SEARCH

SEARCH BY CITATION

The article by Fisher et al. presents intriguing results. Their analysis of thermal data from boreholes in the sediment suggests large temperature variability (of order 6–10°C) primarily over the last 60 years with maximum temperatures approximately 20 years ago at a site (#903) on the continental slope off the southern Middle Atlantic Bight in approximately 450 m depth. Similar techniques suggest no such temperature change at a site (#902) 4.4 km away in 802 m of water.

The waters normally lying along the continental slope of the Middle Atlantic Bight and regions to the north are known as slope waters. These waters extend seaward to the northern edge of the Gulf Stream. Temperatures are typically 6–7°C at depths of 450 m or so, increasing almost linearly towards 10–15°C in shallower waters of 200 m [Stommel, 1965]. Below 700 m, temperatures are in the 4–5°C range. Similar temperatures were shown by Sverdrup et al. [1942] at a station along the slope off Chesapeake Bay in 1932. These same authors note the large variability in temperatures at around 400 m and attribute it to slope-type waters being interspersed with short periods of North Atlantic central (Gulf Stream) waters produced by the presence of eddies or shelfward displacements in the stream itself.