Embracing interactions in ocean acidification research: confronting multiple stressor scenarios and context dependence

Abstract

Changes in the Earth's environment are now sufficiently complex that our ability to forecast the emergent ecological consequences of ocean acidification (OA) is limited. Such projections are challenging because the effects of OA may be enhanced, reduced or even reversed by other environmental stressors or interactions among species. Despite an increasing emphasis on multifactor and multispecies studies in global change biology, our ability to forecast outcomes at higher levels of organization remains low. Much of our failure lies in a poor mechanistic understanding of nonlinear responses, a lack of specificity regarding the levels of organization at which interactions can arise, and an incomplete appreciation for linkages across these levels. To move forward, we need to fully embrace interactions. Mechanistic studies on physiological processes and individual performance in response to OA must be complemented by work on population and community dynamics. We must also increase our understanding of how linkages and feedback among multiple environmental stressors and levels of organization can generate nonlinear responses to OA. This will not be a simple undertaking, but advances are of the utmost importance as we attempt to mitigate the effects of ongoing global change.

High CO2 decreases the long‐term resilience of the free‐living coralline algae Phymatolithon lusitanicum

“…Long-term field experiments incorporating environmental variability (e.g. McCoy, 2013), as well as organismal adaptation, may provide unparalleled insights into the effects of global change (Kroeker, Kordas, & Harley, 2017) on coastal ecosystems. Moreover, the better understanding of the environmental effects in combination with the sublethal effects reported in laboratory experiments will help to forecast the long-term ecological effects of global change (Kamenos, Perna, Gambi, Micheli, & Kroeker, 2016).…”

Species interactions cause non‐additive effects of multiple environmental stressors on communities

“…, Kroeker et al. ). The reported prevalence of non‐additive ecological surprises highlights how the unknown role of species interactions may be contributing to the uncertainty surrounding forecasts of the cumulative impacts of multiple stressors on communities (Paine et al.…”

“…, Kroeker et al. ). Competition can foster compensatory species dynamics that offset the impact of a stressor on a community through release of tolerant species following suppression of more sensitive competitors (Frost et al.…”

Advancing understanding and prediction in multiple stressor research through a mechanistic basis for null models

“…Studies to date have largely focused on twostressor interactions (Griffen, Belgrad, Cannizzo, Knotts, & Hancock, 2016; but see for example Piggott, Salis, Lear, Townsend, & Matthaei, 2015), whereby one stressor modifies (1) the second stressor's intensity (e.g. change in susceptibility to predation (stressor 1) through behavioural effects of stressor 2 such as reduced mobility; for details see Kroeker, Kordas, & Harley, 2017). change in susceptibility to predation (stressor 1) through behavioural effects of stressor 2 such as reduced mobility; for details see Kroeker, Kordas, & Harley, 2017).…”