Ocean Acidification PDF

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Ocean acidification....

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OCEAN ACIDIFICATION: PROCESSES, IMPACTS, AND SOLUTIONS - Blue Planet As pCO2 in the ocean increases, ocean pH goes down = ocean acidification - Oceanographic records do not go back as far as atmospheric records: global pH database is quite new The carbonate buffer system - 1/3 of atmospheric CO2  natural carbon sinks - CO2 dissolves in water  carbonic acid, relatively unstable, will dissociate into bicarbonate (HCO3-) and H+ ions - pH measures H+ concentration, alkalinity measures other ions in sea water - DIC = Dissolved inorganic carbon (CO2, carbonic acid, bicarbonate, carbonate) - pH in ocean atm is = to ~pH 8 Ocean acidification is observable in the ocean - pH observed to be declining by ~0.017 to 0.027 pH per decade - 0.287-0.29pH decline under RCP8.5 by 2100 Why is seawater [CO32-] so important? - Ability for organisms to form CaCO3 shells is directly correlated to the amount of carbonate within the water - Ω > 1 = super saturated - Ω < 1 = under saturated - Arctic has less buffering capacity so change is happening fastest - CO2 dissolved fastest - Polar oceans are becoming more corrosive to calcifying species more quickly Coccolithophores - Almost half of CaCO3 production for our oceans - Important role in the sequestration of carbon into deeper ocean via formation of marine snow - - if already showing evolution?? - Species richness and abundance decreases as the organisms get closer to the CO2 vents where pH goes down Upwelling as a proxy for OA - Deep oceans tend to be cold, oxygen rich, and have high CO2 concentrations - Wind shear pulls up cold water high in CO2 along the coast - Example = north west pacific oyster fishery July 2007 mass die off; corrosive water from upwelling - Availability of carbonate and bicarbonate ions causing mass die off - Chronic effects are shown when saturation hits 2 (1=under saturation) Pteropods - Most sensitive species: aragonite shell - Arctic ocean evident of under saturation through Pteropod research

OA is already showing reef calcification rates Acid base homeostasis - Most smaller marine invertebrates are in equilibrium with their external environment o If pCO2 conc goes up in the water the CO2 in their body will also go up - Not all marine invertebrates can pump out the CO2  metabolic suppression - Any process that is enzyme driven will be affected by changes in pH Ocean acidification ‘solutions’ - MPAs o Removing local stressors will allow for more resilience in the ecosystem - Ocean alkalinity enhancement o Adding buffering capacity to the ocean o Increases carbon sequestration - Super corals: assisted evolution o Stress conditioning, assisted gene flow, modification of microbes, symbiodinium evolution / inoculation - Habitat restoration: blue carbon o Corals near seagrass or mangroves are impacted much less than when they are further away; sequestration of CO2 from the sea water - Reduce carbon footprints o Reducing CO2 emissions...