Antagonistic effect of natural habitat conversion on community adjustment to climate warming in nonbreeding waterbirds

Although the impacts of climate and land-use changes on biodiversity have been widely documented, their joint effects remain poorly understood. We evaluated how nonbreeding waterbird communities adjust to climate warming along a gradient of land-use change. Using midwinter waterbird counts (132 species) at 164 major nonbreeding sites in 22 Mediterranean countries, we assessed the changes in species composition from 1991 to 2010, relative to thermal niche position and breadth, in response to regional and local winter temperature anomalies and conversion of natural habitats. We observed a low-level, nonsignificant community adjustment to the temperature increase where natural habitat conversion occurred. At the sites affected by natural habitat conversion, the relative increase of warm-dwelling species in response to climate warming was 6 times lower and the relative species decline was 3 times higher than in the sites without natural habitat conversion. We found no evidence of community adjustment to climate warming when natural habitat conversion was >5% over 15 years. This strong negative effect suggests an antagonistic interaction between climate warming and habitat change. These results underline the importance of habitat conservation in community adjustment to climate warming.     

Crops' responses to ozone in Mediterranean environments

The Mediterranean environment, and most of the Italian peninsula, presents some peculiarities in terms of crop response to O₃ since most physiological mechanisms activated upon O₃ exposure, such as stomatal closure, often overlap and interact with those that underlie plant adaptation to drought and hyperosmotic stress, which are typical of these environments. OTC and EDU experiments have demonstrated that O₃ causes strong yield losses when crops are grown without water limitations. However, exposure to water or saline stress significantly reduced O₃ effects on crop yield. In this review, we present the methodological approaches that have been used to study plant-ozone interactions in Italy as well as biochemical, physiological and agronomic responses for representative cropping systems of the Mediterranean climate.     

Levels and congener profiles of polybrominated diphenyl ethers (PBDEs) in Zebra mussels (D. polymorpha) from Lake Maggiore (Italy)

Several congeners of polybrominated diphenyl ethers (PBDEs) were monitored in 14 different sampling stations of Lake Maggiore, the second largest Italian lake in regard to surface, volume and average depth, using the sentinel-organism Zebra mussel (Dreissena polymorpha). Results revealed a moderate contamination with summation operatorPBDE levels (BDE-17, -28, -47, -66, -71, -85, -99, -100, -138, -153, -154, -183, -190 and -209) ranging from 40 to 447ngg(-1) lipid weight which are similar to those found in environments polluted by deposition or atmospheric transport. The general order of decreasing congener contribution to the total load was BDE-47>-99>-100>-209, which closely reflected patterns observed in mussels collected in freshwater ecosystems worldwide.     

Assessment of biological effects of environmental pollution along the NW Mediterranean Sea using red mullets as sentinel organisms

A biomonitoring program was carried out in spring and autumn in three pollution hot-spots and sensitive areas of the NW Mediterranean Sea using red mullets (Mullus barbatus) as sentinel organisms and a battery of biomarkers together with gonad histology. In fish from anthropogenic impacted areas (Fos-sur-mer, Cortiou, Arenzano, Delta of Ebro) lysosomal membrane destabilization occurred indicating disturbed health. There were no significant differences in metallothionein (MT) levels among stations. Peroxisomal acyl-CoA oxidase (AOX) activity was highest in fish from Cortiou. Both MT levels and AOX activities were significantly correlated with gamete development. Prevalence of melanomacrophage centers were high in Cortiou in all samplings and in Fos-sur-mer in September samplings. In conclusion, the application of a battery of biomarkers in red mullets provided relevant data for the assessment of environmental pollution in the NW Mediterranean Sea but also showed the difficulties of using native fish as sentinels. For future studies caging strategies are recommended.     

Heterogeneity of soil surface ammonium concentration and other characteristics, related to plant specific variability in a Mediterranean-type ecosystem

Heterogeneity and dynamics of eight soil surface characteristics essential for plants—ammonium and nitrate concentrations, water content, temperature, pH, organic matter, nitrification and ammonification rates—were studied in a Mediterranean-type ecosystem on four occasions over a year. Soil properties varied seasonally and were influenced by plant species. Nitrate and ammonium were present in the soil at similar concentrations throughout the year. The positive correlation between them at the time of greatest plant development indicates that ammonium is a readily available nitrogen source in Mediterranean-type ecosystems. The results presented here suggest that plant cover significantly affects soil surface characteristics.     

Spring and autumn spatial distribution of zooplankton carbon requirement across the Mediterranean Sea

Zooplankton represents a key contributor to the ocean biological pump through its consumption of sinking and suspended carbon. A specific and highly sensitive method to evaluate zooplankton carbon requirement from the sinking flux is through the estimation of the activity of the electron transport system. The present study was carried out from samplings in 2006, and it was focused on the spatial 200–0?m zooplankton carbon demand across 24 sampling stations, along the Mediterranean Sea, from the island of Crete to the Strait of Gibraltar. Its potential day/night variability was evaluated. The zooplankton composition, abundance and biomass were investigated. The carbon demand per unit zooplankton biomass indicates geographical and diel differences among the sampling stations. A higher mean carbon demand was seen for the western Mediterranean with respect to the eastern Mediterranean, which can be justified through the observed ratio of gelatinous:crustacean taxa and the water temperatures recorded. Higher carbon demand was measured in samples collected during the dark hours. The relation to the presence and abundance of actively migrating euphausiids and copepods was discussed. A comparison with data from another of our study carried out in the same study area but in another seasonal period was done.     

Spatial Distribution Patterns,Sources of Heavy Metals,and Relation to Ecological Risk of Surface Sediments of the Cyprus Northern Shelf (Eastern Mediterranean)

In this study, the spatial distribution of metals and the sources of metal pollution were investigated along the Northern Shelf of Cyprus (Mediterranean Sea). The concentrations of heavy metals and organic matter were measured in sediments collected from the Gemi Konagi, Girne, and Gazi Magusa areas. Measured metal values were compared with Mediterranean background concentrations. Cu and Zn concentrations at the Gemi Konagi area and all of the Cr values were higher than Mediterranean backgrounds. The metal levels were evaluated by the enrichment factor (EF), contamination factor (C_f) and degree of contamination (C_d). EF results indicated that heavy metal sources were probably originated from natural processes and mining activities. The C_f values of Hg indicated low contamination. The C_d (degree of contamination) values for all heavy metals also showed a low degree of contamination at the study area. Metal levels were also compared with the numerical Sediment Quality Guidelines (SQG) for an environmental risk assessment. Results showed that sediments were classified as heavily polluted by Cu and moderately polluted by Zn at Gemi Konagi and heavily polluted by Cr and Ni contamination at all sampling areas per the SQG.     

Heavy metal pollution status in surface sediments of Swan Lake lagoon and Rongcheng Bay in the northern Yellow Sea

The national ‘Shandong Peninsula Blue Economic Zone Development Plan’ compels the further understanding of the distribution and potential risk of metals pollution in the east coast of China, where the rapid economic and urban development have been taken off and metal pollution has become a noticeable problem. Surface sediments collected from the largest swan habitat in Asia, the Swan Lake lagoon and the surrounding coastal area in Rongcheng Bay in northern Yellow Sea, were analyzed for the total metal concentrations and chemical phase partitioning of five heavy metals (Cu, Zn, Pb, Cd, and Cr). Metal contents in the studied region have increased significantly in the past decade. The speciation analyzed by the sequential extraction showed that Zn and Cr were present dominantly in the residual fraction and thus of low bioavailability, while Cd, Pb and Cu were found mostly in the non-residual fraction thus of high potential availability, indicating significant anthropogenic sources. Among the five metals, Cd is the most outstanding pollutant and presents high risk, and half of the surface sediments in the studied region had a 21% probability of toxicity based on the mean Effect Range-Median Quotient. At some stations with comparable total metal contents, remarkably different non-residual fraction portions were determined, pointing out that site-specific risk assessment integrating speciation is crucial for better management practices of coastal sediments.     

Anthropogenic influences on a mediterranean Nature Reserve: modelling and forecasting

The lagoon of Biguglia (northeastern Corsica) is one of a number Nature Reserve. Anthropogenic activities are increasing over its watershed however. The present study aims to examine the state of health of the lagoon with the example of two pollutants (Cd and Cu). Water samples were collected in spring and summer 1997. The trace metal fluxes between the various compartments were measured. Transfer processes from the watershed to the lagoon were also examined. The temporal evolution of Cd and Cu content is assessed on the one hand by comparing the present data with former reference work (1992). On the other hand, a 5-box model is implemented in order to reduce the complex functioning of the lagoon to a system of differential equations. With the help of a numerical resolution method, the increase of metallic concentration levels is estimated since 1992. On the basis of 1997 data, two hypotheses are compared. The hypothesis that takes into account a growing increase of anthropogenic activities on the watershed gives, by extrapolation, results that are closer to field measurements. However, even with this hypothesis, the cadmium content in the lagoon is underestimated. This may signify that for this metal the evolution of the lagoon pollution is more important than a linear increase.