ocean acidification lecture hilary palevsky [email protected]
TRANSCRIPT
Absorbing CO2 changes ocean pH
IPCC AR5, Figure SPM.4
Hawaii (Mauna Loa)South Pole
Hawaii (ALOHA)Bermuda (BATS)Canary Is. (ESTOC)
Gary Braasch Photographyhttp://www.worldviewofglobalwarming.org
Gary Braasch Photographyhttp://www.worldviewofglobalwarming.org
What is pH all about anyway?
• pH = -log[H+]• Decrease in pH =
increase in acidity• Logarithmic scale– A decrease of 1 unit is a
10× increase in [H+]– A decrease of 0.1 unit
(observed to date) is a 26% increase in [H+]
Ocean carbonate chemistry
CO2 dissolution in water:
CO2 + H2O ↔ H2CO3
H2CO3 ↔ H+ + HCO3-
HCO3- ↔ H + + CO3
2-
Forming CaCO3 shells:
Ca2+ + CO32- ↔ CaCO3
Ω = [Ca2+][CO32-]/KspWhen Ω < 1, water is undersaturated and CaCO3 will
dissolve
Calcifying organismsGeoduck Blue mussel
Urchins
Pink calcifying algae
Juvenile king crabDungeness crab
• Examples of Puget Sound organisms that build shells, skeletons or other hard parts from CaCO3
Images from Washington State Blue Ribbon Panel on Ocean Acidification Report, 2012
Pteropods: OA poster child
• Zooplankton, swimming snail• Food for young salmon• Shells dissolve in low pH waters• Observed dissolution in situ in
Southern Ocean (Bednaršek et al., 2012)
Pteropods dissolve in water with pH and carbonate chemistry expected for 2100
OA in the California Current System
Gruber et al., 2012
OA in the California Current SystemFeely et al., 2008
Impact on oyster hatcheries in the Pacific Northwest
Barton et al., 2012 WA Blue Ribbon Panel Report
Taylor Shellfish Hatchery,Dabob Bay, WA
Whiskey Creek Hatchery,Netarts Bay, OR
IPCC AR5 SPM.7
IPCC AR5 SPM.8
RCP 2.6 (low future emissions)
RCP 8.5 (high future
emissions)
Future projections