The structuring role of macrophytes in freshwater ecosystems

有些生态系统可以存在于一个以上的状态或制度中。发现为什么一些生态系统保持在一种或另一种状态，以及什么样的扰动会导致制度之间的转变，可能有助于预测生态系统将如何应对新物种的入侵或气候变化。我的研究计划的长期目标是了解湖泊和河流生态系统结构之间的关系，以及这些生态系统的功能。我的主要假设是，大型植物是两个系统的关键结构元素。在河流中，水生植物通过光合作用和呼吸作用影响溶解氧。大型植物为幼鱼提供掩护，但如果代谢足够活跃，也可能产生缺氧区。在草原浅水湖泊中，大型植物通过减少沉积物再悬浮，捕获颗粒，为大型浮游动物提供避难所以及释放减少浮游植物生长的化学物质来影响水的透明度。我建议的研究重点是面对再悬浮预测的基础上物理模型与经验数据，确定是否有选择性地影响颗粒捕集，确定小鱼在控制水的透明度和确定营养物的作用，大型植物生长关系和氧动力学在弓河在2013年大洪水后。 这项研究使加拿大受益，因为它提供了有关河流和湖泊中沉水植物作用的知识，使我们从水生系统中获得的生态系统服务（饮用、灌溉、牲畜饮水、娱乐等清洁水）可以得到保护和维护。 **

Some ecosystems can exist in more than one state or regime. Discovering why some ecosystems remain in one state or another, and what perturbations can cause a shift between regimes, might allow prediction of how ecosystems will respond to invasion by new species or changing climate. The long-term goal of my research program is to understand relations between lake and river ecosystem structure and how those ecosystems function. My major hypothesis is that macrophytes are key structuring elements in both systems. In rivers, macrophytes affect dissolved oxygen through photosynthesis and respiration. Macrophytes provide cover for young fish, yet may also generate hypoxic zones if sufficiently metabolically active. In shallow prairie lakes, macrophytes affect water clarity by reducing sediment resuspension, trapping particles, providing refuge for large-bodied zooplankton and releasing chemicals that reduce phytoplankton growth.***My proposed research focuses on confronting resuspension predictions based on physical models with empirical data, determining whether macrophytes selectively affect particle trapping, determining the role of minnows in controlling water clarity and determining nutrient-macrophyte growth relations and oxygen dynamics in the Bow River following major flooding in 2013.  This research benefits Canada by providing knowledge of the role of submerged macrophytes in rivers and lakes so that the ecosystem services we derive from our aquatic systems (clean water for drinking, irrigation, watering livestock, recreation, etc.) can be protected and maintained.  **