Quantifying and partitioning spatiotemporal variability in secondary production and trophic transfer efficiency in pelagic marine ecosystems

量化和划分中上层海洋生态系统二次生产和营养转移效率的时空变化

• 批准号: RGPIN-2020-07077
• 负责人: Dower, John
• 金额: $ 2.4万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=741274
• 关键词: Quantifying; partitioning; spatiotemporal; variability; secondary

This research aims to measure two factors that, although critically important to understanding marine food chains, have rarely been measured in Canadian waters. The first is known as "secondary production", which is the rate at which zooplankton are produced. Zooplankton are tiny animals (mostly less than 1 cm in size) that feed on single-celled plants (called "phytoplankton") at the base of most marine food chains. Zooplankton are consumed by larger animals - including many young and adult fish, certain marine mammals, and even seabirds. The second factor is referred to as the "trophic transfer efficiency" (TTE). In short, this is an estimate of how much energy is transferred between different levels of the food chain (e.g. from phytoplankton to zooplankton). The higher the TTE the more energy that is transferred up the food chain, and the greater the amount of fish, marine mammals, etc. that can be supported. These two factors are essential components that underlie the mathematical models that oceanographers use to study marine food webs, and to predict how such food webs may change in the future. However, mainly for technical reasons, neither factor is measured directly in the ocean. Instead, modelers have relied on numbers drawn from simplified lab experiments or theoretical studies. My lab has developed a method to directly measure secondary production, based on measuring an enzyme (called chitobiase) that most zooplankton release into the water as they grow. When put together with measures of the rate of phytoplankton growth (known as "primary production" - something that oceanographers have been able to do since the 1960s), we have been able to produce the first direct estimates of TTE in a natural field setting. Over the next five years we will expand our work to begin exploring how secondary production and TTE vary between locations and at different timescale (i.e. seasonally, between years, etc.) off Canada's west coast. The data we generate will be used by researchers at Fisheries and Oceans Canada (and elsewhere) to refine their ecosystem models and improve their ability to forecast how Canada's marine resources may respond to changing ocean climates in the future.

这项研究的目的是测量两个因素，虽然至关重要的理解海洋食物链，很少在加拿大沃茨测量。第一个被称为“次级生产”，这是浮游动物产生的速度。浮游动物是微小的动物（大多数小于1厘米大小），以大多数海洋食物链底部的单细胞植物（称为“浮游植物”）为食。浮游动物被较大的动物-包括许多幼鱼和成鱼，某些海洋哺乳动物，甚至海鸟-消耗。第二个因素被称为“营养转移效率”（TTE）。简而言之，这是对食物链不同层次之间（例如从浮游植物到浮游动物）转移多少能量的估计。TTE越高，转移到食物链上的能量越多，可以支持的鱼类，海洋哺乳动物等的数量越多。这两个因素是海洋学家用来研究海洋食物网的数学模型的基本组成部分，并预测这些食物网在未来可能发生的变化。然而，主要由于技术原因，这两个因素都不是在海洋中直接测量的。相反，建模者依赖于从简化的实验室实验或理论研究中得出的数字。我的实验室已经开发出一种直接测量次级生产的方法，该方法基于测量大多数浮游动物在生长时释放到水中的一种酶（称为壳聚糖酶）。当与浮游植物生长速率的测量（称为“初级生产力”-自20世纪60年代以来海洋学家已经能够做到这一点）放在一起时，我们已经能够在自然场环境中产生TTE的第一个直接估计。在接下来的五年里，我们将扩大我们的工作，开始探索二次生产和TTE如何在不同的地点和不同的时间尺度（即季节性，年度之间等）之间变化。在加拿大西海岸附近我们生成的数据将被加拿大渔业和海洋局（以及其他地方）的研究人员用于完善他们的生态系统模型，并提高他们预测加拿大海洋资源如何应对未来海洋气候变化的能力。