Ocean Acidification: Seasonal and Ontogenetic Effects of Ocean Acidication on Pteropods in the Gulf of Maine

过量的人为二氧化碳溶解到海洋中，导致海洋环境的pH值下降。据预测，这种“海洋酸化”将威胁各种海洋生物，特别是钙化动物，如有壳的翼足类动物。这些远洋腹足类形成文石外壳，是许多具有商业价值的鱼类的猎物，也是碳生物地球化学的重要贡献者。它们的生态系统重要性、丰度和对溶解的敏感性使它们成为研究酸化影响的重要群体。然而，我们对高二氧化碳对翼足类和远洋生态系统的影响的了解，主要局限于对极地生态系统中成虫钙化和呼吸反应的短期研究。目前还没有关于敏感性的季节性研究，我们对二氧化碳对翼足类早期生命阶段的影响的了解也是有限的。反足利马线虫是北大西洋一种特别丰富的生态体翼足类动物，是许多渔业物种和其他顶级捕食者的猎物。这一物种也是缅因湾(GoM)最常见的翼足类动物，在那里它常年存在。因此，考虑到其生态重要性和在易于进入的水域中的丰富程度，反枝藻提供了一种有用的模式翼足类物种的前景。调查人员将进行一系列的短途航行，季节性地从科德角附近的GOM当地水域采集逆转录乳杆菌样本。GOM的碳酸盐化学随季节变化，证明它们有机会评估野生捕获的翼足类动物对二氧化碳自然变化的反应。通过表征水柱的碳酸盐化学特征，并测量全年翼足类动物的代谢率、贝壳质量和基因表达，研究人员将获得翼足类动物对二氧化碳敏感的时间序列。随后，研究人员将利用实验操作来探索季节性驯化对翼足类动物对短期和中期暴露于增强的二氧化碳的反应的影响。翼足类经常在圈养状态下产卵，在世界卫生组织，有在实验室维持这些个体的机构专业知识。在这些优势的基础上，研究人员还将研究二氧化碳对逆转录乳杆菌胚胎和幼虫发育的影响。海洋钙化生物的这些最早的生命阶段被认为是特别敏感的，因为最初的贝壳沉淀和高度活跃的生长和发育过程受到二氧化碳暴露的阻碍。他们还将记录暴露在二氧化碳增加中的翼足类动物胚胎的死亡率、外壳产量、异常和发育速度。智力价值：翼足类是一种大量的钙化浮游动物，长期未被研究，特别是在温带地区。由于其可获得性和生态重要性，白头翁可以作为一种有价值的模式动物发展，既是商业上重要的GOM地区的优势翼足类，也是北大西洋温带水域丰富的翼足类。这项研究的目的是增加我们对逆转录乳杆菌分布的了解，了解它们对二氧化碳自然变化的季节性敏感性，并了解这种暴露如何影响对短期和中期二氧化碳暴露的反应。利用强大的转录技术，这项研究将通过研究逆转录乳杆菌对季节性以及不同酸化持续时间和强度的分子机制，改变我们对这一群体的理解，并与生态系统和有机体水平的指标相联系。此外，这项研究将首次研究二氧化碳对翼足类动物卵的影响，为它们对酸化环境的敏感性提供洞察。广泛的影响：海洋酸化越来越被视为一个紧迫的社会问题。这些生态群落在生物地球化学循环中很重要，是各种商业鱼类的主要猎物，因此，我们寻求对翼足类生态的更好理解将对我们理解海洋酸化对海洋资源的影响具有重要意义。该项目将以多种方式将研究与教育相结合，包括对本科生的培训，以及作为博士后(和合作者)Maas博士职业发展的开创性经验。此外，利用这些极具魅力的微型动物的美学吸引力，研究人员将与记者、艺术家和摄影师合作，继续开发图像和展览，旨在提高公众对海洋酸化影响的认识。

Dissolution of excess anthropogenic CO2 into the ocean is causing the marine environment to decrease in pH. This "ocean acidification" is predicted to threaten a broad variety of marine organisms, particularly calcifying animals such as the thecosome (i.e., shelled) pteropods. These pelagic gastropods form an aragonite shell, are prey for a number of commercially important fish, and are significant contributors to carbon biogeochemistry. Their ecosystem importance, abundance, and sensitivity to dissolution position them as an important group for investigating the impacts of acidification. Our understanding of the effect of high CO2 on pteropods and the pelagic ecosystem, however, is limited primarily to short-term studies of adult calcification and respiration response in the polar ecosystems. There have been no seasonal studies of sensitivity and our understanding of the effect of CO2 on pteropod early life stages is limited. Limacina retroversa is a particularly abundant thecosome pteropod in the North Atlantic, where it is prey for a number of fisheries species and other top predators. This species is also the most common pteropod in the Gulf of Maine (GoM) where it is present year round. L. retroversa thus offers the prospect of a useful model pteropod species, given both its ecological importance and its abundance in readily accessible waters. The investigators will conduct a series of short cruises to sample L. retroversa on a seasonal basis from local waters of the GoM near Cape Cod. The carbonate chemistry of the GoM fluctuates seasonally, proving them with the opportunity to assess the response of wild caught pteropods to natural changes in CO2. By characterizing the carbonate chemistry of the water column and measuring the metabolic rate, shell quality, and gene expression of pteropods throughout the year, the researchers will achieve a time series of pteropod sensitivity to CO2. Subsequently, using experimental manipulations the investigators will explore the effect of seasonal acclimation on pteropod response to short- and medium-term exposure to enhanced CO2. Pteropods frequently lay eggs in captivity, and at WHOI there is institutional expertise in maintaining these individuals in the laboratory. Building on these strengths, the researchers will also study the effect of CO2 on embryonic and larval development in L. retroversa. These earliest life-stages of marine calcifiers are thought to be especially sensitive since initial shell precipitation and the highly energetic processes of growth and development are impeded by CO2 exposure. They will also document mortality, shell production, abnormality, and developmental rate of clutches of pteropod embryos exposed to increased CO2.Intellectual Merit: Thecosome pteropods are an abundant group of calcifying zooplankters that have been chronically understudied, particularly in temperate regions. Due to its accessibility and ecological importance, L. retroversa can be developed as a valuable model, interesting both as the dominant pteropod in the commercially-important GoM region and also an abundant pteropod in the temperate waters of the North Atlantic. The goal of this research is to augment our knowledge of the distribution of L. retroversa, to attain an understanding of their seasonal sensitivity to natural variability in CO2, and to see how this exposure impacts responses to both short- and medium-term CO2 exposure. Using powerful transcriptomic technologies, the research will transform our understanding of this group by investigating the molecular mechanisms of response in L. retroversa to both seasonality and varying durations and intensities of acidification, contextualized by ecosystem- and organism-level metrics. Furthermore the study will examine the effect of CO2 on the eggs of pteropods for the first time, providing insight into their sensitivity to an acidifying environment.Broader Impacts: Ocean acidification is increasingly appreciated as an urgent societal concern. Thecosomes are important in biogeochemical cycles and as key prey for a variety of commercial fish and as such, the improved understanding we seek of pteropod ecology will have important implications for our understanding of the effects of ocean acidification on marine resources. The project will integrate research with education in a number of ways, including the training of undergraduate students as well as serving as a seminal experience in the career development of postdoc (and co-PI) Dr. Maas. Furthermore, taking advantage of the aesthetic appeal of these charismatic microfauna, the researchers will pair with journalists, artists, and photographers to continue to develop images and exhibitions aimed at increasing public awareness of the impacts of ocean acidification.