Contrasting futures for ocean and society from different anthropogenic CO2 emissions scenarios

The ocean moderates anthropogenic climate change at the cost of profound alterations of its physics, chemistry, ecology, and services. Here, we evaluate and compare the risks of impacts on marine and coastal ecosystems and the goods and services they provide for growing cumulative carbon emissions under two contrasting emissions scenarios. The current emissions trajectory would rapidly and significantly alter many ecosystems and the associated services on which humans heavily depend. A reduced emissions scenario consistent with the Copenhagen Accord’s goal of a global temperature increase of less than 2°C—is much more favorable to the ocean but still substantially alters important marine ecosystems and associated goods and services. The management options to address ocean impacts narrow as the ocean warms and acidifies. Consequently, any new climate regime that fails to minimize ocean impacts would be incomplete and inadequate

The human imperative of stabilizing global climate change at 1.5°C

Global mean surface temperature is now 1.0°C higher than the pre-industrial period due to increasing atmospheric greenhouse gases. Significant changes to natural and human (managed) systems have already occurred emphasizing serious near-term risks. Here, we expand on the recent IPCC Special Report on global warming of 1.5°C as well as additional risks associated with dangerous and irreversible states at higher levels of warming, each having major implications for multiple geographies, climates and ecosystems. Limiting warming to 1.5°C rather than 2.0°C is very beneficial, maintaining significant proportions of systems such as Arctic summer sea ice, forests and coral reefs as well as having clear benefits for human health and economies. These conclusions are relevant for people everywhere, particularly in low- and middle-income countries, where climate related risks to livelihoods, health, food, water, and economic growth are escalating with major implications for the achievement of the United Nations Sustainable Development Goals

Man and the Last Great Wilderness: Human Impact on the Deep Sea

The deep sea, the largest ecosystem on Earth and one of the least studied, harbours high biodiversity and provides a wealth of resources. Although humans have used the oceans for millennia, technological developments now allow exploitation of fisheries resources, hydrocarbons and minerals below 2000 m depth. The remoteness of the deep seafloor has promoted the disposal of residues and litter. Ocean acidification and climate change now bring a new dimension of global effects. Thus the challenges facing the deep sea are large and accelerating, providing a new imperative for the science community, industry and national and international organizations to work together to develop successful exploitation management and conservation of the deep-sea ecosystem. This paper provides scientific expert judgement and a semi-quantitative analysis of past, present and future impacts of human-related activities on global deep-sea habitats within three categories: disposal, exploitation and climate change. The analysis is the result of a Census of Marine Life – SYNDEEP workshop (September 2008). A detailed review of known impacts and their effects is provided. The analysis shows how, in recent decades, the most significant anthropogenic activities that affect the deep sea have evolved from mainly disposal (past) to exploitation (present). We predict that from now and into the future, increases in atmospheric CO2 and facets and consequences of climate change will have the most impact on deep-sea habitats and their fauna. Synergies between different anthropogenic pressures and associated effects are discussed, indicating that most synergies are related to increased atmospheric CO2 and climate change effects. We identify deep-sea ecosystems we believe are at higher risk from human impacts in the near future: benthic communities on sedimentary upper slopes, cold-water corals, canyon benthic communities and seamount pelagic and benthic communities. We finalise this review with a short discussion on protection and management methods

Variation in genetic traits of the lugworm Arenicola marina: temperature related expression of mitochondrial allozymes?

Genetic traits of the lugworm Arenicola marina were determined for 4 Atlantic populations from France to Norway and compared with a population from the sub-arctic White Sea in Russia. Seven loci were analysed using horizontal starch gel electrophoresis. A low heterozygosity (0.09 to 0.17) and a non- significant heterozygote deficiency were found in all populations. The genetic identity between lugworms of European Atlantic populations was high, whereas similarity of the Atlantic populations with the population from the White Sea was low. The gene flow between the Atlantic and the White Sea populations must be considered negligible, as deduced from the average high and significant gene differentiation F-ST. In particular, differences in allele frequencies of glucose phosphate isomerase (Gpi) and phosphoglucomutase (Pgm) showed that the White Sea population differed significantly from the others. A very strong correlation existed between the frequency of the alleles of isocitrate dehydrogenases 2-A and -B (Idh2-A and Idh2-B) and the average water temperature. It is concluded that temperature had a selective influence on isocitrate dehydrogenase 2, which, in contrast to isocitrate dehydrogenase 1, was identified as a mitochondrial enzyme. These findings support the hypothesis that mitochondria play a key role in temperature adaptation and the adjustment of critical temperatures. [KEYWORDS: Arenicola marina; genetics; geographic cline; isozyme; lugworm; polychaeta; mitochondria Allele frequency cline; mussel mytilus-edulis; population-genetics; crassostrea-virginica; electrophoretic data; differentiation; polychaeta; selection; oyster; polymorphism]