Evaluation of zoobenthic assemblages and recovery following petroleum spill in a coastal area of Río de la Plata estuarine system, South America

The objective of this work was to analyse zoobenthic assemblages in the coastal sector of the Río de La Plata, Argentina, after a petroleum spill. Sampling stations were located in representative sites of various landscapes. Structure, composition, physico-chemical parameters and seasonal changes were recorded in order to assess taxocenosis evolution during the period 1999–2003. Recovery signs were estimated by means of biotic indices and the presence of sensitive species. Tolerant species were dominant in heavily polluted sites, with low diversity and water quality values, according to the biotic indices used. In certain zones, sediment quality remains impoverished, with a visible oil film on the surface. However, during the last sampling, some points showed an increase in biotic indices, pointing to a slight improvement in environmental conditions.     

Mercury pollution in Ria de Aveiro (Portugal): a review of the system assessment

The Ria de Aveiro (Portugal) is a coast al lagoon adjacent to the Atlantic Ocean and it has an inner bay (Laranjo bay) that received a highly contaminated effluent discharged by a mercury cell chlor-alkali plant from the 1950s until 1994. The aim of this study is to review in a holistic way several research studies that have been carried out in the Ria de Aveiro, in order to evaluate the remobilization of the mercury accumulated within the system and the recovery of the lagoon. The spatial distribution of the total mercury in the surrounding terrestrial environment has also been considered. Results indicate that the main mercury contamination problems in the Ria de Aveiro are confined to the Laranjo bay. Mercury export to the coastal waters and its impact on the nearshore compartments (water column, sediment and biota) are low. No direct effects of the mercury from nearby industrial activities were detected in Aveiro's urban soils, although historical mercury contamination is still affecting soil quality in the immediate vicinity of the chlor-alkali plant, located in Estarreja. Moreover, macrophyte harvesting for human direct or indirect use and the consumption of mussels, crabs and the sea bass from the Laranjo bay may constitute a health risk. Further studies focusing on developing skills for the restoration of the ecosystem are presently underway.     

Environmental indicators as tools for the management of estuaries—Methodology and case study of the Tejo estuary

The need for a better management of estuaries requires an environmental characterization following a methodology that allows the comparison of distinct estuarine systems and the assessment of their evolution. The peculiar characteristics of estuaries, in particular their intrinsic variability, make this characterization difficult and there is no commonly accepted general methodology available. The approach followed in freshwater ecosystems is generally based on the concept of environmental indicators, but such a concept has not been developed for estuaries. Indeed, a different approach is needed here, due to the spatial heterogeneity and the different time scales associated with the processes that control water quality. This paper presents a proposal for a methodology that starts with observed values and uses a procedure to integrate these values in time and space in order to calculatesignificant values, upon whichnormalized indicators are built which take into account criteria based either on legal, scientific or heuristic concentration limits. A normalization is carried out in two steps: (1) application of a mathematical operator to theignificant values, (2) transformation using the concept ofpenalty curves. This methodology may be complemented with the definition ofquality classes, particularly appealing and useful, as tools to communicate with decision makers and the public in general. Water quality data pertaining to the Tejo estuary are used to test the methodology.     

Determination of plate waste in primary school lunches by weighing and visual estimation methods: A validation study

The aim of this study was to validate the visual estimation method for aggregated plate waste of main dish at Portuguese primary school canteens. For this purpose plate waste at school lunch was measured for 505 individual servings, using weighing individual servings and plate waste and visual estimation method by a 6-point scale, as developed by Comstock et al. (1981). A high variability of initial serving weights was found with serving sizes ranging from 88.9 to 283.3 g and with a coefficient of variation ranging from 5.5% to 24.7%. Mean plate waste was 27.5% according to the weighing method. There was a significant bias in the conversion of the visual waste estimations to actual waste, being overestimated by an average of 8.0 g (ranging from ?12.9 g to 41.4 g). According to Bland and Altman plot, the mean difference between methods was of 8.0 g and the amplitude interval was 102.6 g. The study showed that the visual estimation method is not as accurate as the weighing method in assessing nonselective aggregated plate waste at primary school canteens. Our findings are thus very important on considering plate waste assessment, since the wide variation on initial servings introduces a relevant bias when considering standard portions or a random sample of initial servings. Although, greater convenience, time-saving and the possibility to monitor plate waste of large groups, make the visual estimation method an important method to assess plate waste at school canteens, these results highlighted the need of portions standardization and control of initial servings to allow for its use.     

A spatially explicit estimate of the prewhaling abundance of the endangered North Atlantic right whale

The North Atlantic right whale (NARW) (Eubalaena glacialis) is one of the world's most threatened whales. It came close to extinction after nearly a millennium of exploitation and currently persists as a population of only approximately 500 individuals. Setting appropriate conservation targets for this species requires an understanding of its historical population size, as a baseline for measuring levels of depletion and progress toward recovery. This is made difficult by the scarcity of records over this species’ long whaling history. We sought to estimate the preexploitation population size of the North Atlantic right whale and understand how this species was distributed across its range. We used a spatially explicit data set on historical catches of North Pacific right whales (NPRWs) (Eubalaena japonica) to model the relationship between right whale relative density and the environment during the summer feeding season. Assuming the 2 right whale species select similar environments, we projected this model to the North Atlantic to predict how the relative abundance of NARWs varied across their range. We calibrated these relative abundances with estimates of the NPRW total prewhaling population size to obtain high and low estimates for the overall NARW population size prior to exploitation. The model predicted 9,075–21,328 right whales in the North Atlantic. The current NARW population is thus <6% of the historical North Atlantic carrying capacity and has enormous potential for recovery. According to the model, in June–September NARWs concentrated in 2 main feeding areas: east of the Grand Banks of Newfoundland and in the Norwegian Sea. These 2 areas may become important in the future as feeding grounds and may already be used more regularly by this endangered species than is thought.     

Mainstreaming ecosystem-based climate change adaptation into integrated water resources management in the Mekong region

Regional Environmental Change - Efficient, equitable, and transboundary management of the water resources of the Mekong River Basin (MRB) is challenged by ongoing and accelerating alteration of the...     

Three-dimensional modeling of the lower trophic levels in the Ria de Aveiro (Portugal)

The water and the ecosystem dynamics of the Ria de Aveiro, a shallow, multi-branch lagoon located on the northwest coast of Portugal, are simulated using a new fully coupled 3D modeling system. This model couples the hydrodynamic model SELFE (semi-implicit Eulerian-Lagrangian finite element) and an ecological model extended from EcoSim 2.0 to represent zooplankton dynamics. The model application is based on an unstructured grid spatial discretization, which is particularly appropriate for this system given its complex geometry. The baroclinic circulation is calibrated and validated for different environmental conditions, leading to velocity errors smaller than 5 cm/s across the lagoon. Ecological simulations, focused on zooplankton dynamics represented by a site-specific formulation, are then presented and compared against field data for two contrasting environmental conditions: Autumn 2000 and Spring 2001. Results show that the fully coupled model is able to reproduce the dynamics of the ecosystem in the Spring 2001, fitting the model results inside the range of data variation. During this period zooplankton differences between data and model results are of about 0.005 mg C/l (60%), while other ecological tracers’ differences are generally smaller than 20–30% along the several branches of the lagoon. In the Autumn 2000, the model tends to overestimate zooplankton by a factor of 10 and to underestimate phytoplankton and ammonium, with discrepancies of about 0.1 mg C/l and 4.8 μmol N/l, respectively. Factors like the ecological conditions imposed at the boundaries, the input parameters of the ecological model and the simplification of the ecosystem structure, since phytoplankton is the only primary producer considered, may explain the observed differences.     

Environmental performance evaluation of agro-industrial innovations – part 1: Ambitec-Life Cycle,a methodological approach for considering life cycle thinking

As sustainability considerations increasingly dominate the technology development debate worldwide, practical approaches to assess environmental performance of innovations have been warranted. The present study (Part 1) introduces Ambitec-Life Cycle, a method derived from Ambitec-Agro for considering life cycle thinking in the environmental performance evaluation (EPE) of agro-industrial innovations. An agro-industrial innovation case study related to residue recycling is presented, revealing steps in the product life cycle where opportunities are best for technological improvements. In Part 2 (this issue) of this study, a methodological approach for considering the environmental vulnerability of watersheds and to integrate this analysis in EPE methods is presented. This approach is applied to Ambitec-Life Cycle and to the same residue case study, allowing the identification of performance indicators with greater potential to cause impacts at the studied watersheds.