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Ocean Acidification Influences on RI Marine Species: A Review M. Conor McManus March 15, 2017 Ocean Acidification: Offshore vs. Inshore Ocean Acidification - Shelf and Offshore Large-scale physical processes influence global uptake of CO2 •Entrainment and release through vertical mixing, upwelling and downwelling Cape Cod CO2 in water shelfbreak Gulf of Maine Wang et al., 2011 Ocean Acidification: Offshore vs. Inshore Ocean (Coastal) Acidification - Inshore Fresh water, nutrients, and dissolved carbon entering estuaries influences pH and CO2 •Nutrient-driven phytoplankton bloom and subsequent die-off leads to bacteria activity and respiration Nutrients Phytoplankton Bloom Phytoplankton Decomposition & Bacterial Grazing à Inc. Respiration & CO2 Ocean Acidification: Offshore vs. Inshore Ocean (Coastal) Acidification - Inshore Fresh water, nutrients, and dissolved carbon entering estuaries influences pH and CO2 •Nutrient-driven phytoplankton bloom and subsequent die-off leads to bacteria activity and respiration How does acidification influence marine species? Nutrients Phytoplankton Bloom Phytoplankton Decomposition & Bacterial Grazing à Inc. Respiration & CO2 Acidification and Marine Species Mechanisms Low pH generates stress on acid/base reactions and ion transport in finfish - growth, survival, orientation, sensory functions Wes Pratt, NMFS Acidic water ‘dissolves’ calcium shells and structures (corals, shellfish, pteropods, coccolithophores) - growth, shell strength, survival High pCO2 increases photosynthetic uptake (phytoplankton and seaweed) - nutrient cycling, proliferation of certain photosynthetic species 0 Days 15 Days 45 Days 30 Days Pteropods, ocean.si.edu Rhode Island Coastal Shellfish Quahog Low CO2 Bay Scallop Pre-Industrial ~Present Day 2100 2200 High CO2 Ocean acidification may be reducing larval shellfish growth, shell thickness, and survival Talmadge and Gobler 2010 Rhode Island Coastal Shellfish Blue Mussel Net calcification rate (wt% per 60d) Net calcification rate (µmol CaCO3 g FW-1h-1) Increases in pCO2 and decreases in pH and Ωaragonite may cause reduced calcification in additional RI shellfish: blue mussels and soft-shell clams Gazeau et al. 2007 Soft-Shell Clam Ries et al. 2009 Eastern Oyster: More Resistant? High CO2 Quahog Bay Scallop Eastern Oyster Reduced larval survival and growth from current to elevated/future CO2 conditions have been seen for eastern oysters However, oysters seem to be more resilient than other shellfish (quahogs, bay scallops) Low CO2 Tamlage and Gobler, 2009 Large Commercial Industries: American Lobster Studies on elevated CO2 impacts on American lobster provide mixed results (both positive, negative and neutral) Larval mortality and development more responsive to temperature than CO2 Young lobsters (3-4 months old) exposed to elevated CO2: - altered intermolt period - decreased length and weight over growth increments - more susceptible to shell disease (McLean, 2016) Waller et al. 2016 Large Commercial Industries: Squid Kaplan et al., 2013 Increased CO2 levels lead to: - increased larval duration - decreased mantle length - degraded statoliths (used for orientation) Large Commercial Industries: Sea Scallop Incorporating oceanographic data into growth, survival, and recruitment functions can provide us with a better understanding on population patterns Climate forecast data can then be used to predict future population biomass and landings (and revenue) Cooley et al. 2015 Forecast 2008 Conditions Estimated 20% drop in sea scallop biomass and landings, closer to 15% decrease in revenue out to year 2050 11 Finfish Responses to OA Adults and eggs for many finfish species appear to be tolerant of CO2 levels projected for the future Atlantic silverside Larvae, however, have varying responses (negative or neutral) to ocean acidification Negative effects include: •reduced growth •lower survival •tissue damage •morphological deformities •ear bone alterations •loss of sensory performance •altered behavior Baumann et al. 2012 Summer flounder Do these laboratory studies translate to the field/population level? - Generational adaptation? (Miller et al. 2012) - Parental influence on offspring? (Murray et al. 2014) Chambers et al. 2014 Laboratory vs. Field Studies Most acidification-species studies have been in the laboratory. How do these results translate to the field? Soft-shell clam Green et al. 2013 Shellfish require specific substrates to survive Buffering sediments with shell dissolution (CaCO3) corresponded to more softshell clams Potential solution for countering acidification? Synergy Between Multiple Stressors: Coastal Acidification and Hypoxia Coastal acidification often coincides with hypoxia - low oxygen levels - through bacterial drawdown of bottom oxygen Stratification over water column prevents mixing for new O2-rich bottom water These events also create inhabitable areas for marine species Nutrients Phytoplankton Bloom Stratification Phytoplankton Decomposition & Bacterial Grazing à Inc. Respiration & CO2 & Dec. O2 Synergy Between Multiple Stressors: Coastal Acidification and Hypoxia Wallace et al. 2014 Hypoxia and low pH (high acidity, high CO2) are well correlated, but not perfectly Colder water means higher dissolution, meaning its easier to get oxygen in than it is to get carbon dioxide (and acidity) out Synergy Between Multiple Stressors: Coastal Acidification and Hypoxia Bay Scallop Ocean acidification coupled with other ecological stressors (e.g. low oxygen) may provide additive effects Quahog - 2 Months Old Quahog - 4 Months Old Gobler et al. 2014 Indirect Effects: Food Web Simplified Narragansett Bay Ecosystem What do negative effects for some species mean for food web interactions? Modeling exercises indicate negative impacts for shellfish and crustaceans can influence abundances for larger fish and marine mammals (Fay et al. 2017) Closing Remarks and Remaining Questions • pH changes in the marine environment are apparent - Ocean vs. Coastal • Responses to acidification can vary by species and life stage • Laboratory experiments indicate that ocean acidification can have negative effects for marine species - Shellfish (calcium carbonate shells) - Commercially significant species credit: Merrily Cassidy Closing Remarks and Remaining Questions • • • • • • Given species-specific responses, how are others impacted? How are various life stages impacted? Do all laboratory results translate to the field? How do OA-species relationships influence ecosystem functioning? How do OA-species relationships influence commercial harvest and recreation? What management strategies can be implemented to offset potential negative impacts? credit: Merrily Cassidy Lots of accessible info: www.necan.org Information including: • Species Effects • Recent Research • Recorded Presentations • Regional Data Acknowledgements: Nathan Rebuck-NOAA/NMFS/NEFSC Jason Grear-U.S. EPA Qualitative Summary of RI Marine Species •Lobster: Mixed effects on adults, negative impacts on first-year lobsters, neutral influence on larval stage •Sea Scallops: Tough to culture! If sea scallops response is similar to other scallops, predicted decrease in landings and revenue •Bay Scallops: Reduced growth and survival for larvae and juveniles: negative •Clams: Negative impacts for quahogs and soft-shell clams, particularly larvae and juveniles •Eastern Oyster: Some negative impacts indicated for larvae, but more resistant than quahogs and bay scallops •Summer Flounder: mixed results on adults, negative effects in larvae •Whelk (Conch): decrease in fat content, unknown effects on growth and mortality •Squid(s): Longer hatching time, slightly shorter mantle (tubes); all effects were small in magnitude •Jonah Crab: no specific results, other crabs have minimal effects on growth but lower thermal tolerances (higher mortality at high and low temperatures) •Anadromous Fish: Since they spend significant time in freshwater, likely well adapted to deal with OA (e.g. Sea Herring, Striped Bass) •Phytoplankton and Seaweed: Increases in growth, with nutrients and temperature constant
