Automated Determination of Total Dissolved Nitrogen: A Critical Technique for Identifying Nutrient Sources, Cycling Rates and Fate in Freshwaters

点击翻译按钮获取中文摘要

Elevated inorganic nitrogen (N; such as ammonium and nitrate) by human activities threatens aquatic ecosystem health and the security and quality of drinking water supplies. This also radically changes the dissolved carbon:nitrogen (C:N) ratio in surface waters leading to cascading effects such as increased photosynthesis and respiration rates, increases nutrient cycling rates, and shifting surface waters towards nuisance and toxin-producing algae and cyanobacteria. The vast majority of biologically available N is often organic N and this approaches 100% organic N in remote and northern freshwaters, yet this organic N is too infrequently measured and too often measurements vary widely from lab-to-lab due to differences in methods and problems with older instruments. Even in remote and northern freshwaters, this dissolved organic N plays a critical role in how ecosystems function and whether C is stored in sediments for the long-term or lost to the atmosphere as carbon dioxide. Funds are requested to purchase an Analytik Jena Multi N/C 3100 for high quality analysis of total dissolved N. This instrument includes a high-temperature and high-recovery system that can provide very reliable analyses. This instrument will immediately be used by our students so they may complete their research project on time and without compromising quality.