Ocean Circulation and Climate Dynamics

Florida Straits throughflow and its relationship to high northern latitude climate

Sortable Silt in the Florida Strait compared to the North Atlantic.

 The linkage between Gulf Stream intensity and high northern latitude climate is studied in the RASTA and GOLDFLOSS Projects. Ice-rafting and freshwater influx in the North Atlantic persisted with a millenial cyclicity during the late Holocene (Bond et al. 1997). Periods with higher freshwater influx correspond to lower Iceland-Scotland Overflow (ISOW) strength and thus North Atlantic Deep Water (NADW) production as depicted by a Mean Sortable Silt record (10 to 63 µm) from Gardar Drift to the south of Iceland (Bianchi and McCave, 1999). Periods of lower (NADW) production are mirrored by sortable silt minima in Florida Straits' core SO16416-1 inferring a less intense Florida Current and Gulf Stream at these times (Lund and Curry, 2004; Schönfeld et al., 2004). Error bars: standard error (±2 %) for Sortable Silt. Arrows:14C datings. Note that the records may slightly lag each other within the framework of radiocarbon datings.

 

References:

Lund, D.C., and Curry, W.B., 2004. Late Holocene variability in Florida Current surface density: Patterns and possible causes. Paleoceanography, 19, PA4001, doi:10.1029/2004PA001008. 
Bond, G., Showers, W., Chezebiet, M., Lotti, R., Almasi, P., deMenocal, P., Priore, P., Cullen, H., Hajdas, I. and Bonani, G., 1997. A pervasive millennial scale cycle in North-Atlantic Holocene and glacial climates. Science 278: 1257-1266. 
Bianchi, G.G. and McCave, I.N., 1999. Holocene periodicity in North Atlantic climate and deep-ocean flow south of Iceland. Nature 397: 515-517. 
Schönfeld, J., Dullo, W.-C., Kuhnt, W., Lezius, J., Lynch-Stieglitz, J., Nürnberg, D., and Steinlöchner, J., 2004. Late Quaternary variability of the Florida Current linked to North Atlantic Thermohaline Circulation. Abstract, 8th International Conference on Paleoceanography, Biarritz, 5.9. - 10.9.2004; France.