Trophic transfer of fatty acids in marine food webs

海洋食物网中脂肪酸的营养转移

• 批准号: RGPIN-2017-04296
• 负责人: Budge, Suzanne
• 金额: $ 2.91万
• 依托单位: Dalhousie University
• 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=710961
• 关键词: Trophic; transfer; fatty; acids; marine

The research interests of my group are focused on the use of lipids and fatty acids (FA) as tools to study carbon flow and food web dynamics in the marine environment. FA are well suited to such studies because many dietary FA are incorporated into consumers with only minor modifications to structure, making FA useful as indicators or biomarkers of their source. Here, we propose to continue our ongoing work investigating the transfer of FA from prey to predators at low trophic levels by examining trophic transfer efficiencies of FA. This is a measure of the amount of FA deposited in a predator's tissue relative to the amount available in its diet, and we believe these will vary with consumer, concentration of FA and FA structure. Several FA, such as long chain omega-3 FA, are essential nutrients, required for growth and survival by all organisms. In the marine food web, the majority of these essential FA are synthesized only by phytoplankton; thus, it is particularly important to understand the efficiency with which such nutrients are transferred from diet to consumer. Trophic transfer efficiencies can also be incorporated into methods we are developing to estimate consumer diets by comparison of FA patterns, or profiles, in predator and prey. They are important in that application because they allow us to compensate for changes made to the diet FA profile by catabolism and other processes in the predator. We are proposing three specific objectives: 1) examine the influence of FA structure, dietary concentration, tissue and species on transfer efficiency of FA, using calanoid copepods (Calanus finmarchicus), Atlantic pollock (Pollachius virens) and Atlantic salmon (Salmo salar) as model species; 2) test the influence of trophic transfer efficiencies in our statistical models on the accuracy of diet estimates by conducting feeding studies with Atlantic salmon fed different diet mixtures; and 3) incorporate trophic transfer efficiencies of FA into our statistical models and apply to existing datasets from Baffin Island and the Bering Sea to estimate diets of Atlantic and Arctic cod (Gadus morhua and Boreogadus saida). These are ecosystems that are most susceptible to the effects of climate change and make good candidates to detect variation in carbon cycling over time. At larger scope, we will use trophic transfer efficiencies, combined with production levels of FA derived from remote sensing of phytoplankton, to estimate the essential FA budget of the ocean. Fundamentally, we believe that incorporation of these essential nutrients into mechanistic models will improve the accuracy of predictions of ecosystem properties and shifts, ultimately leading to better decision-making regarding management and conservation of our marine resources. Measurement of trophic transfer efficiencies of essential FA, as we have proposed here, is a necessary first step for their inclusion in such models.

我的小组的研究兴趣集中在使用脂质和脂肪酸（FA）作为研究海洋环境中碳流和食物网动态的工具。 FA 非常适合此类研究，因为许多膳食 FA 只需对结构进行微小修改即可被纳入消费者体内，这使得 FA 可用作其来源的指示剂或生物标志物。在此，我们建议继续开展正在进行的工作，通过检查 FA 的营养转移效率，研究 FA 在低营养水平下从猎物到捕食者的转移。这是捕食者组织中沉积的 FA 量相对于其饮食中可用量的衡量标准，我们相信这些会随着消费者、FA 浓度和 FA 结构的变化而变化。多种 FA，例如长链 omega-3 FA，是所有生物体生长和生存所需的必需营养素。在海洋食物网中，大部分必需 FA 仅由浮游植物合成；因此，了解这些营养素从饮食转移到消费者的效率尤为重要。营养转移效率也可以纳入我们正在开发的方法中，通过比较捕食者和猎物的 FA 模式或概况来估计消费者的饮食。它们在该应用中很重要，因为它们使我们能够补偿捕食者体内分解代谢和其他过程对饮食 FA 谱造成的变化。 我们提出三个具体目标：1）以桡足类（Calanus finmarchicus）、大西洋鳕鱼（Pollachius virens）和大西洋鲑鱼（Salmo salar）为对象，研究FA结构、膳食浓度、组织和物种对FA转移效率的影响。模式物种； 2) 通过对喂养不同饮食混合物的大西洋鲑鱼进行喂养研究，测试我们的统计模型中营养转移效率对饮食估计准确性的影响； 3) 将 FA 的营养转移效率纳入我们的统计模型，并应用于巴芬岛和白令海的现有数据集，以估计大西洋和北极鳕鱼（Gadus morhua 和 Boreogadus saida）的饮食。这些生态系统最容易受到气候变化的影响，并且是检测碳循环随时间变化的良好候选者。在更大的范围内，我们将利用营养转移效率，结合浮游植物遥感得出的FA生产水平，来估计海洋的基本FA预算。从根本上说，我们相信将这些必需营养素纳入机械模型将提高生态系统特性和变化预测的准确性，最终导致有关海洋资源管理和保护的更好决策。正如我们在此提出的，测量必需 FA 的营养转移效率是将其纳入此类模型的必要的第一步。