Variability of La Plata River extremely turbid waters using MODIS-Aqua images and its relation to fish habitat selection
Dogliotti, A.I.; Jaureguizar, A.J.; Ruddick, K. (2012). Variability of La Plata River extremely turbid waters using MODIS-Aqua images and its relation to fish habitat selection, in: 44th international Liège colloquium on ocean dynamics "Remote sensing of colour, temperature and salinity – new challenges and opportunities" - May 7-11, 2012. pp. 1
In: (2012). 44th international Liège colloquium on ocean dynamics "Remote sensing of colour, temperature and salinity – new challenges and opportunities" - May 7-11, 2012. GHER, Université de Liège: Liège. 126 pp., meer
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| Auteurs | | Top |
- Dogliotti, A.I., meer
- Jaureguizar, A.J.
- Ruddick, K., meer
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| Abstract |
La Plata River drains the second largest basin in South America after the Amazon River and is considered one of the most turbid rivers in the world. It carries high amounts of nutrients, suspended particulate and dissolved organic matter to the adjacent shelf waters which impact the ocean’s physical, chemical and biological properties. The estuary is an area of high ecological importance. The outer region, where the freshwater (rich in nutrients) interacts with the coastal water, is the spawning and nursery area of many coastal species. The objective of the present study is to analyze the variability and offshore export of La Plata turbid waters into the adjacent continental shelf and its relation to the habitat selection of the whitemouth croaker Micropogonias furnieri. This fish is one of the most important species in terms of biomass that supports the traditional fisheries of the Argentinean, Brasilian and Uruguayan coastal region and its spatial distribution is highly influenced by salinity and turbidity differentially according to the life stage. Satellite ocean color data were used to present the synoptic quantification of turbidity variability on seasonal and interannual timescales for La Plata river plume area. Eight years (2002-2010) of MODIS-Aqua local area coverage were analyzed. Standard ocean colour products are not valid in these extremely turbid waters. Therefore, turbidity maps were generated using near infrared (NIR) and short wave infrared (SWIR) bands with a modified atmospheric correction algorithm which takes into account non-zero reflectance in the SWIR bands. Results show that the spatial distribution pattern of age-classes of Micropogonias furnieri is highly related to specific turbidity ranges. The role of forcing such as river discharge and wind-driven circulation in the redistribution of the sediment plume is also analyzed both at seasonal and interannual time scales using in situ and scatterometer wind data. |
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