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Effect of land use on the biogeochemistry of dissolved nutrients and suspended and sedimentary organic matter in the tropical Kallada River and Ashtamudi estuary, Kerala, India

The effect of land use on the biogeochemistry of small tropical rivers and their estuaries was studied using the Kallada River and Ashtamudi estuary located in the State of Kerala, India, as a model system. Water, suspended matter and sediments collectedduring the monsoon and intermonsoon periods in...

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主要作者: T. C. Jennerjahn K. Soman V. Ittekkot I. Nordhaus S. Sooraj R. S. Priya N. Lahajnar
格式: Printed Book
出版: Biogeochemistry (2008) 90:29-47 2008
在线阅读:http://10.26.1.76/ks/004005.pdf
LEADER 022710000a22001330004500
100 |a T. C. Jennerjahn K. Soman V. Ittekkot I. Nordhaus S. Sooraj R. S. Priya N. Lahajnar 
245 |a Effect of land use on the biogeochemistry of dissolved nutrients and suspended and sedimentary organic matter in the tropical Kallada River and Ashtamudi estuary, Kerala, India 
260 |c 2008 
260 |b Biogeochemistry (2008) 90:29-47 
520 |a The effect of land use on the biogeochemistry of small tropical rivers and their estuaries was studied using the Kallada River and Ashtamudi estuary located in the State of Kerala, India, as a model system. Water, suspended matter and sediments collectedduring the monsoon and intermonsoon periods in 2002 and 2003 were analyzed for dissolved nutrients (nitrate, nitrite, phosphate, silicate) and for phytoplanktonabundance and composition, amino acid contents and stable carbon (C)) and nitrogen (N) isotope ratios. Seasonal and spatial variations of dissolved nutrients and suspended matter along the course of the river point to distinct diVerences in the C and N sources that are controlled by hydrology, geology and land use. Unusually low concentrations ofdissolved silicate and suspended matter suggest low erosion rates of the Precambrian basement rocks and the Wrm lateritic soils in non-agricultural areas. Most dissolved nutrients and suspended particulate organic matter originated from fertilized agricultural soils. The biogeochemistry of sedimentary organic matter indicates that most of the Kallada River load is deposited in the upper Ashtamudi estuary, while the middle andlower parts have a stronger marine inXuence. The spatio-temporal variation of dissolved and particulate river Xuxes clearly indicates an eVect of land use and land cover on the biogeochemistry of the Kallada River. While the phosphate yield was high (6 � 103mol km�2 year�1 or 185 kg km�2 year�1), the N yield was relatively low (10 � 103 mol km�2 year�1 or 141 kg km�2 year�1), which is unlike the situation in many other densely populated regions of tropical Asia  
856 |u http://10.26.1.76/ks/004005.pdf 
942 |c KS 
999 |c 73393  |d 73393 
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