907 resultados para chemosynthetic ecosystems
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The authors would like to thank the leadership of the Deep Ocean Stewardship Initiative (DOSI), including Lisa Levin, Maria Baker, and Kristina Gjerde, for their support in developing this review. This work evolved from a meeting of the DOSI Oil and Gas working group supported by the J.M. Kaplan Fund, and associated with the Deep-Sea Biology Symposium in Aveiro, Portugal in September 2015. The members of the Oil and Gas working group that contributed to our discussions at that meeting or through the listserve are acknowledged for their contributions to this work. We would also like to thank the three reviewers and the editor who provided valuable comments and insight into the work presented here. DJ and AD were supported by funding from the European Union's Horizon 2020 research and innovation programme under the MERCES (Marine Ecosystem Restoration in Changing European Seas) project, grant agreement No 689518. AB was supported by CNPq grants 301412/2013-8 and 200504/2015-0. LH acknowledges funding provided by a Natural Environment Research Council grant (NE/L008181/1). This output reflects only the authors' views and the funders cannot be held responsible for any use that may be made of the information contained therein.
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In the Guaymas Basin, the presence of cold seeps and hydrothermal vents in close proximity, similar sedimentary settings and comparable depths offers a unique opportunity to assess and compare the functioning of these deep-sea chemosynthetic ecosystems. The food webs of five seep and four vent assemblages were studied using stable carbon and nitrogen isotope analyses. Although the two ecosystems shared similar potential basal sources, their food webs differed: seeps relied predominantly on methanotrophy and thiotrophy via the Calvin-Benson-Bassham (CBB) cycle and vents on petroleum-derived organic matter and thiotrophy via the CBB and reductive tricarboxylic acid (rTCA) cycles. In contrast to symbiotic species, the heterotrophic fauna exhibited high trophic flexibility among assemblages, suggesting weak trophic links to the metabolic diversity of chemosynthetic primary producers. At both ecosystems, food webs did not appear to be organised through predator-prey links but rather through weak trophic relationships among co-occurring species. Examples of trophic or spatial niche differentiation highlighted the importance of species-sorting processes within chemosynthetic ecosystems. Variability in food web structure, addressed through Bayesian metrics, revealed consistent trends across ecosystems. Food-web complexity significantly decreased with increasing methane concentrations, a common proxy for the intensity of seep and vent fluid fluxes. Although high fluid-fluxes have the potential to enhance primary productivity, they generate environmental constraints that may limit microbial diversity, colonisation of consumers and the structuring role of competitive interactions, leading to an overall reduction of food-web complexity and an increase in trophic redundancy. Heterogeneity provided by foundation species was identified as an additional structuring factor. According to their biological activities, foundation species may have the potential to partly release the competitive pressure within communities of low fluid-flux habitats. Finally, ecosystem functioning in vents and seeps was highly similar despite environmental differences (e.g. physico-chemistry, dominant basal sources) suggesting that ecological niches are not specifically linked to the nature of fluids. This comparison of seep and vent functioning in the Guaymas basin thus provides further supports to the hypothesis of continuity among deep-sea chemosynthetic ecosystems.
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Deep-sea bivalves found at hydrothermal vents, cold seeps and organic falls are sustained by chemosynthetic bacteria that ensure part or all of their carbon nutrition. These symbioses are of prime importance for the functioning of the ecosystems. Similar symbioses occur in other bivalve species living in shallow and coastal reduced habitats worldwide. In recent years, several deep-sea species have been investigated from continental margins around Europe, West Africa, eastern Americas, the Gulf of Mexico, and from hydrothermal vents on the Mid-Atlantic Ridge. In parallel, numerous, more easily accessible shallow marine species have been studied. Herein we provide a summary of the current knowledge available on chemosymbiotic bivalves in the area ranging west-to-east from the Gulf of Mexico to the Sea of Marmara, and north-to-south from the Arctic to the Gulf of Guinea. Characteristics of symbioses in 53 species from the area are summarized for each of the five bivalve families documented to harbor chemosynthetic symbionts (Mytilidae, Vesicomyidae, Solemyidae, Thyasiridae and Lucinidae). Comparisons are made between the families, with special emphasis on ecology, life cycle, and connectivity. Chemosynthetic symbioses are a major adaptation to ecosystems and habitats exposed to reducing conditions. However, relatively little is known regarding their diversity and functioning, apart from a few “model species” on which effort has focused over the last 30 yr. In the context of increasing concern about biodiversity and ecosystems, and increasing anthropogenic pressure on oceans, we advocate a better assessment of the diversity of bivalve symbioses in order to evaluate the capacities of these remarkable ecological and evolutionary units to withstand environmental change.
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Since the industrial revolution, our world has experienced rapid and unplanned industrialization and urbanization. As a result, we have had to cope with serious environmental challenges. In this context, explanation of how smart urban ecosystems can emerge, gains a crucial importance. Capacity building and community involvement have always been the key issues in achieving sustainable development and enhancing urban ecosystems. By considering these, this paper looks at new approaches to increase public awareness of environmental decision making. This paper will discuss the role of Information and Communication Technologies (ICT), particularly Web-based Geographic Information Systems (Web-based GIS) as spatial decision support systems to aid public participatory environmental decision making. The paper also explores the potential and constraints of these web-based tools for collaborative decision making.
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Climate change and human activity are subjecting the environment to unprecedented rates of change. Monitoring these changes is an immense task that demands new levels of automated monitoring and analysis. We propose the use of acoustics as a proxy for the time consuming auditing of fauna, especially for determining the presence/absence of species. Acoustic monitoring is deceptively simple; seemingly all that is required is a sound recorder. However there are many major challenges if acoustics are to be used for large scale monitoring of ecosystems. Key issues are scalability and automation. This paper discusses our approach to this important research problem. Our work is being undertaken in collaboration with ecologists interested both in identifying particular species and in general ecosystem health.
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Since the industrial revolution, our world has experienced rapid and unplanned industrialization and urbanization. As a result, we have had to cope with serious environmental challenges. In this context, an explanation of how smart urban ecosystems can emerge, gains a crucial importance. Capacity building and community involvement have always been key issues in achieving sustainable development and enhancing urban ecosystems. By considering these, this paper looks at new approaches to increase public awareness of environmental decision making. This paper will discuss the role of Information and Communication Technologies (ICT), particularly Webbased Geographic Information Systems (Web-based GIS) as spatial decision support systems to aid public participatory environmental decision making. The paper also explores the potential and constraints of these webbased tools for collaborative decision making.
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The first Workshop on Service-Oriented Business Networks and Ecosystems (SOBNE ’09) is held in conjunction with the 13th IEEE International EDOC Conference on 2 September 2009 in Auckland, New Zealand. The SOBNE ’09 program includes 9 peer-reviewed papers (7 full and 2 short papers) and an open discussion session. This introduction to the Proceedings of SOBNE ’09 starts with a brief background of the motivation for the workshop. Next, it contains a short description of the peer-reviewed papers, and finally, after some concluding statements and the announcement of the winners of the Best Reviewer Award and the Most Promising Research Award, it lists the members of the SOBNE ’09 Program Committee and external reviewers of the workshop submissions.
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At the turn of the millennium, the Earth’s human population has reached unprecedented levels and its natural resources are being pushed to the limit. Thus, cities are focused on sustainable development and they have begun to develop new strategies for improving the built environment. Sustainable development provides the best outcomes for the human and natural environments by improving the quality of life that protects and balances the ecological, social and economic values. This brings us to the main point: to build a sustainable built environment, cities need to redesign many of their technologies and planning policies within the context of ecological principles. As an environmental sustainability index model, ASSURE is developed to investigate the present environmental situation of an urban area by assessing the impacts of development pressure on natural resources. It is an innovative approach to provide the resilience and function of urban ecosystems secure against the environmental degradation for now and the future. This paper aims to underline the importance of the model (ASSURE) in preserving biodiversity and natural ecosystems in the built environment and investigate its role in delivering long-term urban planning policies.
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Australian climate, soils and agricultural management practices are significantly different from those of the northern hemisphere nations. Consequently, experimental data on greenhouse gas production from European and North American agricultural soils and its interpretation are unlikely to be directly applicable to Australian systems.
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Excessive grazing pressure is detrimental to plant productivity and may lead to declines in soil organic matter. Soil organic matter is an important source of plant nutrients and can enhance soil aggregation, limit soil erosion, and can also increase cation exchange and water holding capacities, and is, therefore, a key regulator of grassland ecosystem processes. Changes in grassland management which reverse the process of declining productivity can potentially lead to increased soil C. Thus, rehabilitation of areas degraded by overgrazing can potentially sequester atmospheric C. We compiled data from the literature to evaluate the influence of grazing intensity on soil C. Based on data contained within these studies, we ascertained a positive linear relationship between potential C sequestration and mean annual precipitation which we extrapolated to estimate global C sequestration potential with rehabilitation of overgrazed grassland. The GLASOD and IGBP DISCover data sets were integrated to generate a map of overgrazed grassland area for each of four severity classes on each continent. Our regression model predicted losses of soil C with decreased grazing intensity in drier areas (precipitation less than 333 mm yr(-1)), but substantial sequestration in wetter areas. Most (93%) C sequestration potential occurred in areas with MAP less than 1800 mm. Universal rehabilitation of overgrazed grasslands can sequester approximately 45 Tg C yr(-1), most of which can be achieved simply by cessation of overgrazing and implementation of moderate grazing intensity. Institutional level investments by governments may be required to sequester additional C.
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Previous research suggests that soil organic C pools may be a feature of semiarid regions that are particularly sensitive to climatic changes. We instituted an 18-mo experiment along an elevation gradient in northern Arizona to evaluate the influence of temperature, moisture, and soil C pool size on soil respiration. Soils, from underneath different free canopy types and interspaces of three semiarid ecosystems, were moved upslope and/or downslope to modify soil climate. Soils moved downslope experienced increased temperature and decreased precipitation, resulting in decreased soil moisture and soil respiration las much as 23 acid 20%, respectively). Soils moved upslope to more mesic, cooler sites had greater soil water content and increased rates of soil respiration las much as 40%), despite decreased temperature. Soil respiration rates normalized for total C were not significantly different within any of the three incubation sites, indicating that under identical climatic conditions, soil respiration is directly related to soil C pool size for the incubated soils. Normalized soil respiration rates between sites differed significantly for all soil types and were always greater for soils incubated under more mesic, but cooler, conditions. Total soil C did not change significantly during the experiment, but estimates suggest that significant portions of the rapidly cycling C pool were lost. While long-term decreases in aboveground and belowground detrital inputs may ultimately be greater than decreased soil respiration, the initial response to increased temperature and decreased precipitation in these systems is a decrease in annual soil C efflux.
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The ways in which a society set standards of behaviour and of conduct for its members vary hugely. For example, accepted practices, recognised customs, spiritually or morally inspired norms, judicially declared rules, executively formulated edicts, formal legislative enactments or constitutionally embedded rights and duties. Whatever form they assume, these standards are the artificial construction of the human mind. Accordingly the law - whatever its form - can do no more and no less than regulate or set standards for human behaviour, human conduct, and human decision-making. The law cannot regulate the environment. It can only regulate human activities that impact directly or indirectly upon the environment. This applies as much to wetlands as components of the environment as it does to any other components of the environment or the environment at large. The capacity of the law to protect the environment and therefore wetlands is thus totally dependent upon the capacity of the law to regulate human behaviour, human conduct and human decision-making. At the same time the law needs to reflect the specific nature, functions and locations of wetlands. A wetland is an ecosystem by itself; it comprises a range of ecosystems within it; and it is part of a wider set of ecosystems. Hence, the significant ecological functions performed by wetlands. Then there are the benefits flowing to humans from wetlands. These may be social, economic, cultural, aesthetic, or a combination of some or of all of these. It is a challenge for a society acting through its legal system to find the appropriate balance between these ecological and these human values. But that is what sustainability requires.The ways in which a society set standards of behaviour and of conduct for its members vary hugely. For example, accepted practices, recognised customs, spiritually or morally inspired norms, judicially declared rules, executively formulated edicts, formal legislative enactments or constitutionally embedded rights and duties. Whatever form they assume, these standards are the artificial construction of the human mind. Accordingly the law - whatever its form - can do no more and no less than regulate or set standards for human behaviour, human conduct, and human decision-making. The law cannot regulate the environment. It can only regulate human activities that impact directly or indirectly upon the environment. This applies as much to wetlands as components of the environment as it does to any other components of the environment or the environment at large. The capacity of the law to protect the environment and therefore wetlands is thus totally dependent upon the capacity of the law to regulate human behaviour, human conduct and human decision-making. At the same time the law needs to reflect the specific nature, functions and locations of wetlands. A wetland is an ecosystem by itself; it comprises a range of ecosystems within it; and it is part of a wider set of ecosystems. Hence, the significant ecological functions performed by wetlands. Then there are the benefits flowing to humans from wetlands. These may be social, economic, cultural, aesthetic, or a combination of some or of all of these. It is a challenge for a society acting through its legal system to find the appropriate balance between these ecological and these human values. But that is what sustainability requires.
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In this Part 2 attention is turned towards the legal arrangements in nation states for managing wetlands. These national arrangements have effect within the international arrangements already mentioned and any regional arrangements that are relevant. However, each national system is a reflection of its own historical, cultural, political and constitutional background. It is the purpose of this Part 2 to review and assess the national approaches to wetlands management. This involves an analysis of a range of instruments. These are: constitutional rules; strategic rules; regulatory rules; and management rules. Each of these sets of rules performs different functions, assumes different forms and is differentially capable of enforcement.
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To complement physical measures or indices of river health a social benchmarking instrument has been developed to measure community dispositions and behaviour regarding river health. This instrument seeks to achieve three outcomes. First, to provide a benchmark of the social condition of communities’ attitudes, values, understanding and behaviours in relation to river health; second, to provide information for developing management and educational priorities; and third, to provide an assessment of the long-term effectiveness of community education and engagement activities in achieving changes in attitudes, understanding and behaviours in relation to river health. In this paper the development of the social benchmarking instrument is described and results are presented from the first state-wide benchmark study in Victoria, Australia, in which the social dimensions of river health, community behaviours related to rivers, and community understanding of human impacts on rivers were assessed.