Generality in multispecies responses to ocean acidification revealed through multiple hypothesis testing. (25th July 2018)

• Record Type: Journal Article
• Authors: Barner, Allison K.; Chan, Francis; Hettinger, Annaliese; Hacker, Sally D.; Marshall, Kelsey; Menge, Bruce A.
• Is Part Of: Global change biology. Volume 24:Number 10(2018)
• Page Start: 4464
• Page End: 4477
• Publication Date: 2018-07-25
• Subjects: allometry -- calcification -- coralline algae -- eco‐physiology -- functional groups -- functional traits -- global change -- rocky intertidal; Climatic changes -- Environmental aspects -- Periodicals; Troposphere -- Environmental aspects -- Periodicals; Biodiversity conservation -- Periodicals; Eutrophication -- Periodicals; 551.5
• DOI: 10.1111/gcb.14372
• Languages: English
• ISSNs: 1354-1013

Abstract

Abstract: Decades of research have demonstrated that many calcifying species are negatively affected by ocean acidification, a major anthropogenic threat in marine ecosystems. However, even closely related species may exhibit different responses to ocean acidification and less is known about the drivers that shape such variation in different species. Here, we examine the drivers of physiological performance under ocean acidification in a group of five species of turf‐forming coralline algae. Specifically, quantitating the relative weight of evidence for each of ten hypotheses, we show that variation in coralline calcification and photosynthesis was best explained by allometric traits. Across ocean acidification conditions, larger individuals (measured as noncalcified mass) had higher net calcification and photosynthesis rates. Importantly, our approach was able to not only identify the aspect of size that drove the performance of coralline algae, but also determined that responses to ocean acidification were not dependent on species identity, evolutionary relatedness, habitat, shape, or structural composition. In fact, we found that failure to test multiple, alternative hypotheses would underestimate the generality of physiological performances, leading to the conclusion that each species had different baseline performance under ocean acidification. Testing among alternative hypotheses is an essential step toward determining the generalizability of experiments across taxa and identifying common drivers of species responses to global change. Abstract : Although many species have similar responses to ocean acidification, we know little about what drives differences among species in their response to ocean acidification. We hypothesized that species that are closely related, live in similar habitats, or have similar traits, should all respond similarly to global change. We tested whether each hypothesis could explain the response of five species of coralline algae to experimental ocean acidification. We find that the effect of ocean acidification on these five species was largely a function of size and without our hypothesis‐testing framework, we would have underestimated similarities in species responses to ocean acidification.