Collaborative Research: A metabolic index to predict the consequences of expanding oxygen minimum zones for midwater ecosystems

合作研究：预测中层生态系统最低含氧区扩大后果的代谢指数

• 批准号: 1458967
• 负责人: Curtis Deutsch
• 金额: $ 16.7万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-10-01 至 2018-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1458967&HistoricalAwards=false
• 关键词: Collaborative; Research; metabolic; index; predict

With climate change, ocean temperatures are expected to increase which in turn will reduce oxygen availability and increase metabolic oxygen demand in marine organisms. The investigators will conduct shipboard physiological experiments for various marine organisms and determine their distributions in relation to environmental conditions within an oxygen minimum zone (OMZ) in the Eastern Pacific Ocean. The goal will be to model and map a Metabolic Index (MI) to predict how vertical and horizontal distributions for these species might change throughout the world's oceans in the future. The MI is defined as the ratio between environmental oxygen supply and temperature-dependent oxygen demand. Oxygen supply includes both the environmental oxygen concentration across a habitat range and the physiological features of organisms that facilitate oxygen uptake, such as gills and circulatory systems. Thus, the MI will integrate measured tolerance and environmental exposure to low oxygen with environmental data. The investigators will measure tolerance to low oxygen, focusing on under-studied organisms, including the effect of temperature and organism size. They will sample along a natural gradient in oxygen content south of the California Current in the Eastern Pacific. The science team and a videographer will develop a blog about deep-sea biology and climate change using web-based and video technologies. Four graduate students will be funded on this project, and in conjunction with a recently developed course in pelagic ecology, several undergraduates will have the opportunity to participate in seagoing research.This research fills a critical need for a physiology-based metric that can be used to predict changing marine communities as the oceans warm and hypoxic zones expand. Modern OMZs are extensive and characterized by deep-water (300-800 m) oxygen partial pressures lethal to most marine organisms, yet thriving communities exist there. Climate change is predicted to further deplete oxygen. The investigators will model and map a Metabolic Index (MI) for diverse marine species to help predict how in vertical and horizontal distributions of species may change throughout the world's oceans in the future. The MI will derive oxygen supply and demand data from published and planned measurements of the minimum environmental partial pressure of oxygen to which individual species are exposed (based on their distributions in the water column) and the minimum requirements to support routine aerobic metabolic demand (from shipboard respiration measurements of individuals). During research cruises in the Eastern Pacific along a gradient of OMZ intensity, the investigators will conduct shipboard physiological measurements to determine metabolic demand for understudied mesozooplankton and gelatinous taxa and determine the size- and temperature dependence for diverse species for incorporation into the MI. Vertically-stratified net sampling and in situ photography will identify and characterize unique OMZ community features, such as the lower oxycline biomass peak present in some OMZs and the oxygen-dependence of day and night habitat depths for vertically-migrating species. The MI will be mapped using climatological data to both test and generate hypotheses about the response of oceanic communities to climate change. In preliminary analysis, the MI suggests a metabolic constraint at a MI of ~2 that may act to limit vertical and horizontal habitat ranges.

随着气候变化，海洋温度预计将上升，这反过来将减少氧气供应，增加海洋生物的代谢需氧量。 调查人员将在船上对各种海洋生物进行生理实验，并确定它们在东太平洋最低含氧区（OMZ）内与环境条件有关的分布情况。目标是建立模型并绘制代谢指数（MI），以预测未来这些物种在世界海洋中的垂直和水平分布可能如何变化。MI定义为环境氧供应与温度依赖性氧需求之间的比率。氧气供应包括整个栖息地范围内的环境氧气浓度和促进氧气摄取的生物体的生理特征，如鳃和循环系统。因此，MI将把测得的低氧耐受性和环境暴露与环境数据结合起来。 研究人员将测量对低氧的耐受性，重点是研究不足的生物体，包括温度和生物体大小的影响。他们将沿着东太平洋加州海流以南的氧气含量自然梯度沿着取样。 科学小组和一名摄像师将利用网络和视频技术开发一个关于深海生物学和气候变化的博客。 该项目将资助四名研究生，结合最近开发的远洋生态学课程，几名本科生将有机会参加海上研究，这项研究满足了对一种基于生理学的指标的迫切需要，这种指标可用于预测随着海洋温暖和缺氧区的扩大而变化的海洋群落。现代的有机物隔离区面积很大，其特点是深水（300-800米）的氧分压对大多数海洋生物都是致命的，但那里仍然存在着繁荣的群落。据预测，气候变化将进一步耗尽氧气。研究人员将为不同的海洋物种建模和绘制代谢指数（MI），以帮助预测未来世界海洋中物种的垂直和水平分布可能如何变化。MI将从公布和计划的个别物种所暴露的最低环境氧分压的测量值（基于其在水柱中的分布）和支持常规有氧代谢需求的最低要求（从船上对个人的呼吸测量值）中得出氧供应和需求数据。 在东太平洋沿着大洋区强度梯度进行研究航行期间，调查人员将在船上进行生理测量，以确定未充分研究的中型浮游动物和胶状分类群的代谢需求，并确定纳入MI的各种物种的大小和温度依赖性。 垂直分层净采样和原位摄影将确定和表征独特的OMZ社区功能，如较低的oxycline生物量峰值存在于一些OMZ和垂直迁移物种的昼夜栖息地深度的氧气依赖。 将利用气候数据绘制MI图，以检验和提出关于海洋群落对气候变化的反应的假设。 在初步分析中，MI表明在MI ~2时的代谢约束可能会限制垂直和水平栖息地范围。