Anthropogenic impacts on the geochemical cycling of nutrients and trace metals within intertidal ecosystems

人为对潮间带生态系统内营养物和微量金属地球化学循环的影响

• 批准号: RGPIN-2022-03482
• 负责人: Bendell, Leah
• 金额: $ 2.04万
• 依托单位: Simon Fraser University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=744698
• 关键词: Anthropogenic; impacts; geochemical; cycling; nutrients

The relationship between ecosystem function and community structure is complex and dynamic. My long term research program is directed at understanding  the mechanisms underlying this complex interplay and how this interplay between ecosystem structure and function changes as we modify our environment. Threats now facing our aquatic ecosystems include a changing climate and pollution, the latter of which the increasing presence of plastics pollution, macro and micro has become arguably one of the greatest concerns of this century. Understanding how these anthropogenic contaminants alter ecosystem structure and function and the role they play in the transfer of toxic compounds such as trace metals, through food webs is urgently needed such that preventative and remediative actions to protect these ecosystems can be put in place. Traditionally, sediments have been characterized as being composed of different geochemical attributes such as organic matter and silt that act as sorption sites for metals that have been released into aquatic environments.  Recent research has indicated that plastics also serve as trace metal sorption sites and as such provide an as yet quantified source and hence entry of toxic metals to benthic food webs.  It is also now recognized that plastics that enter into aquatic ecosystems age through photodegradation. Such aging alters the biophysical properties of the plastics from their virgin state. Hence an important aspect of understanding the mechanisms of how plastics are affecting trace metal cycles within intertidal sediments is to incorporate the dynamic nature of the plastic itself, i.e., environmentally aged plastics versus unaged. My objectives for the next 5 year funding cycle are to; 1) Characterize and determine the distribution of  microplastics within several intertidal regions with different sediment geochemical attributes and  compare the sorption of trace metals (cadmium, lead, zinc, copper) by microplastics of different polymers types and ages, among the intertidal regions, 2) through the application of the radiotracer 109Cd, to determine if the accumulation of cadmium by the bivalves Nuttallia obscurata and Protothacia staminea, from microplastics is dependent on polymer type and shape and 3)determine the role of feeding ecology, i.e., rates of ingestion, retention and egestion in influencing the recovery of microplastics from the bivalves N. obscurata and P. stamenia.  Outcomes of my research programme will add to our knowledge base as to how plastics are impacting our aquatic ecosystems, specifically with respect to the movement of trace metals through food webs. This is turn will improve our ability to predict the risks to both ecosystems and humans, that plastics may present as acting as vectors for the entry of toxic metals into intertidal food webs.

生态系统功能与群落结构之间的关系是复杂的、动态的。我的长期研究计划旨在了解这种复杂相互作用的机制，以及生态系统结构和功能之间的相互作用如何随着我们改变环境而变化。我们的水生生态系统现在面临的威胁包括气候变化和污染，其中塑料污染的日益存在，宏观和微观已经成为本世纪最大的问题之一。迫切需要了解这些人为污染物如何改变生态系统的结构和功能，以及它们在通过食物网转移有毒化合物（如微量金属）方面所发挥的作用，以便采取预防和补救行动来保护这些生态系统。传统上，沉积物的特点是由不同的地球化学属性组成，如有机物和淤泥，它们是释放到水生环境中的金属的吸附点。最近的研究表明，塑料也是痕量金属的吸附点，因此提供了一个尚未量化的来源，从而使有毒金属进入底栖食物网。现在还认识到，进入水生生态系统的塑料通过光降解而老化。这种老化改变了塑料的生物物理特性。因此，理解塑料如何影响潮间带沉积物中痕量金属循环的机制的一个重要方面是将塑料本身的动态性质结合起来，即，环境老化塑料与未老化塑料的对比。 下一个5年融资周期的目标是：1）表征和确定微塑料在具有不同沉积物地球化学属性的几个潮间带区域内的分布，并比较微量金属的吸附（镉，铅，锌，铜）的不同聚合物类型和年龄的微塑料，2）通过放射性示踪剂109镉的应用，以确定是否镉的积累的双壳类Nuttallia obscurata和Protothacia stamarium，从微塑料是依赖于聚合物的类型和形状和3）确定的作用，喂养生态，即，摄食率、滞留率和排泄率对双壳贝类N. obscurata和P.stamenia。 我的研究计划的结果将增加我们的知识基础，以了解塑料如何影响我们的水生生态系统，特别是关于微量金属通过食物网的运动。这反过来将提高我们预测生态系统和人类风险的能力，即塑料可能作为有毒金属进入潮间带食物网的载体。