Factors contributing to variability in acidification and omega in coastal Gulf of Maine waters: What this means to the NH shellfish industry

Transcription

1 Factors contributing to variability in acidification and omega in coastal Gulf of Maine waters: What this means to the NH shellfish industry J. Salisbury, D. Vandemark, C. Hunt, M. Melendez

2 1. OA review from Beth T. 2. What controls changes in acid in the GOM 3. Multiple pathways of acid into coastal waters and possible future trajectories of OA in estuaries 4. Useful OA measurements for the shellfish industry.

3 Recent headlines Ocean acidifica*on decreases mussel byssal a3achment strength (Nature Climate Change) Sassy Scallops: How will shellfish fare as ocean condi*ons shi=? (PLOS One) Oysters, clams and scallops face high risk from ocean acidifica*on, new study finds (The Guardian)

4 Atmospheric temperature and CO 2 : Are they related? Causing some global warming? Probably, but not 100% agreement Causing your ocean to acidify? Definitely

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6 Ocean acidifica<on refers to decreasing ph related to increasing atmospheric CO 2. Terms for discussion: pco 2, ph and Ω pco 2 partial pressure of carbon dioxide (µatm) = CO 2 concentration / solubility (k) ph Index of hydrogen ion concentration Omega (Ω) Saturation index of the mineral aragonite Ω Omega 3-4 Good for calcifying organisms Omega < 1 shells unstable; may dissolve Omega <1.5 oyster and clam larvae stressed

7 In terms of Ocean Acidification, the Gulf of Maine is an interesting place. Big salinity range Freshwater endmember qualities Big temperature range Very productive

8 Two freshwater sources: both poorly buffered against acid DFO, Canada

9 Big seasonal temperature range > 15 C /year DFO, Canada

10 During the mixing season During the growing season Coastal GOM highly productive and.. both the surface and deep waters interact with the atmosphere over short time scales (~annual). Biological processes CO 2 Low High CO 2? High CO 2 From Bozac et al., 2006 (North Sea Example)

11 Ω data from the ECOA cruise, summer 2015.

12 Wilkinson Basin timeseries 44.0 Bowdoin Buoy UNH time series stations in the Gulf of Maine Degrees North 43.0 NERACOOS Great Bay Buoy UNH Coastal Marine Lab UNH-NERACOOS CO 2 Buoy Stellwagen Benthic OA observatory Data shown is primarily from the CO 2 buoy, with supporting pco 2 and bottle data from cruise stations (red) Degrees West -71.0

13 Decadal variability: Do we observe OA from increased atm CO 2? xco2 (ppmv) Preliminary trend analyses, raw data and harmonic fits Preliminary analyses on raw data xco Ω aragonite Ω

14 Decadal variability from > atm CO 2?.. maybe! Trends in the residual (preliminary) xco2 (ppmv) xco y / Mauna Loa was +2.2 ppm y -1 during this time Ω Omega_ar y -1 +/

15 So why don t we see the effects of acidification more clearly? Processes affecting omega in the Gulf of Maine 0.3 Omega Anomaly Omega Anomaly Effects of increasing CO Effects of changing temperature and salinity

16 Zoom in from Omega Aragonite Anomlaly Temperature effects (+0.30) CO2 effects (-0.05) Year

17 Modeled Ω Multiple acid pathways in coastal Maine Implications for the next 25 years J. Salisbury, B. Mook, D. Vandemark, C. Hunt, S. Shellito

18 Coastal and Estuarine Acidification River water freshens the coast and alters its ability to buffer against acid ph (NBS scale) Data from USGS

19 Precipitation is increasing, making the coastal ocean a bit fresher and more poorly buffered against ph

20 and is likely to continue over the next 25 years (Rawlins et al, 2015) Change in Precipita.on Pa0erns: Intense precipitaion events (the heaviest 1 percent) in the coninental U.S. from 1958 to Image Credit: Walsh, J., D. Wuebbles, K. Hayhoe, J. Kossin, K. Kunkel, G. Stephens, P. Thorne, R. Vose, M. Wehner, J. Willis, D. Anderson, S. Doney, R. Feely, P. Hennon, V. Kharin, T. Knutson, F. Landerer, T. Lenton, J. Kennedy, and R. Somerville, 2014: Ch. 2: Our Changing Climate. Climate Change Impacts in the United States: The Third NaIonal Climate Assessment, J. M. Melillo, Terese (T.C.) Richmond, and G. W. Yohe, Eds., U.S. Global Change Research Program, doi: /j0kw5cxt

21 Nutrient enhanced acidification Oxygen + decomposing plant matter à CO 2 + H 2 O à acid How does this affect our bays? Improving or declining?

22 Recent observations in Casco Bay and their implications for the near future

23 8.3 oxygen versus ph Is this a local respira*on signal? OM+O 2 CO 2 8 ph (total) oxygen (umol)

24 oxygen versus ph, colored by salinity High produc*vity during stra*fied condi*ons ph (total) Intense rain episodes oxygen (umol) 27

25 2.5 Omega at the SMTC dock in Casco Bay Omega Aragonite Possible difficulty making shell material below Apr May Jun Jul Aug Sep Oct Nov Month (2015) So far, we ve observed 34 of 150 days at <1.5

26 now freshen the coast on average by 1 salinity unit (1:31) 2.5 Omega at the SMTC dock in Casco Bay Omega Aragonite Apr May Jun Jul Aug Sep Oct Nov Month (2015) Given a similar time series, we would likely experience 58 days at <1.5

27 now freshen plus add in the expected CO 2 increase over the next 25 years (red) 2.5 Omega at the SMTC dock in Casco Bay Omega Aragonite Apr May Jun Jul Aug Sep Oct Nov Month (2015) In this scenario we could experience 89 days at <1.5

28 Different technologies and price points Measuring Omega in Seawater Level (You 1 can t $10k measure it directly) - Measure ph, salinity and temperature continuously - Model Ω Actually need 2 of the following 4 Analy*cal Parameters, plus temperature and salinity Level These 2 can $20k be difficult to measure accurately: - Add continuous pco 2 measurements - Estimate Ω more directly pco 2 = [CO 2 *]/K H Total Alkalinity = [HCO 3- ] + 2[CO 2-3 ] + [B(OH) 4- ] + [OH - ] + [HPO 2-4 ] + Level 3 >$60k - Continuous, real time estimates of Ω from an over- TCO 2 = [CO 2 *] + [HCO 3- ] + [CO 2- determined system (pco 3 ] 2, ph and either Total Alkalinity or TCO 2 ) ph = -log{h + }

29 New Technology Con*nuous pco 2 data the Burkilator (~$25k) Burke Hales, Jesse Vance OSU COAS Provides real-*me pco 2 measurements of incoming seawater Not an off-the-shelf instrument, and requires some technical support Sunburst Sensors sells both wallmounted and deployable systems

30 New Technology Con<nuous pco 2 data the UNH Bubbalator (<$20k) Deployed con*nuously at the UNH Coastal Marine Lab since 2011 First Hatchery deployment (Bevan s Oyster) March, 2014

31 On the subject of less expensive: CO 2 meter.com pco 2 sensor - These units are $219 and could substan*ally lower the cost of pco 2 measurements. - UNH tes*ng suggest that +/- 0.2 Ω is achievable with this unit

32 New Technology Burkilator Deluxe: TCO 2 Low-flow Seawater sample is acidified Effluent Dissolved CO 2 diffuses through a microporous, hydrophobic membrane Evolved CO 2 is swept away by a high-flow CO 2 - free carrier gas with nearly 100% removal efficiency Liquid Sample 10 % HCl Gas-Liquid Exchange Acidified Seawater CO 2 -free carrier gas To detector CO 2 is detected by NDIR

33 New Instrumenta*on for OA Studies Chris Hunt, Research Scien*st, Ph.D Student 33

34 HydroC CO2 Carbon Dioxide Sensor below, extensively tested at the UNH Coastal Marine Lab - A new, robust Total Alkalinity sensor is under development - Targeted for the market in 2014

35 Conclusions: 1) Gulf of Maine is a hyperac*ve system influenced by temperature, salinity and biological processes 2) That tends to hide the effect of ocean acidifica*on caused by increasing CO2 3) Estuaries are even more hyperac*ve and more affected by freshwater and hypoxia 4) Instrumenta*on for measuring OA is available at several price points.

36 Thanks