Novel Biogeochemical Pathways, Patterns and Measurements of Nitrogen and Phosphorus in Lakes and Reservoirs

该建议审查了影响水生生态系统中生物地球化学过程和水质的非生物和生物因素，包括人类因素。引起蓝藻水华的因素及其毒素正在紧张的研究中。对生态系统服务丧失(例如，水质)的关注一直是一个主要焦点。然而，直到最近才考虑到蓝藻对生态系统功能的影响。蓝藻通过产生毒素、抵抗放牧以及作为食草动物的食物质量差，对食物网产生广泛影响。因此，当湖泊被蓝藻主导时，它们的浮游食物网应该不会有效地发挥作用。我将用直接测量食物网周转效率的新技术来检验这一假设。我的下一个目标是比较迪芬贝克湖(SK)磷的两条重要的生物地球化学途径。从河流到水库的磷负荷往往是水质的主要决定因素。同样，浮游磷的再生对维持生产力也很重要。然而，尽管这些过程对湖泊和水库管理具有潜在的意义，但每条路径相对于另一条路径的重要性尚不清楚。因此，我建议对迪芬贝克湖的这两条小径进行测量和比较。我的第三个目标是确定整个湖泊的光氨化速率。这是一个将溶解的有机氮(DON)光分解为生物可利用的营养物质NH的过程

This proposal examines the abiotic and biotic factors, including human, that affect biogeochemical processes and water quality in aquatic ecosystems. The factors giving rise to cyanobacterial blooms and their toxins are under intense research. Concern over the loss of ecosystem services (e.g., water quality) has been a major focus. However, only recently has the effect of cyanobacteria on ecosystem function been considered. Cyanobacteria have widespread impacts on food webs through toxin production, resistance to grazing and as poor food quality for grazers. Hence, when lakes are dominated by cyanobacteria their planktonic food webs should be functioning inefficiently. I will test this hypothesis with novel techniques that directly measure food web turnover efficiency. My next objective is to compare two important biogeochemical pathways of P in Lake Diefenbaker (SK). Loading of P from rivers into reservoirs is often a major determinant of water quality. Similarly, planktonic P regeneration is known to be important to maintain productivity. However, the importance of each pathway relative to the other is unknown, despite the potential significance of these processes for lake and reservoir management. Therefore, I propose to measure and compare both pathways in Lake Diefenbaker. My third objective is to determine whole-lake rates of photoammonification. This is a process by which dissolved organic nitrogen (DON) is photodecomposed to the bioavailable nutrient NH