Ocean Southern/Antarctic

M. J. Orren, P. M. S. Monteiro, Trace elements geochemistry in the Southern Ocean. In Antarctic Nutrient Cycles and Food Webs, W. R. Siegfried, P. R. Condy, R. M. Laws (Eds.), Springer-Verlag, Berlin, (1985), 30-37. 

Smetacek, V., de Baar, H. J. W., Bathmann, U. V. et al. (eds) (1997). Ecology and biogeochemistry of the Antarctic Circumpolar current during austral spring Southern Ocean JGOFS Cruise ANT X/6 of R.V. Polarstem. Deep-Sea Res. II44,1-519. 

AESOPS Antarctic Environment and Southern Ocean Process Study... 

Southern Ocean controi on thermociine nutrient concentrations. APF = Antarctic poiar front,... 

The global natural flux of sulfur compounds to the atmosphere has recently been estimated to be about 2.5 Tmol yr1 (1) which is comparable to the emissions of sulfur dioxide (SO2) from anthropogenic sources (2). A substantial amount of the natural sulfur contribution (0.5-1.2 Tmol yr1) is attributed to the emission of dimethylsulfide (DMS) from the world s oceans to the atmosphere (3.4). One of the major uncertainties in this estimate is due to a scarcity of DMS and other sulfur data from the Southern Hemisphere, particularly the Southern Ocean region between about 40°S and the Antarctic continent, which represents about one fifth of the total world ocean area. 

In this work we compare some of the major results from two field expeditions to the Southern Ocean region. The first expedition was a ship cruise between Punta Arenas/Chile and the west coast of the Antarctic Peninsula, which was conducted during the austral fall season (March 20 - April 28, 1986) as part of the United States Antarctic Research Program (USARP). Details of the ship cruise and a complete discussion of the results have been published elsewhere (12). The second expedition consisted of a series of flight measurements off the west and south coast of Tasmania during the austral summer season (December 3-18, 1986). We discuss preliminary results from 2 of 8 flights which were conducted in marine air masses behind cold fronts moving over the open ocean. 

DMS emission fluxes from Antarctic inshore waters may be important for the tropospheric sulfur budget of Antarctica during summer. The contribution of the Southern Ocean to the global atmospheric sulfur budget (ca. 0.2 Tmol yr1) is consistent with present estimates of the total global DMS emission from the world s oceans (0.5-1.2 Tmol yr1). 

An MAA with a possible restricted geographic occurrence is mycosporine-glycine valine. This MAA was first described from a survey of Antarctic species and was initially observed only in consumer organisms (invertebrates and fish), not any of the sampled primary producers.107 Subsequent studies in the Antarctic have identified this MAA in the diatom Fragilariopsis cylindrus, the haptophyte Phaeocystis sp., and mixed assemblages of Southern Ocean phytoplankton.124 126 128 There have been a few tentative identifications of mycosporine-glycine valine in organisms from... 

Daly KL, DiTullio GR (1996) Particulate dimethylsulfoniopropionate removal and dimethylsulfide production by zooplankton in the Southern Ocean. In Kiene RP, Visscher PT, Keller MD, Kirst GO (eds) Biological and environmental chemistry of DMSP and related sulfonium compounds. Plenum Press, New York, pp 223-238 Davidson AT, Marchant HJ (1987) Binding of manganese by Antarctic Phaeocystis pouchetii and the role of bacteria in its release. Marine Biol 95 481-487 DiTullio GR, Smith WO (1995) Relationship Between Dimethylsulfide And Phytoplankton Pigment Concentrations In The Ross Sea, Antarctica. Deep-Sea Res Part 142 873-892... 

Let us explore the thermocline distribution first. As large-scale oceanic transport occurs primarily along surfaces of equal potential density, it is instructive to inspect variations along such surfaces. Figure 1.4b shows the NO distribution along the potential density surface Gg = 26.80, which represents Sub-Polar Mode Water (SPMW) in the northern hemisphere and Sub-Antarctic Mode Water (SAMW) in the southern hemisphere (Hanawa and TaUey, 2001). Nitrate concentrations near the outcrops, i.e., where the isopycnal surface intersects the surface of the ocean are near zero, but concentrations increase rapidly as one moves away from the outcrops into the ocean s interior. 

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