Dissertation Research: Why Does N-Limitation Occur in Some Arctic Lakes? Understanding Controls of N-Fixation

Cornell Univ - State: Awds Made Prior May 2010, Ithaca NY

Investigators

Abstract

Nitrogen is an essential nutrient to all plants and animals, yet it limits plant growth in many arctic lakes. The Arctic has warmed 2 degrees in the last 30 years. This warming causes frozen ground to melt and nitrogen inputs to lake increase. It is imperative to understand how nitrogen controls plant growth in order to predict how arctic lakes will respond to climate change. Even though the atmosphere is 80% nitrogen, it is unavailable to most plants. Only specialized bacteria can "fix" atmospheric nitrogen and convert it into forms that are available to plants. If these bacteria can fix nitrogen fast enough, plant growth will not be nitrogen limited. However, nitrogen-fixing bacteria do not alleviate the shortage of nitrogen in arctic lakes. The goal of this study is to examine how temperature, light, nutrients, and grazers interact to control nitrogen fixation in these arctic lakes.