tailieunhanh - Biomass and Remote Sensing of Biomass Part 10

Tham khảo tài liệu 'biomass and remote sensing of biomass part 10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 9 Biomass of Fast-Growing Weeds in a Tropical Lake An Assessment of the Extent and the Impact with Remote Sensing and GIS Tasneem Abbasi Chari and S. A. Abbasi Centre for Pollution Control Environmental Engineering Pondicherry University India 1. Introduction The Oussudu watershed is situated at 11 57 North and 77 45 East on either side of the border separating the Union Territory of Puducherry and the Indian state of Tamil Nadu Figure 1 . Apart from playing a crucial role in recharging the ground water aquifers the Oussudu watershed also harbors rich flora and fauna Chari and Abbasi 2000 2002 2005 . This watershed supports Puducherry s largest inland lake Oussudu which is also called -Ousteri a Tamil language hybrid of Oussudu and eri meaning Oussudu lake with a surface area of Km2 and shore line length of Km2. Oussudu lake is such an important wintering ground for migratory birds that it has been identified as one of the heritage sites by IUCN Interactional Union for Conservation of Nature and has been ranked among the most important wetlands of Asia Scott 1989 . In the recent past Oussudu lake and its watershed have been subject to enormous pressures due to the increasing population industrialization and urbanization. The resultant inputs of pollutants - rich in nitrogen and phosphorous - has provided aquatic weeds an opportunity to grow uncontrollably in the lake to the exclusion of other flora. This has led to a defacing of the lake by large patches of ipomoea Ipomoea carnia and other weeds. 2. Methodology Biomass estimation The biomass estimation was done using the total harvest method as per APHA 2005 . Brass rings of 31 cm diameter and m length were used as a sampling units. These rings were placed at 5 representative sites Figure 2 . All the macrophytes that were within the circumference of the rings were then harvested segregated identified packed in polythene covers and labeled appropriately. Some of the samples included grossly .