The importance of low-level nitrogen and carbon to periphyton in Alaskan headwater streams.

Abstract

Alaskan headwater streams are ecologically and economically important habitats for juvenile salmonid development. These low-nutrient environments are relatively untouched by anthropogenic effects and contain little marine-derived nutrients due to their distance inland and narrow channels. Reduction in these nutrient sources places high dependence of stream productivity on allochthonous resources supplied by landscape features within the catchment. The current research investigates the importance of low-level nitrogen and carbon (simulating nutrient levels derived from wetlands and alder trees) by observing the effects of these nutrients on microbial biomass, enzyme activity and metabolism. Results indicate that these low-level nutrient sources may be undervalued resources driving stream productivity and that such features should be considered in land management plans within vulnerable stream catchments. The research presented here may be essential in protecting and maintaining habitats that promote healthy salmonid populations in the Kenai lowlands of Alaska and elsewhere.