| Spring Chlorophyll
Distribution |
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A general pattern is evident where chlorophyll concentration is
greatest in continental shelf waters, intermediate over the deeper
slope water, and lowest in the vicinity of the Gulf Stream and Sargasso
Sea (see upper map figure showing concentration of chlorophyll
during April 2006 from Cape Hatteras to Nova Scotia). High levels
of chlorophyll during spring occur in the tidally mixed central areas of Georges
Bank and Nantucket Shoals, and in the Middle Atlantic Bight estuaries
and coastal waters enriched by estuarine plumes. The high chlorophyll
values (3-8 mg m-3) in the western Gulf of Maine indicate that spring
bloom is underway during April. The same geographic range is used
to illustrate how chlorophyll conditions during April 2006 compare
with the average values for this month, where the average is computed
from April data from 1997 through 2006 (see lower map figure
showing ratio of chlorophyll concentration). The ratio of April
2006 chlorophyll to the 9-year April mean chlorophyll indicates
that levels in the western Gulf of Maine were above normal whereas
levels over Nantucket Shoals and the SNE mid-shelf area were below
normal values for April. Surface chlorophyll levels are also low
just seaward of the Southern New England shelf break (100m isobath),
reflecting the influence of the warm Gulf Stream meander on phytoplankton
production in this region (see April temperature map above). |
For further information, contact:Kevin.Friedland@noaa.gov
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