淡水生态学要点.pptVIP

* 水生态系统常用修复措施 * 人为修复 外源污染控制 底泥疏浚 底泥覆盖 水动力调控 机械除藻和化学除藻 暴气 降低水位及干化 提高透明度 营养盐钝化 水生植物修复 鱼类修复 浮游动物修复 底栖动物的修复 生物浮床 自然修复 * * * * Credit: taken from http://www.aquatic.uoguelph.ca/lakes/waves/wavesfrm.htm * * * * Depth Zone nomenclature: eulittoral = splashzone – fast growing colonizers; subject to scouring; high light; seasonally warm; high DO; exposed to nutrients from tributaries, sheet runoff and groundwater seepage; good indicator of point source nutrient pollution. sublittoral = below the upper 1-2m splash (surf) zone; may be slower growing and longer lived; possibly less seasonality (??); lower light and cooler/colder water; different grazer community from splash zone. Biofilter concept – sediments are rich sources of nutrients, in particular phosphate-P and ammonium-N which diffuse into overlying water. In unproductive, clearwater lakes, the periphyton growing on the bottom can act to absorb some of this flux of nutrients. Macrophyte interactions – macrophytes provide a substrate for growth in the euphotic zone and you will typically see gobs of filamentous periphyton strung between higher plant stems. There may also be a film of non-filamentous algal cells on the plant leaves and stems. This growth may be quite variable in part to intense grazing by invertebrates. Watershed inputs include: tributaries, ground water, surface runoff, shoreline erosion * * * * Most species of fish are simultaneously predator and prey. Relatively few species are herbivores or detritivores and even those are predators on invertebrates during early life stages. Species in each of these guilds have morphological adaptations for their mode of feeding. Planktivores have a terminal mouth and gill structure that enables them to retain zooplankton. They can be sight-feeders or filter feeders but all still need to search for and visually identify their prey item. Some zooplankton have adapted to this by vertically migrating within the water column to avoid those times when pl