Both riverine detritus and dissolved nutrients drive lagoon fisheries

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• 作者：Subbareddy Bonthu^a ; Dipnarayan Ganguly^a ; Purvaja Ramachandran^a ; Ramesh Ramachandran^a ; ^{rramesh_au@yahoo.com} ; Ajit K. Pattnaik^b ; Eric Wolanski^c
• 关键词：Estuarine food web ; Detritus ; Ecosystem model ; Lagoon ; Fish stocks
• 刊名：Estuarine, Coastal and Shelf Science
• 出版年：2016
• 出版时间：20 December 2016
• 年：2016
• 卷：183
• 期：part_PB
• 页码：360-369
• 全文大小：1857 K
• 卷排序：183

文摘

The net ecosystem metabolism in lagoons has often been estimated from the net budget of dissolved nutrients. Such is the case of the LOICZ estuarine biogeochemistry nutrient budget model that considers riverine dissolved nutrients, but not riverine detritus. However the neglect of detritus can lead to inconsistencies; for instance, it results in an estimate of 5–10 times more seaward export of nutrients than there is import from rivers in Chilika Lagoon, India. To resolve that discrepancy the UNESCO estuarine ecohydrology model, that considers both dissolved nutrients and detritus, was used and, for Chilika Lagoon, it reproduced successfully the spatial distribution of salinity, dissolved nutrients, phytoplankton and zooplankton as well as the fish yield data. Thus the model suggests that the riverine input of both detritus and dissolved nutrients supports the pelagic food web. The model also reproduces well the observation of decreased fish yield when the mouth of the lagoon was choked in the 1990s, demonstrating the importance of the physics that determine the flushing rate of waterborne matter. Thus, both farming in the watershed by driving the nutrient and detritus inputs to the lagoon, and dredging and engineering management of the mouth by controlling the flushing rate of the lagoon, have a major influence on fish stocks in the lagoon.