کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4541048 1326705 2009 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Limno-tolerant bacteria govern nitrate concentration in Mandovi Estuary, India
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات زمین شناسی
پیش نمایش صفحه اول مقاله
Limno-tolerant bacteria govern nitrate concentration in Mandovi Estuary, India
چکیده انگلیسی

The spatial and temporal abundances of limno-tolerant and halo-tolerant bacteria were investigated in the tide-dominated Mandovi estuary along the west coast of India. These investigations were carried out in relation to various environmental parameters on a monthly basis at three fixed stations for a year. On an annual basis, the estuary showed an average salinity of 28.2, 17.4, and 12.6 at the mouth, midstream and upstream region. Halo-tolerant retrievable count (HTRC) and limno-tolerant retrievable count (LTRC) of bacteria were in the order of 106 L−1. Among the environmental parameters, a strong negative relationship between salinity and nitrate (r = −0.806; p < 0.001) suggested that 64% of the variation could be due to fresh water influence in the estuary. The limno-tolerant retrievable count (LTRC) brought about 23% variations in nitrate concentration. This influence was maximum during the monsoon (r = 0.522; p < 0.05) especially in the surface waters (r = 0.624; p < 0.001) suggesting nitrate reduction by LTRC. Measurements of nitrate reducing activity (NRA) in whole-water samples along the salinity gradient in the estuary also revealed higher reduction rates at lower salinity upstream. This was further confirmed by culture experiments where the limno-tolerant bacteria showed higher NRA than halo-tolerant forms. It is therefore suggested that LTRC is more actively involved in the variation of nitrate that enters the Mandovi estuary particularly during the monsoon.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Estuarine, Coastal and Shelf Science - Volume 82, Issue 1, 20 March 2009, Pages 29–34
نویسندگان
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