Fall 2013 Update: Summary of Conditions for the Northeast Shelf Ecosystem
Sea surface temperature (SST) in the Northeast Shelf Large Marine Ecosystem during the first half of 2013 moderated compared to the record high temperatures that occurred in 2012; however, temperatures remain above the long-term mean based on both contemporary satellites remote sensing data and ship-board measurements.
This moderating effect was not uniform over the ecosystem. The northern ecoregions of the Gulf of Maine and Georges Bank remained relatively warm whereas the Middle Atlantic Bight cooled to a greater extent.
Spring survey hydrocast data shows that surface and bottom temperatures have moderated since 2012, but remain above average with bottom temperatures being influenced by water entering the ecosystem.
In contrast to the 2012 Gulf of Maine spring bloom which was a long duration, intense bloom that started at the earliest recorded start date, the 2013 was the latest recorded bloom that was so poorly developed its extent was below detection limits. The bloom on Georges Bank was also relatively late and though it could be detected, it was a small bloom in terms of duration and intensity.
Though not a regular feature in the Middle Atlantic Bight, a distinct spring bloom could be measured in 2013.
An analysis of spring transition temperatures shows that there has been an abrupt shift in spring thermal phenology.
2013 spring zooplankton biomass on the Northeast Shelf was the lowest on record for the monitoring time series; the biomasses were lowest for the northern segments of the ecosystem and would appear to be related to the poorly developed spring bloom in the Gulf of Maine area
The Northeast Shelf ecosystem continues to experience wide swings in physical conditions and biological responses that would appear to reflect great variation in the climate system impacting the ecosystem.