Browsing by Author "Athalye, R. P."
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Item Impact of the changing ecology on intertidal polychaetes in an anthropogenically stressed tropical creek, India(2011-12) Quadros, G.; Sukumaran, Soniya; Athalye, R. P.Polychaete assemblages and associated environment of 12 strategically selected intertidal stations along the extremely polluted Thane creek on the west coast of India were studied monthly for a year and compared with past available data to investigate changes in the creek ecology due to various anthropogenic activities like industrial, domestic, and solid waste disposal along with land reclamation. Shannon’s index (H’) varied spatially from 0.4 to 1.5, Margalef richness index (d) from 0.4 to 1.1, and evenness index (j) from 0.3 to 0.7 indicating poor polychaete diversity. Ceratonereis burmensis and Lycastis indica were the most abundant and omnipresent polychaetes in the creek indicating their tolerance and adaptability to various degrees of pollution. Hydro-sedimentological investigations revealed enhancement of total nitrogen (TN) and organic carbon (Corg) load and hypoxic levels of dissolved oxygen (DO) over the years. Slit component of sediment was increasing, with proportionate decrease in clay due to various anthropogenic disturbances. Species richness was correlated positively with clay and negatively with silt. The BIO-ENV analyses indicated the strong influence of No3 - -N, clay and TN on the distribution patterns of polychaetes. Pollution-tolerant polychaetes like Lycastis ounaryensis and Polydora tentaculata were getting replaced by more pollution-resistant species like C. burmensis in the creek due to changing sediment texture, reduced oxygen levels, and increased Corg and TN.Item Occurrence of heavy metals in abiotic and biotic components of the Mangrove ecosystem of Thane creek(2011-11) Borkar, M. U.; Athalye, R. P.; Quadros, GoldinThane Creek long, 72º55 to 73ºE and Lat. 19º.00 to 19º15” N) is 26 km long creek having highly industrilized and urbanized Thane Mumbai Complex along its banks. It receives high amount of untreated domestic sewage and industrial effluent 294 mld and 145 to 260 mld respectively (TMC Report 2000). The present study was carried out during 2001-2002, to assess the heavy metals Zinc, Copper, Cadmium, Lead and Iron in different abiotic and biotic components of mangrove ecosystem of the creek. It was observed that - concentration of the metals Copper, Lead, Zinc and iron was very high in the abiotic and the biotic components while that of Cadmium were negligible, high metal concentration was observed in the crabs Illoplax gangetica a and Uca ssp., the gastropods Assiminia bervicula, Haminia crocata. Melampus signaporensis and unidentifed gastropod, the polychaetes Nereis glandicinta andan unidentified polychaete indicating the tolerance of these organisms to the heavy metals, the leaves of avicennia marina showed accumulation of zinc, while the stem samples had high concentration of iron. Compared to the past data, the concentration of metals was found to be growing in the abiotic and biotic components of Thane creek. All these observations indicate deteriorating conditions of the creek and emphasises the need to check the pollution in the creek.