Faculty Publications
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Item Heterogeneous microbial oceanographic environments: Application of GIS technology in deciphering of microenvironment scenarios off the central west coast of India(2011) Raghavan, B.R.; Nayak, S.R.; Shylini, S.K.; Deepthi, T.; Sadatipour, S.M.T.; Chauhan, P.; Srinivasakumar, T.; Lotliker, A.; Venkat Reddy, D.; Kumaraswami, M.; Ashwini, S.; Nisaj, M.In the vast oceanic microbial environment of 2468.83km 2, GIS modeling techniques involving sixty query steps, enabled the deciphering of Microenvironments as low as 1.19km 2 to 38.6 km 2 for the summer of 2004 and in case of summer 2005 where 84 query steps were involved to decipher Microenvironments of 10.55km 2 to 25.94km 2. Thirtythree sampling stations were established between Betul to Ankola off the central west coast of India accounting for a spatial coverage of 2468.83km 2. GIS query-modeling investigation was carried out using spatial layers of depth, optical parameters (k-Irradiance attenuation Coefficient, c-Beam attenuation coefficient), sediment size parameters (Sediment Mean Size and Sediment Sorting) and Benthic Foraminifera Suborders (Rotaliina, Textulariina, Miliolina, Lagenina). Foraminifera have been used as a surrogate parameter. However, any microbial parameter could proxy for foraminifers providing for the numerical deciphering of microenvironments. This is suggestive of the assimilation of GIS technology for a better appreciation of microbial oceanography. © 2011 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Assessing the effect of calcein incorporation on physiological processes of benthic foraminifera(Elsevier, 2015) Kurtarkar, S.R.; Saraswat, R.; Nigam, R.; Banerjee, B.; Mallick, R.; Naik, D.K.; Singh, D.P.Rosalina sp. was incubated in seawater spiked with calcein (5 mg/l to 20 mg/l calcein), a dye proposed as efficient marker to tag newly formed calcite, to understand its effect on benthic foraminifera. The experiment was conducted at 25 °C and 27 °C temperatures. The growth of Rosalina sp. is not affected by any of the calcein concentrations within the first 4-5 weeks of exposure. Additionally, no distinct difference in abnormality, mortality and reproduction was observed in the control and treatment specimens during the first 3-4 weeks of incubation. The comparable growth, abnormality, mortality and reproduction in both the control and the various treatments suggest that short-term exposure to calcein does not adversely affect benthic foraminifera. However, during the total 15-16 weeks of experiment, more than 50% of the specimens died in all the treatment sets, as compared to < 40% mortality in control sets, thereby suggesting a slight adverse effect of calcein on benthic foraminifera. Additionally, some of the specimens incubated in calcein spiked media were stunted and developed abnormal shells after 5-6 weeks of incubation. Also the lack of reproduction, the increased mortality and abnormality in specimens subjected to very low calcein concentration ($ 5 mg/l) for a longer periods of time (5-6 weeks or more), suggest an adverse effect on benthic foraminifera. Although the percentage of abnormal specimens and the percentage of specimens which reproduced were different for the two temperatures (for similar calcein concentrations), no such difference was observed for growth or mortality. The findings support previous studies which proposed that short-term exposure to low calcein concentration can be used as an effective technique to distinguish newly formed chambers in laboratory experiments with foraminifera. © 2014 Elsevier B.V.