Aquatic Sciences Meeting, Albuquerque 2001

PC07 Spatial and Temporal Connections

Date: Wednesday, February 14, 2001

Location: Southwest Hall

Bisagni, J, J, Univ. of Massachusetts, School of Marine Science & Technology, New Bedfrod, MA, USA, jbisagni@umassd.edu

THE SEASONAL CYCLE OF NITRATE SUPPLY AND POTENTIAL NEW PRODUCTION IN THE GULF OF MAINE AND GEORGES BANK REGIONS

The Gulf of Maine and Georges Bank are highly-productive from the standpoint of total primary production and fisheries. However, despite high levels of primary and fish production on Georges Bank, secondary production is lower than expected. Hypotheses put forth to explain the lower secondary production on Georges Bank are: 1) advective losses, and 2) nitrogen limitation. In order to detect the presence of nitrogen limitation in the region and to understand apparent lower secondary production over Georges Bank, the amounts of new and regenerated primary production are estimated using a quantity termed “potential new production” (PNP). PNP is estimated through vertical integration of nitrate from the surface to the depth of the euphotic zone (1% light level), assuming all nitrate is used by phytoplankton. This paper reports on work to determine the seasonal cycle of new primary production over the Gulf of Maine and Georges Bank using PNP as a proxy for “new” primary production and the negative correlation between near-surface temperature and vertically-integrated nitrate.

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Aquatic Sciences Meeting, Albuquerque 2001

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