Interglacial occurrence of cold-water corals off Cape Lookout (NW Atlantic): First evidence of the Gulf Stream influence
Journal
Deep-Sea Research Part I: Oceanographic Research Papers
Journal Volume
105
Pages
158-170
Date Issued
2015
Author(s)
Abstract
Climatic and oceanographic changes, as occurring at a glacial-interglacial scale, may alter the environmental conditions needed for the development of prolific cold-water coral reefs and mounds. Studies constraining the temporal distribution of cold-water corals in the NE Atlantic suggested the cyclic changes of the Atlantic Meridional Overturning Circulation as the main driver for the development and dispersal of cold-water coral ecosystems. However, conclusions were hindered by lack of data from the NW Atlantic. Aiming to overcome this lack of data, the temporal occurrence of cold-water corals in the Cape Lookout area along the southeastern US margin was explored by U-series dating. Furthermore, the local influence of the regional water masses, namely the Gulf Stream, on cold-water coral proliferation and occurrence since the Last Glacial Maximum was examined. Results suggest that the occurrence of cold-water corals in the Cape Lookout area is restricted to interglacial periods, with corals being present during the last ~7. kyr and also during the Eemian (~125. ka). The reconstructed local environmental conditions suggest an offshore displacement of the Gulf Stream and increased influence from the Mid-Atlantic Bight shelf waters during the last glacial period. During the deglacial sea level rise, the Gulf Stream moved coastward providing present-day-like conditions to the surface waters. Nevertheless, present-day conditions at the ocean sea floor were not established before 7.5. cal. ka BP once the ultimate demise of the Laurentide ice-sheet caused the final sea level rise and the displacement of the Gulf Stream to its present location. Occasional presence of the Gulf Stream over the site during the Mid- to Late Holocene coincides with enhanced bottom current strength and a slightly higher bottom water temperature, which are environmental conditions that are favorable for cold-water coral growth. © 2015 Elsevier Ltd.
Subjects
Cape Lookout; Glacial-Interglacial; Gulf Stream; NW Atlantic; Scleractinian cold-water corals; U-series dating
Other Subjects
Glacial geology; Ocean currents; Oceanography; Sea level; Cape Lookout; Cold-water corals; Glacial-Interglacial; Gulf Stream; NW Atlantic; U-series dating; Rivers; bottom current; climate change; cold water; coral reef; glacial-interglacial cycle; ice sheet; Last Glacial Maximum; meridional circulation; seafloor; surface water; temporal distribution; water mass; Atlantic Ocean; Cape Lookout; Gulf Stream; North Carolina; United States; Anthozoa; Scleractinia
Type
journal article