Volcanic Processes Introduce Chemical Discontinuities into Lowland Tropical Streams: Ecological Response to Geothermally-derived Solutes

这项研究的统一原则是生态系统层面的过程与河流的群落生态之间的联系。与火山作用有关的地热活动对确定中美洲火山脊沿线地表水化学和生物群的区域景观格局具有重要意义。地热过程在河流中引入了天然的化学不连续，例如高水平的可溶活性磷(SRP)，中断了河流的连续体，并影响了基本的生态过程。这项工作的主要目标是测试地热引起的化学不连续如何构成低地热带溪流群落。调查人员(1)确定地热输入是否影响不同光照环境下的藻类初级生产力和群落组成(在森林内部溪流的光隙和遮荫部分以及开阔的牧场溪流中)；(2)分别利用流动生物分析和全系统操纵，评估群落和生态系统层面对模拟的SRP地热输入的响应；(3)确定鱼类如何影响地热不连续地点上方和下方的净初级生产力和藻类群落结构，并研究鱼和磷改良剂对初级生产力的相互作用影响。//

The unifying principal of this research is the linkage between ecosystem-level processes and the community ecology of streams. Geothermal activity associated with volcanism is significant in determining regional landscape patterns in surface water chemistry and biota along the volcanic spine of Central America. Geothermal processes introduce natural chemical discontinuities into streams e.g. high levels of soluble reactive phosphorus (SRP) that interrupt the stream continuum and influence basic ecological processes. The main objective of this work is to test how geothermally- introduced chemical discontinuities structure lowland tropical stream communities. The investigators (1) determine if geothermal nputs affect algal primary production and community composition in different light environments (in light gaps and shaded sections of an interior forest stream and in an open pasture stream); (2) evaluate community- and ecosystem-level response to simulated geothermal inputs of SRP using flow- through bioassays and whole-system manipulations, respectively; and (3) determine how fish influence net primary production and algal community structure above and below sites of geothermal discontinuities and examine interacting effects of fish and phosphorus amendments on primary production. //