Collaborative Research: Midwater animal models: Optical measurement of metabolic transitions in pelagic biota

该奖项是根据2009年《美国复苏和再投资法案》(公法111-5)资助的。尽管覆盖了地球上99%以上的宜居空间，但中水环境及其居民是地球上研究最少的环境之一，主要是由于它们的偏远和技术限制，无法进行直接研究。利用光学技术，包括光谱分析和视频图像分析，对生理功能进行直接、非侵入性的成像，将中水动物(浮游动物和微型浮游动物)转变为理想的生理模型。在这种情况下，透明是远洋环境中普遍存在的伪装策略，从字面上讲，它允许对动物生理学的洞察(即，它有助于生理成像)。因此，现在有可能在中水动物身上进行生理实验，这些实验的复杂性与通常在更强壮的鱼类和哺乳动物上进行的实验相同，但时间分辨率更高。本项目是侵入性较小的采样和光学生理学方法的新组合，将阐明中水生物在极端缺氧条件下生存所采用的代谢策略，这些极端低氧环境是大部分中水环境的特征。研究人员将进一步使用通过这些氧气最低限度区域的二氧化碳浓度变化作为一个自然实验室来测试对海洋酸化的生理反应。他们将量化与氧浓度有关的代谢转变，这些生物在生态上很重要，但研究不足。他们将测试与透明度(即捕食者的可见性)和代谢率相关的假设，以此作为指示捕食者躲避能力的指标。具体地说，研究人员将测量血液氧结合、心率、每搏量、通气率和通气量、组织的氧化状态(NAD+：NADH)和整个动物的耗氧率。并非所有上述参数都与所有待研究物种相关。他们将研究来自各种浮游动物和小藻类的透明代表，包括鱼类、幼虫、毛丝虫、多毛类、水母、盐碱类、两足类和腹足类，但重点将放在头足类上，因为1)它们的闭合循环系统和血液氧结合蛋白允许充分开发和利用光生理技术，2)因为它们独特的生理方面对耐缺氧特别感兴趣，使它们容易受到海洋酸化的影响。这个项目为综合研究海洋生物的生态生理学提供了一个模型。这种方法有可能揭示海洋生物对全球变暖和海洋酸化的耐受性。此外，氧气最低限度区域正在扩大，这可能会对海洋生物群造成严重后果。该项目包括在URI和杜克大学对三名研究生进行与光学生理学相关的独特技术套件的培训。调查人员还将为几名研究生和本科生提供出海机会。该项目将促进与德国科学家及其学生的合作。所要求的船只和潜水时间将尽可能与来自不同机构的科学家和学生分享。此外，深海和海洋生物学对公众的吸引力是巨大的。调查人员将通过Bloom Association(www.BloomAssociation.org)向公众提供获得的图像和视频(其中一些是有史以来拍摄的最近距离和最详细的)。Bloom是一个非营利性协会，其使命是通过对更广泛的公众进行环境问题教育来保护海洋，更具体地说，保护深海。布鲁姆的创造者克莱尔·诺维安过去曾参加过邮轮旅行，并同意参加拟议中的探险活动。

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)." Despite encompassing more than 99% of the livable space on the planet, the midwater environment and its inhabitants are among the least studied on the planet, primarily due to their remoteness and the technological limitations that have precluded direct study. The use of optical techniques, including spectroscopy and video image analysis, for direct, non-invasive imaging of physiological function transforms midwater animals (zooplankton and micronekton) into ideal physiological models. In this case, transparency, a ubiquitous camouflage strategy in the pelagic environment, allows, literally speaking, insights into animal physiology (i.e. it facilitates physiological imaging). Thus, it is now possible to conduct physiological experiments on midwater animals that are of equal complexity, but greater temporal resolution, to those routinely performed on more robust fishes and mammals. The present project is a novel combination of less invasive sampling and optical physiological methods that will elucidate the metabolic strategies employed by midwater organisms for survival in the extreme hypoxia characterizing much of the midwater environment. The investigators will further use the changing CO2 concentrations through these oxygen minimum zones as a natural laboratory to test physiological responses to ocean acidification. They will quantify metabolic transitions relating to oxygen concentration for ecologically important, but understudied, midwater organisms. They will test hypotheses relating transparency (i.e. visibility by predators) and metabolic rates as an indication of the capacity for predator avoidance. Specifically, the investigators will measure blood oxygen binding, heart rate, stroke volume, ventilation rate and volume, oxidation state of the tissues (NAD+:NADH) and whole-animal oxygen consumption rates. Not all of the above parameters are relevant to all species to be studied. They will study transparent representatives from a broad spectrum of zooplankton and micronektonic groups, including fishes, larvaceans, chaetognaths, polychaetes, jellies, salps, amphipods, and gastropods but will focus on cephalopods because of 1) their closed circulatory systems and blood oxygen binding proteins allow the full development and utilization of optical physiological techniques and 2) because unique aspects of their physiology are of special interest for hypoxia tolerance and render them vulnerable to ocean acidification.This project provides a model for an integrated approach to studying the ecological physiology of pelagic organisms. The approach has potential to reveal the tolerance of oceanic organisms to global warming and ocean acidification. Furthermore, oxygen minimum zones are expanding with potentially severe consequences for oceanic biota. The project includes training at both URI and Duke University for three graduate students in a unique suite of techniques relevant to optical physiology. The investigators will also provide opportunities to go to sea for several graduate and undergraduate students. The project will foster collaboration with German scientists and their students. The ship and submersible time requested will be shared to the extent possible with scientists and students from diverse institutions. Further, the public appeal of deep-sea and oceanic biology is great. The investigators will make the images and video obtained (some of the most close-up and detailed ever taken) available to the public via the Bloom Association (www.bloomassociation.org). Bloom is a non-profit association whose mission is to protect the oceans and, more particularly, the deep sea, through education of the greater public about environmental problems. The creator of Bloom, Claire Nouvian, has participated in cruises in the past and has agreed to take part in the proposed expeditions.