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Abstract:In an attempt to clarify the release of trace elements from the seasonal coastal sea ice, samples were periodically collected in a nearshore station inside the Gerlache Inlet (Terra Nova Bay, Western Ross Sea), during the summer 2000/01 and analysed for dissolved and particulate cadmium, copper, iron, manganese and lead, as well as salinity, suspended particulate matter, nutrients and phytoplankton pigments. In order to provide insight on the metal association with the particles included in the sea ice, the metal solid speciation was also investigated. Both vertical distributions within the ice cores and temporal variations at the seawater interface were studied, in an effort to fully characterize the system and correlation among the considered parameters. Concentrations and speciation patterns clearly indicate metal incorporation within the annual sea ice due to resuspension of sediments, followed by release of particulate metals during melting as a primary process affecting trace metal availability in the Antarctic coastal waters.

Abstract:The analysis of the mixing processes involving water masses on the Ross Sea continental shelf is one of the goals of the CLIMA project (Climatic Long-term Interactions for the Mass balance in Antarctica). This paper uses extended Optimum MultiParameter analysis (OMP), which is applied to four datasets collected during the cruises of 1994/95, 1995/96, 1997/98 and 2000/01 in the Ross Sea (Antarctica). Data include both hydrological, (temperature, salinity, and pressure; T, S, and P, respectively) and chemical parameters (O 2 , Si(OH) 4 , PO 4 , and NO 3 +NO 2 ). The OMP analysis is based on the assumption that the mixing is a linear process which affects all parameters equally so that each sample shows physical/chemical properties that are the result of the mixing of some properly selected Source Water Types (SWTs). OMP thus evaluates the best set of contributions by all SWTs to each sample, and allows the spatial distribution and structure of the water masses in a basin to be evaluated. Ocean circulation may subsequently be inferred by means of a deeper analysis of the spreading of the water mass. In this study, the "real" Redfield ratios observed in the Ross Sea were used to correct the equations referring to the chemical parameters in accordance with the extended version of OMP. The solutions include some physically realistic constraints. The results allow a detailed description of the water mass distribution, validated through comparison with some "canonical" thermohaline characteristics of the Ross Sea hydrology. In particular our results verify the spreading of the HSSW over the entire continental shelf and emphasize the key role it plays in the ventilation of the deep waters outside the Ross Sea. In addition a description is given of the intrusion of relatively warm waters coming from the open ocean and flowing at some specific locations at the continental shelf break. isobath, runs NW-SE and links the area in front of Cape Adare to Cape Colbeck. Some depressions in the inner area are deeper than the continental shelf break, and therefore behave as reservoirs of the salty and dense waters.The Circumpolar Deep Water (CDW) is carried by the Antarctic Circumpolar Current (ACC) along the boundary of the Ross Sea, following the shelf slope from east to west. CDW strongly influences the thermohaline circulation of this basin, being the only water mass which provides heat to the shelf waters (Jacobs et al. 1985, Locarnini 1994, Jacobs & Giulivi 1998, Gouretsky 1999. In some specific locations it intrudes onto the Ross continental shelf forming, after the interaction with the shelf waters, the modified CDW (MCDW), which can be identified by a subsurface maximum temperature and minimum dissolved oxygen (Jacobs et al. 1985, Locarnini 1994, Budillon et al. 1999.On the western side of the Ross Sea, the physical features of the water column are also affected by the recurring presence of a substantial coastal ice free area, the Terra Nova Bay polynya (Bromwich & Kurtz 1984, Jacobs et al. 1985, Fusco et al. 2...

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