Physical and chemical constraints on emergent aquatic ecosystem metabolism

UC 331

Alpine glacial loss is resulting in the rapid change and even emergence of downstream lakes; however, little is known about the processes regulating development in these new ecosystems. The unique properties of glacial meltwater impose physical and chemical constraints on lake ecosystem processes, but the degree to which these constraints interact or relax as glaciers recede is not well understood. The nature of these constraints have direct consequences for the fundamental ecological characteristics of the ecosystem. For example, glacial inputs rich in sediment may reduce light thereby limiting primary production, whereas glacial inputs rich nutrients may promote primary production. As these inputs fade, the response of lake biota determine the corresponding changes in biogeochemical cycling. Understanding the relative importance of glacial inputs to the metabolism of emerging aquatic ecosystems may help preserve them and build a framework to predict their trajectory of ecosystem development and future ecological state. In addition, aquatic systems will likely shift from net autotrophic carbon sinks to net heterotrophic carbon sources as glaciers disappear and vegetation colonizes alpine catchments.