Characterization of denitrification activity in zones of groundwater exfiltration within a riparian wetland ecosystem

Movement of agricultural nitrogen (N) into riparian buffers often occurs within discrete seepage or upwelling zones which can limit the ability of the ecosystem to process the nutrient delivered by exfiltrating groundwater. Characterization of the biogeochemical processing of N within these zones is important in assessing the effectiveness of riparian buffers for mitigating nutrient loading of surface waters. The biogeochemical potential for denitrification in zones of exfiltration within a riparian buffer wetland dominated by high-carbon mucky soils was found to be highly stratified by profile depth with substantially higher activity in the surface layer of soil. The denitrification enzyme activity (DEA) within these zones was partly related to the population size of denitrifying microorganisms as measured by the most probable number (MPN) as well as the general microbial population as measured by substrate-induced respiration. The addition of glucose to the DEA assay stimulated enzyme activity indicating that carbon substrate was limiting activity. The stratification patterns of microbial populations and DEA are consistent with new carbon inputs to the ecosystem being most important driver of biogeochemical reactions such as denitrification in this high-carbon environment. A survey of carbon inputs to the ecosystem under study identified two major sources that contribute most of the annual biomass carbon inputs to the wetland: skunk cabbage in early summer and tree leaf litter in the fall. Tests of the ability of annually deposited wetland plant residues to stimulate denitrification and microbial respiration indicated that the degree of stimulation was inversely related to the C/N ratio of these carbon sources.     

Habitat-based conservation priorities for carabid beetles within the Picos de Europa National Park, northern Spain

Quick biodiversity studies on poorly studied taxa and areas are increasingly popular for setting conservation priorities over a wide range of spatial scales. However, the implementation of such studies is complicated by the variable extent to which the different criteria used in prioritisation are correlated to each other. Using methods of constrained ordination, we examined the species-habitat relationships of carabid beetles based on ground beetle assemblages from 22 sites in the Picos de Europa National Park, northern Spain. We found characteristic species assemblages for subalpine meadows, Genista shrublands, and pastures, whereas mown meadows, heathlands, beech and riparian woodlands were occupied by more habitat generalist species. Species associated with subalpine meadows and Genista shrublands tended to be mostly brachypterous and to have geographic ranges restricted to northern Spain. In contrast, we found no relationship between the degree of species' association with pastures and geographic range-wing size type. Although the species richness was higher in riparian woodlands and mown meadows, we suggest a higher conservation value for subalpine meadows and Genista shrublands across the landscape because they sustain characteristic assemblages dominated by species with restricted ranges and reduced powers of dispersal. Our study suggests that preserving areas in the landscape supporting higher biodiversity will not necessarily preserve those species potentially more susceptible to habitat loss and fragmentation. It also supports the feasibility of biodiversity studies based on multivariate techniques for setting conservation priorities over complex landscapes.     

Otter (Lutra lutra) distribution modeling at two resolution scales suited to conservation planning in the Iberian Peninsula

We used the results of the Spanish Otter Survey of 1994-1996, a Geographic Information System and stepwise multiple logistic regression to model otter presence/absence data in the continental Spanish UTM 10×10-km squares. Geographic situation, indicators of human activity such as highways and major urban centers, and environmental variables related with productivity, water availability, altitude, and environmental energy were included in a logistic model that correctly classified about 73% of otter presences and absences. We extrapolated the model to the adjacent territory of Portugal, and increased the model's spatial resolution by extrapolating it to 1×1-km squares in the whole Iberian Peninsula. The model turned out to be rather flexible, predicting, for instance, the species to be very restricted to the courses of rivers in some areas, and more widespread in others. This allowed us to determine areas where otter populations may be more vulnerable to habitat changes or harmful human interventions.     

Fishery by-catches of marine mammals in Galician waters: results from on-board observations and an interview survey of fishermen

Rates of cetacean by-catch were investigated in Galician waters (NW Spain) using a combination of observer trips on fishing vessels, a carcase recovery scheme and an interview survey of fishermen, carried out over two years (1998-1999). All these data sources are suspected of underestimating by-catch due to the sample of co-operating fishermen being, necessarily, self-selecting. No by-catches were seen during observer trips, although not all sectors of the fishery could be covered. The carcass recovery scheme yielded seventeen cetacean carcases over two years, which compares to around 35 by-caught cetaceans recorded annually by the Galician strandings network. Analysis of interview data suggested that around 200 cetaceans might be caught annually in inshore waters and around 1500 in offshore waters. Confidence limits were wide for all estimates. The highest by-catch rates were estimated for gillnets and offshore trawling. The majority of by-catches are small dolphins, probably mainly Delphinus delphis. Smaller numbers of Tursiops truncatus and Globicephala melas are also reported. Comparing the interview estimates of by-catch rates with minimum estimates of population size, it is suggested that by-catches of D. delphis and T. truncatus may be unsustainably high and that routine monitoring of fishery by-catches in Galician fisheries is required.     

Emergence of pathogenic betanodaviruses belonging to the SJNNV genogroup in farmed fish species from the Iberian Peninsula

Betanodaviruses are the causative agents of viral nervous necrosis (VNN) or viral encephalopathy and retinopathy (VER) in cultured marine fish. Based on the RNA2 gene fish nodaviruses have been traditionally classified into four different genotypes and recently a fifth genotype has been proposed. This study presents sequencing data of 24 new nodaviruses obtained from three different fish species: sea bass, Dicentrarchux labrax (L.), sea bream, Sparus aurata L., and Senegalese sole, Solea senegalensis Kaup, cultured in the Iberian Peninsula (Spain and Portugal). Sequence analysis was performed on the T4 region (388 nt) of the coat protein gene. In addition, phylogenetic analysis, according to maximum parsimony and neighbour-joining methods, was performed using these sequences and other nucleotide sequences available in the databases or in the literature. Results obtained indicate that all these new nodaviruses should be classified into the striped jack nervous necrosis virus (SJNNV) genotype. This finding suggests that SJNNV genotype is emerging in the Iberian Peninsula and could easily spread throughout the Mediterranean, representing a serious threat to the fish farming industry.     

Forecasting climate-induced changes in the survival of Snake River spring/summer Chinook salmon (Oncorhynchus tshawytscha)

Effective conservation and management of natural resources requires accurate predictions of ecosystem responses to future climate change, but environmental science has largely failed to produce these reliable forecasts. The future response of Pacific salmon (Oncorhynchus spp.) to a changing environment and continued anthropogenic disturbance is of particular interest to the public because of their high economic, social, and cultural value. While numerous retrospective analyses show a strong correlation between past changes in the ocean environment and salmon production within the north Pacific, these correlations rarely make good predictions. Using a Bayesian time-series model to make successive 1-yr-ahead forecasts, we predicted changes in the ocean survival of Snake River spring/summer chinook salmon (O. tshawytscha) from indices of coastal ocean upwelling with a high degree of certainty (R² = 0.71). Furthermore, another form of the dynamic times-series model that used all of the available data indicated an even stronger coupling between smolt-to-adult survival and ocean upwelling in the spring and fall (R² = 0.96). This suggests that management policies directed at conserving this threatened stock of salmon need to explicitly address the important role of the ocean in driving future salmon survival.     

Evaluating upwelling estimates off the west coasts of North and South America

Both low‐ and high‐resolution studies of wind and upwelling were conducted off the west coasts of North and South America between August 1999 and December 2001. For the low‐resolution study, done at 25 regional sites spanning both coasts, weekly mean winds were calculated from satellite measurements, from geostrophic estimates, and from an operational 100‐km‐resolution global atmospheric model. The satellite‐measured winds, used as the reference, showed that the coastal regions of both North and South America were divided into fairly uniform climatic domains located at higher, mid, and lower latitudes. All three weekly‐mean wind data sets were compared at each of the 25 sites, and then used to estimate upwelling based on the method employed by NOAA's Pacific Fisheries Environmental Laboratory. Within each of the wind domains, model‐derived wind and upwelling estimates agreed with satellite‐derived values better than those from geostrophic‐derived estimates. To investigate variability between the regional sites, a 9‐km‐resolution atmospheric model was run for an area off California which spanned four of the regional sites. This high‐resolution model, verified with satellite measurements, revealed jets of wind curving and intensifying around coastal promontories. These near‐shore wind jets, undetected in the global model, resulted in strong upwelling bands on the order of 50 km alongshore by 20 km offshore. These bands are critical for calculating local upwelling. Our results indicate that regional upwelling estimates for fisheries research can be improved by replacing geostrophic estimates of winds with those from a global atmospheric model. For localized coastal upwelling estimates, however, models with resolution an order of magnitude higher are required.     

Chato Murciano pig and its crosses with Iberian and Large White pigs, reared outdoors. Comparative study of the carcass and meat characteristics

The Chato Murciano pig is an autochthonous breed genetically adapted to the south-east of Spain local conditions and extensive production system. In this work we aimed to compare the quality of the carcass and meat of this local breed and its crosses in outdoor rearing conditions. Samples were taken from the longissimus lumbar muscle of 38 pigs, belonging to three different groups, Chato Murciano (CH), Chato Murciano crossed with Iberian (CH × IB) and Chato Murciano crossed with Large White (CH × LW). The pH values measured at 24 h postmortem were within the normal range. The levels of intramuscular fat were 10.47% for CH, 8.97% for CH × IB, and 11.17% for CH × LW. The CH × LW group showed the highest weights for the most valuable meat cuts. The meat of the Chato Murciano pig and its crosses revealed high levels of iron, copper and phosphorus, and low levels of calcium and sodium.     

Natural variability of fisheries and lunar illumination: a hypothesis

Long‐term synchronous trends in small pelagic fisheries catches around the world suggest that fish populations are governed by the same global climate forcings. Recent findings regarding the population dynamics of zooplankton during the lunar cycle in sub‐tropical waters may shed light on the influence of the lunar cycle on fish spawning and mortality. Here I hypothesize that, in the short‐term, observed changes in zooplankton abundance during the lunar cycle promote periods of enhanced feeding by adult fish and lower mortality (and increased growth) in their early planktonic stages. Furthermore, a striking 9‐year periodicity in sardine and anchovy mortality was inferred in four major upwelling areas, coinciding with the long‐term variability in lunar illumination. It is suggested that both short‐ and long‐term changes in lunar illumination should be considered when modelling the effect of climate on the natural variability of fisheries.     

Seasonal and interannual variations of oceanographic conditions off Mangalore coast (Karnataka, India) in the Malabar upwelling system during 1995–2004 and their influences on the pelagic fishery

Mangalore coast is well known for its multi‐species and multi‐gear fisheries and the fishery and oceanographic features of this region is a true representation of the Malabar upwelling system. Ten years of study (1995–2004) of oceanographic parameters has been carried out from the inshore waters off Mangalore to understand their seasonal and interannual variations and influences on the pelagic fishery of the region. Attempt has been also made to understand the influence of local and global environmental conditions on the alternating patterns of abundance between the Indian mackerel and oil sardine from the area. Field‐ and satellite‐derived oceanographic data have shown that coastal upwelling occurs during July–September with a peak in August resulting in high nutrient concentrations and biological productivity along the coast. Nearly 70% of the pelagic fish catch, dominated by oil sardine and mackerel, was obtained during September–December, during or immediately after the upwelling season. Catches of scombroid fishes were significantly related to cold Sea Surface Temperature, while such relationships were not observed for sardines and anchovies. Significant positive correlations were observed between the ENSO events (MEI) and seawater temperature from the study area. The extreme oceanographic events associated with the cold La Niña, which preceded the exceptional 1997–98 El Niño event, were responsible for the collapse of the pelagic fishery, especially the mackerel fishery along the southwest coast of India (Malabar upwelling system). Coinciding with the collapse of the mackerel fishery, oil sardine populations revived during 1999–2000 all along the southwest coast of India. Tolerance of oil sardine to El Niño / La Niña events and the low predatory pressure experienced by their eggs and larvae due to the collapse of mackerel population might have resulted in its population revival.