Padma, P; Dr.Muraleedharan Nair, S(Cochin University of Science & Technology, October , 2008)
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Abstract:
This study was aimed at to characterize the spatio-temporal trends in
the distributional characteristics of various species of nitrogen and phosphorus as
well as to elucidate the factors and processes aflecting these nutrients in the
dissolved, particulate and sedimentary phases of a river estuarine system. The
main area of study is Chalakudy river in Kerala, which is a fresh water system
originating from Anamalai hills and ending at Arabian Sea. Its basin is between
I00 05 ’ to I00 35’ North latitude and 76” 15 ’ to 760 55’ East longitude. Being a
riparian bufler zone, the dynamics of nutrient mobility tend to be more complex
and variable in this river-estuarine system.The diflerent species of nitrogen estimated from the filtrate were nitrite-N, nitrateN,
ammonia-N, urea-N, total nitrogen and residual nitrogen. The diflerent forms
of phosphorus estimated from the filtrate were phosphate-P, total-P and residualP.
Pre weighed sediments as well as particulate matter were analysed for
quantijying nitrite-N, nitrate-N, ammonia-N and urea-N. Total nitrogen was estimated after digestion with potassium persulfate. Fractionation of phosphorus
in sediment/particulate matter was performed by applying sequential extraction
procedure. The dijferent forms of phosphorus thus estimated were loosely bound
(exchangeable) P, Fe/Al bound P, polyphosphates, Ca bound P and refractory P.
Sedimental total P was also measured directly by applying digestion method.The analyses carried out in this bimonthly annual survey have revealed specific
information on the latent factors influencing the water quality pattern ofthe river.
There was dependence among the chemical components of the river sediment and
suspended matter, reflecting the water quality. A period of profound
environmental change occurred and changes in various species had been noted in
association with seasonal variations in the waterway, especially following
enhanced river runoff during the monsoon. The results also successfully
represented the distribution trend of nutrients during the rainy as well as dry
season. Thus, the information gathered in this work will also be beneficial for
those interested or involved in river management, conservation, regulation and
policy making in regional and national levels.
Description:
Dept.of Chemical Oceanography,Cochin University of Science and Technology.
Neetha, Joseph; Dr. Shanta, Achuthankutty(Cochin University of Science and Technology, June , 2012)
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Abstract:
This thesis entitled spatial and temporal variarion of microbial community structure in surficial sediments of cochin estuary.In the estuarine and coastal systems, organic matter (OM) is derived not only from autochthonous primary production, but also from allochthonous (terrestrial) organic matter (OM) delivered by river discharge and runoff. A significant portion of the OM sinks through the water column and is ultimately stored in carbon pool in the sediments.Analysis of spatial and temporal variation in benthic microbial community of a tropical estuary was conducted for the first time using non selective measures that affirms that PLFA approach is a sensitive and reliable method in determining microbial community structures of surficial sediments of estuary.The close relationship between the concentrations of the microbial fatty acids and total biomass indicates that bacteria could account for the largest proportion of the biomass in the sediments.This is first study that has documented the changes in microbial community composition linkage to biotic and abiotic variables in benthic estuarine ecosystem. This contemporaneous community will be the backdrop for understanding the response of autochthonous community to increasing anthropogenic stress.
Description:
Department of Marine Microbiology,National Institute of Oceanography