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

人类社会从淡水中获得的生态系统服务价值在单位面积上超过了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，但它们受到前所未有的威胁。营养丰富是淡水生态系统中最重要的压力来源之一。目前对这一应激源的了解在很大程度上局限于初级生产的无机营养资源(即磷酸盐、硝酸盐或铵)的作用，或有害藻华的频率和强度。然而，淡水中广泛存在的有机营养化合物(例如蛋白质、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。迫切需要研究以解决这种不确定性，主要原因有三：i)在包括气候变化和土地管理在内的多种因素的推动下，许多淡水中有机营养化合物的浓度正在增加；ii)有机养分资源可支配总养分的可获得性，特别是在无机养分资源有限的高度敏感的低营养系统中；iii)有机养分资源即使在营养丰富的系统中也可能继续发挥重要作用，因为其化学计量比以及碳等关键元素的加入。在这方面，该项目的总体目标是大大促进对有机营养资源对淡水生物多样性和初级生产的控制的了解。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。这一认识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要贡献。两个具有区域和国家意义的案例/项目合作伙伴对这项研究的坚定承诺和资金证明了该项目可能产生重大影响。

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.