Balch-NASA ACE OPCC Meeting; June A sharp, step-decrease in the carbon fixation of the Gulf of Maine...but why? William Balch Bigelow Laboratory for Ocean Sciences W. Boothbay Harbor, ME

Balch-NASA ACE OPCC Meeting; June Science Questions behind this talk… SQ-1: What are the standing stocks, composition, & productivity of ocean ecosystems? How and why are they changing? SQ-2: How and why are ocean biogeochemical cycles changing? How do they influence the Earth system? SQ-3: What are the material exchanges between land & ocean? How do they influence coastal ecosystems, biogeochemistry & habitats? How are they changing? SQ-5: How do physical ocean processes affect ocean ecosystems & biogeochemistry? How do ocean biological processes influence ocean physics? SQ-6: What is the distribution of algal blooms and their relation to harmful algal and eutrophication events? How are these events changing?

Balch-NASA ACE OPCC Meeting; June Addressing these questions requires both remote sensing and in-water measurements… GNATS-Gulf of Maine North Atlantic Time Series 12+ year transect time series across Gulf of Maine (35 years if you include historical data on same line) Sample design is to use flexible schedule vessels (ferries, small research vessels) that can specifically target clear-sky days for concurrent satellite and ship measurements. Due to this sampling model, GNATS has provided 19.7% of all chlorophyll matchups & 13.3% of radiance match-ups in SeaBASS for MODIS Aqua plus SeaWiFS (not including Terra or MERIS…)

Balch-NASA ACE OPCC Meeting; June Intensive GNATS Program ( ; 12+ years) -What are we sampling? Hydrography (SST, Salinity; XBTs, MVP profiles of T,S, chlorophyll fluorescence to 100m) Chemistry (NO 3 +NO 2, PO 4, SiO 2 ) Biogeochemistry (POC, PIC, DOC, Biogenic Si) Biology (chlorophyll a, phaeopigments, 14 C primary production & calcification, phytoplankton enumeration- coccolithophorids, Flow-CAM functional groups Bio-Optical measurements –Inherent optical properties [spectral absorption (total and dissolved), scattering, backscattering, acid-labile backscattering, volume scattering function –Apparent optical properties [above-water spectral upwelling radiance, sky radiance, downwelling irradiance] –Seasonal Slocum glider missions along the GNATS transect (T, S, CDOM fluor, Chl Fluor, b bp 531nm,AOPs at 7 wavelengths)

GNATS cruise track

Embedding GNATS into the changing climatology of New England … GNATS

Variance in precipitation has increased…

GNATS has seen some of the century’s most extreme precipitation events… GNATS Gardner Maine: 3 rd driest year in 100+ years Gardiner Maine: wettest year in over 100+ years         Of 8 years >1.4m y -1, half during GNATS

Balch-NASA ACE OPCC Meeting; June Our transect between Portland and Yarmouth is roughly east-west temporal bias to late spring to early fall. Year-round effective 2007; Use the Hovmoller space-time diagrams Summer Solstice SPACE TIME Longitude Year Yarmouth, Nova Scotia Portland, Maine

Longitude (deg W) Dist. from Yarmouth, NS (km) WMCC Ext EMCC JB SS 70 Note decrease in salinity on west side of Gulf during wet years (in WMCC and Ext EMCC, associated with increased river discharge). Year round sampling

Top 50m temperature gradient ( o C m -1 ) Longitude (deg W) Dist. from Yarmouth, NS (km) WMCC Ext EMCC JB SS 70 Note vertical temperature gradient in top 50m decreased in ExtEMCC in and in SS in ’07&’09 Year round sampling

NO3+NO2 (  M) Longitude (deg W) Dist. from Yarmouth, NS (km) WMCC Ext EMCC JB SS 70 Note step increase in log DIN after 2007…due to mixing of deeper, nutrient-rich water to surface? Decreased drawdown? Year round sampling

Longitude (deg W) Dist. from Yarmouth, NS (km) WMCC Ext EMCC JB SS 70 Note step increase in in the Si(OH)4:DIN in 2007 & 2008 across the GOM; river supplied silicate? Vertical mixing of deeper silicate-rich water? Year round sampling

Longitude (deg W) Dist. from Yarmouth, NS (km) WMCC Ext EMCC JB SS 70 Note increase in CDOM on west side of Gulf (likely associated with increased river discharge…) Year round sampling

Longitude (deg W) Dist. from Yarmouth, NS (km) WMCC Ext EMCC JB SS 70 Pmax (mg C m -3 d -1 ) Note significant step decrease in log maximum primary production after 2007 Year round sampling

Cmax (mg C m -3 d -1 ) Longitude (deg W) Dist. from Yarmouth, NS (km) WMCC Ext EMCC JB SS 70 Note significant step decrease in log calcification after 2007… Year round sampling

Longitude (deg W) Dist. from Yarmouth, NS (km) WMCC Ext EMCC JB SS 70 a pg440 : a  440 Note Regions of high ratio don’t make it to JB but nearshore values reach 15 on both sides of Gulf. High values before 2005 Year round sampling

Balch-NASA ACE OPCC Meeting; June So what is causing these changes? Clearly, vertical mixing has changed in upper 50m Clearly, surface nutrients have gone up POC & PIC-specific growth rates have decreased, hence decreased nutrient draw down Extraordinary amounts of freshwater injected into the GOM Increased grazing? We’ve always pre-filtered samples through 250um Nitex mesh to remove large grazers. Some inhibitory substance introduced? CDOM? Chelators with river-born sediments? Xenobiotic?

Balch-NASA ACE OPCC Meeting; June Future Activities GNATS funding ran out December 2010 but we are working to re-establish funding, especially to a) capture ongoing ecosystem changes plus b) continue calibration/validation of MODIS and soon- to-launch VIIRS in optically complex coastal waters Paper- Space/time and anomaly analysis Paper- Decadel variations in particle types and size Paper- Glider-based analysis of carbon production

Balch-NASA ACE OPCC Meeting; June Conclusions New England has undergone major changes in climatology over the last century (mainly warming and increased variance in precipitation…the latter showing extreme levels in the last decade) Over the decadal scale of GNATS, such changes have resulted in increased river input into the Gulf of Maine with associated colored dissolved organic matter injections well away from the coast The GoM has seen a step change in a wide variety of variables (hydrographic, nutrient chemistry, optical, biological) associated with the record-breaking precipitation year (2005). Cause and effect? Future predictions of ecosystem variability associated with climate change are complex and can be counterintuitive, particularly due to interactive effects of variables. This makes a strong case for coordinated, multiplatform measurements in order to better predict ecosystem impacts.

Balch-NASA ACE OPCC Meeting; June Acknowledgements D. T. Drapeau, B. C. Bowler, E. S. Booth, J. Goes, E. Lyczskowski, D. Alley, Laura Lubelczyk (Bigelow Laboratory), L. A. Windecker (U.C. Santa Barbara), E. Olson (WHOI), A. Ashe (U.Maine) + 70 others (occasional trips) for 148 crossings covering >44,000 km (the circumference of Earth) and 427 person days at sea over 12+ years. Staff and crew of the M/S Scotia Prince, F/V Ella & Sadie, R/V Argo Maine, R/V Connecticut and high- speed ferry, “The CAT” NASA for funding

Balch-NASA ACE OPCC Meeting; June Thank you!

Balch-NASA ACE OPCC Meeting; June Backup slides

Longitude (deg W) Dist. from Yarmouth, NS (km) WMCC Ext EMCC JB SS Diatom Biomass (  g L -1 )

Longitude (deg W) Dist. from Yarmouth, NS (km) WMCC Ext EMCC JB SS 70 POC-specific growth rate (d -1 ) Note significant step decrease in POC-specific growth rate after 2007 Year round sampling

Longitude (deg W) Dist. from Yarmouth, NS (km) WMCC Ext EMCC JB SS 70 PIC-specific growth rate (d -1 ) Note, typical values of 0.1 to 0.3 per d; significant step decrease in PIC-specific growth rate after 2008 Year round sampling