Department of Zoology, University of British Columbia, Vancouver, V6T 1Z4, British Columbia, Canada.
Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, V6T 1Z4, British Columbia, Canada.
Ecology. 2020 Aug;101(8):e03073. doi: 10.1002/ecy.3073. Epub 2020 Jun 15.
Physiological responses to ocean acidification are thought to be related to energetic trade-offs. Although a number of studies have proposed that negative responses to low pH could be minimized in situations where food resources are more readily available, evidence for such effects on individuals remain mixed, and the consequences of such effects at the community level remain untested. We explored the potential for food availability and diet quality to modify the effects of acidification on developing marine fouling communities in field-deployed mesocosms by supplementing natural food supply with one of two species of phytoplankton, differing in concentration of fatty acids. After 12 weeks, no species demonstrated the interactive effects generally predicted in the literature, where a positive overall effect of diet mitigated the negative overall effects of acidification. Rather, for some species, additional food supply appeared to bring out or exacerbate the negative effects of low pH. Community richness and structure were only altered by acidification, while space occupation and evenness reflected patterns of the most dominant species. Importantly, we find that acidification stress can increase the relative abundance of invasive species, even under resource conditions that otherwise prevented invasive species establishment. Overall, the proposed hypothesis regarding the ability for food addition to mitigate the negative effects of acidification is thus far not widely supported at species or community levels. It is clear that acidification is a strong driving force in these communities but understanding underlying energetic and competitive context is essential to developing mechanistic predictions for climate change responses.
生理对酸化的响应被认为与能量权衡有关。虽然许多研究提出，在食物资源更容易获得的情况下，对低 pH 的负面反应可以最小化，但这些对个体的影响的证据仍然存在分歧，而这种影响在群落水平上的后果仍未得到检验。我们通过用两种浮游植物中的一种补充自然食物供应，来探索食物供应和饮食质量是否可以在野外部署的中观模型中改变酸化对发育中的海洋污垢群落的影响，这两种浮游植物在脂肪酸浓度上有所不同。12 周后，没有一种物种表现出文献中普遍预测的相互作用效应，即饮食的总体积极效应减轻了酸化的总体负面影响。相反，对于某些物种，额外的食物供应似乎带来或加剧了低 pH 的负面影响。群落丰富度和结构仅受酸化影响，而空间占用和均匀度反映了最优势物种的模式。重要的是，我们发现酸化压力可以增加入侵物种的相对丰度，即使在资源条件下，否则会阻止入侵物种的建立。总的来说，关于食物添加减轻酸化负面影响的能力的假设在物种或群落水平上还没有得到广泛支持。很明显，酸化是这些群落的一个强大驱动力，但理解潜在的能量和竞争背景对于开发气候变化响应的机制预测至关重要。
