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Seasonal stratification and property distributions in a tropical estuary (Cochin estuary, west coast, India)

DRS at CSIR-National Institute of Oceanography

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Title Seasonal stratification and property distributions in a tropical estuary (Cochin estuary, west coast, India)
 
Creator Shivaprasad, A.
Vinita, J.
Revichandran, C.
Reny, P.D.
Deepak, M.P.
Muraleedharan, K.R.
NaveenKumar, K.R.
 
Subject salinity stratification
seasonal variations
river discharge
salt-wedge estuaries
 
Description The intratidal, spring–neap and seasonal variations in stratification were examined in the Cochin estuary. The observations established a strong connection with the distribution of chemical and biological properties. The influence of tides and river discharge forcing in water column stability was quantified using potential energy anomaly (PEA) and stratification parameter. Partially mixed (neap) and well mixed (spring) conditions during low river discharge (dry) period were altered in monsoon by the salt wedge intrusions. The ecological impact of salt wedge propagation on high tides bringing upwelled water to the system was evident from the bottom hypoxic, high chlorophyll a and nutrient rich conditions. Phosphate and nitrite concentrations were higher at the bottom saline conditions but silicate and nitrate were clearly supplied by river water. However, during ebb tide this front was driven out of the estuary. The periodic advance and retreat of the salt wedge was inevitable in making the system immune from extended hypoxia/anoxia and maintaining the health of the Cochin estuary. For the seasonally varying river flow in the estuary, salt intrusion receded with increasing river flow in monsoon and rebounded with decreasing river flow in dry season. During monsoon, the intense flushing and reduction in salinity field expansion seemed to be responsible for the limited chlorophyll a levels along the surface of the Cochin estuary.
 
Date 2013-02-04T04:36:31Z
2013-02-04T04:36:31Z
2013
 
Type Journal Article
 
Identifier Hydrology and Earth System Sciences, vol.17; 2013; 187-199
no
http://drs.nio.org/drs/handle/2264/4238
 
Language en
 
Relation Hydrol_Earth_Syst_Sci_17_187.jpg
 
Rights © Author(s) 2013. CC Attribution 3.0 License.
 
Publisher European Geosciences Union