56 research outputs found

    Non-linearities, regime shifts and recovery: The recent influence of climate on Black Sea chlorophyll

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    The Black Sea ecosystem experienced severe eutrophication-related degradation during the 1970s and 1980s. However, in recent years the Black Sea has shown some signs of recovery which are often attributed to a reduction in nutrient loading. Here, SeaWiFS chlorophyll a (chl a), a proxy for phytoplankton biomass, is used to investigate spatio-temporal patterns in Black Sea phytoplankton dynamics and to explore the potential role of climate in the Black Sea's recovery. Maps of chl a anomalies, calculated relative to the 8 year mean, emphasize spatial and temporal variability of phytoplankton biomass in the Black Sea, particularly between the riverine-influenced Northwest Shelf and the open Black Sea. Evolution of phytoplankton biomass has shown significant spatial variability of persistence of optimal bloom conditions between three major regions of the Black Sea. With the exception of 2001, chl a has generally decreased during our 8 year time-series. However, the winter of 2000-2001 was anomalously warm with low wind stress, resulting in reduced vertical mixing of the water column and retention of nutrients in the photic zone. These conditions were associated with anomalously high levels of chl a throughout much of the open Black Sea during the following spring and summer. The unusual climatic conditions occurring in 2001 may have triggered a shift in the Black Sea's chl a regime. The long-term significance of this recent shift is still uncertain but illustrates a non-linear response to climate forcing that makes future ecosystem changes in the pelagic Black Sea ecosystem difficult to predict. © 2008 Elsevier B.V. All rights reserved

    Calf health from birth to weaning. I. General aspects of disease prevention

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    Calfhood diseases have a major impact on the economic viability of cattle operations. This is the first in a three part review series on calf health from birth to weaning, focusing on preventive measures. The review considers both pre- and periparturient management factors influencing calf health, colostrum management in beef and dairy calves and further nutrition and weaning in dairy calves

    Trace Elements and Carbon and Nitrogen Stable Isotopes in Organisms from a Tropical Coastal Lagoon

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    Trace elements (Fe, Mn, Al, Zn, Cr, Cu, Ni, Pb, Cd, Hg, and As) and stable isotope ratios (δ13C and δ15N) were analyzed in sediments, invertebrates, and fishes from a tropical coastal lagoon influenced by iron ore mining and processing activities to assess the differences in trace element accumulation patterns among species and to investigate relations with trophic levels of the organisms involved. Overall significant negative relations between trophic level (given by 15N) and trace element concentrations in gastropods and crustaceans showed differences in internal controls of trace element accumulation among the species of different trophic positions, leading to trace element dilution. Generally, no significant relation between δ15N and trace element concentrations was observed among fish species, probably due to omnivory in a number of species as well as fast growth. Trace element accumulation was observed in the fish tissues, with higher levels of most trace elements found in liver compared with muscle and gill. Levels of Fe, Mn, Al, and Hg in invertebrates, and Fe and Cu in fish livers, were comparable with levels in organisms and tissues from other contaminated areas. Trace element levels in fish muscle were below the international safety baseline standards for human consumption

    Prevention of fall incidents in patients with a high risk of falling: design of a randomised controlled trial with an economic evaluation of the effect of multidisciplinary transmural care

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    Background. Annually, about 30% of the persons of 65 years and older falls at least once and 15% falls at least twice. Falls often result in serious injuries, such as fractures. Therefore, the prevention of accidental falls is necessary. The aim is to describe the design of a study that evaluates the efficacy and cost-effectiveness of a multidisciplinary assessment and treatment of multiple fall risk factors in independently living older persons with a high risk of falling. Methods/Design. The study is designed as a randomised controlled trial (RCT) with an economic evaluation. Independently living persons of 65 years and older who recently experienced a fall are interviewed in their homes and screened for risk of recurrent falling using a validated fall risk profile. Persons at low risk of recurrent falling are excluded from the RCT. Persons who have a high risk of recurrent falling are blindly randomised into an intervention (n = 100) or usual care (n = 100) group. The intervention consists of a multidisciplinary assessment and treatment of multifactorial fall risk factors. The transmural multidisciplinary appraoch entails close cooperation between geriatrician, primary care phys

    Marine mammals and Good Environmental Status: Science, Policy and Society; Challenges and Opportunities

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    The Marine Strategy Framework Directive has become the key instrument for marine conservation in European seas. We review its implementation, focusing on cetacean biodiversity, using the examples of Spain and the Regional Seas Convention, OSPAR. The MSFD has been widely criticised for legal vagueness, lack of coordination, uncertainty about funding, and poor governance; its future role within EU Integrated Maritime Policy remains unclear. Nevertheless, the first stages of the process have run broadly to schedule: current status, environmental objectives and indicators have been described and the design of monitoring programmes is in progress, drawing on experience with other environmental legislation. The MSFD is now entering its critical phase, with lack of funding for monitoring, limited scope for management interventions, and uncertainty about how conservation objectives will be reconciled with the needs of other marine and maritime sectors, being among the main concerns. Clarity in governance, about the roles of the EU, Member States, Regional Seas Conventions and stakeholders, is needed to ensure success. However, even if (as seems likely) good environmental status cannot be achieved by 2020, significant steps will have been taken to place environmental sustainability centre-stage in the development of Integrated Maritime Policy for EU seas.Postprin

    The EBM-DPSER conceptual model: integrating ecosystem services into the DPSIR framework

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    There is a pressing need to integrate biophysical and human dimensions science to better inform holistic ecosystem management supporting the transition from single species or single-sector management to multi-sector ecosystem-based management. Ecosystem-based management should focus upon ecosystem services, since they reflect societal goals, values, desires, and benefits. The inclusion of ecosystem services into holistic management strategies improves management by better capturing the diversity of positive and negative human-natural interactions and making explicit the benefits to society. To facilitate this inclusion, we propose a conceptual model that merges the broadly applied Driver, Pressure, State, Impact, and Response (DPSIR) conceptual model with ecosystem services yielding a Driver, Pressure, State, Ecosystem service, and Response (EBM-DPSER) conceptual model. The impact module in traditional DPSIR models focuses attention upon negative anthropomorphic impacts on the ecosystem; by replacing impacts with ecosystem services the EBM-DPSER model incorporates not only negative, but also positive changes in the ecosystem. Responses occur as a result of changes in ecosystem services and include inter alia management actions directed at proactively altering human population or individual behavior and infrastructure to meet societal goals. The EBM-DPSER conceptual model was applied to the Florida Keys and Dry Tortugas marine ecosystem as a case study to illustrate how it can inform management decisions. This case study captures our system-level understanding and results in a more holistic representation of ecosystem and human society interactions, thus improving our ability to identify trade-offs. The EBM-DPSER model should be a useful operational tool for implementing EBM, in that it fully integrates our knowledge of all ecosystem components while focusing management attention upon those aspects of the ecosystem most important to human society and does so within a framework already familiar to resource managers

    The trace metal chemistry of a tropical hypersaline basin: Evidence from field and laboratory experiments

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    Field observations were made of the distribution of trace metals in water and sediments along a chlorinity gradient from 20-160‰ in the seasonally hypersaline Ceuta lagoon, Sinaloa, Mexico. The observations revealed a non-consecutive behaviour of the metals (with respect to chlorinity) with a rapid loss of metals to the sediments from chlorinity 20-50‰, a net desorption of metals from the sediments from 50-155‰ and finally, precipitation with halite or the last bitters. Radiochemical laboratoty experiments were performed to examine possible solid-solution formation of Ni, Co and Mn with the calcium carbonate and gypsum phases formed during seawater evaporation and the partition of Co and Mn between suspended sediments and seawater throughout the chlorinity range of the lagoon. From the laboratory experiments and a simple descriptive model of a hypersaline basin, it was concluded that the behaviour of trace metals in the lagoon results from variations in the adsorption/desorption equilibria with the sediments rather than solid solution formation
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