OA ORGANISM RESPONSES TO HIGH pCO2 & LOW pH Flashcards
what has there been a linked increase in between the atmosphere and surface ocean (<50m)? what units is it measured in?
what two factors have there been a concomitant decline in due to this?
CO2 (ppm)
seawater pH and carbonate (CO32-) concentration
what is the amount of carbonate in the oceans affected by? (3 things)
temperature, salinity, pressure
processes like … … and … see positive effects from ocean acidification, because they’re driven by CO2.
whereas, … species are negatively affected by reductions in pH because they need to use more energy to create … and … structures, so those organisms have negative long term implications from this.
nitrogen fixation
photosynthesis
calcareous
skeletal
shell
what are the trends based on multi-species experiments or observational studies in naturally acidified systems?
- increases in 1° Producer biomass
- decreases in taxonomic diversity
- some species able to survive or even thrive in high CO2 conditions
there is a variation in organism response to ocean acidification depending on the life stage, with a large survival range between larvae, juveniles and adults. growth is much reduced in … and … stages, as is their m…
why is … morphology important?
larval
juvenile
metabolism
larval morphology is important to understand bc underpins whether organisms/species survive; if larvae don’t thrive, they can’t replenish adult populations so over time the species will go extinct
what process is likely related to declining pH, which is indicated through the decline in shell length of mussels where pH is lower? why is this the case?
oxygen consumption
decrease in oxygen consumption is an indicator of metabolic repression; animals don’t have enough available energy to pour into processes like calcification
they reduce metabolic rates for as long as possible until the conditions are favourable again
what are the impacts on metabolic rate & calcification in the brittle star Amphiura filiformis? what is the cost of this process?
- metabolic up-regulation to maintain/increase calcification and compensate dissolution due to increased seawater acidity
the spaces filled with muscle tissue become much larger, causing muscle wastage and they’re unable to survive over the long term.
what other sound-related consequence occurs as a result of OA?
- reduction in biological sound level overall
- reduction in snapping shrimp snaps
what behaviour is impaired as a result of OA, demonstrated in the eastern oyster and mud crab?
foraging behaviour
how does ocean acidification impact species behaviour?
- shown to impair organisms’ ability to respond to environmental cues
- they aren’t able to find homing sites as efficiently
- affecting predator-prey links
- which then becomes an issue for the wider food web
what sort of experiments are needed on ocean acidification? what is the focus of current experiments on?
- more long-term experiments are needed
- focus is still on a limited set of taxa
- ocean acidification isn’t an isolated phenomenon, but is occurring at the same time as changes in temperature, deoxygenation, eutrophication, habitat destruction etc.
SUMMARY
since 2005, understanding the p…, b…, e… and ecosystem impacts of ocean acidification top the political agenda
organism responses may depend on l… s…, length of …, levels of …/… used
organism responses are species …, but particularly … species are likely to be more negatively affected
altered behaviour in marine … (e.g., predator a…, predation i…) may weaken …-… links in marine food webs, causing cascading effects on … structure and function
m… experiments are extremely valuable, but more n… observations are needed.
political, behavioural, ecological
life stage
experiments
CO2/pH
specific
calcareous
consumers
avoidance
inhibition
predator-prey
community
manipulative
natural
