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Titel |
Seasonal stratification and property distributions in a tropical estuary (Cochin estuary, west coast, India) |
VerfasserIn |
A. Shivaprasad, J. Vinita, C. Revichandran, P. D. Reny, M. P. Deepak, K. R. Muraleedharan, K. R. Naveen Kumar |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1027-5606
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Digitales Dokument |
URL |
Erschienen |
In: Hydrology and Earth System Sciences ; 17, no. 1 ; Nr. 17, no. 1 (2013-01-21), S.187-199 |
Datensatznummer |
250017684
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Publikation (Nr.) |
copernicus.org/hess-17-187-2013.pdf |
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Zusammenfassung |
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. |
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