Refining knowledge of biogeochemical cycling and ecological interactions within the Lake Erie watershed

有害藻华(HABS)和低溶解氧(DO)水平是大型水体的主要问题，与高磷输入和藻类生长和衰退加剧有关。虽然流域管理计划有助于减少湖泊接受的营养负荷，但HAB频率最近有所增加，DO浓度目标没有始终如一地实现，特别是在劳伦斯五大湖。这种管理策略的失败与某些部分磷的可用性增加有关，尽管总负荷有所下降，并归因于土地管理方法、气候变化和长期土壤储存之间的复杂局部相互作用。虽然有许多关于营养物来源的理论，但还没有找到解决它们的有效性和反复出现的赤潮的解决方案。最近的管理失败是由于我们对营养物质的运输机制、复杂的过程相互作用和相关的湖泊生物地球化学反应的不完全了解。在填补这些知识空白之前，新的管理战略的潜在影响是无法预测的。这项研究计划将通过在伊利湖流域周围部署移动监测单元，每小时监测陆地、河流、海岸线和深湖界面上的物理、化学和生物相互作用，提高我们对赤潮和湖泊健康阈值驱动因素的了解。模型仍然是模拟管理战略有效性的最佳可用工具，但它们的准确性仅限于我们对过程的理解。从历史上看，观测的不确定性和生物地球化学知识的缺乏阻碍了模型对富营养化问题产生有用的管理解决方案。利用新的监测数据，将实施流域-湖泊模型，减少观测不确定性，以模拟通过陆地、河流和湖泊走廊的沉积物、化学、水文和生物通量。将模拟减少赤潮发生频率和增加湖泊DO浓度的土地管理策略，并根据未来气候和土地利用的潜在变化评估其长期弹性。通过生成关于特别容易发生变化的地区(热点)的新信息，突出管理优先区域，并制定新的、更具弹性的管理策略，使未来面对变化时能够维持更健康的湖泊，从而提高我们对土地管理与水生态系统之间相互作用的理解，使政策制定者、居民和湖泊使用者受益。产生的高分辨率监测信息的大型数据库将有利于广泛的用户，包括政府(MOECC和EC)、当地土地所有者、工业(水处理厂)和其他研究人员。

Harmful algal blooms (HABs) and low dissolved oxygen (DO) levels are major concerns in large waterbodies, and have been linked with high phosphorus inputs and intensified algal growth and decay. While watershed management plans have helped to reduce nutrient loads received by lakes, HAB frequency has recently increased and DO concentration targets have not consistently been met, particularly in the Laurentian Great Lakes. This failure of management strategies has been linked to increasing availability of certain fractions of phosphorus, despite declines in the total loads, and attributed to complex local interactions between land management approaches, climate change and long-term soil storage. Although there are many theories as to the nutrient sources, a solution to their availability and that of the recurring HABs has not yet been found.Recent management failures result from our incomplete knowledge of nutrient transport mechanisms, complex process interactions and associated lake biogeochemical responses. Until these knowledge gaps are filled, the potential effects of new management strategies cannot be predicted. This research program will improve our knowledge of threshold drivers of HABs and lake health through deploying mobile monitoring units around the watershed of Lake Erie, monitoring physical, chemical and biological interactions across land, river, shoreline and deep lake interfaces at hourly intervals.Models remain the best available tools to simulate efficacy of management strategies, however they are only as accurate as our process understanding. Historically observational uncertainty and a lack of biogeochemical knowledge has obstructed models from generating helpful management solutions to eutrophication issues. Using the new monitoring data a catchment-lake model will be implemented, with reduced observational uncertainty, to simulate sediment, chemical, hydrological and biological fluxes through the terrestrial, riverine and lake corridor. Land management strategies for reducing frequency of occurrence of HABs and increasing lake DO concentrations will be simulated, and their long term resilience assessed under potential future changes in climate and land-use.Improvement of our understanding of interactions between land management and aquatic ecosystems benefits policy makers, residents and users of the lake by generating new information on areas particularly vulnerable to change (hotspots), highlighting areas for management priority and generating novel, more resilient management strategies enabling a healthier lake to be sustained in the face of future change. The large database of high resolution monitoring information generated will be beneficial to a wide range of users, including government (MOECC and EC), local landowners, industry (water treatment plants), and other researchers.