Sea surface temperatures in the Northeast Shelf Large Marine Ecosystem during 2012 were the highest recorded in 150 years, according to the latest Ecosystem Advisory issued by NOAA’s Northeast Fisheries Science Center (NEFSC).
These high sea surface temperatures (SSTs) are the latest in a trend of above average temperature seen during the spring and summer seasons, and part of a pattern of elevated temperatures occurring in the Northwest Atlantic, but not seen elsewhere in the ocean basin over the past century.
The advisory reports on conditions in the second half of 2012.
Sea surface temperature for the Northeast Shelf Ecosystem reached a record high of 14 degrees Celsius (57.2°F) in 2012, exceeding the previous record high in 1951. Average SST has typically been lower than 12.4 C (54.3 F) over the past three decades.
Sea surface temperature in the region is based on both contemporary satellite remote-sensing data and long-term ship-board measurements, with historical SST conditions based on ship-board measurements dating back to 1854. The temperature increase in 2012 was the highest jump in temperature seen in the time series and one of only five times temperature has changed by more than 1 C (1.8 F).
The Northeast Shelf’s warm water thermal habitat was also at a record high level during 2012, while cold water habitat was at a record low level. Early winter mixing of the water column went to extreme depths, which will impact the spring 2013 plankton bloom. Mixing redistributes nutrients and affects stratification of the water column as the bloom develops.
Between the shallow, gently sloping continental shelf and the abyss of the deep ocean lies the steep continental slope. The edge between the shelf and the slope is called the shelf break. Phytoplankton, zooplankton, fish, seabirds, whales, and dolphins thrive in the waters above the shelf break, supported by nutrients brought from great depths by upwelling. MIT/WHOI Joint Program student Jessica Benthuysen analyzed how the currents near the shelf break south of Cape Cod control upwelling.
Source : ENN
