Deglacial diatom productivity and surface ocean properties over the Bermuda Rise, northeast Sargasso Sea
Gil, Isabelle M.
Keigwin, Lloyd D.
Abrantes, Fatima G.
MetadataShow full item record
Diatom assemblages document surface hydrographic changes over the Bermuda Rise. Between 19.2 and 14.5 ka, subtropical diatom species and Chaetoceros resting spores dominate the flora, as in North Atlantic productive regions today. From 16.9 to 14.6 ka, brackish and fresh water diatoms are common and their contribution is generally coupled with total diatom abundance. This same interval also contains rare grains of ice-rafted debris. Coupling between those proxies suggests that successive discharge of icebergs might have stimulated productivity during Heinrich event 1 (H1). Iceberg migration to the subtropics likely created an isolated environment involving turbulent mixing, upwelled water, and nutrient-rich meltwater, supporting diatom productivity in an otherwise oligotrophic setting. In addition, the occurrence of mode water eddies likely brought silica-rich waters of Southern Ocean origin to the euphotic zone. The persistence of lower-salinity surface water beyond the last ice rafting suggests continued injection of fresh water by cold-core rings and advection around the subtropical gyre. These results indicate that opal productivity may have biased estimates of meridional overturning based on 231Pa/230Th ratios in Bermuda Rise sediments during H1.
Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 24 (2009): PA4101, doi:10.1029/2008PA001729.
Showing items related by title, author, creator and subject.
Cruise Report C-138 : scientific activities undertaken aboard SSV Corwith Cramer, Miami, Florida - Bermuda - Dominican Republic - Miami, Florida, 23 March to 1 May 1995 Howard, William R. (SEA Education Association, 1995-05)This report outlines the scientific and academic program conducted aboard SSV Corwith Cramer during March and April, 1995. It consists of summaries of research stations occupied, data collected, and highlights some of ...
Cruise Report W-46 : scientific activities undertaken aboard R/V Westward, Woods Hole - Bermuda - Nova Scotia - Woods Hole, 06 June 1979 - 18 July 1979 Farmer, Mary W. (SEA Education Association, 1979-07)The objective of this cruise report is to compile the data collected by 23 undergraduate students, three staff scientists, and two visiting scientists on cruise W-46 of the R/V Westward. The report presents an overview ...
Cruise Report C-210 : Scientific data collected aboard SSV Corwith Cramer, Key West, FL – St. Georges, Bermuda – Falmouth Harbor, Antigua – Christiansted, St. Croix, USVI, 28 March 2007 – 04 May 2007 Proskurowski, Giora (SEA Education Association, 2007-05)An extensive oceanographic investigation of the subtropical North Atlantic was conducted during Sea Education Association’s cruise C-210, Key West, FL to St. Croix, USVI (via Bermuda and Antigua, see Figure 1). As part ...