How do we overcome abrupt degradation of marine ecosystems and meet the challenge of heat waves and climate extremes?

Abstract

Extreme heat wave events are now causing ecosystem degradation across marine ecosystems. The consequences of this heat‐induced damage range from the rapid loss of habitat‐forming organisms, through to a reduction in the services that ecosystems support, and ultimately to impacts on human health and society. How we tackle the sudden emergence of ecosystem‐wide degradation has not yet been addressed in the context of marine heat waves. An examination of recent marine heat waves from around Australia points to the potential important role that respite or refuge from environmental extremes can play in enabling organismal survival. However, most ecological interventions are being devised with a target of mid to late‐century implementation, at which time many of the ecosystems, that the interventions are targeted towards, will have already undergone repeated and widespread heat wave induced degradation. Here, our assessment of the merits of proposed ecological interventions, across a spectrum of approaches, to counter marine environmental extremes, reveals a lack preparedness to counter the effects of extreme conditions on marine ecosystems. The ecological influence of these extremes are projected to continue to impact marine ecosystems in the coming years, long before these interventions can be developed. Our assessment reveals that approaches which are technologically ready and likely to be socially acceptable are locally deployable only, whereas those which are scalable—for example to features as large as major reef systems—are not close to being testable, and are unlikely to obtain social licence for deployment. Knowledge of the environmental timescales for survival of extremes, via respite or refuge, inferred from field observations will help test such intervention tools. The growing frequency of extreme events such as marine heat waves increases the urgency to consider mitigation and intervention tools that support organismal and ecosystem survival in the immediate future, while global climate mitigation and/or intervention are formulated.

Know Thy Anemone: A Review of Threats to Octocorals and Anemones and Opportunities for Their Restoration

“…Management interventions, such as genetic, reproductive, physiological, population/community, and environmental interventions, can be used to great effect in conservation and restoration efforts, though these techniques are not without complications (van Oppen et al, 2017; National Academies of Sciences Engineering and Medicine, 2019). For example, assisted evolution may be a viable method for increasing within-species resistance to ongoing pressures, and should be considered when trying to mitigate the effects of long term, unavoidable disturbances in conjunction with other short term methods (van Oppen et al, 2015(van Oppen et al, , 2017Ainsworth et al, 2019). As the topic of assisted evolution is beyond the scope of this review, please see van Oppen et al (2015Oppen et al ( , 2017 for further discussion.…”

Nitrogen enrichment in macroalgae following mass coral mortality

“…Although it is not yet known how long these nutrients remain in the system, if other environmental conditions are favourable enough, then corals might still be able to recover (Graham et al 2015). However, if these same reefs are also facing other local anthropogenic stressors, such as nutrient runoff or overfishing of herbivores, then large coral mortality events may result in competitive advantages to benthic organisms such as macroalgae, leading to a benthic regime shift (Ainsworth et al 2019). This emphasises the critical need to manage local stressors by detecting and reducing nutrient runoff and other drivers, especially on reefs that do still have high abundance of corals, and/ or have recently bleached.…”

Evolving the narrative for protecting a rapidly changing ocean, post‐COVID‐19

“…The consequences for climate and ecosystems have been enormous, with increases in ocean heat waves and other extreme events around the world (Holbrook et al, 2019; IPCC, 2019; Ainsworth et al, 2020; Cheung & Frölicher, 2020) and a much greater contribution of melting ice and snow to sea‐level rise than expected. Accelerating declines in sea ice, glaciers, ice sheets, and permafrost, as well as reductions in snow (Baxter et al, 2019; Connolly et al, 2019; Farquharson et al, 2019; Golledge et al, 2019; Maurer et al, 2019), together are contributing to accelerating sea‐level rise (Dieng et al, 2017; Nerem et al, 2018), threatening coastal and island habitability, ports and infrastructure, tourism, and coastal archaeology and food production (IPCC, 2019; Kulp & Strauss, 2019; Dawson et al, 2020).…”