In the Ross Sea the dominant feature was the relatively high concentration of VHOC found in Ross Sea bottom water (or High Salinity Shelf Water, HSSW; (Orsi and Wiederwohl, 2009), a very dense water mass generated by the formation of sea ice and brine rejection. For halocarbons produced in the surface water or sea ice, this process may explain the elevated concentrations in the bottom waters. The environmental half-lives of halocarbons

in sea water at low temperatures are relatively long (i.e., CHBr3 and CH2Br2 half-lives are 686 and 183 years, respectively; (Jeffers et al., 1989 and Vogel et al., 1987). Therefore, this water may keep its halocarbon signature for extended Trametinib periods of time. Few investigations of halocarbon distributions have been made in waters in the Southern Ocean (Abrahamsson et al., 2004a, Butler et al., 2007, Carpenter et al., 2007, Hughes et al., 2009 and Reifenhauser and Heumann, 1992). In the Weddell Sea within 40 km of the continental Sea ice (depth, ca. 500 m), CHBr3 has been found to reach mean values of 57 pmol L− 1 in the surface

mixed layer (Carpenter et al., 2007), which is approximately 8–10 times higher than the concentrations we found (Table 2). For the iodinated compounds CH2I2 and CH2BrI, they found concentrations approximately 10–20 times higher than ours. In contrast, the concentrations of CH2ClI were similar. They click here suggest that the elevated surface concentrations (78 pmol L− 1 compared to underlying waters of ~ 50 pmol L− 1) originated from production of sea ice algae in the water column, even though they cannot rule out a possible production inside the sea ice followed by a transport out in the water column. Hughes et al. (2009) also found higher levels of CHBr3 and CH2Br2, with concentrations of 280 and 30 pmol L− 1, respectively. Their measurements were also conducted close to land (4 km) with a bottom depth of ca. 500 m. They suggested that these high concentrations were related to a phytoplankton bloom

based on coincidence of high chlorophyll values. However, both these studies (Carpenter et al., 2007 and Hughes et al., 2009), are coastal measurements and are likely to contain a high background Olopatadine of halocarbons from macro algal productions. A more comparable dataset was presented by Butler et al. (2007), where surface water and air measurements were performed during the Blast III expedition Feb.–April 1996. They measured average concentrations (~ 8 pmol L− 1) of CHBr3 that were comparable to ours, and concluded that some parts of the surface waters in the Southern Ocean could act as both a source and a sink with respect to CHBr3. Biogenic halocarbon formation is strongly related to photosynthesis and respiration (Abrahamsson et al., 2004b, Ekdahl et al., 1998 and Manley, 2002), and the magnitude of this production is species specific (Ekdahl, 1997, Hughes et al., 2006 and Scarratt and Moore, 1996).