exam 4 Flashcards
biogenic sedimentary structures
biologically produced structures that include tracks, trails, burrows, borings, fecal pellets and other traces made by organisms
hydromechanical and mechanical digging
what burrowers use to burrow
thixtropy
watery sediment with high silt clay content have this, become more viscous with more movement
hydromechanical burrowing mechanism
fluid fills hydrostatic skeleton, circular muscles contract elongating the body while longitudinal muscles contract to bring body together
penetration anchor
opposite end of organism that is most likely the shell that anchors the body from moving backward
terminal anchor
the head of the foot, that anchors into sediment once stretched to allow for the remaining body to be pulled further into sediment
mechanical displacement burrowing
using spade-shaped digging tools to burrow into sediment powered by muscular force
biogenic structures from burrowing
-burrowing in mud increases water content of sediment
-increases grain size
-alters vertical and 3D mechanical, chemical structure
biogenic grading of sediment
ingests small particles deep in sediment and expels them on surface of sediment
interstitial animals
elongated worm like form, live in water between sand grains
soft-sediment microzones
strong vertical chemical gradients
-gradient is strongly affected by biological activity
redox potential discontinuity (RPD)
boundary between oxygenated zone and anoxic zone
organic
particulate organic matter derived from sedimenting phytoplankton, seaweeds, and sea grasses
benthic deposit feeding
ingest organic and inorganic matter then release as fecal pellets
head down and surface browsing
head down-feed within sediment depth and defecate on surface
surface-feed on surface microorganisms such as diatoms
microbial stripping hypothesis
deposit feeders are most efficient at digesting and assimilating benthic microbes like diatoms and bacteria
deposit feeder sediment interactions
creates watery surface layer, large grain size, microbial growth and transfer of POM
suspension feeding
feed on small particles, low Re within chamber (bivalves) higher Re outside
passive suspension feeding
utilize natural flow of water to bring particles to their feeding structures
-needs orientation in current, pressure drag, and particles concentration may be low
active suspension feeding
use ciliary or muscular activity to create feeding currents to bring particles to mouth
-high saturation and possible clogging of particles, ability to create current and keep siphon erect
gill feeding bivalves and particle sorting and selection
cilia on gills allow for interception of non-nutritional particles to be removed before entering the gut. adaptation to allow for more valuable particles
carnivores issues
-low pop size-move to prey patches
-capture of prey
-limitations on depth, sensory etc.
-feeding while avoiding predation themselves
how predators detect prey
vision and odor detection
examples of moray eel
phyrangeal jaw and sharp teeth to pull prey down throat
lobster
crusher and cutter claw
snapping shrimp
snaps jaws so quickly becomes a sort of stun gun for prey
conus striatus
uses a chiton harpoon to strike prey with venom
herbivore feeding issues
need to attack plants, chemical defense of plants. feeding while avoiding predation
cellulose feeding
obtains nitrogen with symbiotic nitrogen-fixing bacteria
mechanisms leading to spring phytoplankton blooms and declines
high amounts of phosphates and nitrates at surface as well as available sunlight make spring highest bloom production season
mixing depth
real depth at which all water is thoroughly mixed due to wind
critical depth
calculated depth above which total oxygen produced by phytoplankton in the water column equals total consumed
the sverdrup model of spring phytoplankton blooms
if mixing depth is less than the critical depth=bloom
mixing depth > critical depth =no bloom
roles of grazers in regulating phytoplankton
there are less zooplankton to graze to be able to regulate bloom in winter, creating growth into spring
role of POM sinking in decline of phytoplankton
diatoms and POM sink removes nutrients from water and decline of bloom until upwelling next spring
geographic variation in phytoplankton blooms
march-september arctic
peak in spring and peak in fall-temperate
steady with decline in summer-tropic
benthic pelagic coupling
nutrient exchange between benthic and pelagic in very shallow estuaries that fuel more phytoplankton growth
vertical exchange in fall-winter and spring-summer nutrients
cold dense water sinks in fall-winter making mixing depth increase compared to spring/summer
wind storms and upwellings
windstorms push surface water away from offshore and upwells nutrient rich water from lower depths
absorption
molecular absorption
of light energy
light scattering
light interaction with particles
exponential decline of light with depth
violet/blue can be absorbed in deepest waters, why everything underwater is tinted more blue
action spectrum
utilization of different wavelengths of light by a given species for photosynthesis, use of different light absorbing molecules or “pigments”
chlorophyll a absorption and accessory pigments
chlorophyll a- wavelengths >600nm
accessory- wavelengths <600nm
pattern of attenuation of light of different wavelengths with increasing depth
depth reduces light attenuation in all wavelengths but is highest in blue/green
relationship between photosynthesis and light intensity
there is a peak in net photosynthesis, but then too much light intensity Weill decrease the rate of photosynthesis
nutrients
substances required by plants. resources that can be limited in supply
nitrogen and its forms
nitrogen- used for amino acids in proteins
nitrate NO3-most abundant
nitrite NO2
ammonium NH4-excretion product in water column but taken up the fastest
new production
nutrients for primary production may derive from circulation of nutrients from below the surface waters(upwelling NO3, NO2)
generated production
nutrients derive from recycling in surface waters from excretion NH4
nitrogen fixation
process of taking form of nitrogen and making it into a useable form
nitrifying bacteria
convert NH4 to NO2, or NO2 to NO3
denitrifying bacteria
convert NO3 to NH4
nitrate reducing bacteria
return NO3 to atmosphere as N2
nitrogen cycle
N2 dissolved into water or NH4 in water, fixed between NO2 NO3 or NH4, returns to atmosphere as N2
phosphorus
occurs dissolved in water mainly as phosphate PO4, required for synthesis of ATP source of energy for cellular reactions
phosphorus cycle
goes between dissolved inorganic phosphorus-organic phosphorus-external phosphorus sources and sinks
limiting nutrient
nitrogen limiting oceanic nutrient-limits phytoplankton growth in seawater which limits growth to rest of food chain
silicon
important limiting element for diatoms because of skeleton construction, much silica taken up in Antarctic Ocean by abundant diatoms
iron
important cofactor in oxygen production step of photosynthesis. in source of ferredoxin-electron acceptor donor than can enhance phytoplankton growth in high-nitrogen low-chlorophyll regions
sources of iron
airborne terrigenous iron as dust from the land, volcanoes, along oceanic ridges
microbial loop concept
bacteria feeds on DOC and POC from other species, introducing energy into food web, then gets eaten by larger creatures, cycle continues
biomass
the mass of living material present at any time, expressed as grams per unit area/volume= standing stock
productivity
the rate of production of living material per unit time per area/volume
primary productivity
productivity due to photosynthesis
secondary productivity
productivity due to consumers of primary producers
food chain
linear sequence shown which organisms consume which other organisms
trophic levels
level/position an organism occupies in a food chain
food web
more complex diagram showing feeding relationships among organisms, not restricted to a linear hierarchy
transfers between trophic levels
not complete
- some material not eaten
-not all eaten is converted with 100% efficiency
-metabolic costs are a lot
budget for ingested food
I=E+R+G
ingested, egested, respired, growth
trophic level transfer efficiency and calculation
measured by food chain efficiency (E)
amount extracted from a trophic level divided by amount of energy supplied to that level
(range from 10-50%)
transfer between trophic level calculation
P=BE^n
P=production at highest level
B=primary production
E=food chain efficiency
n=number of links between levels
oceanic food webs and the productivity and food chain efficiencies
varies on
-primary productivity
-food chain efficiency
-number of trophic levels
-area of ocean covered
potential fish production
greatest potential is in upwelling zone
bottom-up
bottom up= control of food chain by amount of primary production
top-down
control of food chain by variation in top predators
GPP
gross primary productivity- total carbon fixed during photosynthesis
NPP
net primary productivity- total carbon fixed during photosynthesis minus that part which is respired, what is available to higher trophic levels
oxygen technique
there is an addition of O2 from photosynthesis and a subtraction from respiration, can be measured using Winkler method or polarographic oxygen electrode
used when primary production is high ex. shelf
light-dark bottle technique
1/2 light and 1/2 dark bottles measured over same period of time
light=oxygen from photosynthesis minus respiration
dark=oxygen from respiration only
conversion of GPP estimated by oxygen technique to carbon units
GPP=375(L-D)x divided by PQ
radiocarbon technique for measuring primary production
give known amount of bicarbonate to phytoplankton after a time and measure total carbon removed by cells from solution
useful where primary production is low ex. open ocean
satellite approaches
satellites can use photometers to use wavelength to measure chlorophyll and seawater temperature
global patterns of primary production based on oxygen
shelfs and coastal areas are nutrient rich, open oceans and gyre centers r poor
radiocarbon
method of determining age of an object based on radioactive isotope of carbon
diversity
variety and variability of life on earth
speciation and extinction
balance of this explains regional patterns- new species and extinction of other species
biogeographic patterns of diversity
isolate groups of species come from isolation and strong environmental gradients
provinces
sum of many species coinciding boundaries, or a statistical construct of different species assemblages that co-occur in a region
geographic barriers
temperature breaks, basins, Panama upheavals
geography related to evolutionary history
geography can be proven to be related to speciation by evolutionary trees to patterns of geographic occurrence
phylogeography
study of historical processes that may be responsible for the past to present distributions of lineages
importance of barriers
different groups of evolutionarily related species found in long isolation periods create new species closely related to each other
patterns of extinction and colonization of rocky shore fauna over last 3.5 million years
persistent boundary (Florida) can isolate populations of several species
major gradients of species diversity
latitudinal diversity gradient
within-habitat
number of species living in the same habitat type
between-habitat
number of species living in all habitat types
latitudinal gradients of diversity
number of species increases toward the equator. persistent yet differs for different groups
explanations of regional diversity differences
presence of predators might enhance coexistence or competitor may drive inferior species to local extinction, recent historical events
factors causing high diversity rates
greater speciation rate, lower extinction rate, greater area
center of origin theory
high diversity centers are places where most species are produced and retained
species richness and area relationship
stable habitat can reduce rate of extinction by persisting in smaller population sizes ex. deep sea
mass extinction
short period of time where a high percentage of biodiversity dies out
estimating diversity and its value
the number of species known in a habitats is poorly known making it severely underestimated
habitat destruction
natural habitat is no longer able to support its native species
habitat fragmentation
emergence of discontinuities within an organisms habitat that causes fragmentation and ecosystem decay
habitat degradation
habitat can no longer support species due to pollution, invasions, over-utilization, etc
conservation strategies
marine protected areas/reserves, legislation
foundation species
a species that has a large contribution towards creating an ecosystem to support other species ex. corals
trophic cascading species
when an entire trophic level is suppressed
functional redundancy
species lost is compensated by other species contributing similarly to functioning
marine protected areas
reserves set aside to allow population to thrive and spill over into unprotected areas
marine invasions
arrival of non native species with strong ecological effects
