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The health of the ocean, central to human well-being, has now reached a critical point. Most fish stocks are overexploited, climate change and increased dissolved carbon dioxide are changing ocean chemistry and disrupting species throughout food webs, and the fundamental capacity of the ocean to regulate the climate has been altered. However, key technical, organizational, and conceptual scientific barriers have prevented the identification of policy levers for sustainability and transformative action. Here, we recommend key strategies to address these challenges, including (1) stronger integration of sciences and (2) ocean-observing systems, (3) improved science-policy interfaces, (4) new partnerships supported by (5) a new ocean-climate finance system, and (6) improved ocean literacy and education to modify social norms and behaviors. Adopting these strategies could help establish ocean science as a key foundation of broader sustainability transformations.

IntroductionHistorically considered to be a single cosmopolitan species, the so calledOctopus vulgarisspecies complex (OVSC) is now recognized to be a group of (at least) six cryptic species:O. americanus(in the west Atlantic),O. vulgaris(in the northeast Atlantic and Mediterranean Sea),O.aff. vulgaris(in the region of South Africa),O. tetricus(southeastern Oceania),O. sinensis(northwestern Pacific), andO. djinda(western Australia). The potentially different environmental preferences of this highly cryptic species complex may result in distinct consequences under future environmental conditions.MethodsThe present study employed species distribution models (SDM) using MaxEnt to investigate potential changes in habitat suitability and geographical distribution of the OVSC in the future (i.e., 2050, and 2100), across four representative concentration pathway scenarios (RCP-2.6, 4.5, 6.0, and 8.5, CMIP5).ResultsDifferential responses were observed in the OVSC species analyzed. Specifically,O. vulgarisandO. tetricusexhibited a severe loss in distribution across their predicted range;O. americanusexhibited projected extirpation close to the equator, with limited expansion towards the poles;O.aff. vulgariswas projected to lose half of its current distribution;O. sinensisexhibited moderate losses, with projected increases in northern areas; and finally,O. djindaexhibited limited losses to its distribution. Except forO. sinensis, increasing RCP severity exacerbated changes in mean habitat suitability and projected distribution gains and losses.DiscussionUltimately, this study provides information on the potential biogeographical effects of marine climate change on a key worldwide ecological and economic resource to further disentangle the effects over each OVSC species, with the goal of assisting toward the sustainable management of octopus species at the global scale.

Sustainable development of marine resources requires a robust national coastal and ocean policy and harmonization of environmental management systems in areas of overlapping interests among nations. This is becoming increasingly important in the efforts of governments worldwide. Critical issues related to the exploitation of natural resources and the degradation of marine ecosystems, coupled with global crosscutting environmental issues such as climate change and climate-related hazards, require forging cross-border cooperation and international consensus on ensuring ecosystem-based approach principles in marine management and maritime domain awareness and security as reflected in the U.N.’s Sustainable Development Goals. Increasing the scale of marine planning processes entails increased cooperation on humankind’s shared endowment of global oceans and interconnected marine systems. As a result, interactions across the world are multiplying, which intensifies the dialogue of civilisations. The following exploration of a roadmap for developing an Integrated Marine/Maritime Policy in the Asia-Pacific region reveals enhanced opportunities for maintaining environmental integrity and sustainability in transboundary areas while considering local, regional, and global socio-economic and environmental challenges. This is a science-policy analysis of the marine-related practices of the region under consideration. The key here is to improve environmental safety and strengthen global security because of coherent actions jointly adopted in a setting of mutual respect and unity by a shared purpose to create reliable foundations for sustainable development in the Asia-Pacific region.

AbstractEcological impact of global change is generated by multiple synchronous or asynchronous drivers which interact with each other and with intraspecific variability of sensitivities. In three near-natural experiments, we explored response correlations of full-sibling germling families of the seaweed Fucus vesiculosus towards four global change drivers: elevated CO2 (ocean acidification, OA), ocean warming (OW), combined OA and warming (OAW), nutrient enrichment and hypoxic upwelling. Among families, performance responses to OA and OW as well as to OAW and nutrient enrichment correlated positively whereas performance responses to OAW and hypoxia anti-correlated. This indicates (i) that families robust to one of the three drivers (OA, OW, nutrients) will also not suffer from the two other shifts, and vice versa and (ii) families benefitting from OAW will more easily succumb to hypoxia. Our results may imply that selection under either OA, OW or eutrophication would enhance performance under the other two drivers but simultaneously render the population more susceptible to hypoxia. We conclude that intraspecific response correlations have a high potential to boost or hinder adaptation to multifactorial global change scenarios.

Abstract Marine policymakers are facing increasing calls to consider the resilience of communities that rely on coastal and marine ecosystem goods and services, and the resilience of natural systems themselves. These calls are in response to increasing threats to coastal communities from external factors such as coastal hazards, possibly associated with climate change, reductions in natural capital often caused by over-fishing and invasive species, and drivers that act to change local and regional economic conditions leading to changes in employment and inequality. However, most communities have had little experience in explicitly managing for resilience. Similarly, our understanding of the factors that make a natural or social system resilient is also somewhat limited. Furthermore, there is a lack of consensus-based definitions and performance measures for assessing resilience. These factors, along with other barriers, will need to be overcome before effective resilience-based management can be implemented.

In coastal temperate regions such as the Baltic Sea, calcifying bivalves dominate benthic communities playing a vital ecological role in maintaining biodiversity and nutrient recycling. At low salinities, bivalves exhibit reduced growth and calcification rates which is thought to result from physiological constraints associated with osmotic stress. Calcification demands a considerable amount of energy in calcifying molluscs and estuarine habitats provide sub-optimal conditions for calcification due to low concentrations of calcification substrates and large variations in carbonate chemistry. Therefore, we hypothesize that slow growth rates in estuarine bivalves result from increased costs of calcification, rather than costs associated with osmotic stress. To investigate this, we estimated the cost of calcification for the first time in benthic bivalve life stages and the relative energy allocation to calcification in three Mytilus populations along the Baltic salinity gradient. Our results indicate that calcification rates are significantly reduced only in 6 psu populations compared to 11 and 16 psu populations, coinciding with ca. 2–3-fold higher calcification costs at low salinity and temperature. This suggests that reduced growth of Baltic Mytilus at low salinities results from increased calcification costs rather than osmotic stress related costs. We also reveal that shell growth (both calcification and shell organic production) demands 31–60% of available assimilated energy from food, which is significantly higher than previous estimates. Energetically expensive calcification represents a major constraint on growth of mytilids in the estuarine and coastal seas where warming, acidification and desalination are predicted over the next century.

In many temperate regions, brown macroalgae fulfil essential ecosystem services such as the provision of structure, the fixation of nutrients and carbon, and the production of biomass and oxygen. Their populations in many regions around the globe have declined and/or spatially shifted in recent decades. In this review we highlight the potential global and regional drives of these changes, describe the status of regionally particularly important brown macroalgal species, and describe the capacity of interactions among abiotic and biotic factors to amplify or buffer environmental pressure on brown macroalgae. We conclude with a consideration of possible management and restoration measures.