The distributions of halocarbons in the Amundsen and Ross Seas are mainly influenced by the presence of sea ice. This is supported by several findings: H 89 nmr halocarbon concentrations in surface waters in ice-covered areas exceeded those of the biologically productive surface layer in the two polynyas; elevated concentrations of halocarbons were measured in brine; and surface waters in open waters were under-saturated with respect to bromoform. The halocarbon distribution in the two seas differed considerably, mainly due to the large
Ross Sea polynya and the formation of high salinity shelf water in the western Ross Sea. Halocarbons were found not to be a homogenous group of compounds, and they could be divided into two groups depending on the halogen involved. Iodinated compounds, with relatively shorter environmental half-lives in sea water, could be related to the abundance of Phaeocystis in the Ross Sea, whereas
brominated forms may be related more to community processes in conjunction with the unique physical environment provided by ice and snow. Saturation anomalies for the sea water/air and ice/brine/air systems also showed that sea ice was a major source of naturally produced halocarbons for the atmosphere, and in particular CHBr3 and CH2ClI. It can be concluded that the surface mixed layer of Antarctic seas acts both as a source and a sink for volatile halogenated organic carbons. The following are the supplementary data related to this article. Supplementary material. Incubation data from 7 ice stations and absolute limit of detection. We thank the officers and crew of Alectinib solubility dmso the R.V.I.B. Oden for their help during the cruise, as well as our OSO 2007 colleagues. We especially thank Daniel Barrdahl for assistance during the expedition. This research was supported by NSF grants ANT-0741380 and ANT-0836112 to
WOS, the Swedish Research Council, Knut och Alice Wallenbergs Foundation, and the Swedish Polar Research Secretariat. Section plots were made in Ocean Data View ( Schlitzer, 2011). “
“Due to its biological necessity, iron (Fe) is a key resource for marine phytoplankton (Geider and La Roche, 1994) and is considered as the limiting nutrient in a number of oceanic regions (Moore et al., 2013). These include the classic DNA ligase high nutrient low chlorophyll regions of the Southern Ocean (de Baar et al., 1995), equatorial Pacific (Martin et al., 1994), sub-Arctic Pacific (Martin and Fitzwater, 1988) and to a lesser extent seasonally in the North Atlantic (Nielsdóttir et al., 2009). Moreover, Fe can also regulate the rates of nitrogen fixation by diazotrophs in tropical regions (Schlosser et al., 2014). Accordingly most ocean general circulation and biogeochemistry models (OGCBMs) that seek to represent ocean biogeochemical cycling, including those concerned with climate change, represent Fe. The process of organic complexation by molecules known as ligands is a key feature of the ocean Fe cycle.