Marine ecology

what abiotic changes occur with climate change

increase in sea surface temperature, decrease in pH

what are the 5 main impacts of climate change on coral reefs?

1. temperature increase leads to coral bleaching
2. decrease in pH leads to reduced calcification rates
3. sea level rise
4. altered ocean circulation patterns leads to food supply changes
5. increased frequency of severe weather events leads to physical damage

what are zooxanthellae

algae that live within coral and take up its waste and helps with photosynthesis

how does coral bleaching work?

when zooxanthellae are stressed, the thylakoid membranes in their chloroplasts are degraded and free radicals are released, causing their expulsion from the coral

what structure of coral is more tolerant to thermal stress? least tolerant?

large coral with thick tissues and slow growth rates are most tolerant, while branched and tubular growth forms are least tolerant

how can coral expand its range?

coral large can move to cooler areas and allow range expansion

what effect does nutrient stress play on corals? (3 things)

excess nitrogen and phosphorous send a stress signal to zooxanthellae and causes them to be expelled

excess nutrients allows growth of the algae that outcompete coral

crown of thorns thrives on higher nutrient levels, then they kill coral

what is alpha diversity

local diversity within a quadrant, reef complex etc

what is beta diversity

diversity within a community

what is gamma diversity

regional diversity- larger areas

what is species richness

how many species there are

what is species evenness

the abundance of each species relative to other species

does does COML stand for

census of marine life

what does the COML show

productivity is inverse to biome size and the most productive biomes are most threatened by humans and climate change

what is benthic

seafloor

what is pelagic

water column

does benthic diversity increase or decrease with depth

decrease

is benthic or pelagic diversity greater?

benthic

what latitude are oceanic taxa the most diverse?

30-60ºN

is diversity greater at the coast or deeper waters?

coast

what temperatures of waters holds higher diversity

warm waters

how does diversity increase ecosystem functioning?

niche partitioning allows more efficient use of resources due to interspecific competition

more species allows more resilience to hardship

what is facilitation

one species positively influences another

what is sampling artefact

high species richness increases the probability that an effective species is present

what is complementarity

species differ in their resource use which benefits other organisms and the ecosystem

characteristics of abyssal plains

soft sediment environment with low biomass

how does grain size/sorting affect the ecosystem

controls mobility, feeding mode and bacterial processes of a community

how does water drain in well sorted grain

quickly

how does water drain in poorly sorted grain

slowly or not at all

what do herbivores eat

microalgae, seaweed, seagrass

what do predators eat

ciliates, benthic invertebrates, juvenile and adult macrofauna

what do scavengers eat

dead material

what do suspension feeders eat

particulate matter in the water column

how mobile are suspension feeders

low mobility

what do suspension feeders need in order to attain food

a good water current

can suspension feeders generate their own currents?

yes, with cilia

why cant suspension feeders and deposit feeders live in the same environments

suspension feeders need higher currents, which do not contain enough food for deposit feeders while deposit feeders need more turbidity with may clog feeding mechanisms of suspension feeders

what do deposit feeders eat

particulate matter in the sediment

what kind of sediment do deposit feeders live in

muddy sediments, more clay

what is unique about tellinid clams feeding mechanism

in fast currents, they can be suspension feeders while in slow currents they can be deposit feeders

how does crab tunnel digging change with changing conditions

in sandy environments crabs dig short tunnels that dont last long, while in muddy environments crabs dig long tunnels that last a long time

benefits of bioturbation

allows nutrient cycling, increases availability of oxygen

downfalls of bioturbation

may disrupt biofilm which serves as a food source for some other organisms

what do sediment stabilizers do

bind sediment together and stop it from moving around

what do sediment destabilizers do

move sediment around

what kind of food webs are most stable?

complex food webs

why are complex food webs more stable

many weak interactions allow more plasticity (adaptability) and there is redundancy

what is the portfolio effect

if consumers have several food sources, primary producers don’t fluctuate so much

how does salinity affect food webs

phytoplankton grows well in mixed salt and fresh water, so an influx in primary producers supports higher numbers of other organisms

how does habitat affect diet

out by the sea organisms are fueled by primary producers like phytoplankton and kelp, while inland they are chemotrophs

what is fecundity

ability to produce abundance of offspring

relationship of fecundity and female size

increase of fecundity with female size

why is protecting large females important for supporting a population?

larger females have higher fecundity, protecting them can help a population recover

how do MPAs effect ecosystem stability

increase species richness and restore food webs

what is a trophic niche

sum of all species trophic interactions

what does a greater trophic niche mean?

that a community is more resilient to change

what is the most stable kind of resource use within a population

generalist population with generalist individuals

what is the least stable kind of resource use within a population

specialist population with specialist individuals

how do humans affect trophic niche width

building bridges and dams can cause habitat fragmentation which narrows the niche

characteristics of healthy systems

taller food web

more links

more sources of basal carbon

characteristics of impaired systems

shorter food web

fewer links, less invertebrates

changes in physical environment

single source of basal carbon

what drives the biological carbon pump

the pelagic food web

what are pelagic primary producers

diatoms, phytoplankton

how does region affect food webs

coastal regions have shorter food webs, larger organisms and more efficient transfer of energy

what is the diel vertical migration

mesopelagic animals migrate down during the day and up at night

what is the physical carbon pump

movement of carbon dioxide from the atmosphere down to the ocean floor by diffusion and downwelling

where/when does the physical carbon pump occur

high latitudes, during winter

steps of the biological carbon pump

1. fixing of CO2 through photosynthesis to produce carbon
2. carbon moved into deep water by downward flux
3. carbon is remineralised (broken down and sent back up)

what is the carbonate counter pump

fixes particulate inordanic carbon but releases CO2 at the same time

what is the biological gravitational pump

gravity takes particles downwards

what is the PIP eddy subduction pump, and where does it occur

carbon is pushed down based on ocean mixing/spinning, occurs in coastal regions with wind currents

what is the PIP mixed layer pump, and how do seasons affect it?

thermocline going up and down pushes matter down, matter from summer is shallow but in the winter the matter is broken down and it sinks

what is the PIP mesopelagic migration pump

deep animals migrate to surface waters to feed, and return down low during the day and take carbon with them by respiring and excreting waste

what is the PIP seasonal lipid pump, where does it occur?

zooplankton grazing on phytoplankton in the spring to increase lipid stores, but when they migrate to deeper water they catabolize these lipids and release them. occurs at higher latitudes

what pump exports the most carbon

the BGP (biological gravitational pump)

what pump is least subject to mineralisation?

the seasonal lipid pump

where on the globe is the most carbon fixed?

high latitudes and coastal regions

why is carbon sequestration higher at higher latitudes

phytoplankton sinks quickly with cold water so it is more efficient

what does traditional monitoring of eDNA involve

collection of specimens for identification and DNA extraction

advantages of eDNA

no taxonomic expertise required, faster results, cheaper and noninvasive

disadvantages of eDNA

reference databases are incomplete, contamination may occur

what are marine heatwaves

prolonged and extreme warming of ocean temperatures

causes or marine heatwaves

warming of atmosphere, ocean currents build up warm water, reduced wind speeds

el nino and marine heatwaves

el nino increases heatwaves in east pacific

la nina and marine heatwaves

la nina increases heatwaves in west pacific

how do heatwaves change as the climate warms

heatwaves are more frequent and more intense

how do heatwaves impact benthic invertebrates

cause reproductive failure and mass mortality because of deoxygenated water and high temps

how do heatwaves impact marine forests

decline in marine forests overall, less productive communities

how do heatwaves impact marine sponges

sea sponge bleaching and death

how do heatwaves impact food webs / trophic interactions

food sources depleted, ecosystem shifts

how do heatwaves impact ecosystem services

commercial loss of fishing industry

strategies to help restore marine ecosystems after heatwave

prime early life stages to heat, breed heat tolerant strains

what differentiates a primary larval form

have cilia for feeding and locomotion

what differentiates a secondary larval form

they have setae instead of cilia for feeding and locomotion

advantages of a complex (larval and adult) life style

different food sources, decreased competition and overcrowding, reproductive niches

benefits of larval dispersal

reduced competition for food, reduced chance of inbreeding, reduced risk of extinction

what is planktotrophy

no planktonic stage, have small eggs with high fecundity, high mortality, and high dispersal

what is lecithotrophy

larval form with non feeding larvae, low mortality, low dispersal

What is thorson’s rule

species producing planktonic larvae are rarer at higher latitudes, feeding stage is skipped or a planktonic life style

what is the most common larvae state

planktotrophic larvae (feeding larvae)