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Abstract:
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The Cochin estuary (CE), which is one of the largest wetland ecosystems,
extends from Thanneermukkam bund in the south to Azhikode in the north. It
functions as an effluent repository for more than 240 industries, the characteristics of
which includes fertilizer, pesticide, radioactive mineral processing, chemical and
allied industries, petroleum refining and heavy metal processing industries
(Thyagarajan, 2004). Studies in the CE have been mostly on the spatial and temporal
variations in the physical, chemical and biological characteristics of the estuary
(Balachandran et al., 2006; Madhu et al., 2007; Menon et al., 2000; Qasim
2003;Qasim and Gopinathan 1969) . Although several monitoring programs have been
initiated in the CE to understand the level of heavy metal pollution, these were
restricted to trace metals distribution (Balachandran et al., 2005) or the influence of
anthropogenic inputs on the benthos and phytoplankton (Madhu et al., 2007;Jayaraj,
2006). Recently, few studies were carried out on microbial ecology in the
CE(Thottathil et al 2008a and b;Parvathi et al., 2009and 2011; Thomas et al., 2006;Chandran and Hatha, 2003). However, studies on metal - microbe interaction are
hitherto not undertaken in this estuary. Hence, a study was undertaken at 3 sites with
different level of heavy metal concentration tounderstand the abundance, diversity and
mechanisms of resistance in metal resistant bacteria and its impact on the nutrient
regeneration. The present work has also focused on the response of heavy metal
resistant bacteria towards antibacterial agent’s antibiotics and silver nanoparticles |