Investigating the role of organic nutrient resources in controlling biodiversity and production in freshwater ecosystems

按单位面积计算，人类社会从淡水中获得的生态系统服务价值超过所有其他内陆生态系统。尽管河流、湖泊和湿地具有环境、经济和社会价值，但它们正受到前所未有的威胁。营养富集是淡水生态系统中最重要的压力源之一。目前对这一应激源的理解主要局限于无机营养资源（即磷酸盐、硝酸盐或铵）在初级生产中的作用或有害藻华的频率和强度。然而，淡水中发现的各种有机营养化合物（如蛋白质、核酸或氨基酸、磷脂等）对这些生态系统的结构和功能的重要性仍然高度不确定。迫切需要研究解决这一不确定性的主要原因有三个：1)在包括气候变化和土地管理在内的多种因素的驱动下，许多淡水中有机营养化合物的浓度正在增加；Ii)有机养分资源可以主导总养分有效性，特别是在无机养分资源有限的高度敏感的低养分系统中；iii)由于有机营养资源的化学计量和碳等关键元素的掺入，即使在营养丰富的系统中，有机营养资源也可能继续发挥重要作用。在此背景下，该项目的总体目标是显著提高对有机养分资源对生物多样性和淡水初级生产的控制的理解。该项目将为控制河流生态系统底栖生物生长和群落动态的机制提供新的、基本的理解。这种了解将对设计和执行适当的管理战略以养护和恢复淡水作出重大贡献。两个区域和国家重要案例/项目合作伙伴对研究的坚定承诺和资助证明了该项目可能产生的重大影响。

The value of the ecosystem services derived from fresh waters by human society exceeds all other inland ecosystems on a per unit area basis. Despite their environmental, economic and social value, rivers, lakes and wetlands are subject to unprecedented threats. Nutrient enrichment is among the most significant stressors within freshwater ecosystems. Current understanding of this stressor is largely constrained to the role of inorganic nutrient resources (i.e. phosphate, nitrate or ammonium) for primary production or the frequency and intensity of harmful algal blooms. However, the importance of the wide range of organic nutrient compounds found in fresh waters (e.g. proteins, nucleic or amino acids, phospholipids, etc) for the structure and function of these ecosystems remains highly uncertain. Research to address this uncertainty is urgently required for three primary reasons: i) the concentration of organic nutrient compounds is increasing in many fresh waters, driven by multiple factors including climate change and land management; ii) organic nutrient resources can dominate total nutrient availability, particularly in highly sensitive low nutrient systems where inorganic nutrient resources are limited; and iii) organic nutrient resources may continue to be significant even in nutrient-enriched systems, due to their stoichiometry and incorporation of critical elements such as carbon. In this context, the overarching aim of this project is to significantly advance understanding of the control exerted by organic nutrient resources on the biodiversity and primary production of fresh waters. The project will deliver new, fundamental understanding of the mechanisms controlling growth and community dynamics within the benthos of river ecosystems. This understanding will make critical contributions to the design and implementation of appropriate management strategies to conserve and restore fresh waters. The potential for significant impact from the project is evidenced by strong commitment and funding for the research from two regionally- and nationally-significant Case/project partners.