Satellite-derived multi-year trend in primary production in the Arctic Ocean

Abstract

Spaceborne one month averaged data, predominantly from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and partly from the Moderate Resolution Imaging Spectroradiometer (MODIS), were used to investigate changes in primary production (PP) by phytoplankton in the Arctic Ocean from 1998 to 2010. Several PP retrieval algorithms were tested against the collected in situ data, and it was shown that the algorithm by Behrenfeld and Falkowski gave the best results (with the coefficient of correlation, r, equal to 0.8 and 0.75, respectively, for the pelagic and shelf zones). Based on the performed test, the Behrenfeld and Falkowski algorithm was further applied for determining both the annual PP in the Arctic and the PP trend over the above-mentioned time period. Results of our analysis indicate that PP in the Arctic has increased by ˜15.9% over 13 years (1998–2010). This finding, as well as the absolute annual values of PP remotely quantified in the present study, is at odds with analogous numerical assessments by other workers. These disagreements are thought to be due to differences in the applied methodologies of satellite data processing such as cloud masking and determination of phytoplankton concentration within (1) overcast areas and (2) areas of massive growth of coccolithophores as well as (3) in the shelf zone prone to a significant influence of land and river run-off.

Acknowledgements

This research was performed under the FP7 Programme (grant ‘MONARCH-A FP7-SPA.2009.1.1.02’). We express our gratitude to Dr Svetlana Milutinovich (Nansen Centre, Bergen, Norway) for assisting us in the realization of the PP codes, Drs Stephane Maritorena (Earth Research Institute, University of California, Santa Barbara, USA) and Robert O'Malley (Department of Botany and Plant Pathology, Oregon State University) for consulting us on the procedure of cloud flagging developed under the MEASURE Project, as well as personalities and institutions who provided us with in situ data as specified in Section 1.1. Also, we are grateful to Mr Evgeny Morozov for his valuable advice.