Oceanography The Official Magazine of
The Oceanography Society
Volume 21 Issue 04

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Volume 21, No. 4
Pages 108 - 117


The Decadal View of the Mid-Atlantic Bight from the COOLroom: Is Our Coastal System Changing?

Oscar Schofield Robert Chant Bronwyn Cahill Renato Castelao Donglai GongAlex Kahl Josh Kohut Martin Montes-HugoRamaya Ramadurai Patricia RameyXu Yi Scott Glenn
Article Abstract

Spatial ocean-observing technologies are permitting researchers to collect data for sustained periods on broad continental shelves. Key technologies used are satellites, high-frequency (HF) radar, and autonomous underwater gliders, which together have allowed study of Mid-Atlantic Bight (MAB) dynamics for the past decade. MAB stratification is the dominant feature regulating annual phytoplankton productivity. Stratification begins in the spring, and by early summer forms one of the world’s sharpest thermoclines (temperatures range from ~ 30° to 8°C in just a few meters). Strong stratification deprives the euphotic zone of nutrients until it erodes later in the year. Therefore, it is not surprising that during late autumn and winter, when stratification has eroded, the largest and most recurrent MAB phytoplankton blooms are observed. These fall/winter blooms occur on the inner shelf; the offshore extent of the phytoplankton appears to be limited by light. Comparison of data from the 1970s and 1980s to the last decade suggests phytoplankton bloom size on the MAB has changed, with the magnitude of the fall and winter blooms declining. Declines in the fall are consistent with the hypothesis that erosion of MAB stratification is occurring later in the season. Declines in winter appear to be associated with an increase in winter winds that enhance winter mixing, which in turn increases the light limitation of the phytoplankton. The increase in winter winds occurred during transition to a positive phase of the Atlantic Multidecadal Oscillation. Our experience emphasizes the importance of spatial time series for studying broad continental shelves.


Schofield, O., R. Chant, B. Cahill, R. Castelao, D. Gong, A. Kahl, J. Kohut, M. Montes-Hugo, R. Ramadurai, P. Ramey, X. Yi, and S. Glenn. 2008. The decadal view of the Mid-Atlantic Bight from the COOLroom: Is our coastal system changing? Oceanography 21(4):108–117, https://doi.org/10.5670/oceanog.2008.08.


Editor’s Note: Oceanography does not usually permit citation of articles that are in review; however, because of the rapidly advancing nature of this issue’s topics, we are making an exception. Updates on the status of manuscripts cited as in review here will be posted on the CoOP Web site (http://www.skio.usg.edu/coop).

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