1. Coastal Upwelling Equatorward winds along a coastline lead to offshore Ekman transport Mass conservation requires these waters replaced by cold, denser waters Brings nutrients into surface waters creating blooms Creates dynamic height gradients - currents

2. Coastal Upwelling

8. April 2000 CalCoFI Cruise

11. At smaller scales... Strong west winds

12. Ocean Biogeochemistry in a Nutshell Light energy drives the net fixation of carbon Within the euphotic zone, nutrients & CO 2 produce CO 2 & fixed carbon Below the euphotic zone, the rxn’s reverse Pelagic Ecosystems NUTS CO 2 Fixed Carbon O2O2 h

13. Coastal Upwelling California Current April 1978 AVHRR - SST CZCS Chlorophyll SST Chl

14. Respiration & Remineralization remineralizers h CO 2 O2O2 PlantsNUTS Biological processes consume plants & O 2 to make CO 2 & nutrients

15. Euphotic Zone Euphotic Zone – PP happens Aphotic Zone - Respiration & Remineralization Depth of Euphotic Zone is f(water clarity) 100% Light1% Light

16. Euphotic Zone Defined as the depth where the light = 1% of the surface value A function of plant biomass or chlorophyll concentration Varies from 10 to 130 m Typically, Z eu = 3 * Secchi depth

17. CalCoFI Light Profiles % surface light Depth (m) Secchi = 7 m Secchi = 18 m

18. The Upwelling Conveyor Belt Highest NUTS & CO 2 High NUTSLow NUTS High ChlLow ChlLower Chl Sinking Flux of Carbon

19. CO 2 CO 2(aq) (CO 2 + H 2 O) photosynthesis respiration H 2 CO 3 HCO 3 - + H + ocean food web K1K1 K2K2 CO 3 -2 + 2H + Carbonate Chemistry calcifiers

20. Increasing CO 2 : Increases acidity (lowers pH) Lowers CO 3 - availability Lowers CaCO 3 (s) saturation state Acidification Calderia & Wickett, Nature [2003]

21. Increasing CO 2 : Increases acidity (lowers pH) Lowers CaCO 3 (s) saturation state “  ” Multiple forms of CaCO 3 : aragonite, calcite, Mg-calcite with different solubility More Seawater Chemistry  = [Ca 2+ ][CO 3 2- ] / K sp Δ[CO 3 2- ] = [CO 3 2- ] obs - [CO 3 2- ] sat

22. -Shell forming plants & animals reduced shell formation (calcification) lower reproduction & growth rates -Habitat loss (reefs) -Less food for predators humans, fish, whales -Possible negative effects on larvae Biological Impacts warm-water corals cold-water corals lobsters, crabs some plankton pteropods planktonic snails scallops, clams, oysters

23. Published by AAAS R. A. Feely et al., Science 320, 1490 -1492 (2008) Fig. 1. Distribution of the depths of the undersaturated water (aragonite saturation < 1.0; pH < 7.75) on the continental shelf of western North America from Queen Charlotte Sound, Canada, to San Gregorio Baja California Sur, Mexico

24. Published by AAAS R. A. Feely et al., Science 320, 1490 -1492 (2008) Fig. 2. Vertical sections of (A) temperature, (B) aragonite saturation, (C) pH, (D) DIC, and (E) pCO2 on transect line 5 off Pt George

25. Review Wind stress along coasts leads to divergence of surface Ekman transport This drives to coastal upwelling and forms a coastal jet This drives the productivity of eastern boundary currents Important for acidification of the coastal ocean