Invasive species are often generalists that can take advantage of formerly unexploited resources. The existence of such vacant niches is more likely in species-poor systems like the Baltic Sea. The suspension feeding wedge clam, Rangia cuneata, native to estuarine environments in the Gulf of Mexico, was sighted for the first time in the southeastern Baltic in 2010 and a few years later in the northern Baltic along the Swedish coast. To explore possible competition for food resources between R. cuneata and the three native clams inhabiting Baltic shallow soft bottoms, stable isotope and fatty acid analyses were conducted. There was no overlap between R. cuneata and any of the native species in either stable isotope or fatty acid niches. This suggests efficient partitioning of resources; multivariate analyses indicate that separation was driven mainly by δ¹³C and by fatty acids reflecting diatoms and cyanobacteria, respectively (e.g. 16:1ω7 and 18:3ω3). R. cuneata reflected seasonal variation in phytoplankton more than other clams reflecting higher trophic plasticity. In conclusion, the addition of R. cuneata to the Baltic shallow soft bottoms suggests the existence of a vacant trophic niche in these sediment habitats, however the long-term effects on other species and nutrient cycling requires further studies focusing on the population dynamics of R. cuneata and its impact on the Baltic Sea ecosystem.

Biophysical impacts of aquaculture, with consequences for biodiversity, vary with species and culture systems and include issues such as: nutrient enrichment/removal, chemicals, land use, species introductions, genetic flow to wild populations, disturbance of balance or introduction of pathogen/parasites, consumption of capture fishery resources, energy, and greenhouse gas emissions. Guiding principles, labeling schemes and various tools are needed to analyze performance and conformance. Ecological footprints and life-cycle analysis aim to capture biophysical performance, including up- and downstream effects of policy decisions. Aquaculture provides a range of services but also makes demands and impacts on ecosystem functions, services, and thus biodiversity.

Transformation toward a sustainable future requires an earth stewardship approach to shift society from its current goal of increasing material wealth to a vision of sustaining built, natural, human, and social capital—equitably distributed across society, within and among nations. Widespread concern about earth’s current trajectory and support for actions that would foster more sustainable pathways suggests potential social tipping points in public demand for an earth stewardship vision. Here, we draw on empirical studies and theory to show that movement toward a stewardship vision can be facilitated by changes in either policy incentives or social norms. Our novel contribution is to point out that both norms and incentives must change and can do so interactively. This can be facilitated through leverage points and complementarities across policy areas, based on values, system design, and agency. Potential catalysts include novel democratic institutions and engagement of non-governmental actors, such as businesses, civic leaders, and social movements as agents for redistribution of power. Because no single intervention will transform the world, a key challenge is to align actions to be synergistic, persistent, and scalable.

The increasing frequency of extreme events, exogenous and endogenous, poses challenges for our societies. The current pandemic is a case in point; but once-in-a-century weather events are also becoming more common, leading to erosion, wildfire and even volcanic events that change ecosystems and disturbance regimes, threaten the sustainability of our life-support systems, and challenge the robustness and resilience of societies. Dealing with extremes will require new approaches and large-scale collective action. Preemptive measures can increase general resilience, a first line of protection, while more specific reactive responses are developed. Preemptive measures also can minimize the negative effects of events that cannot be avoided. In this paper, we first explore approaches to prevention, mitigation and adaptation, drawing inspiration from how evolutionary challenges have made biological systems robust and resilient, and from the general theory of complex adaptive systems. We argue further that proactive steps that go beyond will be necessary to reduce unacceptable consequences.

Introduced macroalgae becoming invasive may alter ecological functions and habitats in recipient ecosystems. In the Western Indian Ocean (WIO), non-native strains of the native macroalgae Eucheuma denticulatum were introduced for farming practices and consequently spread into the surrounding seascape. We investigated potential effects of non-native and native strains of this macroalgae on a branching coral. We conducted a four-factor field experiment where we examined growth and holdfast development of introduced and native E. denticulatum on live and dead branches of Acropora sp. in the presence and absence of herbivores in Unguja Island, Zanzibar. Moreover, we estimated coral and macroalgae condition by visual examinations, gene expression analyses, and photosynthetic measurements. Macroalgae did not attach to any live coral and coral condition was not impacted by the presence of E. denticulatum, regardless of geographical origin. Instead, necrotic tissue on the macroalgae in areas of direct contact with corals indicated damage inflicted by the coral. The biomass of E. denticulatum did not differ between the replicates attached to live or dead corals in the experiment, yet biomass was strongly influenced by herbivory and replicates without protection from herbivores had a significantly lower biomass. In the absence of herbivory, introduced E. denticulatum had significantly higher growth rates than native algae based on wet weight measurements. These results contribute to an increased understanding of environmental effects by the farming of a non-native strain of algae on corals and stresses the importance to maintain viable populations of macroalgal feeding fishes in such areas.

We consider two aspects of the human enterprise that profoundly affect the global environment: population and consumption. We show that fertility and consumption behavior harbor a class of externalities that have not been much noted in the literature. Both are driven in part by attitudes and preferences that are not egoistic but socially embedded; that is, each household's decisions are influenced by the decisions made by others. In a famous paper, Garrett Hardin [G. Hardin, Science 162, 1243-1248 (1968)] drew attention to overpopulation and concluded that the solution lay in people abandoning the freedom to breed. That human attitudes and practices are socially embedded suggests that it is possible for people to reduce their fertility rates and consumption demands without experiencing a loss in wellbeing. We focus on fertility in sub-Saharan Africa and consumption in the rich world and argue that bottom-up social mechanisms rather than top-down government interventions are better placed to bring about those ecologically desirable changes.

Sustainability within planetary boundaries requires concerted action by individuals, governments, civil society and private actors. For the private sector, there is concern that the power exercised by transnational corporations generates, and is even central to, global environmental change. Here, we ask under which conditions transnational corporations could either hinder or promote a global shift towards sustainability. We show that a handful of transnational corporations have become a major force shaping the global intertwined system of people and planet. Transnational corporations in agriculture, forestry, seafood, cement, minerals and fossil energy cause environmental impacts and possess the ability to influence critical functions of the biosphere. We review evidence of current practices and identify six observed features of change towards 'corporate biosphere stewardship', with significant potential for upscaling. Actions by transnational corporations, if combined with effective public policies and improved governmental regulations, could substantially accelerate sustainability efforts.

Several papers have reported on the development of antibiotic resistance and implications for human medicine but fewer deal with environmental impacts of antibiotic use. Marine sea cage aquaculture in SE Asia is often established close to coral reef ecosystems. Large amounts of antibiotics are used in the cultivation of fish and lobster and hence released directly into the environment. This study investigates the antibiotic practices in sea cage farms producing fish and spiny lobster in Vietnam, mainly for the domestic market. There are approximately 3500 sea cage farms in Vietnam and we performed semi-structured interviews with 109 sea cage farmers asking them if they use antibiotics and if so; what sort/when/how often/how much. We found that the Vietnamese cage farmers are using antibiotics in an unstructured way, which seems to have little or no effect on the survival of the stock, or profit of the farm. The fact that the farmers live at their farm and use the sea next to the cages both for fishing and collecting filter-feeding bivalves for direct consumption, as well as a toilet, poses an additional risk for the spreading of human antibiotic resistant pathogens. Thirteen different antibiotics were found in the study. Eighty-two percentage of the lobster farmers and 28% of the fishfarmers used antibiotics. The average amounts used were over 5 kg per produced ton of lobster and about 0.6 kg per ton of fish, which is much higher than in other studies. Several antibiotic substances listed as critical and highly important for human medicine by WHO were used prophylactically and routinely with little control and enforcement of regulations. We tested and detected antibiotic resistance to Tetracycline, Vancomycin and Rifampicin in the coral associated bacteria Bacillus niabensis as far as 660m from fish farms with resistance decreasing with distance from the cage farms. The antibiotics are likely to have negative effects on the coral-symbiont relationship adding further risks to an already stressed environment.