The tunicate Salpa thompsoni ecology in the Southern Ocean. II. Proximate and elemental composition

Detailed determination of Salpa thompsoni elemental composition has been carried out on specimens collected in the Eastern Bellingshausen Sea and at the northern edge of the Weddell Gyre during austral autumn (April and May) of 1996 and 2001. More than 170 Antarctic tunicates S. thompsoni were analysed to determine wet weight (WW), dry weight (DW), ash-free dry weight (AFDW) and elemental composition (C, N content, proteins, carbohydrates and lipids) of different sizes and stages. Dry weight comprised 6.4% (aggregate form) to 7.7% (solitary form) of the WW. AFDW amounted to ~44% of the DW. Carbon and nitrogen contents (Carbon: 17–22%, Nitrogen: 3–5% of the DW) of both aggregate and solitary forms were found to be high relative to data reported in the literature. Although some unidentified organic compounds are not included in our carbon budget, the findings of this study show higher than previously reported nutritional values of S. thompsoni. In spite of this, a shift from a krill-dominated towards a salp-dominated ecosystem would have dramatic consequences for organisms at higher trophic levels.     

Compatible intracellular ion composition of the host improves carbon assimilation by Zooxanthellae in mutualistic symbioses

Cytosymbiotic algae within the host's plasma are exposed to completely different ionic conditions than microalgae living in the sea. The altered ionic gradients, in particular, could be the reason for higher in hospite carbon assimilation levels. To study the effect of varying extracellular ionic conditions on isolated zooxanthellae, their photosynthetic capacity in pure seawater was compared to that in a test medium in which the concentrations of the major inorganic ions, the pH and the osmolality were adjusted to the conditions measured in the host cytoplasm. In this test medium the ratio between oxygen evolution and carbon fixation was 1.2:1.0; in contrast, zooxanthellae in the hyperionic seawater medium showed a comparatively higher oxygen production (2.6:1.0). These results are attributed to a higher energy demand for ion regulation of the isolated algae in the hyperionic medium. Isolated cytosymbionts in seawater need more energy both for the readjustment to the original intracellular ion concentration within the host cell and also for the maintenance of a much steeper gradient during incubation under hyperionic conditions outside the host. The particular intracellular ion concentration of the host cells could have been a decisive evolutionary factor for the very successful establishment of the mutualistic symbioses between anthozoans and dinoflagellates more than 200 million years ago.     

Modelling small groundwater systems: experiences from the Braunton Burrows and Ainsdale coastal dune systems,UK

Coastal dunes are delicate systems that are under threat from a variety of human and natural influences. Groundwater modelling can provide a better understanding of how these systems operate and can be a useful tool towards the effective management of a coastal dune system, e.g. by identifying strategically important locations for flora and fauna and guiding the planning of management operations through predicting impacts from climatic change, sea level rise and land use management. Most dune systems are small, typically of the size 10–100 km², compared with inland groundwater systems. Applying conventional groundwater modelling approaches to these small systems presents a number of challenges due to the local scale of the system and the fact that the system boundaries (sea, drains, ponds etc.) are close to the main body of the aquifer. In this paper, two case studies will be presented using different modelling approaches to understand the groundwater balance in two dune systems in the UK. The studies demonstrate that, although conventional hydraulic models can describe the general system behaviour, a fuller understanding of the recharge mechanisms and system boundaries is needed to represent adequately system dynamics of small groundwater systems.     

A systemic methodology for risk management in healthcare sector

The recent biomedical, technological, and normative changes have led healthcare organizations to the implementation of clinical governance as a way to ensure the best quality of care in an increasingly complex environment. Risk management is one of the most relevant aspects of clinical governance and approaches put forward in literature highlight the necessity to perform comprehensive analyses intended to uncover root causes of adverse events.Contributing to this field, the present paper applies Reason’s theory of failures to work out a systemic methodology to study risks impacting not only directly but also indirectly on patients. Also, the steps of such approach are organized around Human Reliability Assessment phases, in order to take into account the human component of healthcare systems. This framework is able to foster effective decision making about reducing failures and waste and to improve healthcare organizations’ maturity towards risk management.The developed methodology is applied to the pharmacy department of a large Italian hospital. An extensive validation in different healthcare settings is required to fully prove benefits and limitations.     

Catchment–coastal zone interaction based upon scenario and model analysis: Elbe and the German Bight case study

This paper presents a holistic strategy on the interaction of activities in the Elbe river basin and their effects on eutrophication in the coastal waters of the German Bight. This catchment–coastal zone interaction is the main target of the EUROCAT (EUROpean CATchments, catchment changes and their impact on the coast) research project, with the Elbe being one of eight case studies. The definition of socio-economic scenarios is linked with the application of models to evaluate measures in the catchment by estimation of nutrient emissions with MONERIS (MOdelling Nutrient Emissions in RIver Systems), and their effects on coastal waters with the ecosystem model ERSEM (European Regional Seas Ecosystem Model). The cost effectiveness of reduction measures will then be evaluated by application of the CENER model (Cost-Effective Nutrient Emission Reduction) and a multi-criteria analysis. Finally, the interpretation of ecological integrity is used as a measure to describe ecological impacts in an aggregated form.     

Grasshopper assemblage response to conservation ecological networks in a timber plantation matrix

Grasshopper assemblages are well known to be sensitive and responsive to changes occurring in habitats, enabling their application as bioindicators. Large-scale ecological networks (ENs) have been proposed as a conservation mitigation measure, and are used extensively in southern Africa to offset the impacts on biodiversity of commercial afforestation. Here, grasshopper response to an EN of 15 semi-natural grassland sites embedded in an exotic timber plantation matrix was investigated over two time periods, one year apart. The aim was to determine which environmental variables had a significant effect on grasshoppers, whether this response was robust among seasons, and the extent of phylogenetic variability in the response. The results showed that grasshopper species responded strongly and consistently to area of the site, time lapse since the last fire, and inconsistently to proportion of short grasses. Generalized least squares models with phylogenetic adjustment showed that there was a strong phylogenetic signal in species response to habitat quality, illustrating that site occupancy patterns were distinct for species from different subfamilies. Since grasshopper assemblages are more sensitive to internal patch-level environmental factors of ENs than to patch isolation, ENs may indeed be a suitable mitigation measure, although effectiveness is expected to vary among taxa.