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: 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=745683
• 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.

这项研究旨在衡量两个因素，尽管对于理解海洋粮链至关重要，但在加拿大水域中很少衡量。第一个被称为“二级生产”，这是产生浮游动物的速率。浮游动物是在大多数海洋食品链的底部以单细胞植物（称为“浮游植物”）为食的小动物（大部分小于1厘米）。浮游动物被大型动物所消耗 - 包括许多年轻和成年鱼类，某些海洋哺乳动物，甚至是海鸟。第二个因素称为“营养转移效率”（TTE）。简而言之，这是对不同水平的食物链（例如从浮游植物到浮游生物）之间传递多少能量的估计。 TTE越高，可以支持的鱼类，海洋哺乳动物等的能量越多，可以支持的鱼类，海洋哺乳动物等。这两个因素是海洋学家用来研究海洋食品网的数学模型的基础的重要组成部分，并预测这种食物网将来如何变化。但是，主要是出于技术原因，这两个因素都直接在海洋中测量。取而代之的是，建模者依赖于简化的实验室实验或理论研究的数字。我的实验室已经开发了一种基于测量大多数浮游动物随着生长的酶释放到水中的酶（称为Chitobiase）的方法，可以直接测量二级生产。当将浮游植物生长速率（称为“初级生产” - 自1960年代以来海洋学家能够做到这一点）结合在一起时，我们已经能够在自然野外环境中产生第一个直接估计TTE的直接估计。在接下来的五年中，我们将扩大我们的工作，以开始探索位置之间的二级生产和TTE在加拿大西海岸的不同时间表之间以及不同时间尺度（即季节性，年份等）之间的变化。我们生成的数据将被加拿大渔业和海洋（以及其他地方）的研究人员使用，以完善其生态系统模型，并提高他们预测加拿大海洋资源如何对未来不断变化的海洋气候做出反应的能力。