The principal component analysis conducted suggested THg to be related to the properties of the watershed (high degree of forest cover and low degree of agricultural land use), size and age of the reservoir, water residence time and the levels of nutrients in the reservoir.
Tropical ecology kricher pdf creator drivers#
In addition to the reservoir size, the role of land use, nutrient loading, biome and sediment properties ( e.g., organic carbon content) was tested as potential drivers of THg levels. Our study suggests reservoir size to be an important parameter determining the concentration of THg accumulating in tropical reservoir sediments, with THg ranging up to 50 ng g −1 in reservoirs with an area exceeding 400 km 2 and from 100 to 200 ng g −1 in reservoirs with an area less than 80 km 2. The concentration of THg in all analyzed depth intervals of 22 sediment cores from the five contrasting reservoirs investigated ranged from 16 to 310 ng g −1 ( n = 212, in the different sediment cores, the maximum depth varied from 18 to 96 cm). The objective of this study was to identify key drivers of the accumulation of total Hg (THg) in tropical reservoir sediments. It is unclear to what extent variations in physical features and biogeochemical factors of the reservoir impact Hg accumulation. Once produced, MeHg can bioaccumulate to harmful levels in organisms. The creation of reservoirs could, however, lead to conditions that promote the accumulation of mercury (Hg) in surface sediments and the subsequent production of methylmercury (MeHg). Thousands of dams are currently under construction or planned worldwide to meet the growing need for electricity.
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