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

本研究的统一原则是生态系统级过程与溪流群落生态学之间的联系。与火山活动相关的地热活动在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方面具有重要意义。地热过程给河流带来了天然的化学不连续，例如高水平的可溶性活性磷（SRP），它中断了河流的连续性并影响了基本的生态过程。这项工作的主要目的是测试地热引入的化学不连续如何构造低地热带溪流群落。研究人员(1)确定地热输入是否会影响不同光照环境（森林溪流内部的光照间隙和阴影部分以及开阔的牧场溪流）中藻类的初级生产和群落组成；(2)分别通过生物分析和全系统操作，评估群落和生态系统水平对SRP模拟地热输入的响应；(3)确定鱼类如何影响地热不连续点上下的净初级产量和藻类群落结构，并检查鱼类和磷修正对初级产量的相互作用。//

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. //