaries ephemeral

A
  • changes in sea level (ice cap formation, thawing)
  • sedimentation (infill estuaries)
  • tectonic activity (creates, destroys basins)
405
Q

estuary characteristics that impact benthic communities

A
  • S variabilities
  • low O2 conditions (especially fjords)
  • tides
  • sediment transport
  • geological age
406
Q

why low O2 especially problematic in fjords

407
Q

estuary diversity

A
  • low compared to other systems
  • unique mix of marine, freshwater
  • highly productive
  • abundance, diversity decline upstream in river
408
Q

controls on estuarine organism distribution

A
  • early models emphasize S

- recent models emphasize interaction btw S and other processes

409
Q

Remane diagram

A

number of species vs salinity (river on left - ocean on right)

  • species minimum in the estuary
  • different types of organisms
  • developed in Baltic sea
  • assumes S is driving factor
410
Q

problems w/ Remane

A
  • largely qualitative
  • variables poorly defined
  • extrapolating from Baltic to all estuaries not valied
411
Q

Baltic

A
  • tideless
  • marginal sea
  • fixed S gradient, consistent btw mouth and inner
  • well mixed w/ stark change at ocean in narrow channel
  • very highly impacted ecosystem
412
Q

Estuary species hypotheses, Remane, Barnes

A

Remane- 3 groups: freshwater, brackish-water, marine; attempts to link absolute S w/ organism distr.
Barnes- 2 groups: no brackish species

413
Q

Attrill estuary organism distribution model

A

-predicts that salinity variability, NOT absolute S, more important for predicting biodiversity

414
Q

important difference btw Remane model and Attrill model

A

Remane: hypothetical, qualitative model
Attrill: actual testable hypothesis

415
Q

Attrill’s salinity experiment

A
  • samples collected along Thames estuary, 4x/year

- find mean alpha-diversity negatively correlated w/ salinity range (r2 = 0.425)

416
Q

Why did Attrill find only moderate relationship btw diversity and salinity range

A
  • organisms good at dealing w/ S or using behavioural strategies to deal with it
  • other physical factors contribute (O2, sediment, light, etc)
  • biological factors as well (competition, predation, food)
417
Q

main difference between estuaries and other systems

A

-lots of animals (secondary production) but very few plants and algae (PP)

418
Q

where do estuarine organisms get all their energy if PP is low

A

Detritus: allochthonous, autochthonous

419
Q

Allochthonous

A

produced from ecosystem outside but adjacent to estuary

eg. salt marsh, mangrove, sea grass, terrestrial detritus

420
Q

using isotopes to assess dietary sources along length of estuary

A
  • shows large variability in food source dependent on estuarine location
  • upper estuary = terrestrial source
  • lower estuary = marine source
421
Q

marine isotope signature

A

∂13C enriched

∂34S enriched (ca. 10)

422
Q

terrestrial isotope signature

A

∂13C depleted

∂34S enriched (ca. 10)

423
Q

estuary ecological interaction framework

A

factor #1: salinity

other smaller factors: turbidity, substrate, ecological interactions, more important on finer scale

424
Q

turbidity impact on estuary

A

control suspension feeders

425
Q

human distribution

A

-44% of humans live w/i 150km of coast

426
Q

Halpern et al human impact study

A
  • no area is unaffected by human influence

- large fraction, 41%, strongly affected by multiple drivers

427
Q

human impacts on estuaries

A
  • habitat destruction, alteration
  • introduction of invasives (ballast water)
  • climate change, sea level rise
  • pollution
  • eutrophication, oxygen shortage
428
Q

autochthonous

A

produced within the system

429
Q

hypoxia

A
  • dissolved seawater oxygen levels below normal (subjective)
  • less than 2mg O2/L
  • negative response in many taxa
  • change in microbial activity
430
Q

anoxia

A
  • oxygen is (almost) completely absent, below detection limit
  • subjective
  • pretty much nothing around except bacterial mats
431
Q

oxygen measurement units

A
  • most oceanographers use concentration
  • physiologists use P_O2
  • difficult for communication
432
Q

oxygen concentration of a water mass depends on

A
  • concentration it when last in contact with air
  • time since contact with air
  • physical impediments to water circulation
  • biological activity (respiration)
  • temperature
433
Q

OMZ

A
  • oxygen minimum zones
  • occur naturally in many regions
  • likely in productive regions, especially if circulation restricted
  • Arabian sea, Peruvian upwelling zone, SI
434
Q

SI OMZ

A
  • sill in satellite channel restricts flow into estuary

- natural OMZ at ca. 130m

435
Q

dead zone

A
  • non-natural low oxygen conditions

- Gulf of Mexico,

436
Q

Why is Gulf of Mexico low O2

A
  • low to begin with
  • exacerbated by anthropogenic agriculture
  • Mississippi river drains all major US agricultural lands
  • lots of fertilizer - high PP - lots of OM – decreased O2 – fish kills
437
Q

normal oxygen conditions

A

normoxia

>2.4mg O2/L, average 8

438
Q

current state of ocean oxygen

A

-low oxygen conditions increasing
-existing minima expanding, shallowing
new zones established
-reports growing at exponential rate

439
Q

why are OMZs and dead zones expanding

A
  • directly related in increased fertilizer use
  • exacerbated by climate change (increased T, stratification)
  • OMZs increasing mostly from global warminng
  • DZs increasingly mostly from eutrophication
440
Q

difference between natural OMZ and anthropogenic one

A

-OMZ are a persistent feature, longer timescales, larger scale, organisms have more time to adapt

441
Q

duration, intensity of hypoxia in dead zones

A
  • in 50%, hypoxia is seasonal
  • in 25% hypoxia is periodic
  • in 17% its episodic/ infrequent
  • in the rest, hypoxia is permanent
442
Q

seasonal hypoxia

A

spring - summer

  • significant negative impacts (fish kills)
  • widespread, long-term, organisms can’t get away
443
Q

periodic hypoxia

A

days-weeks

-higher recovery

444
Q

stages of hypoxia

A

stage 1. episodically, OM enhanced, hypoxia only when water stratifies

  1. periodic, few fish kills
  2. critical; seasonal and persistent; 50% of dead zones in this stage
  3. permanent; anoxia in bottom water, anaerobic respiration, H2S production (toxic)
445
Q

Animal production in critical stage hypoxia

A

boom and bust cycles

  • reproduce, recolonize when hypoxia absent
  • die, bust when hypoxia sets in
446
Q

respiration

A

OM + O2 – CO2 + H20
OM + SO4 – H2S + CO2
OM + NO3 – N2 + O2

447
Q

anaerobic respiration

A
  • bacterial
  • utilize range of oxidants (NO3, SO4, MnO2, Fe2O3, etc)
  • may produce toxic byproducts (eg. H2S)
448
Q

episodic hypoxia

A

-usually early warning sign that system has reached critical level

449
Q

permanent hypoxia

A
  • usually due to persistent, long-term eutrophication

- eg. Baltic Sea

450
Q

denitrification

A

using NO3 as oxidant
NO3 - NO3 - NO - N2O - N2
nitrate - nitrite - nitric oxide - nitrous oxide - nitrogen gas

451
Q

hypoxia and sediment

A

shifts RPD up

452
Q

Pcrit

A
  • critical oxygen threshold for normal physiological processes
  • long-term evolutionary adaptation
453
Q

below Pcrit

A
  • organism fails to regulate O2 consumption
  • hypoxia, not enough O2 to sustain physiologic processes
  • gene expression
  • morphology
  • behaviour
  • death
  • reproduction
454
Q

shift in Pcrit value

A
  • change organisms sensitivity to low O2

- shift right = more sensitive to low O2 (eg. Antarctica organisms)

455
Q

adaptations to low O2

A

high gill SA, high ventilation rate, blood O2-binding proteins w/ high affinity for O2

456
Q

Pcrit vs minimum environmental P_O2

A
  • positively correlated

- relationship plateaus

457
Q

molecular hypoxia response

A
  • upregulate processes that improve O2 absorption
    eg. hemoglobin synthesis
  • upregulate anaerobic metabolism
  • downregulate protein synthesis (growth), locomotion, metabolic activity, conserve O2
458
Q

other impacts of hypoxia

A
  • reduced feeding activity
  • reduced efficiency of reproduction
  • negative impacts on fitness
459
Q

hypoxia and reproduction

A
  • slow/stop gonad development
  • impaired fertilization
  • decreased hatching success
  • increased mortality
460
Q

behavioural response to hypoxia

A
  • most effective in short term
  • mobile - move
  • surface breathe
  • leave burrows
  • stretch siphon
461
Q

behavioural hypoxia response trade-offs

A

many make organisms more vulnerable to predation (e.g. extending siphon higher, air-breathing)

462
Q

morphological response to hypoxia

A
  • phenotypic plasticity

- longer, thinner gills in low O2 (more SA)

463
Q

hypoxia threshold study

A
  • find that the conventional 2mg O2/L hypoxia definition below sublethal and lethal thresholds for 1/2 species studied
  • therefore, # of systems affected by hypoxia is underestimated
  • our current threshold is too low
464
Q

different taxa hypoxia tolerance

A
  • crustaceans highest threshold, fastest mean lethal time, most vulnerable
  • lots of variability
465
Q

proposed new hypoxia threshold

A

90 percentile = 4.59 mg O2/L

466
Q

habitat compression

A

habitat squeeze

  • rising sea level + human land use
  • hypoxia squeezing marine organisms to surface, limited regions
467
Q

ecosystem changes from a switch from normoxia - hypoxia

A 
demersal fish - pelagic
macrobenthos - meiobenthos
suspension feeders - deposit
larger body size - smaller 
k-selection - r-selection
longer food chain - shorter
468
Q

why would hypoxic environment select for pelagic fish

A

higher in water column - more O2

469
Q

why would hypoxic environment select for meiobenthos

A

more tolerant of low O2

470
Q

how hypoxia influences E transfer

A

normoxia: 25-75% energy transfer
hypoxia: decreased E to mobile predators, increased % to microbes
anoxia: 100% to microbes

471
Q

hypoxia recovery

A
  • more severe hypoxia, more likely to lag in recovery

- lage = hysteresis

472
Q

NEPTUNE

A

North-East Pacific Time-series Undersea Network Experiments project

  • 6 nodes
  • hydrothermal vents, abyssal plain, OMZ, submarine canyon, cold seeps
  • cabled observatory, loop, real-time
  • convergent and divergent plates
473
Q

JDF plate

A

itty bitty

in between caribbean, pacific, cocos

474
Q

cabled observatory advantages

A
  • high-resolution
  • long-term
  • interdisciplinary monitoring
  • variable timescale
  • real time connectivity
  • online
  • limitless power
  • automated data QC
  • observe episodic processes
  • measure multiple variables
  • remote control instruments
475
Q

traditional oceanography

A
  • deploy gear from ocean vessel
  • trips usually weeks long, expensive, short periods of time
  • limited understanding of stochastic, seasonal events
  • miss rare species
476
Q

oceanographic sediment sampling

A
  • grabs
  • box corer
  • multi-core
  • benthic trawl
  • dredge
477
Q

advantage of manned submersible

A
  • in situ observation
  • delicate sampling
  • conduct manipulative experiments
  • navigate complex topography
478
Q

manned submersible disadvantage

A
  • power limitation (max 12-16hr)
  • high costs (100k/day)
  • weather limitations
  • possible pilot, researcher risks
479
Q

ROV advantage

A
  • longer dives, nearly unlimited power
  • versatile sampling
  • no pilot, researcher risk
  • dexterous manipulator arm
480
Q

cabled seafloor observatory

A

-observatory linked to land by submarine cables providing power, communication

481
Q

autonomous seafloor observatory

A

moored-buoys provide power to seafloor instruments, satellite communicates to land

482
Q

multi-instrument platform

A
  • unmanned system at fixed site, connected to land acoustically or via junction box
  • instruments, sensors, command module
483
Q

VENUS

A

Victoria Experimental Network Under the Sea

  • 3.5m node
  • -instrument platforms
  • wet mate connectors (plug in under water)
  • real time
  • multiple temporal scales
484
Q

cabled observatory limitations

A
  • can’t measure everything (reproductive state, physiological condition, metabolism)
  • can’t sample organisms, genetics
485
Q

NEPTUNE instrumentation

A

CTD, ADCP, ZAP, Oxygen sensor, Nitrate sensor, pH, pCO2, fluorometer, sediment trap, hydrophone, fixed video camera, seismometers, bottom pressure recorder, vertical profilers

486
Q

ongoing NEPTUNE research projects

A
  • whalebone colonization in submarine canyon w/ OMZ
  • zooplankton ontogenetic migration in Barkley canyon
  • C export
  • vent fauna, diffuse flow dynamics at Endeavour
487
Q

how much data does ONC collect

A

> 400 instruments in the water
5000 sensors
8 million measurements/day
3billion measurements/yr

488
Q

what are coral reefs

A
  • massive biogenic limestone structures deposited by hermatypic
  • along w/ other framework builders
489
Q

coral limestone

A

aragonite

CaCO3

490
Q

other coral framework builders

A
  • encrusting coralline algae

- calcareous green algae

491
Q

hermatypic corals

A
  • reef-building
  • stony corals
  • Order Scleractinia (Class Anthozoa, Subclass Hexacorallia)
  • some solitary, majority colonial
492
Q

hermatypic morphology

A

branched - quicker growing, susceptible to storms

massive (mound) - slow growing, irregular shaped

493
Q

coral morphology differences are important for

A
  • different protection/response to wave action

- different growth rate

494
Q

polyp morphology

A

gastrodermis - nutrient absorption, location of zooxanthellae
tentacles - location of nematocysts

495
Q

zooxanthellae

A

-densities of millions/polyp
-dinoflagellates but no flagella, no swimming ability
-acquisition unclear
-never obtained from water column
genus Symbiodinium

496
Q

zooxanthellae benefits

A
  • access to sunlight
  • stable, protected env’t
  • receive coral metabolic waste (C_org, NH3, PO4)
497
Q

coral benefits from zooxanthellae

A
  • E-rich carbs, nutrients (from photosynthesis)
  • removal of org waste (dont have to worry about toxicity)
  • aid CaCO3 deposition (requires high E)
498
Q

hermatypic coral feeding

A
  • heterotrophic feeding: zoop, small organisms at night
  • capture w/ namatocysts
  • feed for protein, amino acids, waste products for zoox
499
Q

obtaining nutrients in more than one way

A

polytrophic

500
Q

coral feeding pattern

A

day: autotrophic, polyps contracted
night: heterotrophic, polyps extend, use tentacles

501
Q

coral secretions

A
  • epidermis mucous
  • UV protection
  • feeding net to trap bacterioplankton, detritus
502
Q

other PP in coral system

A

turf algae
sand algae
benthic algae

503
Q

Turf algae

A
  • many species
  • small, bushy, close to bottom, 1-10 mm
  • often filamentous
504
Q

sand algae

A
  • root in sand

- relative to Spartina

505
Q

benthic algae

A
  • macroalgae
  • hard substrate
  • calcareous form
506
Q

coral reef consumers

A
  • sponges (filter water, cleaners)
  • molluscs
  • echinoderms
  • annelids
  • crustaceans
  • fishes
507
Q

trophic guild

A

group of organisms that exploit same resource often in similar way

508
Q

fish guilds in coral reef

A 
herbivores- wrasse, gobies
coral feeders- parrotfish, puffer
detritus feeder - grey mullet
benthic invert feeder - butterfly fish, grunt
midwater invert feeder - damselfish
small fish feeder- snapper
midwater piscivore- carangids
large piscivore- shark, snapper, barracuda
509
Q

herbivorous coral reef fish

A
  • eat algae
  • keep coral clean
  • remove up to 100% of algae/day - keep standing stocks very low
  • prevent phase shift
510
Q

coral-feeding fish

A
  • parrotfish, puffers, filefish, butterfly fish
  • feed directly on polyps of fast-growing species
  • consume skeleton
  • feed on weaker polyps
  • increase resilience
511
Q

resilience

A

ability of an ecosystem to absorb shock, resist phase shift, regenerate after disturbance

512
Q

substratum and coral

A
  • require hard CaCO3 surface for attachment
  • may require coralline algae to deposit first
  • coralline algae also help hold reef together
513
Q

coral natural resilient

A
  • recover from natural disturbance events like storms

- sensitive to shocks, e.g. T changes

514
Q

affects coral resilience

A
  • recruitment and survivorship
  • water quality
  • stable consolidated substratum
  • amount of macroalgal cover
  • herbivores that remove algae
  • animals that remove unhealthy corals
515
Q

magroalgae and coral

A
  • dense mats shade, overgrow corals

- impede recruitment

516
Q

if herbivorous fish are removed in coral reef

A
  • phase shift to turf algae
  • overgrowth of coral by algae
  • low ecosystem resilience
  • corals very stressed
517
Q

coral herbivore diversity

A
  • indo-pacific: lots of fn redundancy

- caribbean: less fish, lots of echinoderms (Diadema urchin), low fn redundancy

518
Q

Diadema in Caribbean

A
  • very important algal grazer

- 95% Caribbean die-off resulted in algal overgrowth - phase shift

519
Q

Diadema in Pacific

A
  • naturan urchin die-off
  • shorter phase shift
  • other herbivores took over algae grazing role
  • high fn redundancy = higher ecosystem resilience
520
Q

coral reef and predators

A
  • maybe strong?
  • not clear
  • lots of chemical defenses
521
Q

coral reef mutualism

A
  • grouper fish and cleaner fish (spa stations)
  • fish, shrimp in same burrow
  • clown fish, anemone
522
Q

removal of cleaner fish from reef

A
  • reduced number of species

- reduced abundance

523
Q

coral reef interaction summary

A
  • highly productive, efficient
  • foundation species that support large biodiv.
  • fn redundancy important
  • role of predators unclear
  • mutualism highly prevalent, ecologically important
524
Q

coral zonation

A
  • majority have clear zonation
  • more abundant, dense close to shore, sparser w/ depth
  • bigger, heartier species in breaker zone
  • flat, round, short in deeper zones (better light absorption)
525
Q

elkhorn coral

A

large antlers grow in direction of current

526
Q

coral competition

A
  • space extremely limited
  • outcompete each other by overgrowth, shading (faster growing win?)
  • slow growers digest neighbours
527
Q

why is space competition so tight in corals

A

need shallow depth (light) + hard substrate

528
Q

coral reef threats

A
  • coral bleaching
  • disturbance: predators, disease, storms, natural or anthro
  • ocean acidification
529
Q

coral bleaching causes

A
  • increaed T
  • increased UV
  • OA
  • turbidity/sedimentation
  • coral disease
  • ∆S
  • exposure
  • pollution
530
Q

Mass bleaching events

A
  • 6 since 1979

- correlated w/ anomalously warm T’s (El-Nino)

531
Q

coral reef threats, predators

A

crown-of-thorn Seastar

  • venomous thorn-like spines
  • digests (liquifies) entire corals w/ crazy stomach acids
  • natural member of reef but sometimes become voracious predators
  • leave trails of coral skeletons, rapidly colonized by algae
532
Q

crown-of-thorns predators

A
  • few

- harlequin sharks, giant triton

533
Q

CoT good?

A
  • promote ecological succession

- prevent fast-growing corals from overgrowing

534
Q

coral disease

A

white band disease- bacterial, declines of elk horn

black band disease- cyanobacteria, sulfide accumulation, toxicity

535
Q

ocean buffering system

A

CO2g - CO2aq + H2O HCO3- CO3^2- + H+

536
Q

current state of ocean buffering system

A

pH ca. 8.1-8.2

bicarbonate ions&raquo_space; carbonate ions

537
Q

acidification studies

A
  • majority find - response
  • all corals show - response
  • organisms w/o CaCO3 can also be sensitive to OA
  • some taxa were found to increase
538
Q

ocean zones based on light

A

euphotic (daylight) zone
disphotic (twilight) zone
aphotic (midnight) zone

539
Q

euphotic zone

A
  • epipelagic

- 200m max, usually much less

540
Q

twilight zone

A
  • mesopelagic zone
  • ca. 200-1000m
  • max extent of detectable light
  • no photosynthesis
541
Q

midnight zone

A
  • bathypelagic (ca 1-4km), abyssopelagic (4-6km), hadalpelagic (>6km)
  • below 1000m
  • no light
542
Q

seafloor average depth

543
Q

deep-sea land features

A
  • abyssal plain
  • seamount
  • MOR
  • trenches
  • overlying waters (>1km)
544
Q

deepest trench

A

Mariana’s

10.91 km

545
Q

Abyssal plains

A
  • largest ecosystem on E
  • deep basins btw continental margins and MORs
  • flat, homogenous physical conditions, soft sed, few attachment sites
  • mostly unexplored
  • cold and salty
546
Q

factors affecting deep-sea life

A
  • light
  • temperature
  • salinity
  • oxygen
  • habitat
  • pressure
  • food
547
Q

light in the deep sea

A
  • decreases w/ depth
  • no photosyn
  • no light at all below 1km
  • animals in total darkness, visual processes highly limited
  • difficulties for finding mates, food, E
548
Q

physical characteristics in the deep sea (T, S, O)

A
  • constant, cold and salty
  • O2 non-limiting in many regions
  • has biggest hypoxic/anoxic zones in ocean
  • O2 less homogenous, varies basing to basin
549
Q

deep sea habitats

A
  • mostly soft sediment (abyssal planes)
  • some ‘oases’
  • few attachment sites
550
Q

deep sea and pressure

A
  • 1atm increase per 10m
  • up to 1100atm
  • average 380atm
551
Q

deep sea and food supply

A
  • very low
  • unpredictable
  • some ‘oases’
552
Q

Deep-sea food sources

A
  • POM from surface PP (marine snow)
  • chemosynthesis
  • food falls (carcasses)
553
Q

deep sea POM

A
  • surface processes have large impact on deep
  • PP mostly above 200m
  • amount in deep depends on density in surface, food web
  • particles consumed, decomposed before reach deep
  • deep POM = moults, fecal pellets, marine snow
  • 1-3% reaches deep
554
Q

adaptations to low food availability, deep sea

A
  • conserve E
  • enormous mouths
  • expandable stomach
  • flexible jaw
  • unique feeding modes
555
Q

conserving energy in the deep

A
  • watery muscles
  • fatty tissues
  • weak skeletons
  • no scales
  • poorly developed respiratory, circulatory, nervous systems
  • no migratory behaviour
  • dont invest energy in non-essential body parts
  • many body parts not necessary w/ that much P
556
Q

Viperfish

A
  • unhinge jaw like snake

- lure on elongated dorsal fin to attract prey

557
Q

deep-sea feeding modes

A
  • deposit
  • suspension
  • mucous nets (larvacean)
  • predation (fish, tunicate)
  • scavenging (hagfish, shrimp)
558
Q

dominant feeding mode in deep

A
  • deposit (soft sed)

- 80% of fauna

559
Q

deep sea deposit feeders

A

polychaetes, holthurians, isopods, amphipods, bivalves

560
Q

deep sea suspension feeding

A
  • less common due to low food supply
  • sporadic, common in areas w/ high suspension load
  • sponges, anemones, barnacles, mussels
561
Q

Larvacean

A
  • feed w/ up to 1m wide mucous net
  • found down to 2000m
  • net clogs in 1-2 days - discarded - important C sink
  • form blooms, important mesozooplankton fraction
562
Q

larvacean discarded nets

A

‘sinkers’

  • sink up to 800m/day
  • density up to 4/m^2/d
563
Q

Tripod fish

A
  • sit on seafloor facing current
  • eat plankton
  • use tactile/mechanosensory cues
  • mouth at right height to capture zoop, shrimp, small fish swimming by
  • take advantage of current, save E not swimming
564
Q

effects of limited food on abyssal ecology

A
  • reduced faunal density

- size of deep-sea fauna

565
Q

deep-sea fauna density

A
  • food supply too low to supply large numbers
  • ca 5-10X fewer organisms in mesopelagic than epipelagic
  • ca. 50-100X fewer org. in deep sea than epi.
566
Q

size of deep-sea fauna

A
  • generally small compared to epipelagic, dwarfs

- but also gigantism

567
Q

examples of deep sea gigantism

A

isopods, amphipods, spider crab, colossal squid, stingray

568
Q

why gigantism?

A
  • reduced SA:V (less exchange)
  • slower growth rate
  • slow metabolic rate
  • k-selection
569
Q

K-selection characteristics

A
  • few eggs, slow gametogenesis, late reproductive maturity, breed once
  • low metabolic rate, activity, small size
  • slow growth, high longevity, low pop. density
570
Q

unique deep sea adaptations

A
  • cellular membranes w/ high proportion fatty acids
  • bioluminescence
  • dark pigmentation
  • no schooling
  • extreme reproduction
571
Q

high fatty acid membranes

A

-maintain fluidity at low T, high P

572
Q

bioluminescence function

A
  • attract prey
  • attract mates
  • repel predators
573
Q

lack of schooling behaviour, deep sea

A
  • increases competition in an already low resource habitat

- increases predation risk

574
Q

deep-sea exploration

A
  • majority since 1960s
  • submersibles, ROVs in 80’s helped
  • international collaboration to map deep-sea
575
Q

CeDAMar

A

Census of the Diversity of Abyssal Marine Life

  • describe abyssal biodiv
  • baseline data
576
Q

CeDAMar major findings

A
  • extreme is normal

- rare is common (no real dominants)

577
Q

Area hypothesis

A
  • species diversity increases w/ area
  • then diversity should be highest in deep-sea
  • linear?
578
Q

Area hypothesis drawbacks

A
  • find parabolic pattern, not linear
  • highest diversity at mid depth
  • other factors involved such as food and location
  • hyperbolic in western N Atl, linear in easter N Atl
579
Q

alpha diversity

A

typically species richness

580
Q

beta diversity

A

similarity between two communities

581
Q

why is alpha diversity different in western vs eastern Atlantic

A
  • POC flux much large in E vs W
  • higher productivity in W (Fe)
  • dependent on surface processes
582
Q

deep sea threats`

A
  • deep sea mining
  • climate change
  • waste deposition
583
Q

manganese nodules

A
  • polymetallic or Mn
  • concentric layers of minerals
  • microscopic - 20cm
  • economically important - Mn, Ni, Cu, Co, Fe
584
Q

climate change in deep sea

A
  • highly dependent on surface processes
  • warming may decrease PP
  • may select for lighter (lower sinking) organisms
585
Q

hydrothermal vents

A
  • discovered in 1977 by Alvin
  • expanded understanding of life limits
  • associated w/ tectonics (MORs, volcanic seamounts)
  • 690 sites discovered, predict ca. 900 more
  • majority at spreading ridges
586
Q

hydrothermal fluid

A
  • geothermally heated (black smokers 350+ ºC)
  • acidic, anoxic, sulfide rich, mineral rich
  • significant gradients
587
Q

vent biology

A
  • most live in diffused fluids, ca. 2ºC
  • some in hotter T, Pompeii worm
  • unique adaptations
588
Q

Pompeii worm

A

Alvinella

  • up to 10cm
  • burrow in chimneys
  • up to 80ºC, most thermotolerant eukaryote known
589
Q

photosynthesis vs chemosynthesis

A

photo: CO2 + Nut. + H20 – OM + O2
chemo: CO2 + Nut. + O2 + H2S – OM + S + H20
- fueled by oxidation
- bacteria, archaea

590
Q

HTV zonation

A
  • based on chemical, T gradient, feeding style (symbiosis, predation)
  • Alvinellids, tube worms, bivalves, suspension feeders, periphery
591
Q

animal diversity and distribution at Endeavour

A
  • ca 30% explained by abiotic factors
  • facilitation increases in importance toward periphery
  • negative interactions important in harsh conditions
592
Q

community succession in East Pacific Rise

A
  • microbial mats grow around new vent extrusion, attract scavengers
  • w/i 1yr mats reduced, small tube worms take over
  • w/i 2yrs giant tubeworms dominate
  • w/i 3yrs mussels appear
  • by 4yr mussels colonized tubes, bivalves begin to dominate
593
Q

when HTV stop venting

A

shift to suspension feeders - hard, raised surfaces

594
Q

HTV puzzle

A
  • different organisms around the world
  • some major differences between basins - low exchange
  • lower differences within basins
595
Q

HTV gene flow

A
  • limited dispersal capabilities: stepping-stone model

- long-distance dispersal capabilities: island model

596
Q

vent larvae

A
  • variable
  • some can disperse far some can not
  • very difficult to study
597
Q

remaining HTV questions

A
  • connectivity: pop. sources/sinks, timescales
  • biodiversity: # species, factors that drive distribution, biodiv
  • ecosystem services: biogeochemical cycles
598
Q

food falls

A
  • significant nutrient pulse
  • fish, whales, other carcasses
  • quickly colonized and devoured
  • uniques species
  • support large # organisms
  • last 20-50 years
599
Q

bone-eating worm

A

Osedax spp.

600
Q

fallen carcasses estimated to provide

A

0.5g nutrients/m^2 /yr

601
Q

whale fall studies

A
  • purposeful implantations on sea floor

- repurpose washed-up carcasses

602
Q

whale fall succession

A
  1. mobile-scavenger stage
  2. enrichment oppotunist stage
  3. sulphophilic stage
603
Q

Mobile-scavenger stage, whale fall

A
  • 0.5-1.5 months after settlement
  • 4 months- 1.5 years
  • deep-sea necrophages remove soft tissue
  • non-specialized scavengers
  • eat 40-60kg/day
  • short lived, difficult to observe
  • eg. hagfish, lithodid crabs, rattails, sleeper shark
604
Q

scavenging rate depens on

A

carcass weight

605
Q

enrichment opportunist stage, whale tall

A
  • 1-2 years
  • organically enriched seds., exposed bone
  • 20,000-45,000 ind./m^2
  • low diversity
  • 1-3m radius around carcass
  • proceeds until O2 depletion
606
Q

enrichment opportunist stage biology

A
  • heterotrophic macrobenthos take advantage of enriched sed.

- opportunistic bone-eating epifauna polychaetes, crustaceans, bacteria, white gastropods, juvenile bivalves

607
Q

Osedax

A

bone-eating polychaete

  • sexual dimorphism (small m lives inside fm)
  • morphologically diverse, several lineages, colonize different types of bones
  • falls are ephemeral - how are they widely distributed?
608
Q

Osedax morphology

A

ovisac - rooting structure full of symbiotic bacteria, secretes bone dissolving chemical

  • tube
  • plume
  • oviduct
609
Q

sulphophilic stage

A

chemoautotrophic

  • 2-50yrs
  • species-rich, trophically complex, skeleton emits HS from anaerobic breakdown of bone lipid
  • > 200 microfauna species
  • dominated by anaerobic bacteria
  • sulphur-oxidizing bacteria
  • slowly decrease lipid content over decades
610
Q

whale bones

611
Q

anaerobic decomposition of bone lipid

A
  1. SO4- (sulphate) reduction inside bone by heterotrophic bacteria – flux HS- from bone
  2. HS- (sulphide) oxidizing chemoautotrophic bacteria
612
Q

base of sulphophilic whale fall stage food web

A
  • sulphate-reducing bacteria
  • sulphide-oxidizing bacteria
  • organisms containing chemoautotrophic symbionts
613
Q

the rest of the sulphophilic whale fall stage food web

A
  • 1º consumers: feeding on chemoautotrophic bacteria
  • 2º, 3º consumers, etc.
  • scavengers
  • including: bacterial mats, isopods, galatheids, polychaetes, limpets, snails
  • specialists
614
Q

Whale fall stage 4

A

hypothesized reef stage

-sspension feeders take advantage of hard substrates and particulate detritus

615
Q

whale falls provide

A
  • Org, S-rich habitat islands
  • hotspots of biodiversity and evolutionary novelty
  • unique niches for specialists
616
Q

reduction in whale-falls

A
  • ca. 75% in N Atl
  • globally ca. 65% sperm whales
  • due to whaling
617
Q

Cold seeps

A
  • hydrocarbons (CH4), suffices, bubble through surface
  • much cooler than HTV
  • bacteria nutrition, methanotrophic bacteria (free, symbiotic)
  • bacteria form carbonates
  • less diversity than HTV, last longer
618
Q

cold seep biology

A
  • similar to HTV
  • infauna, epifauna
  • bivalves, bacteria, tubeworms, etc.
  • slower growth rates
619
Q

cold seep succession

A

-bacteria – bivalves w/ symbionts – CaCO3 build up – tubeworms – cold seep turns off – shift to coral reef community

620
Q

cold seep threats

A
  • hydrocarbons - oil exploration

- knowledge

621
Q

Main themes

A
  1. Ocean contains amazing biodiversity and provides many ecological functions
  2. Biodiversity is depleted by anthropogenic activity
  3. Biodiversity is important for ecosystem function
  4. Much remains unknown
622
Q

Antarctica

A
  • majority is deep, >3km
  • majority of studies are shallow
  • majority of knowledge on animals, especially crustaceans
  • microbial life underrepresented
  • low # verts, but lots of experts (big, charismatic)
  • knowledge gap
623
Q

polar threats

A
  • fishing, exploitation
  • tourism (increased from 7000-35,000 in 15yrs)
  • climate ∆- T, ice, acidification
  • invasives (?)
624
Q

Caribbean knowledge

A
  • complex current, impacts nutrients
  • majority deep, >2km
  • focus on shallow
  • many species described
  • low # microbes studied
  • high # crustaceans
  • know more than proportional amount about fish
625
Q

Caribbean S-A curves

A

lot’s of work to be done on mollusks, fishes starting to plateau, echinoderms pretty well described

626
Q

Caribbean threats

A
  • coral reef degradation
  • increasing human population- coastal development, pollution
  • invasives
  • climate ∆
  • exploitation, over-fishing
627
Q

Canadian marine ecosystems

A
  • longest coastline in world, 243,791 km
  • 16% worlds coastline, 17% of worlds oceans
  • 3 unique basins
  • huge diversity, many ecosystems
628
Q

Canadian marine threats

A
  • climate change
  • over-fishing
  • shoreline development
  • eutrophication
  • no biodiversity baseline
629
Q

Canadian Pacific

A
  • cold
  • California/Alaska current influence
  • seasonal freshwater input
630
Q

Candian Atlantic

A
  • cold
  • driven by Labrador current, Gulf stream
  • seasonal freshwater
  • seasonal ice coverage
  • Bay of Fundy, unique
631
Q

Canadian Arctic

A
  • ice most of yer

- influenced by Labrador current, Beaufort Gyre, freshwater discharge

632
Q

Canadian marine biodiversity

A
  • min 16,000 species
  • 9500 microbes (up to 54,500)
  • 1650 phyto
  • 900 fish
  • 52 marine mammals
  • only 48% of organisms described named and classified
633
Q

comparing Canadian basins

A

Arctic- more phyto and crustaceans than the others, SA curve steep

  • W Canada more diverse than E
  • E better studied, closest to flat SA curve
  • W richest seaweed flora in world (650spp)
634
Q

CoML

A

Census of Marine Life

  • 2000-2010 investigation of diversity, distribution, abundance of marine life
  • 540 expeditions, 2700 scientists, 80 countries
  • 6000 potentially new species
  • first list of global marine species
  • 90% or marine life is microbial
635
Q

common marine ecology challenges

A
  • learn more about small taxa: phytoplankton, microbes
  • increase sampling in under-sampled habitats
  • train new generation of taxonomists

2016/2017 (15 decks)

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