Another Decade of Marine Climate Change Experiments: Trends, Progress and Knowledge Gaps

Abstract

Anthropogenic climate change is a significant driver of change in marine ecosystems globally. To improve mechanistic understanding of the impact of climate-related stressors, experimental work on marine organisms has intensified in recent decades. A previous synthesis paper published nearly a decade ago established that Marine Climate Change Experiments (MCCEs) published from 2000–2009 were primarily laboratory-based and focused on single stressors and individual focal temperate species. Using consistent methodology, we compared the 2000–2009 analysis to experiments published in the following decade (i.e. 2010–2019) to assess recent trends in MCCEs and to determine to what extent knowledge gaps and research priorities have been addressed. The search returned 854 papers, vs. 110 from the 2000s, indicating considerable intensification of research effort and output. We found again that single species studies were most common, particularly with benthic invertebrates as model organisms, and that laboratory-based research comprised over 90% of all studies. However, multiple stressor experiments increased substantially, where tests for interaction effects between ocean acidification (i.e., increased pCO2) and warming were particularly common. Furthermore, a wider range of model species were studied and more community-level experiments were conducted in the 2010s compared with the 2000s. In addition, studies on behavioral responses, transgenerational effects, genetic adaptation and extreme climatic events increased markedly. These recent advances in MCCEs have undoubtedly improved understanding of how climate change will affect marine organisms and the communities and ecosystems they underpin. Going forward, biases in the type and distribution of model organisms should be addressed to enhance general understanding of responses to environmental change. Similarly, experiments should manipulate a greater number and range of climate and non-climate factors and increase the number of target organisms to increase realism. Finally, where possible, further research should be combined and contextualized with field-based experiments and observations to better reflect the complexity of marine ecosystems and yield more representative responses to ocean climate change.

Biological Impacts of Marine Heatwaves

“…The volume of research relating to both the drivers of and biological responses to MHWs has increased dramatically in recent years (Hobday et al 2018a). Research on the impacts of MHWs has utilized a range of complementary approaches, including observational studies in natural systems, controlled experiments in both field and laboratory settings, and modeling studies (Bass et al 2021). This recent research effort has significantly advanced our understanding of MHW impacts.…”

“…While observational studies of responses to MHWs are correlative, experimental approaches can instead infer causation and improve mechanistic understanding of impacts. Experimental research on marine climate change impacts has intensified dramatically in recent decades, with an increasing number of studies focused on MHWs (Bass et al 2021). Controlled manipulations can be used to determine cause-effect relationships for single stressors (in this case, MHWs) in isolation, helping to disentangle their effects from those of other stressors in the marine environment.…”

“…In marine ecology, the majority of climate change experiments focus on a single species in isolation and/or manipulate a single stressor (e.g., temperature or ocean acidification; Bass et al 2021), even though species interact within complex communities and are often responding to multiple simultaneously. While significant progress toward more ecologically relevant controlled experiments has been made, many laboratory-based experiments suffer from experimental artifacts and low realism.…”

A Regional View of the Response to Climate Change: A Meta-Analysis of European Benthic Organisms’ Responses

“…These changes in the ocean physico-chemical properties have consequences for marine organisms including changes to growth, calcification, reproduction, metabolic processes, and survival; these effects though are highly variable across taxonomic groups (Kroeker et al, 2013;Cattano et al, 2018;Bindoff et al, 2019;Sampaio et al, 2021). While the development of the climatic drivers over the next decades is broadly well understood (Cooley et al, 2022) and a vast range of responses of individuals and their developmental stages exemplified, upscaling to the response of larger groups, ecosystems and their services is a vast challenge, despite scientific literature on individual studies accumulating (Bass et al, 2021).…”

Effect of Animal Stocking Density and Habitat Enrichment on Survival and Vitality of Wild Green Shore Crabs, Carcinus maenas, Maintained in the Laboratory

“…Animals may need to be held captive in the laboratory environment for a prolonged time period due to seasonal field sampling constraints or long-term experimental designs. Given the sheer volume of laboratory work using marine animals, notably in the context of environmental change [ 3 , 4 ], the welfare implications of keeping marine animals in laboratory conditions for long-term periods has increasing pertinence [ 5 , 6 ].…”