Surface Salinity Reconstructions for the North Atlantic

Dr. Anders Carlson

Collaborators:

Delia Oppo (WHOI), Rose Came (Caltech), Heather Benway (WHOI), Lloyd Keigwin (WHOI),

This project is compiling and constructing surface salinity reconstructions for the North Atlantic (0 to 60 degrees North) for the last deglaciation (~21 to 10 ka). During the last deglaciation, Atlantic meridional overturning circulation switched on and off again at least twice (e.g. McManus et al., 2004, Nature) (see figure below). We are investigating what the surface salinity response was to these changes in ocean circulation and the possibility that a self-limiting system may exist between surface water density and overturning circulation.

Figure of proxies of temperature, AMOC and surface salinity for the last deglaciation. (a) GISP2 δ¹⁸O (Grootes et al., 1993). (b) ²³¹Pa/²³⁰Th from the North Atlantic (a proxy for AMOC) (McManus et al., 2004). (c) Reconstructions of surface δ¹⁸O seawater from the subtropical North Atlantic (MD95-2042) (red) (using Shackleton et al., 2000 and Bard, 2002) and Tropical Atlantic (black) (Schmidt et al., 2004).