José A. Juanes

The Prestige Oil Spill in Cantabria (Bay of Biscay). Part I: Operational Forecasting System for Quick Response, Risk Assessment, and Protection of Natural Resources

Abstract In this paper, we present the operational forecasting system developed to assist in the response to the 2002 Prestige oil spill in Cantabria. The objective of the system developed was to forecast the wave climate, tidal and wind currents, and oil spill trajectories to provide a technical assessment to decision makers for a response to the oil spill. The two main components of the system were data collection and processing and integration with numerical models for forecasting. The information from overflights received daily became essential in achieving a correct initial position of the oil slicks. Meteorological and oceanographic data were also received daily by means of an emergency protocol established between Puertos del Estado (Spain), the Naval Research Laboratory (USA), and the University of Cantabria (Spain). These data were used to run the trajectory model, the wave propagation model, and the shallow depth-integrated flow model. The information generated by the numerical simulations was presented to the decision makers every day in the form of maps that were easy and quick to interpretation as a tool to help in the response planning. In addition, to develop a defensive or protection strategy for sensitive areas like estuaries and marshes, a hydrodynamic study was carried out by the University of Cantabria in all the estuaries of the region. The result of this study consisted of a boom deployment plan for each.

Oil spill vulnerability assessment integrating physical, biological and socio-economical aspects: Application to the Cantabrian coast (Bay of Biscay, Spain)

A methodology has been developed to carry out an integrated oil spill vulnerability index, V, for coastal environments. This index takes into account the main physical, biological and socio-economical characteristics by means of three intermediate indexes. Three different integration methods (worst-case, average and survey-based) along with ESI-based vulnerability scores, V(ESI), proposed for the Cantabrian coast during the Prestige oil spill, have been analyzed and compared in terms of agreement between the classifications obtained with each one for this coastal area. Results of this study indicate that the use of the worst-case index, V(R), leads to a conservative ranking, with a very poor discrimination which is not helpful in coastal oil spill risk management. Due to the homogeneity of this coastal stretch, the rest of the methods, V(I), V(M) and V(ESI), provide similar classifications. However, V(M) and V(I) give more flexibility allowing three indexes for each coastal segment and including socio-economic aspects. Finally, the V(I) procedure is proposed here as the more advisable as using this index promotes the public participation that is a key element in the implementation of Integrated Coastal Zone Management (IZCM).

Assessment of the effects of a marine urban outfall discharge on caged mussels using chemical and biomarker analysis

To assess the presence of endocrine disruptors in treated marine outfall discharges and their possible effects, mussels (Mytilus galloprovincialis) were caged in the environmental mixing zone of the outfall of the Santander sanitation system and in one control area. After 30, 60 and 90 days, samples were collected to perform chemical analyses (metals, anionic surfactants, alkylphenols, bisphenol A, phthalates and estrogenic hormones), biomarkers of general stress (lysosomal membrane stability-LMS, histopathology) and biomarkers of endocrine disruption (vitellogenin-like proteins and gonad index). There were no significant differences between outfall and control sites on contaminant levels, except for 4-tert-octylphenol which was higher in the outfall site. Bacteriological counts were higher in the outfall area. No relevant differences in biomarkers were detected between treated and control mussels. A significant reduction in LMS occurred in both groups after 90 days caging, indicating a stress situation possibly related to caging or to post-spawning reproductive state.

Assessing the effects of treated and untreated urban discharges to estuarine and coastal waters applying selected biomarkers on caged mussels

To assess effects of urban discharges, biomarkers were measured in caged mussels in northern Iberian Peninsula. Lysosomal membrane stability and histopathology of gonad and digestive gland were analysed as general effect biomarkers. Exposure to specific pollutants was evaluated by autometallographical detection of metals, peroxisomal acyl-CoA oxidase activity, micronucleus test and transcription levels of vitellogenin and MT20 genes. Health status of mussels was impaired after 3 days of caging at the untreated outfall discharge and at the waste water treatment plant effluent discharge to the estuary. The most relevant finding was the significant up-regulation of vitellogenin gene transcription in male mussels exposed to the untreated outfall discharge. Metals and xenoestrogenic endocrine disruptors were bioavailable in some discharges and disturbed the health status of mussels. Biomarkers were effective in the assessment of effects of urban discharges and could be implemented in operative controls required to assess the risks associated to effluent discharges.

Biological criteria for the exploitation of the commercially important species of Gelidium in Spain

Exploitation of the commercially-important species of Gelidium in Spain (G. sesquipedale and G. latifolium) and development of the industry occurred after World War II, as a consequence of their use as resources for the extraction of agar. This resulted in the implementation of several harvesting methods, the most important of which is the gathering of cast seaweeds, both from the shore and the sea. From the very beginning, direct exploitation of these species (i.e. plucking) was controversial because of possible adverse ecological effects. Consequently, several biological and ecological studies of both species of Gelidium were begun. This included such aspects as growth, biomass production, productivity, reproduction, regeneration capacity and agar yield. Recently, the growing interest in using and conserving this resource has led to increased knowledge of the biology and ecology of these species. In this paper, we provide an overview of the research carried out by different Spanish groups and suggest guidelines for rational management of these resources.

Microdistribution patterns of macroinvertebrate communities upstream and downstream of organic effluents

The present study analyses the distribution patterns of macroinvertebrate communities in four microhabitats (riffles, glides, leaf litter and bank roots) upstream and downstream of two waste water treatment plant (WWTP) effluents in northern Spain rivers. Macroinvertebrate communities were analysed in November 2006 by taking 5 samples from each of the microhabitats under unaffected (upstream WWTP) and affected (downstream WWTP) conditions, respectively. Water velocity, depth, substrate coarseness and hydraulic stress by means of the Froude number were also estimated at all sampling locations. Under unaffected conditions, the abundance and presence/absence of certain macroinvertebrate taxa were mainly determined by hydraulic characteristics (water velocity and Froude number) and feeding resource availability. However, neither macroinvertebrate richness nor abundance were neither significantly correlated with hydraulic stress nor substrate coarseness, although the number of macroinvertebrate taxa increased in microhabitats with high structural complexity. Macroinvertebrate abundance increased downstream of both WWTPs, while macroinvertebrate richness was not adversely affected by the organic enrichment of water. The structure and composition of macroinvertebrate communities occurring in riffles was similar under unaffected and affected conditions, while communities from leaf litter and submerged bank roots showed important changes above and below the WWTPs, indicating that they are probably the most appropriate communities for water quality assessment.

Differential reattachment capacity of isomorphic life history phases of Gelidium sesquipedale

Vegetative reproduction is an important phenomenon in the propagation of Gelidium species, having significant implications for its ecology and commercial cultivation. This work is an experimental study of one of five sequential processes included in the vegetative propagation of Gelidium sesquipedale: the reattachment of rhizoidal filaments differentiated from apical fragments.

Medium-term assessment of the effects of the Prestige oil spill on estuarine benthic communities in Cantabria (Northern Spain, Bay of Biscay)

A specific monitoring program was implemented in the estuaries of Cantabria (northern Spain) in order to assess the medium-term effects (2003-2005) of the Prestige oil spill (POS) on benthic macroinvertebrate communities. A control-impact design was adopted, examining four unaffected and five oil-affected estuaries. High mortalities and significant differences in overall richness and diversity between the control and impacted estuaries were not detected. Some changes in the temporal evolution of species abundance were observed for some key species, but these could not be related to the spillage event. It was not possible to ensure that low magnitude effects had not occurred, due to the high range of natural variability of benthic communities, the confounding effects of other contamination sources and the absence of previous reference conditions.

A model for predicting the temporal evolution of dissolved oxygen concentration in shallow estuaries

The design of sewage discharge systems in estuaries needs to consider the dissolved oxygen concentration among other water quality indicators. Due to the great number of factors affecting the dissolved oxygen, the prediction of the temporal evolution of this element requires the use of mathematical tools. In the case of shallow estuaries with extensive intertidal zones, the complexity of this task increases since the water domain varies continuously. This work describes a numerical model which solves the vertical integrated transport equation including the effect of extensive tidal flats. The model makes use of the tidal velocities computed by a previous run of a hydrodynamic model. This procedure allows the dissolved oxygen modelling to be performed using a larger time step than that used for the velocity field calculation. The numerical scheme developed for the model guarantees that even in the drying and wetting of intertidal areas the water column dissolved oxygen concentration is not modified by numerical errors. The representations of the processes included in the model (advection, dispersion and reaction) have been validated successfully in several theoretical cases. An application to the Urdaibai Estuary, a shallow estuary in the Basque Country, Northern Spain, is also presented.

The Prestige Oil Spill in Cantabria (Bay of Biscay). Part II. Environmental Assessment and Monitoring of Coastal Ecosystems

Abstract Assessment and monitoring activities constituted two main tasks of the emergency response system implemented by the regional government of Cantabria (north Spain) after the Prestige oil spill. The assessment covered four types of environmental units: estuaries, rocky shores, sand beaches, and subtidal areas, up to a 300-m depth. Monitoring procedures included the chemical quantification of total hydrocarbons and polycyclic aromatic hydrocarbons in water, sediments, and benthic organisms (clams and goose barnacles), and the analysis of structural changes in intertidal communities. Disturbance of oil cover was significantly more extensive in coastal areas, rather than in estuarine areas, where 50,000 m2 were directly covered by fuel. Otherwise, the presence of oil in subtidal areas was a rare event. Results from the bioeffects analyses were in agreement with the overall impact assessments, pointing to the coastal habitats as the areas where the bioavailability of toxic components from the Prestige spill presented a significant level of risk.