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Organic Matter Metabolism in a Coastal Ocean Ecosystem. Patricia Matrai Mike Sieracki Nicole Poulton Carlton Rauschenberg. Bigelow Laboratory for Ocean Sciences W. Boothbay Harbor Maine. NASA OCRT 4/11-13/06 Newport, RI.
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Organic Matter Metabolism in a Coastal Ocean Ecosystem Patricia Matrai Mike Sieracki Nicole Poulton Carlton Rauschenberg Bigelow Laboratory for Ocean Sciences W. Boothbay Harbor Maine NASA OCRT 4/11-13/06 Newport, RI
In Collaboration with: University of New Hampshire Center for Coastal Ocean Observation and Analysis Janet Campbell Joe Salisbury
Talk outline • Project objectives • Study site and measurements • Some first year results • Respiration models • Preliminary remote sensing results • Conclusions
Project Objectives • Primary Objectives: • Can microbial respiration be modeled by temperature, chlorophyll, primary production, and DOM? • If so, how well can surface water respiration be estimated by satellite remote sensing? • Secondary Objectives: • What is the balance of planktonic microbial respiration to primary production in a river plume system? • How does planktonic food web structure relate to the system metabolic balance?
Gulf of Maine Primary Study Area (GoMOOS C) (GoMOOS B)
Study Methods • Monthly cruises from Kennebec River (Bath, Maine) to Portsmouth, NH • 5 Stations, surface samples • Respiration (24h O2 incubations) • Primary production (12h 14C incubations) • Microplankton and particle analysis • FlowCAM, flow cytometry, microscopy • Size spectra, 0.2 - >200 µm • Chlorophyll, T, S, TOC, POC, ∆13C, nutrients • Bacterial single-cell respiration (CTC)
Temperature and Salinity Temperature pattern similar at all stations River and plume stations show spring and fall runoff peaks (low salinity)
Bacteria and <20µm Phytoplankton Abundances Eukaryotes Synechococcus Heterotrophic Bacteria
Apr Oct Dec Jun Microphytoplankton Abundance(15 - 200 µm, FlowCAM)
Seasonal Trends in Chlorophyll, Primary Production, and Respiration Resp Chl 1° Prod
Seasonal Trends in POC, Nutrients, and δ13C/12C Resp PO4 Chl POC δ13C/12C NO3 + NO2 1° Prod
River Coast Annual Station MeansDownstream:Chlorophyll declines1° Production declinesRespiration increases Chl PP Resp
Surface respiration vs. primary production (µgC L-1 d-1) Overall system mean: R is 30% of P 1:1
Surface respiration vs. primary production (µgC L-1 d-1) 1:1 Spring bloom May, June River + plume Aug, Sept
Ecosystem relationships Cole et al. 1988, White et al. 1991, del Giorgio et al. 1997 Method #1 BA = f(Chl) BR = f(BA, T) Method #2 BP = f(BA, T) BR = f(BP, T) Method #3 BR = f(NPP) Rivkin & Legendre 2001
Example Gulf of Maine Respiration Images13 May 2005 CHL SST BR1 (BA) BR2 (BP)
Conclusions • Kennebec River plume/Gulf of Maine system is dynamic, biologically rich, and productivePrimary production exceeds respiration most of the year, R was 30% of P for the whole system over 1 year.Preliminary estimates of respiration from remote sensing data using ecosystem relationships are within an order of magnitude of in-water measurements, but further analysis and validation are needed.
And Thanks to: Carbon Cycle Science Kay Kilpatrick, RSMAS, U. Miami Ben Tupper, Bigelow Laboratory Paul Pelletier, Capt. R/V Gulf Challenger Chris Hunt, Mike Novak, UNH Coastal Transect crew