BivCRS2 - Time dependence of thermal tolerance in marine bivalves: extant fauna and implications for palaeo-analogues

生理学在研究气候变化对海洋外温带和生态系统的影响方面的相关性目前受到生理现象和生态系统一级过程之间的定量联系有限的限制。就目前而言，这样的证据仍然很少，对于遥远的过去来说，更是如此。拟议的项目BivCRS2希望通过确定那些塑造和限制极端条件下依赖时间的生存的机制的数量贡献来填补这一空白。显然，对机制的理解只能从现存的动物身上得出，假设这些机制仍然存在，这些机制在遥远的过去塑造了动物的命运，解释了在逐渐的环境变化下动物丧失的模式和不可逆转的情况。事实上，数量有限的研究已经在一方面报告气候对生态系统一级物种的影响的实地研究和另一方面确定这种影响的原因的实验室研究之间建立了明确的联系。除了温度及其极端情况的影响外，实验室研究和连续的荟萃分析揭示了海洋动物对极端低氧和海洋酸化的脆弱性，极端低氧的影响与物种温度范围以外的极端温度一样强烈。因此，极端温度和极端缺氧可能会造成短期的致命影响，然而，它们也具有综合影响。BivCRS2在第二阶段的主要目标是提高预测能力，以确定物种对气候变化反应的统一原则，并量化物种群体不同和特定脆弱性的基础机制。因此，在古模式研究的背景下，BivCRS2将解决物种为什么以及如何专门研究有限但不同的温度范围，为什么和在什么温度下它们对积累的二氧化碳敏感，并沿着相同的路线，它们如何处理环境中的缺氧症。阶段1比较(D)牡蛎和扇贝主动维持健康的能力。第二阶段将讨论它们的被动容忍能力，即支撑这种能力的一套机制，以期对环境极端容忍的时间限制产生影响。重点是，在热窗的pejus界限之外，变暖、酸化和缺氧(“致命三重奏”)的相互作用如何改变耐受限度和能力，例如通过代谢抑制、改变酸碱参数、利用抗氧化防御、能量储备和模式以及厌氧代谢能力。功能范围的缩小可能会导致主动热耐量的缩小，从而带来表达的和延长的被动耐受性的潜在好处。

The relevance of physiology in studies of climate change effects on marine ectotherms and ecosystems is currently constrained by limited availability of quantitative links between physiological phenomena and ecosystem level processes. Such evidence is still scarce for the present, and even more so for the deep past. The proposed project BivCRS2 wants to fill this gap by identifying the quantitative contribution of those mechanisms that shape and limit the time dependent survival under extreme conditions. Clearly, an understanding of mechanisms can only be derived from extant fauna, assuming that those mechanisms are still in place that have shaped the fate of fauna in the deep past, explaining the patterns and irreversibility of faunal losses under progressive environmental change. A limited number of studies have in fact established clear links between, on the one hand, field studies reporting a climate-induced effect on species at ecosystem level and, on the other hand, laboratory studies establishing the reasons for such an effect. In addition to the effects of temperature and its extremes, laboratory studies and consecutive meta-analyses have revealed vulnerability of marine fauna to extreme hypoxia and ocean acidification, with extreme hypoxia having an effect as strong as temperature at extremes outside of the thermal range of species. Temperature and hypoxia extremes are thus candidates to cause short term lethal impacts, however, they also have combined effects. The main goal of BivCRS2 within phase 2 is to increase predictive power for characterizing unifying principles of species responses to climatic changes and to quantify the mechanisms underpinning different and specific vulnerabilities of species groups. In the context of palaeo-patterns research in BivCRS2 will therefore address why and how species are specialized on limited but different temperature ranges, why and at what temperatures they are sensitive to accumulating CO2 and along the same lines, how they deal with ambient oxygen deficiency. Phase 1 compares(d) the capacities of oysters and scallops to sustain fitness actively. Phase 2 will address their passive tolerance capacity, the set of mechanisms underpinning such capacity, with a view on the implications for the time limitation of tolerance to environmental extremes. The focus is on how, beyond pejus limits of the thermal window, interactions of warming, acidification, and hypoxia (“deadly trio“) may shift limits and capacities of tolerances, e.g. through metabolic depression, shifting acid-base parameters, and exploitation of antioxidative defence, energy reserves and mode, and capacity of anaerobic metabolism. Reduced functional scope may cause a narrowing of active thermal tolerance with the potential benefit of expressed and extended passive tolerance.