Labrador Sea

The RGB composite of the coefficients of determination of the individual linear correlation coefficients (Figure 2.26) shows that for the northern hemisphere high correlations of volatilisation rate and wind speed in the Atlantic Ocean can be found in the Gulf Stream and low values in the Labrador Sea and the adjacent Davis Strait. High correlations with the sea surface temperature are located near 45 °N close to the eastern coast of the American continent, in the Baltic Sea, North Sea and in... 

PFOA observations To evaluate MPI-MCTM model results observational data of PFOA from ship cruises in the Atlantic, Indian and Pacific Oceans were taken from literature (summarised in Yamashita et al (2008)). The data was collected between 2002 and 2006 in a global ocean monitoring initiative. Samples were taken from ocean surface water. Vertical profiles were sampled in the Labrador sea, the Mid Atlantic ocean, the South Pacific ocean and the Japanese sea, where water probes were done at several depths down to 5500 m. The limit of quantification for PFOA was determined as 6 pg/L. 

Vertical profiles from different ocean regions differ significantly from each other. In the Labrador Sea (Figure 3.16a) PFOA concentrations are 50 pg/L at the surface for both model results and observations. For AOl and A02 modelled profiles are almost identical, while observed profiles behave differently. Concentrations in water sample at AOl are relatively constant throughout depth, except for subsurface water, where PFOA concentration decreases, and water below 2000 m in which concentrations increase. Modelled concentrations, as well as observed ones at A02, decrease until 500 m, and remain constant down to 2000 m. In waters below 2000 m PFOA concentration increases for observations, but decreases in the model results. Yamashita et al (2008) suggest that water masses from the surface down to 2000 m were well mixed due their convective formation. The subsurface is explained... 

Locations of disseminated (nonphosphorite) authigenic CFA occurrence, as well as locations of phosphorites. Areas with substantial phosphorite deposits include the East China Sea between Korea and Japan, Ceara Rise, Saanich Inlet, eastern and western equatorial Pacific, California Borderland Basins, Gulf of St. Lawrence, Labrador Sea, Long Island Sound, Gulf of Mexico, North Atlantic continental platform, and Iberian margin in the northeastern Atlantic. Source From Ruttenberg, K. C. (2003). Treatise on Geochemistry, Elsevier Ltd. pp. 585-643. 

Oceanic temperatures and levels are also rising (Levitus 2000). According to models, greenhouse warming is expected to cause a collapse in the Labrador Sea convection, with the consequence of a further rise in the sea level (IPCC 1995). 

Weinstein, S.E. and S.B. Moran. 2004. Distribution of size-fractionated particulate trace metals collected by bottles and in-situ pumps in the Gulf of Maine-Scotian Shelf and Labrador Sea. Mar. Chem. 87 121-135. 

Wolfe GV, Levasseur M, Cantin G, Michaud S (2000) DMSP and DMS dynamics and microzooplankton grazing in the Labrador Sea application of the dilution technique. Deep-Sea Res Part I Oceanogr Res Pap 47 2243-2264 Wolfe GV, Steinke M (1996) Grazing-activated production of dimethyl sulfide (DMS) by two clones of Emiliania hux-leyi. Limnol Oceanogr 41 1151-1160 Wolfe GV, Steinke M, Kirst GO (1997) Grazing-activated chemical defence in a unicellular marine alga. Nature 387 894-897... 

Wolfe GV, Levasseur M, Cantin G, Michaud S (2000) DMSP and DMS dynamics and microzooplankton grazing in the Labrador Sea application of the dilution technique. Deep-Sea Res Part I 47 2243-2264... 

Measurements of CH3CI have been reported in the Labrador Sea that were at or below saturation, while warmer waters south of the Gulf Stream and all Pacific samples were consistently supersaturated (Moore et al., 1996a). No correlation was observed with chlorophyll a. The authors concluded that earlier estimates of the sea to air flux were overestimates and that there... 

Heinrich layers HI, H2, H4, and H5 have several distinctive characteristics that distinguish them from ambient IRD, and they are derived from a mix of provenance components that are all consistent with derivation from a small region near Hudson Strait. Heinrich layers H3 and H6 have different sources, at least in the eastern North Atlantic. Less is known about H6, but H3 appears to have a Hudson Strait source in the southern Labrador Sea and western Atlantic, consistent with a similar but weaker event compared to the big four. Important related questions are as follows How many types (provenance, flux, etc.) of Heinrich layers are there Are IRD events in previous glacial intervals akin to the six in the last glacial period ... 

Hesse R. and Khodabakhsh S. (1998) Depositional facies of late Pleistocene Heinrich events in the Labrador Sea. Geology 26(2), 103-106. 

Lucotte M., Mucci A., and Hillairemarcel A. (1994) Early diagenetic processes in deep Labrador Sea sediments reactive and nonreactive iron and phosphorus. Can. J. Earth Set 31, 14—27. 

Additional evidence for the factors that force millennial-scale climate change comes firom the study of layers of sand-sized material that are transported to the sea by ice. During the last glacial period there are six layers of ice-rafted debris (IRD) in the North Atlantic firom the Labrador Sea across to France (Fig. 7.23). The layers are tens... 

Figure 3. Schematic of the time vs. depth distribution of floats released at various times during a diel cycle of nocturnal mixing and diurnal stratification in the Labrador Sea [E. D Asaro and G. Dairiki unpublished data as shown in 2]. The heavy line (a composite of three separate float deployments) depicts a possible depth history of a non-motile plankton over the 24 h period. Note that trajectories are terminated once they enter the stable diurnal thermocline since they actually start to ascend due to very slight positive buoyancy of the floats.

Mysak, L.A., Manak, D.K. and Marsden, R.F. (1990) Sea-ice anomalies observed in the Greenland and Labrador Seas during 1901-1984 and their relation to an interdecadal Arctic climate cycle. Climate Dynamics, 5, 111-133. 

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