Psychrotrophic Metal Tolerant Bacteria for Mobilisation of Metals in Antarctic Waters

Introduction Antarctic has for a long time been viewed as a pristine environment as compared to other oceanic regions experiencing both local and global anthropogenic influences only over larger time scales (Bonner 1984, Evans et al., 2000). This remotest region of the earth is a model system where human assisted biological invasion can be understood (Rudolph and Benninghoff, 1977; Vincent, 1988). However, it is now being established that microbial diasporas are also reaching Antarctic from land masses (Walton, 1990). Heavy metals occur naturally in the ecosystem with large variations in concentration and are required by living organisms in varying amounts. These metals can be iron, cobalt, copper, manganese, molybdenum, and zinc. In modern times, the concentration of heavy metals, have been increasing in all ecosystems including the Antarctic (Hur et al., 2007). The krills from these regions harbour heavy metals at varying concentrations (Yamamoto et al., 1987). Petri and Zauke (1993) reported that metal concentrations show considerable interspecific heterogeneity. The cadmium (Cd) levels observed in caridean decapods (Chorismus antarcticus and Notocrangon antarcticus) were highest among marine crustaceans (13 mg/kg dry weight). Yet other crustaceans like amphipod Maxilliphimedia longipes and the isopod Aega antarctica (6-8 mg/kg) show that they do not have requirements for reduced metals. This led to the suggestion that in monitoring studies, Antarctic organisms may no longer serve as the basis for global...

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