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dc.contributor.authorAbdulAzeez, S.
dc.contributor.authorGireeshkumar, T.R.
dc.contributor.authorMuraleedharan, K.R.
dc.contributor.authorVignesh, E.R.
dc.contributor.authorJaleel, A.K.U.
dc.contributor.authorArya, K.S.
dc.contributor.authorNair, R.C.
dc.contributor.authorRatheesh, R.
dc.date.accessioned2023-12-10
dc.date.accessioned2023-12-10T13:28:36Z
dc.date.available2023-10-26
dc.date.available2023-12-10T13:28:36Z
dc.date.issued2023
dc.identifier.citationMarine Pollution Bulletin, vol.197; 2023; Article no: 115696
dc.identifier.issn0025-326X
dc.identifier.otherhttps://www.sciencedirect.com/science/article/abs/pii/S0025326X23011311
dc.identifier.urihttps://doi.org/10.1016/J.MARPOLBUL.2023.115696
dc.identifier.urihttp://drs.nio.res.in/drs/handle/2264/9146
dc.descriptionIF(JCR2023) = 5.8
dc.description.abstractSeasonal upwelling and the associated incursion of hypoxic waters into the coastal zone is a widely studied topic over different upwelling zones. However, its persistence or variations over short time scales are poorly addressed. The present study, therefore, brings out a first report on hourly variations in the temperature, salinity and dissolved oxygen recorded by an environmental data buoy equipped with sensors, deployed in the nearshore waters of Alappuzha (southeastern Arabian Sea) from April to August 2022. The characteristic feature of the Alappuzha coast is the development of mud banks during the southwest monsoon, providing a tranquil environment suitable for continuous sensor-based measurements when the sea remains turbulent elsewhere. The results showed that despite an advance in the upwelling intensity, there is a significant variation in the oxygen concentration in the study domain on a diurnal scale. In general, the nearshore region was under hypoxia during the first half of the day (00:00 to 12:00 h), which increased steadily to reach normoxic and supersaturated levels during the rest of the day (12:00 to 24:00 h). Statistical analysis showed that winds significantly correlate to the coastal environment's subsurface oxygen concentration. During the morning hours, the wind was weak, and the water column remained stratified over the subsurface hypoxic water layer. The situation changed in the afternoon (12:00 h onwards), as there was a steady increase in the local wind speed (>5 m/s), which was sustained during the rest of the day. A local wind speed >5 m/s can disturb the stratification and enhance the mixing process from 12:00 to 24:00 h. The total kinetic energy of 11.5 J/m3 is the threshold for this oxygen supersaturation. These findings emphasize the role of wind-induced mixing in alleviating coastal hypoxia, highlighting the need for further biogeochemical and ecological investigations into the impacts of alternating oxic-hypoxic conditions in nearshore waters.
dc.languageen
dc.publisherElsevier
dc.relation.isreferencedbySCI
dc.rightsOnly the author version of the copright reserved papers uploaded. Contact drs@nio.org for any complaints regarding copyright violations
dc.titleFactors influencing nearshore hypoxia in the southeastern Arabian Sea: A sensor-based study
dc.typeJournal Article
dc.affiliation.authorCSIR-National Institute of Oceanography, Kochi, Kerala, India


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