A beel thicky infested with water hyacinth
A beel thicky infested with water hyacinth
A beel thicky infested with water hyacinth
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Important rolc in determining the chemical quality of <strong>water</strong>. The chemical and physical<br />
load brought tn by rain <strong>water</strong> or surface runsff gets concentrated by evaporation and<br />
altcred by chemical and biological interaction <strong>with</strong>in the system. causing seasonal<br />
variat~ons of various parameters.<br />
Biological characteristics<br />
The ltvtng parl of the ecosystem or the biotic communities in <strong>water</strong> is governed<br />
by thc vanations of physical and chemical features of the wata body and trophic<br />
interactions associated <strong>with</strong> it. Biottc communities of the ecosystem can be categorized<br />
broadly as ( I) aurorrophs and (2) hererorrophs. The autotrophs include photosynthetic<br />
ptgmenl bring microscopic plants, plankton and macrophytes. Heterotrophs categov<br />
tncludcs consumers and decomposers The pr~mary organic productivity and the fish<br />
ylcld polcntlal of a <strong>water</strong> body thus dcpnds largely on the relat~ve abundance of<br />
various communit~cs and the~r associations. Beels are generally cons~dered as h~ghly<br />
cutroph~catcd system <strong>with</strong> h~gh rate of primary product~vity. The energy produced at the<br />
prlnlary stagc r e.. phytoplankton and macrophytes are transformcd into h~ghcr troph~c<br />
levels through food chams. It IS the eficiency at which this energy 1s transfomrrtd Into<br />
fish lcvcl that detcrmtnes the effccttveness of management In <strong>beel</strong>s. tao maln<br />
path\vays.~,r:. the grci:tng choir1 and the cit7rrrrw clrrrin are found. In the grarlng chaln.<br />
prlmaq productlv~ty IS done by phytoplankton whlch IS grazed by zooplankton. 111 case<br />
of dctr~tus cham, the macrophytes produce the pnrnary energy. In the absence ot' fish<br />
feeding on tnacrophytes, these plants die and settle at the bottom adding to detrltus In<br />
such cases, detritivorous fish flourish and contribute to fishery.<br />
SAI.IENT ECOL.OGICA1, FEATURES OF BEELS IN ASSAM<br />
Soil quality<br />
Soil is vital in maintaining the productivity of any <strong>water</strong> body. It is one of the<br />
main interfaces through which nummt is released to the <strong>water</strong> medium. Apart from<br />
helping mineralization of the organic deposits at the bonom, soil provides shelter and<br />
food to the benthic fauna and flora, which play a significant role in maintaining the<br />
nutnent status of overlying <strong>water</strong>. Dishibution of soil types in Assam is illustrated in<br />
Fig. 3. Soils of the floodplain wetlands receive additional input in terms of organic<br />
matter. inorganic minerals. silt and clay. Since most of the floodplain wetlands are