4 resultados para Many-fermion systems

em Plymouth Marine Science Electronic Archive (PlyMSEA)


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Ecosystem services provided by the marine environment are fundamental to human health and well-being. Despite this, many marine systems are being degraded to an extent that may reduce their capacity to provide these ecosystem services. The ecosystem approach is a strategy for the integrated management of land, water and living resources that promotes conservation and sustainable use in an equitable way (UN Convention on Biological Diversity, 2000). Its application to marine management and spatial planning has been proposed as a means of maintaining the economic and social value of the oceans, not only in the present but for generations to come. Characterising the susceptibility of services (and combinations of services) to particular human activities based on knowledge of impacts on biodiversity and ecosystem functioning (as described in preceding chapters) is a challenge for future management of the oceans. In this chapter, we highlight the existing, but limited knowledge of how ecosystem services may be impacted by different human activities. We discuss how impacts on one service can impact multiple services and explore how the impacts on services can vary both spatially and temporally and according to context. We focus particularly on the effects on ecosystem services of activities whose impacts on biodiversity and ecosystem functioning have already been considered in previous chapters. Some of these activities are associated with poor management of ecosystem benefits, for example, from provisioning services (aquaculture and fisheries), or with excessive input of wastes, fertilisers and contaminants into the system overburdening the waste treatment and assimilation services. Other impacts are associated with the construction of structures or use of space designed to generate benefits from environmental services such as the presence of water as a carrier for shipping, or sources of wind, wave and tidal power. We discuss the trade-offs that are made, consciously or otherwise, between different ecosystem services, which arise from human activities to optimise or manage specific ecosystem services.

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Background: Increasing concentrations of atmospheric greenhouse gases (GHG) and its impact on the climate has resulted in many international governments committing to reduce their GHG emissions. The UK, for example, has committed to reducing its carbon emissions by 80% by 2050. Suggested ways of reaching such a target are to increase dependency on offshore wind, offshore gas and nuclear. It is not clear, however, how the construction, operation and decommissioning of these energy systems will impact marine ecosystem services, i.e. the services obtained by people from the natural environment such as food provisioning, climate regulation and cultural inspiration. Research on ecosystem service impacts associated with offshore energy technologies is still in its infancy. The objective of this review is to bolster the evidence base by firstly, recording and describing the impacts of energy technologies at the marine ecosystems and human level in a consistent and transparent way; secondly, to translate these ecosystem and human impacts into ecosystem service impacts by using a framework to ensure consistency and comparability. The output of this process will be an objective synthesis of ecosystem service impacts comprehensive enough to cover different types of energy under the same analysis and to assist in informing how the provision of ecosystem services will change under different energy provisioning scenarios. Methods: Relevant studies will be sourced using publication databases and selected using a set of selection criteria including the identification of: (i) relevant subject populations such as marine and coastal species, marine habitat types and the general public; (ii) relevant exposure types including offshore wind farms, offshore oil and gas platforms and offshore structures connected with nuclear; (iii) relevant outcomes including changes in species structure and diversity; changes in benthic, demersal and pelagic habitats; and changes in cultural services. The impacts will be synthesised and described using a systematic map. To translate these findings into ecosystem service impacts, the Common International Classification of Ecosystem Services (CICES) and Millennium Ecosystem Assessment (MEA) frameworks are used and a detailed description of the steps taken provided to ensure transparency and replicability.

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Strong ocean current systems characterize the Southern Ocean. The genetic structure of marine phytoplankton species is believed to depend mainly on currents. Genetic estimates of the relatedness of populations of phytoplankton species therefore should provide a proxy showing to what extent different geographic regions are interconnected by the ocean current systems. In this study, spatial and temporal patterns of genetic diversity were studied in the circumpolar prymnesiophyte Phaeocystis antarctica Karsten using seven nuclear microsatellite loci. Analyses were conducted for 86 P. antarctica isolates sampled around the Antarctic continent between 1982 and2007. The resultsrevealed highgenetic diversity without singlegenotypes recurringeven amongisolateswithin a bloom or originating from the same bucket of water. Populations of P. antarctica were significantly differentiated among the oceanic regions. However, some geographically distant populations were more closely related to each other than they were to other geographically close populations. Temporal haplotype turnover within regions was also suggested by the multilocus fingerprints. Our data suggest that even within blooms of P. antarctica genetic diversity and population sizes are large but exchange between different regions canbe limited. Positive and significant inbreeding coefficients hint at further regional substructure of populations, suggestingthat patches, once isolated from one another, may not reconnect. These data emphasize that even for planktonic species in a marine ecosystem that is influenced by strong currents, significant breaks in geneflow may occur.

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Global warming and its link to the burning of fossil fuels has prompted many governments around the world to set legally binding greenhouse gas reduction targets which are to be partially realised through a stronger reliance on renewable (e.g. wind) and other lower carbon (i.e. natural gas and nuclear) energy commodities. The marine environment will play a key role in hosting or supporting these new energy strategies. However, it is unclear how the construction, operation and eventual decommissioning of these energy systems, and their related infrastructure, will impact the marine environment, the ecosystem services (i.e. cultural, regulating, provisioning and supporting) and in turn the benefits it provides for human well-being. This uncertainty stems from a lack of research that has synthesised into a common currency the various effects of each energy sector on marine ecosystems and the benefits humans derive from it. To address this gap, the present study reviews existing ecosystem impact studies for offshore components of nuclear, offshore wind, offshore gas and offshore oil sectors and translates them into the common language of ecosystem service impacts that can be used to evaluate current policies. The results suggest that differences exist in the way in which energy systems impact ecosystem services, with the nuclear sector having a predominantly negative impact on cultural ecosystem services; oil and gas a predominately negative impact on cultural, provisioning, regulating and supporting ecosystem services; while wind has a mix of impacts on cultural, provisioning and supporting services and an absence of studies for regulating services. This study suggests that information is still missing with regard to the full impact of these energy sectors on specific types of benefits that humans derive from the marine environment and proposes possible areas of targeted research.