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Sargassum fusiforme is a seaweed species that plays an important role in the diverse communities of the flora and fauna of coastal food webs. Assessments of its biomass and energy allocation in addition to allometric organ growth have important ecological value for understanding the community structure, carbon storage, and resource assessment of seaweed beds during periods in which they thrive. In this study, the morphology of Sargassum fusiforme and the biomass of organs and total organisms in the maturation period were studied, and the allometric relationships for different organs of Sargassum fusiforme were analyzed using the standardized major axis (SMA). In the maturation period of Sargassum fusiforme, branch number, height × stem diameter were the prior independent variables, and the optimum biomass was y = 0.002x1.107 (R2 = 0.923). The biomass allocation ratio of blades was the highest (38.33%), followed by stems (32.90%) and receptacles (28.77%). The growth rates of the various organs were found to differ, and the rate of biomass increase for the blades and stems tended to converge. The rate of receptacle biomass growth of Sargassum fusiforme was the highest in the maturation period, and the rate of organ biomass increase was Wb < Ws < Wt < Wr, which reflects the trade-off with energy allocation as a strategy used by Sargassum fusiforme.

Projected growth in the international shipping industry is set to outstrip CO2 reductions arising from incremental improvements to technology and operations currently being planned and implemented. Using original scenarios, this paper demonstrates for the first time that it is possible for a nation's shipping to make a fair contribution to meeting global climate change commitments, but that this requires transformation of the sector. The scale and nature of technology change varies depending on the level of demand and how this is satisfied. The scenarios show that to develop successful marine mitigation policy, it is essential to consider the interdependencies between ship speed, level and pattern of demand for services, and the extent and rate of innovation in propulsion technology. Across the scenarios, it is difficult to foresee how deep decarbonisation can be achieved without an immediate, fleet-wide speed reduction; and a land-based energy-system transition strongly influences shipping demand, which in turn, influences the extent of required low-carbon propulsion technology change. Setting the industry on a 2 °C heading requires multifaceted and near-term changes in the shipping sector, but these are unlikely to materialise without a major shift by stakeholders to realise new and innovative deep decarbonisation policies in the coming decade.

This paper explores the utility of qualitative scenario approaches to examine the potential impacts of climate change on marine biodiversity conservation on the east coast of Australia. This region is large and diverse, with considerable variation in marine biodiversity and, concomitantly, considerable diversity in the likely impacts from climate change. The results reinforce a number of key points. Engaging with stakeholders in scenario planning provides not only a focus to discuss the future in a disciplined way, but also provides ongoing reference points for contemporary decision making and planning. The paper illustrates how qualitative scenario planning provides opportunities to address the challenges of marine biodiversity conservation in a changing environment.

The Marine Stewardship Council is the leader in seafood ecolabel certification. Despite its high impact in promoting sustainable fishing and securing price premiums, a large proportion of fisheries withdraw from the scheme during or after certification. We, therefore, investigate the factors influencing the likelihood of withdrawal. To achieve this, we analysed publicly available information from 301 fisheries that have embarked on the certification process using survival analysis methods to investigate the withdrawal rate. It was found that the fishing gear used, and geographical location were the principal factors affecting the likelihood of withdrawal and that the risk of withdrawal is greatest during the full-assessment process and the first five years of certification. Our study also reviews the uneven global expansion of MSC ecolabelling by region and identifies factors that influence withdrawal and need to be considered in fisheries entering MSC certification.

Previous research in the domain of maritime energy efficiency has mainly addressed concerns regarding individual experiences and organizational barriers. Reflection on the reciprocal human-technology relationship, interaction design and its impact on the practitioners’ learning and organizational decision-making process is rather scarce. Informed by focus group interviews, this paper describes the essence of practitioners’ activities and the nature of interaction design and proposed improved design for energy efficiency monitoring systems. Findings suggest knowledge sharing for a mutual understanding onboard ships is critical to energy efficiency. Learning can go beyond the embodiment of individual cognitive change but becomes a collective and collaborative achievement mediated by technology, which informs opportunities for interaction design. The design needs to consider the context in which knowledge mobilisation occurs and facilitate collaborative learning. With more intelligent systems introduced to the shipping industry, it is important to consider the impact of mediating technologies in management practices and mediating technologies can be integrated into a broader collaborative learning paradigm emerging between the ship and shore. This study highlights those social-cultural dimensions important to establishing a common ground between practitioners, management and advanced technologies.

Caulerpa, a (sub) tropical seaweed, is a notorious taxonomic group and an invasive seaweed worldwide. Similar to several species that have been introduced to benthic habitats through aquariums, Caulerpa sertularioides has also been introduced into Korean aquariums, although it is not native to the region. Thus, it is necessary to evaluate the potential of this species for invading domestic macroalgal habitats. Therefore, an indoor mesocosm experiment was conducted to examine the ecophysiological invasion risk of non-native seaweed C. sertularioides under various climate conditions and exposure to three future climate scenarios: acidification (doubled CO2), warming (5 °C increase from ambient temperature), and greenhouse (GR: combination of acidification and warming); additionally, we compared the invasion risk between future and present climates (control: 20 °C and 470 µatm CO2). High CO2 concentrations and increased temperatures positively affected the photosynthesis and growth of C. sertularioides. Photosynthesis and growth were more synergistically increased under GR conditions than under acidification and warming. Consequently, the performance of this potentially invasive species in the native macroalgal Korean habitat will be higher in the future in coastal environments. Therefore, proper management is required to prevent the geographic expansion of C. sertularioides in the Korean coastal ocean.

Shipping contributes roughly 2.8 % of global anthropogenic greenhouse gas (GHG) emissions, and this is projected to increase in the decades to come. The main regulator of the shipping industry, the International Maritime Organization (IMO), bears the responsibility for developing climate change regulation. Yet the IMO decarbonisation target remains only a 50 % reduction by 2050, and, while regulatory measures have been adopted, these mostly focus on increasing the energy efficiency of ships, not the reduction of total sector GHG emissions. The result is that carbon emissions from shipping continue to rise and are projected to increase by anything up to 50 % by 2050. While many studies are undertaken on the impact of efficiency regulations or the potential for market-based mechanisms, we argue in this piece that missing from this discussion is the potential for a target of full decarbonisation, in line with the IPCC recommendation, allied with a complete ban on the use of fossil fuels in shipping by 2050. This policy would provide certainty to the market and allow industry actors to undertake the transition in a level playing field. Without such a clear signal, carriers and shipowners will transition much more slowly to alternative fuels alongside continued long-term use of fossil fuels. We argue that this position should be actively considered and evaluated, with a tapered timeline to phase out the use of fossil fuels by this date. Instead of focusing research only on the marginal gains of partial policies, scholars and policymakers should prepare plans and evaluate scenarios linked to a clear goal of real zero by 2050.

Abstract The recreational uses of coastal lagoons (also known locally as salt ponds) contribute significantly to the important tourism economy of the southern part of the US state of Rhode Island. The lagoons are valued highly for the wide range of recreational services they provide, such as fishing, clamming, rowing, boating, or merely relaxing. Outdoors on or near the water, weather conditions may influence individual recreation decisions strongly. A changing climate is expected to affect weather conditions in Rhode Island, thereby potentially influencing when, how, and how much recreation will take place in the coastal areas of the state. Through direct observations of human activities on coastal lagoons, the sensitivity of coastal recreational uses to changes in weather conditions was assessed. If future changes in climate bring warmer temperatures and more intense wind and rain events, our results suggest that there may be a decrease in relaxing, rowing, and fishing on coastal lagoons when days are hotter and a decrease in rowing and fishing when days are windier. Nevertheless, warmer temperatures also may lengthen the summers, leading to an overall increase in the peak coastal recreation season. However, during the hottest periods, there may be a shift toward more motor boating and away from other uses, motor boaters were more resistant than other users to changes when temperatures increase. Understanding how weather and climate influence coastal recreation could help coastal managers and businesses better plan for the future in Rhode Island and other coastal environments worldwide.