Avoiding coral reef functional collapse requires local and global action

Coral reefs face multiple anthropogenic threats, from pollution and overfishing to the dual effects of greenhouse gas emissions: rising sea temperature and ocean acidification [1]. While the abundance of coral has declined in recent decades [2 and 3], the implications for humanity are difficult to quantify because they depend on ecosystem function rather than the corals themselves. Most reef functions and ecosystem services are founded on the ability of reefs to maintain their three-dimensional structure through net carbonate accumulation [4]. Coral growth only constitutes part of a reef’s carbonate budget; bioerosion processes are influential in determining the balance between net structural growth and disintegration [5 and 6]. Here, we combine ecological models with carbonate budgets and drive the dynamics of Caribbean reefs with the latest generation of climate models. Budget reconstructions using documented ecological perturbations drive shallow (6–10 m) Caribbean forereefs toward an increasingly fragile carbonate balance. We then projected carbonate budgets toward 2080 and contrasted the benefits of local conservation and global action on climate change. Local management of fisheries (specifically, no-take marine reserves) and the watershed can delay reef loss by at least a decade under “business-as-usual” rises in greenhouse gas emissions. However, local action must be combined with a low-carbon economy to prevent degradation of reef structures and associated ecosystem services.

Colliding stories; how discourses in ocean acidification are subsumed in climate change

Like climate change, ocean acidification is a globally complex problem caused by increasing atmospheric CO2 as a result of human consequences from carbon intensive social practices. Using inductive discourse methods and thematic analysis, this study examines the complex interplay of social ideas using Hajer’s storyline framework as the method of choice to draw comparisons between narrative features in ocean acidification and climate change discourses and identifies whether ocean acidification is characterised together or separately from climate change as a result of new storylines. Any separation may not only benefit ocean acidification but may also alter the current resolution pathway for climate change. Interview research drives emergent narrative themes which are configured using data coding categories. The number of categories is limited partly by design to make it easier to interpret and analyse interview participant viewpoints and their corresponding storylines. Narratives are contextualised into three emergent themes with focus on political, technological and social pathways, with particular focus on storylines that are energised and routinised by participants through social everyday practice.

Assessing the risk of climate change to aquaculture: a case study from south-east Australia

A qualitative screening-level risk assessment was developed to evaluate relative levels of risk from climate change to aquaculture industries. The assessment was applied to 7 major industries in the temperate south-east region of Australia and involved a simple, transparent and repeatable methodology that was appropriate for a range of different aquaculture systems and taxa. Two key stages were involved: the development of comprehensive expertise-based literature reviews or ‘species profiles’ and a scoring assessment, with the latter providing a defined framework within which industries could be ranked (from high to low risk). In addition to informing the second stage of the risk assessment process, the species’ profiles also highlighted important climate change drivers and key information uncertainties and knowledge gaps. There was good resolution among the scoring assessments, with only 2 industries receiving the same risk score. The results indicated that oysters farmed from wild spat (Sydney rock oysters Saccostrea glomerata) were at most risk to climate change, with warm temperate hatchery-based finfish species (yellowtail kingfish Seriola lalandi) being the least at risk. This study provides critical guidance for scientists, resource managers and stakeholders for future research, both in addressing key knowledge gaps and focussing the development of more detailed risk analyses for high risk aquaculture industries in south-east Australia.

Addressing ocean acidification as part of sustainable ocean development

Many of the declarations and outcome documents from prior United Nations international meetings address ocean issues such as fishing, pollution, and climate change, but they do not address ocean acidification. This progressive alteration of seawater chemistry caused by uptake of atmospheric carbon dioxide (CO2) is an emerging issue of concern that has potential consequences for marine ecosystems and the humans that depend on them. Addressing ocean acidification will require mitigation of global CO2 emissions at the international level accompanied by regional marine resource use adaptations that reduce the integrated pressure on marine ecosystems while the global community works towards implementing permanent CO2 emissions reductions. Addressing ocean acidification head-on is necessary because it poses a direct challenge to sustainable development targets such as the Millennium Development Goals, and it cannot be addressed adequately with accords or geoengineering plans that do not specifically decrease atmospheric carbon dioxide levels. Here, we will briefly review the current state of ocean acidification knowledge and identify several mitigation and adaptation strategies that should be considered along with reductions in CO2 emissions to reduce the near-term impacts of ocean acidification. Our goal is to present potential options while identifying some of their inherent weaknesses to inform decisionmaking discussions, rather than to recommend adoption of specific policies. While the reduction of CO2 emissions should be the number one goal of the international community, it is unlikely that the widespread changes and infrastructure redevelopment necessary to accomplish this will be achieved soon, before ocean acidification’s short-term impacts become significant. Therefore, a multi-faceted approach must be employed to address this growing problem.

A steep learning curve

Ocean acidification, caused by the uptake of anthropogenic carbon dioxide, is a significant stressor to marine life. Ulf Riebesell charts the rapid rise in ocean acidification research, from the discovery of its adverse effects to its entry into the political consciousness.

Preparing to manage coral reefs for ocean acidification: lessons from coral bleaching

Ocean acidification is a direct consequence of increasing atmospheric carbon dioxide concentrations and is predicted to compromise the structure and function of coral reefs within this century. Research into the effects of ocean acidification on coral reefs has focused primarily on measuring and predicting changes in seawater carbon (C) chemistry and the biological and geochemical responses of reef organisms to such changes. To date, few ocean acidification studies have been designed to address conservation planning and management priorities. Here, we discuss how existing marine protected area design principles developed to address coral bleaching may be modified to address ocean acidification. We also identify five research priorities needed to incorporate ocean acidification into conservation planning and management: (1) establishing an ocean C chemistry baseline, (2) establishing ecological baselines, (3) determining species/habitat/community sensitivity to ocean acidification, (4) projecting changes in seawater carbonate chemistry, and (5) identifying potentially synergistic effects of multiple stressors.

Que faire face à l’acidification des océans ? (in French)

Ce Policy Brief est une synthèse d’un article proposé en juillet 2012 à la revue Environmental Management, en cours d’évaluation.

Integrating climate and ocean change vulnerability into conservation planning

Tropical coastal and marine ecosystems are particularly vulnerable to ocean warming, ocean acidification, and sea-level rise. Yet these projected climate and ocean change impacts are rarely considered in conservation planning due to the lack of guidance on how existing climate and ocean change models, tools, and data can be applied. Here, we address this gap by describing how conservation planning can use available tools and data for assessing the vulnerability of tropical marine ecosystems to key climate threats. Additionally, we identify limitations of existing tools and provide recommendations for future research to improve integration of climate and ocean change information and conservation planning. Such information is critical for developing a conservation response that adequately protects these ecosystems and dependent coastal communities in the face of climate and ocean change.

Blue Ribbon Panel report

Gov. Gregoire’s Blue Ribbon Panel on Ocean Acidification released its recommendations on 27 November  2012.

Ocean acidification – what can we do?

This policy brief is based on a more comprehensive article submitted to Environmental Management in July 2012, and currently under review.