Ocean Acidification Flashcards
What are the stats regarding humanity’s carbon emissions?
Fossil fuels and cement contribute 88% (7.7 billion metric tonnes per year)
Land use change - 12% (1.1 billion mtpy)
Where does humanity’s carbon go?
Atmosphere - 47% (4.1)
Land - 27% (2.4)
Ocean - 26% (2.3)
What is the chemistry of CO2 in sea water?
CO2+H2O H2CO3 HCO3- + H+
Carbon dioxide + Water Carbonic Acid Bicarbonate Ion + Hydrogen Ion
Stats on Ocean CO2 levels
Oceans are principal sink for anthropogenic CO2
Estimated 30% rise in H+ in ocean surface layers since early 1900s
Atmospheric pressure of CO2 will double pre-industrial levels by 2100
Drop in pH of 0.5 units by 2100
Describe a lab experiment into the effects of ocean acidification
Riebesell et al., 2000
E.huxleyi and G.oceanica (phytoplankton species)
- Showed diminished calcification
- increased malformation of coccoliths and coccospheres
Describe a mesocosm experiment into ocean acidification
Wood et al., (2008)
Investigated the effects of acidification on the brittlestar Amphiura filiformis - found that calcification increased, thus regeneration of limbs increased but at a cost of muscle wastage
Describe a field experiment into ocean acidification
Hall-Spencer et al., 2008
- volcanic vent experiment
- Coralline algal biomass was significantly reduced and gastropod shells were dissolving due to periods of carbonate sub-saturation. The species populating the vent sites comprise a suite of organisms that are resilient to naturally high concentrations of p CO2 and indicate that ocean acidification may benefit highly invasive non-native algal species.
How are organisms responding to ocean acidifciation? Study
Rodolfo-Metalpa et al., 2011
Gross calcification of limpets to increase at low pH
How is ocean acidification affecting predator induced defences?
Bibby et al., 2007
Some gastropods can alter shell thickness in response to the presence of a predator
Littorina littorea (intertidal gastropod) loses ability to thicken shell under low pH
What areas are most at risk in terms of organisms affected? Why?
Antarctic benthic macroorganisms
- slow growth
- already vulnerable to bottom trawling, cable and pipe laying, oil and gas exploration
- likely to be more vulnerable than warm water and coral reefs
How could fish help with ocean acidification?
We also predict that fish carbonate production may rise in response to future environmental changes in carbon dioxide, and thus become an increasingly important component of the inorganic carbon cycle.
Fish waste could help balance ocean pH
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Additional Reading causes - CO2
Orr 2011
An increase in CO2 results in decrease in pH
Additional Reading - coral pH
Anderson et al. 2009
Coral has an inability to calcify at low pH
Additional Reading - sea vents
Fabricius et al., 2011 & Hall-Spencer et al., 2008
CO2 vents
- less diversity but same coverage
- increased amounts of sea grass
Additional Reading - sea snail
Harris et al., 1999
Haliotis spp. showed 5-50% growth reductions at low pH
