Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic
Volume 8, issue 5
Biogeosciences, 8, 1213–1223, 2011
https://doi.org/10.5194/bg-8-1213-2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.
Biogeosciences, 8, 1213–1223, 2011
https://doi.org/10.5194/bg-8-1213-2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 19 May 2011

Research article | 19 May 2011

Large variability in continental shelf production of phytoplankton carbon revealed by satellite

B. F. Jönsson1, J. E. Salisbury2, and A. Mahadevan1 B. F. Jönsson et al.
  • 1Department of Earth Sciences, Boston University, Boston, Massachusetts, USA
  • 2Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, New Hampshire, USA

Abstract. We estimate the net production of phytoplankton in the Gulf of Maine (GoM) over a 3-yr period using satellite ocean color data in conjunction with surface velocities from a high-resolution operational ocean circulation model. Chlorophyll (Chl-a) and light attenuation (K490) products are combined with a carbon to chlorophyll model to estimate the phytoplankton carbon (PC) stock in the euphotic layer. A satellite-based productivity, termed NCPe in analogy with net community production (NCP), is derived by tracking changes in satellite-derived PC from one satellite image to the next, along water parcel trajectories calculated with surface velocities from the ocean circulation model. Such an along-trajectory analysis of satellite data discounts the effect of advection that would otherwise contribute to the temporal change between consecutive images viewed in the fixed reference frame. Our results show a high variability of up to ±500 mg C m−2 d−1 in NCPe on spatial scales of 10–100 km. A region-wide median NCPe of 40–50 mg C m−2 d−1 is often prevalent in the Gulf, while blooms attain peak values of 400 mg C m−2 d−1 for a few days. The spatio-temporal variability of NCPe in this region, though conditioned by seasonality, is dominated by events lasting a few days, which if integrated, lead to large inter-annual variability in the annual carbon budget. This study is a step toward achieving synoptic and time-dependent estimates of oceanic productivity and NCP from satellite data.

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