Outline u Krill u Pteropods u Copepods u Forams

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1 Ocean Acidification Impacts on Marine Plankton in Alaskan Waters Richard A. Feely 1, Nina Bednarsek 1,2 and Shallin Busch 3 1 Pacific Marine Environmental Laboratory/NOAA, 2 JISAO/UW, 3 NWFSC/NOAA Outline u Krill u Pteropods u Copepods u Forams On behalf of dozens of scientists at PMEL and University of Alaska Photo credit: Meghan Shea

2 Sensi&vity to OA along US West Coast Busch and McElhany 2016 PLOS

3 Major players in the pelagic food web Krill Pteropods Copepods

4 Larval krill survival and development reduced in low ph treatments 2 sets of experiments, 6-22 day duration, broods from 110 females

5 Larval krill survival and development reduced in low ph treatments Current conditions in Puget Sound McLaskey et al 2016 Marine Ecology Progress Series

6 Global Importance of Pteropods Ø Pteropods are shelled pelagic snails and belong to zooplankton group. Ø Found in all ocean basins mostly in the upper 200 m. Ø Vital role within epipelagic food webs: high abundance, high grazing rates and important food source for higher trophic levels. Ø Pteropods contribute 20-42% to global carbonate budget (Bednaršek et al., 2012). Ø Pteropods in Alaskan waters with high ecological and economic importance; times higher abundances that in the other regions. 30% salmon survival can be explained by pteropod abundance in the GOA. Ø Sensitive to small-scale changes in the environment; thus considered an indicator of good health of the ecosystem

7 Pteropods are ideal OA indicator: Implication of Ocean Acidification on Vertical Distributions and Shell Dissolution of Pteropods and Heteropods in the CCE-LTER study area because: Ø they are ubiquitous and methods established. Ø they respond to the small changes in Ω ar very quicklyà Ω ar primary response variable, not confounded by other environmental variables à sensitive and specific indicator. Ø Biological responses can be monitored in a rapid, costeffective, easy-to-use way. Ø Early warning signal à before the population effects

8 Pteropods as indicators-increased shell dissolution Shell dissolution closely corresponds to carbonate chemistry conditions in the natural environment. Pteropods from the Gulf of Alaska and Chukchi Sea have evidence of severe shell dissolution. A Gulf of Alaska

9 Dissolu'on and calcifica'on as indicators of present and future impacts Pteropod responses (shell state under light microscope and scanning electron microscope, and calcification) along the aragonite saturation state related to their biological status. With the progressing decrease in the aragonite saturation state from left to right on the x-axis, dissolution increases and the level of calcification (indicated by the fluorescence) decreases. Weisberg et al 2016

10 Mean prosome length in µm Top: Adult Species Bottom: Life stages of Paracalanus Sp. Open Symbols: High CO 2. Closed Symbols: Low CO 2. after Garzke et al 2016.

11 Santa Barbara Basin Sediment Trap and Sediment Time-series Using Foraminifera Shells to Es'mate Paleo-[CO32-] Area density (µg/µm2) representa>ve of shell thickness of planktonic foraminifera G. bulloides is significantly correlated with ambient [CO32-] (Osborne et al., 2016). a 100 µm b c 20 µm µm 2000 Year G. bulloides area density based [CO32-] reconstruc>on for the last century plomed with model es>mates of [CO32-] (1980Time-series of area density compared to PFEL upwelling index (inverted y-axis). present). (Emily Osborne et al., in prep).

12 Santa Barbara Basin Sediment Trap and Sediment Time-series Using Foraminifera Shells to Es'mate Paleo-[CO 3 2- ] Year G. bulloides area density based [CO 3 2- ] reconstruc>on for the last century and model projec>ons of [CO 3 2- ] for this century plomed with model es>mates of [CO 3 2- ] (1980- present). (Emily Osborne et al., in prep).

13 . Key Messages u Larval krill show evidence for reduced survival and development in low ph treatments. u Pteropod dissolution and calcification is significantly impacted by anthropogenic carbon. With decreasing aragonite saturation state dissolution increases and calcification decreases. u Copepods show strong negative response to warming which is partially offset by acidification. u Foram shell density decreases with decreasing carbonate ion concentration. Feely et al (in prep)