Schelske Claire L, Lowe Edgar F, Battoe Lawrence E, Brenner Mark, Coveney Michael F, Kenney William F
Department of Geological Sciences, University of Florida, Gainesville 32611-2120, USA.
Ambio. 2005 May;34(3):192-8.
Lake Apopka is a shallow, hypereutrophic lake in north-central Florida that experienced an abrupt shift in primary producer community structure (PPCS) in 1947. The PPCS shift was so abrupt anecdotal accounts report that dominant, submersed aquatic vegetation was uprooted by a hurricane in 1947 and replaced by phytoplankton within weeks. Here we propose two hypotheses to explain the sudden shift to phytoplankton. First, hydrologic modification of the drainage basin in the late 1800s lowered the lake level ca. 1.0 m, allowing the ecosystem to accommodate moderate, anthropogenic nutrient enrichment through enhanced production in the macrophyte community. Second, additional hydrologic changes and large-scale agricultural development of floodplain wetlands began in 1942 and altered the pattern and scale of phosphorus loading to the lake that triggered the rapid shift to phytoplankton dominance in 1947. Historic land-use changes and paleolimnological data on biological responses to nutrient loading support these hypotheses.
阿波普卡湖是佛罗里达州中北部一个浅水的富营养化湖泊，其初级生产者群落结构（PPCS）在1947年发生了突然转变。PPCS的转变非常突然，轶事记载称，1947年一场飓风将占主导地位的沉水水生植物连根拔起，并在几周内被浮游植物取代。在此，我们提出两个假说来解释向浮游植物的突然转变。第一，19世纪后期流域的水文改造使湖面水位下降了约1.0米，使生态系统能够通过大型植物群落产量的增加来适应适度的人为养分富集。第二，1942年开始了额外的水文变化和洪泛平原湿地的大规模农业开发，改变了湖泊磷负荷的模式和规模，从而在1947年引发了向浮游植物优势的快速转变。历史土地利用变化和关于生物对养分负荷反应的古湖沼学数据支持了这些假说。
