446 Aquatic Ecology Flashcards

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1
Q

why study aquatic ecology

A

aquatic ecosystems & resources critical to human survival, health, well being

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2
Q

ecosystem processes

A
hydrologic flux, storage
biological productivity
biogeochemical cycling, storage
decomposition
maintenance of biological diversity
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3
Q

ecosystem “goods”

A
food
construction materials
medicinal plants
wild genes for domestic plants and animals
tourism and recreation
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4
Q

ecosystem “services”

A
maintain atmospheric gaseous composition
regulate cimate
cleanse water/air
pollinate crops 
generate/maintain soils
store/cycle nutrients
absorbe/detoxify pollutants
maintain hydro. cycles
provide beauty, inspiration, research
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5
Q

human disturbances affecting coastal ecosystems

A
  1. Fishing, Pollution, Mechanical habitat destruction, introductions, climate change
    (fishing always preceded other disturbances, others change in order)
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6
Q

inputs and concerns

A

organic (livestock), fertilizer, rain, pollutants, pathogens, pharma-care, invasive species, nitrate leaching

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7
Q

adverse effects of eutrophication

A
increased biomass of plankton
shifts in phytoplankton (may be to toxic)
increased epiphytes
coral reef loss 
decreased water transparency
oxygen depletion
increased fish kills
loss of desirable fish species 
reduction in fish/shellfish harvest
decreased aesthetic value
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8
Q

chemical characteristics of aquatic ecosystems

A

nutrients

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9
Q

biological characteristics of aquatic ecosystems

A

foodweb

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10
Q

limnology

A

the study of inland waters - lakes (both freshwater and saline), reservoirs, rivers, streams, wetlands, and groundwater - as ecological systems interacting with their drainage basins and the atmosphere.

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11
Q

algal biomass vs nutrient

A

chl vs. Total phosphorus (TP)

increasing on log scale but large variation above/below the line

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12
Q

why measure TP as nutrient load?

A

most limiting resource

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13
Q

high nutrient, lower than expected Chl (algae)

A

more large fish, preying on large grazers

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14
Q

small algae

A

larger, efficient grazers
larger biomass
larger planktivorous fish
system is more efficient

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15
Q

system with lots of small planktivorous fish

A

prey upon small grazers

larger algae

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16
Q

high density of small fish

A

low density of large zooplankton
higher Chl (algae)
greener water, lower O2

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17
Q

small grazer, shallow lake, Chl vs. TP

A

high productivity, but less than small grazer system in med-large lake- less O2, less insolation, less space…

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18
Q

empirical data

A

observational

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19
Q

experimental data

A

manipulate variable

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20
Q

response of lake ecosystem to nutrient loading experiment

A

same [nutrient], #large fish vary

w/o large fish = small zooplankton = more algae

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21
Q

epilimnion

A

the upper layer of water in a stratified lake, ~constant T, mixed layer

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22
Q

lakes with high grazing, low TP

A

clear water, more light penetration, more heat deeper, larger metalimnion, less steep T gradient, deeper O2 max, photosynthesis can occur throughout metalimnion

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23
Q

metalimnion

A

thermocline, T changes more rapidly with depth than it does in the layers above or below, highest density, layer of ‘stuck’ algae

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24
Q

indicator of water transparency

A

secchi depth

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25
Q

lake with low grazing, high TP

A

high Chl = low transparency = low O2, higher and smaller metalimnion, less light penetration, steeper T slope in metalimnion, light just barely penetrates meta., photosynthesis cannot occur throughout metalimnion, O2 goes to 0, system is reducing (like saanich inlet)

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26
Q

zooplankton size under high fish density

A

~80% less than 0.2mm

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27
Q

zooplankton size under low fish density

A

~40% less than 0.2mm

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28
Q

hypolimnion

A

the lower layer of water in a stratified lake, typically cooler than the water above and relatively stagnant, ~constant T, O2

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29
Q

algae biomass with time

A

low grazing= increased biomass w/ t

intense grazing = very low slope, barely increasing

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30
Q

TP with time

A

low grazing = increased TP w/ t
intense grazing = very low slope, barely increasing
low grazing = more algae = more TP

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31
Q

dissolved P with time

A

low grazing = very low slope, barely increasing

intense grazing = high slope, increasing

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32
Q

why is there higher dissolved P with intense grazing

A

high grazing = lots of dissolved P b/c not being taken up by algae
size of fish controls [algae] which controls [dissolved vs. particulate P]

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33
Q

length of algae as a function of biomass of algae in large grazer system

A

as biomass increases, size increases (more removed = more nutrients available to the fewer)

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34
Q

length of algae as a function of biomass in small grazer system

A

increased biomass = smaller size (more biomass means higher quantity means less nutrients available to each)

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35
Q

algae size and phosphate turnover time

A
small algae (large grazer system) = slower nutrient turnover = long phosphate turnover time
large algae (small grazer system) = faster Phosphate turnover time
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36
Q

when you have large particles, the overall particle load

A

is made up of more large particles, median is higher

large particles = less small particles

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37
Q

add nutrients

A

overall particle size shift to larger particles

= long phosphate turnover time

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38
Q

add nutrients and fish

A

shift to more smaller particles

= shorter phosphate turnover time

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39
Q

so… as average size of plankton declines..

A

larger slope, uptake efficiency increases, turnover time is shorter
AND transparency declines

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40
Q

how changes in biology = changes in physics

A

thermal structure, penetration of light, accumulated energy/heat content

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41
Q

fetch

A

longest open length of a water body through which wind can blow

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42
Q

change in epilimnion with fetch

A

increased fetch = increased depth of epilimnion (more wind = more wind mixing)

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43
Q

downward heating intensity vs. penetration of solar radiation

A

increasing surface area of water body (fetch) vs. increasing water transparency

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44
Q

increasing fetch & transparency

A

deeper epilimnion, more heat, more energy, greater depth for photosynthesis, more O2

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45
Q

role of biology on mixing rate

A

affects clarity of lake which affects insolation absorption which affects stratification

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46
Q

sedimentation, total phosphorus rates highest in

A

+N (nutrients added, no small fish, large zooplankton)

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47
Q

secchi depth highest in

A

control then +N

deepest when no small fish

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48
Q

chlorophyll highest in

A

+NF (nutrients, small fish, small zooplankton grazers, larger algae)

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49
Q

summer O2 profile, control vs. +F

A

+F higher O2 in epilimnion
lower O2 in metalimnion and hypolimnion
O2 max is higher in water column in +F and goes to 0 with depth

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50
Q

summer O2 profile, +N, +NF

A

+N higher O2 at all depths

+NF goes to 0 in hypolimnion

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51
Q

lake St. George

A
large # planktivorous fish
low secchi depth
smaller daphnia
shallower epilimnion depth
higher TP
higher Chl
strongly eutrophic
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52
Q

Haynes lake

A
less planktivorous fish
deeper secchi depth
deep epilimnion depth
larger daphnia length
lower TP
lower Chl
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53
Q

Julian days

A

continuous count of days since the beginning of the day starting at noon on January 1

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54
Q

hypolimnetic oxygen changes with season

A

oxygen depletion from spring – summer (lowest O2 with +F)

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55
Q

hypolimnetic oxygen chantes in Haynes lake and lake StGeorge

A

both reach min. in June, S.G. stays at ~0 for rest of summer, H. increases to second max in late July-early August. Lake H. never goes to 0

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56
Q

algae size and relative sedimentation rate

A

small grazer system = short phosphate turnover time = lower relative sedimentation

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57
Q

why larger grazer system has higher relative sedimentation

A

large things sediment more, greater proportion sink, heavier, less efficiently used (P turnover)

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58
Q

absolute sedimentation rates

A

would be higher in small grazer system because there’s so much more

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59
Q

toxic algal groups

A

cyanobacteria, dinoflagellates, diatoms

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60
Q

problems with algal blooms

A

toxins, anoxia, habitat loss, recreational loss, health risks

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61
Q

anthropogenic P, N to aquatic systems lead to

A
eutrophication
algal blooms
fatal algal toxins
anoxia- loss of diversity/habitat
proliferation of waterborne pathogens
increased chlorination byproducts in drinking water
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62
Q

waterborne pathogens especially important in

A

tropical/subtropical regions, can be related to cholera

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63
Q

forms of land-use

A
agriculture
farming
waste disposal
fertilizer
harvesting
hydrology
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64
Q

effects of N,P loading are different

A

depending on structure of system
shallow vs. deep
large vs. small fish

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65
Q

population growth

A

increasing pop., more mouths to feed, more land-use required, world fertilizer growth, more N,P loading,

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66
Q

obtaining N, P for fertilizer

A

N atmospherically available, easier to obtain. P not atmospherically available, geological nutrient, limited

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67
Q

problem with speed of population growth

A

available, cultivatable agricultural land is NOT increasing, need GMOs to keep up with pop. increase

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68
Q

GMOs to keep up w/ pop. increase

A

rices that can grow through floods - multiple crops/year

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69
Q

problem with GMOs that allow us to increase agricultural yield

A

leaching soil nutrients, more and more fertilizer

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70
Q

population growth and water shortage

A

water hungry plants and animals (and nutrient loading)

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71
Q

examples of water hungry crops

A
70L/apple
3400L/kg rice
140L/cup of coffee
120L/glass of wine 
15,500L/ kg of beef
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72
Q

changes in atmospheric NH4

A

30% increase in urea use as fertilizer (1960-1990)

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73
Q

observed relationship between N,P and Chl

A

positively correlated

nitrogen more tightly correlated

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74
Q

eutrophication defined as

A

excessive growth of algae, often associated with bluegreen and other harmful algal blooms

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75
Q

determines types of algal bloom

A

amount of nutrients, composition of nutrients (TN:TP)

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76
Q

N:P ratios for different runoff types

A
unfertilized field N:P 250
forests 75
rainfall 25
manure seepage 9
sewage 5
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77
Q

nutrient composition ratio

A

dependent on where nutrients come from

dictates algal bloom

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78
Q

bluegreen algae associated with what nutrient composition

A

low N:P ratio (towards the manure, sewage deposits)

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79
Q

differential response to increased [P] in N limited vs. P limited ecosystem

A

N limited systems does not respond as strongly to increased P

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80
Q

increasing phosphorus concentration =

A

increased dominance of cyanobacteria

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81
Q

other controls on levels and types of algal biomass blooms

A

seasonality of nutrient inputs (coastal and freshwater ecosystem)
physical properties of receiving system
structure of foodweb

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82
Q

N:P ratio as a control in number of red tides

A

as N:P decreases, #red tides increases, highest below 16

duration of blooms longer when N:P

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83
Q

redfield ratio

A

N:P
16:1

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84
Q

increasing nutrient, increasing algal biomass

A

responses are not proportional in all systems, dependent on structure of foodweb (small vs. large grazers) and physical structure of ecosystem

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85
Q

physical lake structure and response to changes in nutrients

A

deeper lakes can take more ‘abuse’ before showing response (less likely to become eutrophic)

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86
Q

algae harmful to animals, humans

A

cyanobacteria (bluegreen)
dinoflagellates
some diatoms

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87
Q

types of algal toxins

A

neurotoxins
hepatotoxins
lipo-polysaccharides

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88
Q

neurotoxins

A

alkaloids, b/g algae

cause neurodegenerative symptoms through disruption in communication between neutrons and muscles

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89
Q

neurotoxin examples

A

anatoxin-a, saxotoxin, neosaxotoxins, Nostoc, Anabaena, Oscillatoria, Aphanizomenon

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90
Q

hepatotoxins

A

peptides

affect liver, cause weakness, vomiting, diarrhea, respiratory blockages

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91
Q

hepatotoxin examples

A

Anatoxin-a, saxotoxin, neosaxotoxins, Nostoc, Anabaena, Oscillatoria, Microcystis

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92
Q

Lipo-polysaccharides

A

cause skin irritation (dissolve skin)

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93
Q

neurotoxin bioaccumulation

A

accumulate in nervous system (cerebral), show up with age

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94
Q

fertilizer use and red tides

A

increased fertilizer use tightly correlated with increased # of red tides

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95
Q

TP, TN and toxin forming algae concentration

A

both positive correlations

steeper increase in toxin forming algae with increased TP then increased TN

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96
Q

concentration of microcystin vs. toxigenic biomass

A

increasing. the more biomass present, the more of the toxic variety

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97
Q

microcystin

A

class of toxins produced by certain freshwater cyanobacteria

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98
Q

ubiquity of cyanobacteria

A

terrestrial, freshwater, brackish, marine, widespread = potential for widespread human exposure

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99
Q

β-N-methylamino-L-alanine

A

BMAA- novel neurotoxic amino acid from cyanobacteria (and many algal taxa around the world), ubiquitous, accumulate and slowly release through time, found in brain tissues of people who die of ALS and other neurodegenerative disease

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100
Q

BMAA in guam

A

high concentration in coralloid roots of cycad trees– concentrated in fleshy seed– flying fox forage on seed– accumulate– Chamorro people eat them– die of ALS-PDC. 50-100X incidence rate anywhere else

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101
Q

BMAA biomagnification

A

free BMAA–cyanobacteria 0.3µg/g— cycad 37µg/g – flying foxes 3556µg/g – Chamorro people

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102
Q

Chamorro people

A

highest rate of neurodegenerative disease in the world

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103
Q

water categories based on nutrient richness

A

Oligotrophic- nutrient poor
Mesotrophic- good clarity, average nutrient
Eutrophic- enriched with nutrients, good plant growth, possible algal blooms
Hypertrophic- excessively enriched with nutrients, poor clarity, devastating algal blooms

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104
Q

lake Taihu

A

went from oligotrophic (1960) to eutrophic-hypertrophic in 90’s
population growth, livestock growth
toxins produced

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105
Q

ALS

A

amyotrophic lateral sclerosis

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106
Q

BMAA exposure in desert dust

A

soldiers found to have high levels of BMAA, suffering from neurodegenerative disease from Iraq desert pools. dormant until rain season. inhaled, especially around Gulf War.

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107
Q

sporadic ALS in Annapolis, Maryland

A

found to come from Chesapeake Bay blue crabs, BMAA in Chesapeake Bay food web common risk factor

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108
Q

fa cai, Mandarin; and fat choy, Cantonese

A

Nostoc grown and harvested to make soup during New Years celebration. Banned now, mostly artificial, but some still contain Nostoc (BMAA).

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109
Q

driving force in aquatic system

A

foodweb

changes to food web have cascading effects

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110
Q

ecosystem productivity depends on

A

transfer efficiency of nutrients and energy along foodweb- affected by changes in predators and prey- any affects = cascading changes

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111
Q

shifts in food web structure and function, implications for

A

predator/prey effects
contaminant transfer
biodiversity
productivity

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112
Q

energy transfer efficiency in small plankton, small fish system

A

less efficiency transfer

113
Q

predatory invertebrates

A

comets with small fish for prey, added system complexity

114
Q

food web views

A

bottom-up - ratio dependent, more inputs = more outputs

top-down - limits bottom up, predators self regulate

115
Q

predator self regulation

A

eat too much and use up all resources

116
Q

k

A

carrying capacity of system

117
Q

low k

A

low resources, nutrients, space

118
Q

predator/prey biomass vs. carrying capacity models

A

R-O model: predator increase w/ k, prey constant
A-G: both increase but predator growth is smaller than prey growth
Getz: both increase parallel to each other, prey higher
predator self limitation: prey increases, predator constant

119
Q

Fretwell trophic level biomass vs environmental productivity

A

alternate trophic levels have parallel relationships

level 3 grazes down level 2 which helps increase level 1

120
Q

Fretwell-Oksanen trophic level biomass vs environmental productivity

A

predators keep prey constant
levels 1&3 parallel increase, 2 constant while they increase
when 2 is increasing, level 1 is constant

121
Q

Ginzburg-Getz-Ardith trophic level biomass vs environmental productivity

A

all increasing
ratio dependent
highly contradicted system, level can’t increase at a ratio dependent manner, would self restrict

122
Q

Persson trophic level biomass vs environmental productivity

A

looks the same as F-O only 2 trophic levels exist. one is increasing while the other is constant

123
Q

length of food chain

A

affects accumulation process and efficiency

124
Q

each food web interaction (energy transfer)

A
  • 10-15% of E

shorter food chain = more efficient

125
Q

Menge and Sutherland, views on top down regulation in food webs

A

physical disturbance shortens food chains, most organisms will shift diet depending on food availability

126
Q

Hairston, Smith, Slobodkin , views on top down regulation in food webs

A

predator/prey interaction bring in self regulatory processes. predators regulate herbivores, releasing plants to become resource limited

127
Q

Freewill and Oksanen, views on top down regulation in food webs

A

top trophic levels and even numbered steps below are resource limited, trophic levels odd numbered steps below are predator limited

128
Q

McQueen, views on predator and resource co-limitation in food webs

A

top-down diminishes efficiency at bottom of food chain, but both affect each other

129
Q

Getz, views on top down regulation in food webs

A

inference hypothesis- predators interfere with each other- prevent efficient exploitation of resources, prey can increase

130
Q

Mittelbach, views on top down regulation in food webs

A

predators require different resources as they grow (ontogenetic shift)

131
Q

Lei bold, views on top down regulation in food webs

A

control of prey by consumer is not always consistent (shifts to less edible species)

132
Q

Sinclair and Norton, views on top down regulation in food webs

A

starvation-weakened prey become more vulnerable to predation or disease

133
Q

predator negative feedback, self regulation

A

interference competition
exploitative competition
depletion of nutritious, palatable, accessible prey

134
Q

algal biomass vs. potential productivity, even link system (hypothetical)

A

2-link (algae, zooplankton), increased productivity will not increase algal biomass

135
Q

algal biomass vs. potential productivity, odd links system (hypothetical)

A

potential productivity can increase, 3rd link consumes 2nd link and allows 1st link to grow

136
Q

TP, indicator of

A

productivity

137
Q

fishing down top of foodweb

A

shifting average trophic level (down)
significant decline in average trophic level of fish catch, average size of fish becoming smaller
crowding down foodweb?

138
Q

how to define trophic level

A

analyze gut content

139
Q

as average catch increases

A

average trophic level decreases, Pauley et al., 1998

140
Q

cascading effects of the loss of apex predatory sharks from a coastal ocean

A

11 species of shark- all declining from overfishing
different species of mesopredators - all increasing
termination of scallop fishery

141
Q

effects of fish in river food webs

A

one of first experiments on river ecosystem to demonstrate cascading effect of predators on lower trophic levels are consistent w/ observations from other ecosystem (remove large fish, small fish dominant, algal biomass increased, odd/even # trophic level limitations)

142
Q

major change in food web concept theories

A

foodwebs are not closed systems. local interaction in one ecosystem may reverberate into another.
ex. aquatic system affecting terrestrial

143
Q

aquatic system affecting terrestrial example

A

fish eating larval dragonfly– decrease dragonfly abundance – increase honeybee abundance – increase pollination
no fish– pollination significantly decreased

144
Q

shrimp stocking theory

A

add more food, they will produce more

145
Q

shrimp stocking results

A

reduced number of spawner, reduces numbers of bears and eagles

146
Q

what happened with the shrimp stocking?

A

the introduced shrimp (Mysis) come up in water column at nigh and prey on the kokanee/trouts food but stay at the bottom of the lake during the day- reducing fish prey

147
Q

Lake Victoria changes

A

introduced Nile Perch (1954) to increase European sport fishing; HAD extremely high diversity before; major shift to invasive species, basically replaced natives, loss of diversity and food web interactions

148
Q

stability and diversity

A

higher diversity = higher stability

149
Q

Haplochromis

A

zooplanktivorous cichlid, significantly decreased since introduction of nile perch

150
Q

one positive side to nile perch introduction

A

more protein for Kenyan people

151
Q

trophic downgrading

A

apex consumers were ubiquitous for my’s, extensive cascading effects as diverse as disease, wildfire, carbon sequestration, invasive species, biogeochemical cycles: process, function, resilience

152
Q

trophic cascades: see otter populations

A

eat sea urchins- sea urchins destroy roots of kelp- kelp bed declines harm many species (home to many species, similar to corals)

153
Q

trophic cascade: sea star

A

absence of sea star= loss of diversity in tidal community; sea stars increase species diversity by preventing competitive dominance of mussles

154
Q

trophic cascade: Long Lake, Michigan experiment

A

large mouth bass - prey on minnows– graze on algae. right side of lake has bass = clear lake, left side has no bass = decrease clarity. bass indirectly reduce phytoplankton, indirectly increase clarity

155
Q

trophic cascade: sharks

A

without sharks/apex predators don’t have complex food web, can’t have clear water, can’t have coral reefs

156
Q

trophic cascades: Brier Creek

A

predatory bass extirpate herbivorous minnows, promote growth of benthic algae, alter colour of water

157
Q

trophic cascade: arctic fox

A

preys on birds, decrease bird population– decrease nutrient input (poop)– grasslands turn to tundra

158
Q

trophic cascades: predatory cats

A

remove large predators– herbivores increase and ‘clean up’ forest floor (less leaf litter and forest floor plants)

159
Q

trophic cascade: wolf

A

wolf– elk– more, greener riparian vegetation

160
Q

trophic cascade: wildebeest

A

eradication of virus– recovery of native ungulates– decline of woody vegetation in Serengeti

161
Q

sea otters absent

A

fish abundance decreased
mussel growth decreased
gulls- diet shift from fish to invertebrates
bald eagles- diet shift– decrease in mammals, fish; increase in birds

162
Q

trophic cascades: fire

A

rinderpest (viral) decreases wildebeest which decreases vegetation control which increases fire risk
40% more burn with virus

163
Q

trophic cascade: disease

A

fishing decreases lobster– decreases sea urchin density– increases epidemics
~30% increase in epidemic without fishing

164
Q

trophic cascade: atmosphere

A

bass decrease minnow, decrease zooplankton, decrease phytoplankton, increase atmospheric C influx

165
Q

trophic cascade: soil

A

fox decreases seabirds, which decrease soil nutrients

166
Q

trophic cascade: water

A

spawning salmon decrease particulate suspension, decreases stream particulate load

167
Q

trophic cascade: invasive species

A

predatory birds decrease non-indigenous spiders

168
Q

trophic cascades: biodiversity

A

coyotes decrease mesopredators which decrease small vertebrates

169
Q

preceded all other human disturbance

A

overfishing – ecological extinction

170
Q

fishing and nile perch

A

type of fishing determine survivorship (age), survivorship determines prey taken by nile perch

171
Q

nile perch predation on haplochromines

A

decreasing: no fishing, gill nets, beach seines, gill nets + seines

172
Q

salmon life cycle

A

freshwater- eggs, rearing of juveniles
estuary- smolt (0-1yr)
ocean- juvenile, growth (1-4yrs)
estuary- returning to freshwater to spawn
freshwater - spawning, death- contribute nutrients

173
Q

importance of salmon in the ocean

A

orca
harbour seal
commercial fishery

174
Q

importance of salmon in freshwater

A

sport fishery
cultural fishery
bear, eagle, gull, coyote, otter, raven, crow, trout

175
Q

simplified salmon life cycle

A

incubation– fry– smolt– adult– return

176
Q

salmon fry

A

recently hatched, very young

177
Q

smolt

A

young salmon, ~2yrs, ready to return to sea, changes to system for saltwater life

178
Q

salmon return related to

A

size of smolts

179
Q

~2inch smolts

A

4-8% return rate

180
Q

~6inch smolt

A

10-20% return rate

181
Q

smolt weight

A

is significantly decreased with increasing density, there is a limit to how many fish a system can produce (carrying capacity)

182
Q

salmon and nutrient-foodweb dynamics

A

more nutrients– larger algae– small/inefficient grazers– low growth, small smolts, low adult return

183
Q

fertilization of lake, 1983

A

TP increases, algal biomass increases, daphnia size and biomass increase

184
Q

impact of lake fertilization on smolt size

A

1yr old smolts small increase in size

2yr old smolts large increase in size

185
Q

impact of lake fertilization on fry/smolt density

A

both increasing

186
Q

fry stocking of lake, 1987

A

TP, algal biomass drop off, daphnia size and biomass drop, average smelt size drops off, fry and smelt density increase for a few years then drop off, change in zooplankton composition
over capacity

187
Q

smolt size vs. daphnia size

A
positively correlated
(larger, efficient grazers = larger fish)
188
Q

important factors in the highly variable growth pattern of sockeye smolts

A

fry density
size of zooplankton
lake features

189
Q

size of 1yr old smolts and total zooplankton biomass

A

available food is not a good predictor of smolt size

190
Q

size of 1yr old smolts and mean size of Daphnia

A

quality of food is a better predictor of smelt growth and size

191
Q

smolt size and nutrient levels

A

smolt size and fry density higher in high nutrient system, but not increasingly so, systems ‘level off’ in all nutrient levels

192
Q

photic depth vs. turbidity, and colour

A

photic depth rapidly drops off in both, but quicker with increased turbidity

193
Q

light penetration, clear lake

A

euphoric depth 16.4m

secchi depth 7.2m

194
Q

light penetration, stained lake

A

euphotic depth 7.4m

secchi depth 4.3m

195
Q

light penetration, glacial lake

A

euphotic depth 6.5

secchi depth 1.5m

196
Q

thermal traits, clear lake

A

max T 14º
mean T 7.8º
heat budget 11.8 kcal/cm^2

197
Q

thermal traits, stained lake

A

max T 16.2º
mean T 6.9º
heat budget 10.8 kcal/cm^2

198
Q

thermal traits, glacial lake

A

max T 11º
mean T 5.9º
heat budget 11.6 kcal/cm^2

199
Q

vertical mixing patterns in different lakes

A

depth as a function of T

heat budget is area ‘under the curve’

200
Q

depth vs. T, clear lake

A

med T at surface, drop off, med T at depth

201
Q

depth vs. T, stained lake

A

highest T as surface, rapid drop off, lowest T at depth

202
Q

depth vs. T, glacial lake

A

coldest at surface, T remains ~constant at every depth, winds up being highest T at depth b/c other 2 drop off to lower T

203
Q

Primary production in different lake types

A

Chl vs. TP
positively correlated, high slope in clear lake
positively correlated, med slope in stained lake
no real relationship in glacial lake

204
Q

glacial lakes

A
lowest light penetration
lowest T's (med. heat budget)
constant T with depth
higher TP
lower Chl then clear
produces smallest fish and lowest smolt biomass
205
Q

1yr old smolt weight vs. age and different lake types

A

age vs. weight tightly positively correlated
clear lakes - fish at whole spectrum of the best fit line
stained - ~half way up line
glacial lake- only the lowest part of the line

206
Q

smolt length in lake types

A

clear 95mm
stained 71mm
glacial 69mm

207
Q

smolt weight in lake types

A

clear 7.9g
stained 3.3g
glacial 2.6g

208
Q

smolt biomass vs. euphotic depth

A

clear - positively correlated

stained, glacial - only points at small euphotic depths, euphotic depths can’t be very deep in these lakes

209
Q

smolt biomass vs. zooplankton biomass

A

clear - positively correlated
stained- positively correlated but only goes ~half way up line
glacial - only points at small smolt/zoop biomasses

210
Q

SST shift study, Eastern Bering Sea

A

2002-2005 warm, 2006-2007 cold

use N isotopes in zooplankton to study shifts in foodwebs

211
Q

Eastern Bering Sea sampling

A

cruises in sep. 2003, 2007
collected juvenile salmon, forage fish, zooplankton
186 stations
13,000 fish, 600 zooplankton samples analyzed for N, C isotopes

212
Q

juvenile salmon studied in eastern Bering Sea

A

sockeye, pink, chum, coho, chinook

213
Q

change in abundance of juvenile salmon

A

in cold years juvenile salmon distribution decreased in all species types
pacific cod abundance increased

214
Q

∂13C tells

A
where food comes from in relation to shore
more depleted (more - ) = off-shore
less depleted (less - ) = near-shore
215
Q

∂15N vs ∂13C

A

trophic enrichment of 15N up foodweb

216
Q

algae ∂15N

A

4-8‰

217
Q

∂15N, inverts.

A

8-14‰

218
Q

∂15N, forage fish

A

10-14‰

219
Q

predatory fish, ∂15N

A

10-18‰

220
Q

why trophic enrichment of 15N?

A

organisms preferentially utilize the lower molecular weight isotope leading to enrichment of the heavier one

221
Q

∂15N in plankton

A

must be determined for every group of plankton to set a baseline, then this baseline can be used to determine trophic level in the fish

222
Q

juvenile salmon trophic position above zooplankton

A

2005 ~2

2007

223
Q

why were juvenile salmon higher in trophic level in warm years

A

more food available, growing bigger/faster, consuming fish

224
Q

why juvenile salmon lower in trophic level in cool years

A

less nutrients available, less food available

225
Q

differences in N vs. S Eastern Bering Sea (EBS)

A

S: large shift in trophic level from warm - cold years
N: little change in trophic level

226
Q

increasing nutrients of a system

A

may enhance smolt production through enhanced 1º, 2º productivity (but only up to k)

227
Q

survival of smolts

A

can increase with increasing size of smolts

228
Q

adults returns/recruits per spawner

A

may increase with increasing smolt size

229
Q

high density of salmon fry

A

can dampen impacts of nutrients on smolt size and production by:
limiting resources available,
reducing efficiency of nutrient/energy transfer,
reducing growth/survival of fry and smolts

230
Q

anadromous

A

fish, born in fresh water, spend most of life in the sea and returns to fresh water to spawn. Salmon, smelt, shad, striped bass, and sturgeon

231
Q

management of anadromous fisheries

A

integrate ecological and fishery science to better understand and quantify linkages between freshwater and marine phases

232
Q

challenges facing sustainable fisheries

A
  • conflicting interests of stake holders and end users

- stocking/fertilization of lakes/streams beyond carrying capacity

233
Q

to develop meaningful management models

A
  • synthesize long-term data to determine carrying capacity and relate to spawners and production of smolts
  • develop better long-term data on fry/smolt production and relation with adult return
234
Q

upwelling systems

A

less than 2% of the ocean
contribute 7% to global marine PP
contribute 20% of global fish catch

235
Q

CCS

A

California Current System
from the top of VI down
wind moves water south, causes upwelling, huge economic value to BC

236
Q

Subarctic Current, Alaska Current

A

North of VI

boundary between varies in position, strength, and timing throughout the year and year-year

237
Q

current system changes

A

affect fish catch

238
Q

economic value of upwelling systems

A

ex-vessel value at least $200million
economic spin-off orders of magnitude larger
sport fishing ~$2billion
recreational, shipping value

239
Q

ex-vessel value

A

post-season adjusted price/lb for first purchase of commercial harvest, usually established by determining average price for an individual species, harvested by a specific gear, in a specific area

240
Q

Important biological processes in the CCS

A
basin conditions:
PDO
NPGO
ENSO
local conditions:
upwelling
Temperature
Salinity
241
Q

PDO

A

pacific decadal oscillation, oscillates between warm and cool phases,
leading principal component of North Pacific monthly sea surface temperature variability

242
Q

NPGO

A

northern pacific gyre oscillation

243
Q

ENSO

A

El Niño - Southern Oscillation

244
Q

High PDO effects (generally)

A

high salmon survival in Alaska
lower salmon survival here and N US (lower nutrients)
inverse production regimes

245
Q

Inverse production regimes

A

“portfolio effect”
provide stability
diverse stock responses = lower variability overall

246
Q

recruitment

A

abundance of fish entering a targeted population determined by growth, abundance, and survival

247
Q

classes of study in fisheries oceanography

A

1.determination of parameters that
define habitats of different life-history stages
2.integrated assessment of the “health” of the ecosystems
3. assessment of
the effects of climate variability on recruitment

248
Q

first few weeks that young salmon spend at sea

A

appears to be when year class strength is set, critical survival period

249
Q

Oceanic Niño Index (ONI)

A

3month running mean of SST anomalies in Niño 3.4 region of equatorial Pacific
(5°N–5°S, 120°–170°W).
An El Niño event is defined to occur when ONI > 0.5°C for 5 consecutive months

250
Q

copepod diversity

A
summer: low- sub-Arctic
waters dominate, naturally
contain low diversity
winter: highly diverse assemblage of subtropical copepods
negative PDO: less diversity
positive PDO: more diversity
indicator/sentinel species
251
Q

ENSO characteristics

A

large scale climate patterns
warm anomaly across equator
fish that are expected to come back, don’t

252
Q

ENSO now

A

safely say one of the 3 strongest on record
likely to be the strongest on record
~60% chance it will revert to La Niña mid2016

253
Q

NPGO affected by

A

regional and basin-scale variations in wind-driven up welling and horizontal advection

254
Q

NPGO affects

A

salinity, nutrient concentrations

255
Q

NPGO fluctuations cause

A

changes in phytoplankton concentrations and variability up trophic level

256
Q

NPGO now

A

variability is increasing

bad NPGO year = bad fish stocks everywhere, little-no portfolio effect

257
Q

warm-water copepods

A

small, not high quality energy reserves

258
Q

cold-water copepods

A

larger, adapted to survive cool T’s, large lipid reserves, more energetic food source

259
Q

effects of local conditions on salmon, primary production

A

increase Chl = increased resident fish yield

but.. salmon aren’t resident, don’t appear to be driven by Chl

260
Q

PDO cool phase, copepods

A

transport boreal coastal copepods into california current from gulf of alaska

261
Q

PDO warm phase, copepods

A

transport sub-tropical copepods into NCC from transition zone offshore

262
Q

mechanisms that bring copepods to shore dictated by

A

physics

263
Q

why do salmon care about copepod species

A

early marine life mortality is size-selective (predation, gape limitation), smolts 99% mortality,
growth in early marine life is critical, large fish = higher survival

264
Q

quality of prey and growth

A

high quality prey = more energy = grow faster
smolts feeding on low quality of prey reach ~1/2 size of smolts on high quality prey in 1yr
quality vs. quantity appears to drive fish stock

265
Q

linking climate to salmon survival

A

Bayesian networks- can use quantitative, qualitative, expert opinion, to test various scenarios. provide probabilistic framework in addition to hypothesis testing.

266
Q

testing WCVI chinook

A

fish tissue samples fall of 2000-2009
stable isotope analysis to geneticallyy ID (make sure local)
remain resident w/i few hundred km of natal stream until winter
analyze stomach content

267
Q

∂13C offshore

A

depleted (more negative)

low productivity

268
Q

∂13C indicator

A

strong indicator for salmon survival - can predict how many salmon will return based on ∂13C

269
Q

difficulties of examining isotope records

A

~months worth of data to distinguish
shifting diet and habitat with growth
interannual effects

270
Q

results of WCVI chinook study

A

find NPGO to be driving factor affecting survival

271
Q

why does NPGO affect survival

A

directly impacts ∂13C

indirectly: SST–copepods–zooplankton–∂13C–survival

272
Q

what does PDO affect?

A

leads to ∂15N (trophic level), not connected to survival

273
Q

effects of changing SST

A

shift species distribution, bring new species, new copepods, effect salmon species?

274
Q

climate change effects

A

intensify winds, stronger upwelling - may increase productivity, change migration patterns, affect precipitation patterns

275
Q

effects of changes in precipitation

A

warm dry summers lethal to salmon stock

truck fish from lake to river/ocean?

276
Q

ocean acidification

A
CO2 sink
CO2 + H2O -- HCO3 + H
decreasing pH
affect critical life stages
killing VI shellfish stocks
277
Q

jack salmon

A

Chinooks that return to the fresh water one or two years earlier than their counterpart

278
Q

most consisten eutrophication effects

A

shifts in algal species composition

increased frequency/intensity of nuisance blooms

279
Q

carrying capacity definition

A

maximum number of individuals of a given species that an area’s resources can sustain indefinitely without significantly depleting or degrading those resources