Basal food resource quality and trophic energy flow across the biofilm-consumer interface: aquatic ecosystem response to environmental stressors

生物膜-消费者界面的基础食物资源质量和营养能量流：水生生态系统对环境压力的反应

• 批准号: RGPIN-2019-06603
• 负责人: Lavoie, Isabelle
• 金额: $ 2.04万
• 依托单位: Institut national de la recherche scientifique
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=716203
• 关键词: Basal; food; resource; quality; trophic

Agriculture is the dominant contributor to eutrophication in many watersheds in Canada. Adequate monitoring of potential impacts from agriculture is thus essential to make informed management decisions for freshwater resources. Biological assessment is an approach that provides information on the response of organisms subjected to environmental pressures, allowing for an evaluation of how anthropogenic activities are affecting the biota. To date, bioassessment of aquatic ecosystems has generally been based on changes in taxonomic composition of assemblages. Yet, despite providing reliable estimates of ecosystem health, taxonomy-based indices are focused on individual organism groups (e.g. algae, invertebrates) without evaluating impacts across the food web, and provide limited insight into the effects of stressors that act at the ecosystem scale. There is thus a need to develop biomonitoring tools that incorporate community function and food web dynamics to reflect ecological attributes of whole ecosystems. Fatty acid (FAs) are vital for organisms (e.g., energy, reproduction, cell membranes). Certain essential FAs are transferred from food sources to consumers with no or minimal modification, which is fundamental for invertebrate growth/reproduction and for energy transfer efficiency to higher trophic levels. FA profiles in stream biofilms thus represent a proxy for basal resource quality, i.e., the nutritional quality at the base of the food web. FA profiles change under various conditions, and could be used as a biomarker to evaluate the effects of anthropogenic stressors such as eutrophication and climate warming. However, new knowledge is needed to support the use of FAs in biomonitoring, in particular to confirm the response of this biomarker to eutrophication from agricultural land use in combination with warmer water temperatures. With this NSERC-Discovery grant, I will address five short-term objectives: (1) Quantify the spatial and temporal variability in biofilm FAs; (2) Quantify the response of biofilm FAs under different phosphorus conditions and the relationship with algal taxonomic composition and diatom-based index values; (3) Establish relationships between land use and biofilm FAs to identify thresholds of change; (4) Determine the relationship between biofilm FAs and primary consumer FAs under eutrophic conditions characteristic of agricultural streams; (5) Assess whether the effects of eutrophication on biofilm FAs at the base of the trophic chain are exacerbated by increased water temperatures. My NSERC-Discovery program involves fundamental and applied research based on mesocosm experiments and field studies. The results will improve our comprehension of threats to biodiversity and ecosystem function by providing a better understanding of how food webs will be impacted by agricultural land use and eutrophication in a warming climate.

农业是加拿大许多流域富营养化的主要贡献者。因此，对农业的潜在影响进行充分监控对于做出明智的管理决策至关重要。生物评估是一种提供有关受环境压力的生物反应的信息，可以评估人为活动如何影响生物群。迄今为止，水生生态系统的生物评估通常是基于组合分类学组成的变化。然而，尽管提供了可靠的生态系统健康估计值，但基于分类的指标仍集中在单个生物体（例如藻类，无脊椎动物）上，而没有评估食物网络的影响，并对在生态系统量表上起作用的压力源的影响有限。因此，有必要开发生物监测工具，以结合社区功能和食物网络动态，以反映整个生态系统的生态属性。 脂肪酸（FAS）对于生物体至关重要（例如能量，繁殖，细胞膜）。某些必需的FA从食物来源转移到没有或最少修改的消费者中，这对于无脊椎动物生长/繁殖以及能量转移效率至较高的营养水平至关重要。因此，溪流生物膜中的FA轮廓代表了基础资源质量的代理，即食物网的基础上的营养质量。 FA轮廓在各种条件下变化，并且可以用作生物标志物，以评估人为应激源（例如富营养化和气候变暖）的影响。但是，需要新的知识来支持FA在生物监测中的使用，特别是为了确认该生物标志物对农业用地利用的富营养化的反应，并结合较高的水温。 有了这项NSERC划分的赠款，我将解决五个短期目标： （1）量化生物膜FAS的空间和时间变化； （2）在不同的磷条件下量化生物膜Fas的响应，以及与藻类分类学组成和基于硅藻的指数值的关系； （3）建立土地使用与生物膜FAS之间的关系以识别变化的阈值； （4）确定在农业流的富营营养条件下，生物膜FAS与主要消费者FA之间的关系； （5）评估富营营养对营养链底部生物膜FA的影响是否因水温升高而加剧。 我的NSERC发现计划涉及基于中验实验和现场研究的基本和应用研究。结果将通过更好地理解对食物网在温暖的气候下如何受到农业土地利用和富营养化的影响，从而提高我们对生物多样性和生态系统功能威胁的理解。