941 resultados para marine community dynamics


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This article examines male street prostitution in Manchester, England, and draws some comparisons to its female counterpart in this city. While the two sectors have some important similarities, we also find significant differences in the physical and social ecology of the places in which they work, in their behavior patterns, and in individuals’ demographics and work experiences. We find that ecological dif- ferences between the male and female markets have a major impact on partici- pants’ work practices, opportunities, and integration into the local community. The data also indicate that it is incorrect to speak of a monolithic male street market or sector in Manchester because sellers shift between settings (street, bar, and escorting), unlike the female street sector. We also find that the males demonstrate more diversity in their repertoires for earning money. The findings have implications for local government policy and for outreach workers who work with these populations.

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The provision of physical and social infrastructure in the form of roads, green spaces and community facilities has traditionally been provided for by the state through the general taxation system. However, as the state has been transformed along more neoliberal lines, the private sector is increasingly relied upon to deliver public goods and services. Planning gain agreements have flourished within this context by offering another vehicle through which local facilities are privately funded. Whilst these agreements reflect the broader dynamics of neoliberalism, they are commonly viewed as a tool which can be employed to challenge these very dynamics by empowering local communities to secure more just planning outcomes. This paper counters such claims. Based on evidence gathered from 80 interviews with planners, councillors, developers and community groups in Ireland, the paper demonstrates how planning gain agreements have been strategically redeployed by the holders of political and economic power to serve their own ends. In seeking to understand why and how this has occurred, specific consideration is given to the changing power dynamics between the state and private capital under neoliberalism. The paper highlights how institutional arrangements have enabled developers to infiltrate the political sphere in more subtle and implicit ways than ever before. We conclude by arguing that planning gain must be understood as a mechanism which has been manipulated in ways which essentially work to preserve and enhance, rather than redress, existing power imbalances in the planning system by facilitating large scale transfers of wealth upwards in society.

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Arrays of tidal energy converters have the potential to provide clean renewable energy for future generations. Benthic communities may, however, be affected by changes in current speeds resulting from arrays of tidal converters located in areas characterised by strong currents. Current speed, together with bottom type and depth, strongly influence benthic community distributions; however the interaction of these factors in controlling benthic dynamics in high energy environments is poorly understood. The Strangford Lough Narrows, the location of SeaGen, the world’s first single full-scale, grid-compliant tidal energy extractor, is characterised by spatially heterogenous high current flows. A hydrodynamic model was used to select a range of benthic community study sites that had median flow velocities between 1.5–2.4 m/s in a depth range of 25–30 m. 25 sites were sampled for macrobenthic community structure using drop down video survey to test the sensitivity of the distribution of benthic communities to changes in the flow field. A diverse range of species were recorded which were consistent with those for high current flow environments and corresponding to very tide-swept faunal communities in the EUNIS classification. However, over the velocity range investigated, no changes in benthic communities were observed. This suggested that the high physical disturbance associated with the high current flows in the Strangford Narrows reflected the opportunistic nature of the benthic species present with individuals being continuously and randomly affected by turbulent forces and physical damage. It is concluded that during operation, the removal of energy by marine tidal energy arrays in the far-field is unlikely to have a significant effect on benthic communities in high flow environments. The results are of major significance to developers and regulators in the tidal energy industry when considering the environmental impacts for site licences.

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n January 2014, the Northern Ireland Policing Board (NIPB) commissioned the University of Ulster to conduct research into public confidence in policing to help inform the work of the Board and its oversight of police service delivery. More specifically, the research team were tasked with exploring ‘the influence that politicians, community leaders and the media have on public confidence in policing in Northern Ireland’. To date, the subject of ‘confidence in policing’ within a Northern Ireland context has been relatively under researched, both in academic and policy terms. Thus, the present research is the first empirical research to be produced in Northern Ireland which considers the issue of confidence in policing from the perspective of community leaders, politicians and the media – including the key influences and dynamics which underpin police confidence at a community level.

The report begins with a comprehensive review of academic literature, policy documents and contemporary events related to confidence in policing. The research then provides an overview of the methodology used to undertake the research, with the remainder of the report comprised of the findings from the discussions with representatives from the media, political parties and the community and voluntary sector who participated. The report concludes with an overview of the central findings along with a series of recommendations.

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New challenges posed by global environmental change have motivated scholars to pay growing attention to historical long-term strategies to deal with climate extremes. We aim to understand long-term trends in community responses to cope with droughts, to explain how many preindustrial societies coevolved with local hydro-climatic dynamics and coped with climate extremes over time. The specific goals of this work are: (1) to analyze how local communities experienced droughts over long periods of time and (2) to document the spectrum of recorded community responses to drought. Our research covers over one century (1605-1710) of responses to drought in the community of Terrassa, Barcelona, Spain. Data were collected through archival research. We reviewed and coded 2076 village council minutes. Our results show that the local community adopted a mixture of symbolic, institutional, and infrastructural responses to drought and that drought-related decisions varied through time. We discuss adaptation strategies on the basis of the distinct physical signals of drought propagation and the role of nonclimatic historical factors, such as warfare and public debt, in shaping responses. We conclude that long-term perspectives on premodern history and comparable empirical studies are fundamental to advance our understanding of past social responses to hydro-climatic extremes.

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Local communities collectively managing common pool resources can play an important role in sustainable management, but they often lack the skills and context-specific tools required for such management. The complex dynamics of social-ecological systems (SES), the need for management capacities, and communities’ limited empowerment and participation skills present challenges for community-based natural resource management (CBNRM) strategies. We analyzed the applicability of prospective structural analysis (PSA), a strategic foresight tool, to support decision making and to foster sustainable management and capacity building in CBNRM contexts and the modifications necessary to use the tool in such contexts. By testing PSA in three SES in Colombia, Mexico, and Argentina, we gathered information regarding the potential of this tool and its adaptation requirements. The results suggest that the tool can be adapted to these contexts and contribute to fostering sustainable management and capacity building. It helped identify the systems’ dynamics, thus increasing the communities’ knowledge about their SES and informing the decision-making process. Additionally, it drove a learning process that both fostered empowerment and built participation skills. The process demanded both time and effort, and required external monitoring and facilitation, but community members could be trained to master it. Thus, we suggest that the PSA technique has the potential to strengthen CBNRM and that other initiatives could use it, but they must be aware of these requirements.

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On an increasingly populated planet, with decreasing biodiversity and limited new opportunities to tap unexploited natural resources, there is a clear need to adjust aspects of marine management and governance. Although sectarian management has succeeded in addressing and managing some important threats to marine ecosystems, unintended consequences are often associated with overlooking nonlinear interactions and cumulative impacts that increase the risk of surprises in social-ecological systems. In this paper, we begin to untangle science-governance-society (SGS) interdependencies in marine systems by considering how to recognize the risk of surprise in social and ecological dynamics. Equally important is drawing attention to our state of preparedness, adaptation, and timeliness of response in ecosystem governance and society, which involve fostering transformations away from rigid and nonintegrated structures of governance. More inclusive decision-making processes, deeper understanding of complexity, and colearning across SGS can help to build constructive solutions that are likely to benefit multiple stakeholders and build capacity to understand and respond to change.

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This paper discusses the advantages of using a combined environmagnetic and geochemical approach to the provenance and characterization of distal IRDs occurring during the Last Glacial Period in core CI12PC3 from the Galicia Interior Basin (GIB). Six Heinrich layers (HL1-6) have been identified in the area in base to the detection of distinct populations of exotic magnetic mineral assemblages alien to the local/regional sedimentation environment. Their extension has been determined by Ca/Sr and Si/Sr ratios and their provenance by 143Nd/144Nd and 87Sr/86Sr isotopic ratios and FORCs. The sedimentary expression of HL is characterized by the presence of distal Ice Rafted Detritus (IRD). Distal IRD magnetic signatures in the GIB consist of (i) an increase of one order of magnitude in the peak amplitude of magnetic susceptibility from background values, (ii) a general coarsening of the magnetic grain size in a mineral assemblage dominated by titano-magnetites, (iii) FORC distributions pushing towards the coarse MD or PSD component, and (iv) thermomagnetic curves depicting the occurrence of several magnetite phases. These four features are very different from the fine-grained biogenic magnetic assemblages characterized by the combination of lower MS and higher coercivity values that dominate the predominant mixtures of the non-interacting SSD and PSD components in the non-IRD influenced background sedimentation. Our results show that the last 70.000 yr of sedimentation in the GIB were controlled by the relative contribution of local detrital material derived from the Iberian Variscan Chain and IRD alien material from the iceberg melting during the Heinrich Events. They also show two main IRD provenance fields: Europe and Canada. And that the later is more important for for HL1, HL2, HL4 and HL5. FORCs analysis complemented the isotopic information and provided a very unique information, indicating that glacial flour may not always have the same provenance as IRD and that ice-melted derived suspended sediment has its own dynamics and may reach further and/or persists longer than IRD.

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Seasonal and interannual changes (1993e2012) of water temperature and transparency, river discharge, salinity, water quality properties, chlorophyll a (chl-a) and the carbon biomass of the main taxonomical phytoplankton groups were evaluated at a shallow station (~2 m) in the subtropical Patos Lagoon Estuary (PLE), Brazil. Large variations in salinity (0e35), due to a complex balance between Patos Lagoon outflow and oceanic inflows, affected significantly other water quality variables and phytoplankton dynamics, masking seasonal and interannual variability. Therefore, salinity effect was filtered out by means of a Generalized Additive Model (GAM). River discharge and salinity had a significant negative relation, with river discharge being highest and salinity lowest during July to October. Diatoms comprised the dominant phytoplankton group, contributing substantially to the seasonal cycle of chl-a showing higher values in austral spring/summer (September to April) and lowest in autumn/winter (May to August). PLE is a nutrient-rich estuary and the phytoplankton seasonal cycle was largely driven by light availability, with few exceptions in winter. Most variables exhibited large interannual variability. When varying salinity effect was accounted for, chl-a concentration and diatom biomass showed less irregularity over time, and significant increasing trends emerged for dinoflagellates and cyanobacteria. Long-term changes in phytoplankton and water quality were strongly related to variations in salinity, largely driven by freshwater discharge influenced by climatic variability, most pronounced for ENSO events. However, the significant increasing trend of the N:P ratio indicates that important environmental changes related to anthropogenic effects are undergoing, in addition to the hydrology in the PLE.

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Enzyme-mediated decomposition of soil organic matter (SOM) is controlled, amongst other factors, by organic matter properties and by the microbial decomposer community present. Since microbial community composition and SOM properties are often interrelated and both change with soil depth, the drivers of enzymatic decomposition are hard to dissect. We investigated soils from three regions in the Siberian Arctic, where carbon rich topsoil material has been incorporated into the subsoil (cryoturbation). We took advantage of this subduction to test if SOM properties shape microbial community composition, and to identify controls of both on enzyme activities. We found that microbial community composition (estimated by phospholipid fatty acid analysis), was similar in cryoturbated material and in surrounding subsoil, although carbon and nitrogen contents were similar in cryoturbated material and topsoils. This suggests that the microbial community in cryoturbated material was not well adapted to SOM properties. We also measured three potential enzyme activities (cellobiohydrolase, leucine-amino-peptidase and phenoloxidase) and used structural equation models (SEMs) to identify direct and indirect drivers of the three enzyme activities. The models included microbial community composition, carbon and nitrogen contents, clay content, water content, and pH. Models for regular horizons, excluding cryoturbated material, showed that all enzyme activities were mainly controlled by carbon or nitrogen. Microbial community composition had no effect. In contrast, models for cryoturbated material showed that enzyme activities were also related to microbial community composition. The additional control of microbial community composition could have restrained enzyme activities and furthermore decomposition in general. The functional decoupling of SOM properties and microbial community composition might thus be one of the reasons for low decomposition rates and the persistence of 400 Gt carbon stored in cryoturbated material.

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Most major cities in the eastern United States have air quality deemed unhealthy by the EPA under a set of regulations known as the National Ambient Air Quality Standards (NAAQS). The worst air quality in Maryland is measured in Edgewood, MD, a small community located along the Chesapeake Bay and generally downwind of Baltimore during hot, summertime days. Direct measurements and numerical simulations were used to investigate how meteorology and chemistry conspire to create adverse levels of photochemical smog especially at this coastal location. Ozone (O3) and oxidized reactive nitrogen (NOy), a family of ozone precursors, were measured over the Chesapeake Bay during a ten day experiment in July 2011 to better understand the formation of ozone over the Bay and its impact on coastal communities such as Edgewood. Ozone over the Bay during the afternoon was 10% to 20% higher than the closest upwind ground sites. A combination of complex boundary layer dynamics, deposition rates, and unaccounted marine emissions play an integral role in the regional maximum of ozone over the Bay. The CAMx regional air quality model was assessed and enhanced through comparison with data from NASA’s 2011 DISCOVER-AQ field campaign. Comparisons show a model overestimate of NOy by +86.2% and a model underestimate of formaldehyde (HCHO) by –28.3%. I present a revised model framework that better captures these observations and the response of ozone to reductions of precursor emissions. Incremental controls on electricity generating stations will produce greater benefits for surface ozone while additional controls on mobile sources may yield less benefit because cars emit less pollution than expected. Model results also indicate that as ozone concentrations improve with decreasing anthropogenic emissions, the photochemical lifetime of tropospheric ozone increases. The lifetime of ozone lengthens because the two primary gas-phase sinks for odd oxygen (Ox ≈ NO2 + O3) – attack by hydroperoxyl radicals (HO2) on ozone and formation of nitrate – weaken with decreasing pollutant emissions. This unintended consequence of air quality regulation causes pollutants to persist longer in the atmosphere, and indicates that pollutant transport between states and countries will likely play a greater role in the future.

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Atlantic Menhaden Brevoortia tyrannus is a commercially and ecologically important forage fish abundant on the Atlantic Coast of the United States. We conducted spatial and temporal analyses of larval Atlantic Menhaden using data collected from two large-scale ichthyoplankton programs during 1977-1987 and 1999-2013 to construct indices of larval abundance and survival over time, evaluate how environmental factors affect early life survival, and examine how larvae are distributed in space to gain knowledge on spawning and larval dispersal. Over time, we found larval abundance to increase, while early life survival declined. Coastal temperature, wind speed, and Atlantic Multidecadal Oscillation were found to potentially explain some of this decline in survival. Over both periods, we found evidence spawning predominantly occurs near shore, from New York to North Carolina, increasing in intensity southwards. While the general spatial patterns were consistent, we observed some localized variation and overall expansion of occupied area by larvae.

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As advances in numerical modelling techniques support the increased confidence in predictions from computer simulations, the need remains to have experimental verification built into the design process. This paper outlines the experimental investigation carried out on a shielded vertical axis turbine in a marine environment. The experiments consist of performance measurements and the use of particle image velocimetry on a small scale device in a marine current flume. The results demonstrate that the performance of the device can be modelled numerically; in particular, the results show that the numerical model used can correctly predict the increase in performance with Reynolds number.

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Bivalve aquaculture is seriously affected by many bacterial pathogens that cause high losses in hatcheries as well as in natural beds. A number of Vibrio species, but also members of the genera Nocardia and Roseovarius, are considered important pathogens in aquaculture. The present work provides an updated overview of main diseases and implicated bacterial species affecting bivalves. This review focuses on aetiological agents, their diversity and virulence factors, the diagnostic methods available as well as information on the dynamics of the host-parasite relationship.

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Although protists are critical components of marine ecosystems, they are still poorly characterized. Here we analysed the taxonomic diversity of planktonic and benthic protist communities collected in six distant European coastal sites. Environmental deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) from three size fractions (pico-, nano- and micro/mesoplankton), as well as from dissolved DNA and surface sediments were used as templates for tag pyrosequencing of the V4 region of the 18S ribosomal DNA. Beta-diversity analyses split the protist community structure into three main clusters: picoplankton-nanoplankton-dissolved DNA, micro/mesoplankton and sediments. Within each cluster, protist communities from the same site and time clustered together, while communities from the same site but different seasons were unrelated. Both DNA and RNA-based surveys provided similar relative abundances for most class-level taxonomic groups. Yet, particular groups were overrepresented in one of the two templates, such as marine alveolates (MALV)-I and MALV-II that were much more abundant in DNA surveys. Overall, the groups displaying the highest relative contribution were Dinophyceae, Diatomea, Ciliophora and Acantharia. Also, well represented were Mamiellophyceae, Cryptomonadales, marine alveolates and marine stramenopiles in the picoplankton, and Monadofilosa and basal Fungi in sediments. Our extensive and systematic sequencing of geographically separated sites provides the most comprehensive molecular description of coastal marine protist diversity to date.