Factors driving sediment compositional change in the distal area of the Ria de Vigo (NW Spain): oceanographic processes vs. paleopollution

Environmental Science and Pollution Research - We analyze potential Late Holocene metal contamination along a sediment core collected in the distal zone of Ria de Vigo (North Spain). Statistical...     

Evidence of earliest human occurrence in Europe: the site of Pirro Nord (Southern Italy)

Some flint lithic artifacts were discovered in the fissure fillings of the well-known Pirro Nord site (Apulia, Southern Italy). The lithic industry, composed by three cores and some flakes, has been found to be associated to an Early Pleistocene vertebrate fossil assemblage. The fossil association contains a wide range of micromammals, including Allophaiomys ruffoi and Episoriculus gibberodon and large mammals including Bison degiulii and Equus altidens together with African elements as the gelada baboon Theropithecus and the saber-toothed cat Megantereon whitei. It defines the latest Villafranchian chronological unit (Pirro Nord Faunal Unit) in the Western European mammal biochronology. The lithic industry of Pirro Nord represents the oldest occurrence of the genus Homo in Europe as it is attributable to a chronological interval between 1.3 and 1.7 Ma. This supports the hypothesis that the genus Homo, with Oldowaian technology, extended its range in Europe, probably from western Asia, during the first half of the Early Pleistocene. The new discovery from Pirro Nord changes the chronology of the first arrival of hominids in Europe and offers new perspectives in the debate about the human dispersal in the Early Pleistocene.     

Extent of intracellular storage in single and dual substrate systems under pulse feeding

The study investigated the effect of acetate/starch mixture on the formation of storage biopolymers as compared with the storage mechanism in systems fed with these compounds as single substrates. Experiments involved two sequencing batch reactor sets operated at steady state, at sludge ages of 8 and 2 days, respectively. Each set included three different runs, one fed with acetate, the other with starch and the last one with the acetate/starch mixture. In single substrate systems with pulse feeding, starch was fully converted to glycogen, whereas 25 % of acetate was utilized for direct microbial growth at sludge age of 8 days, together with polyhydroxybutyric acid (PHB) storage. The lower sludge age slightly increased this fraction to 30 %. Feeding of acetate/starch mixture induced a significant increase in acetate utilization for direct microbial growth; acetate fraction converted to PHB dropped down to 58 and 50 % at sludge ages of 8 and 2 days respectively, while starch remained fully converted to glycogen for both operating conditions. Parallel microbiological analyses based on FISH methodology confirmed that the biomass acclimated to the substrate mixture sustained microbial fractions capable of performing both glycogen and PHB storage.     

Benthic Response to Mucilaginous Aggregates in the Northern Adriatic Sea: Biochemical Indicators of Eutrophication

In summer 1997, gelatinous aggregates appeared in the Adriatic Sea, covering large areas of the northern basin. This study deals with the comparison between the biochemical composition of the sedimentary organic matter in summer, 1996 (when no aggregates appeared), and in summer, 1997 (during the appearance of aggregates). the biochemical composition of organic matter in surface sediments (determined in terms of proteins, carbohydrates, lipids, phytopigments and nucleic acids) has been investigated in two areas along the coast of the NW-Adriatic Sea in order to characterize benthic processes during aggregate deposition on the sea floor. During mucilage accumulation, a significant increase of biochemical compounds was observed, and chlorophyll-a and carbohydrate concentrations doubled their concentrations. in contrast, protein concentrations decreased, so that overall biopolymeric carbon content (expressed as the sum of lipid, protein and carbohydrate carbon equivalents) did not display significant differences between sampling periods (1579.3 in June, 1996 1678.8 μgCg^-1 and June, 1997). the protein to carbohydrate ratio decreased from 4.9 in June, 1996 to 1.8 in June, 1997. Mucilage production in June, 1997, modified significantly the biochemical composition of the sedimentary OM, thus affecting the potential availability of OM to benthic consumers. We hypothesise that the production of highly refractory composition of the sedimentary OM during mucilage accumulation might have an important biogeochemical implications.     

Assessment of an Interpretive Program for U.S. Coast Guard Personnel

Abstract: The goal of this research was to measure the effect of a print-based interpretive program on acceptance by U.S. Coast Guard personnel of an endangered-species protection program. We used a within-subjects design to measure changes in eight survey items measuring beliefs about endangered species. There were significant changes in three items. The initial attitude toward endangered species was a strong predictor of subsequent response in a "regression to the mean effect" in which the least change was found in subjects with the highest initial scores on attitude items. Our results suggest that the print-based program was effective at changing the most highly targeted attitudes, but had little effect on more general attitudes.     

BVOC emissions, photosynthetic characteristics and changes in chloroplast ultrastructure of Platanus orientalis L. exposed to elevated CO2 and high temperature

To investigate the interactive effects of increasing [CO₂] and heat wave occurrence on isoprene (IE) and methanol (ME) emissions, Platanus orientalis was grown for one month in ambient (380 μmol mol⁻¹) or elevated (800 μmol mol⁻¹) [CO₂] and exposed to high temperature (HT) (38 °C/4 h). In pre-existing leaves, IE emissions were always higher but ME emissions lower as compared to newly-emerged leaves. They were both stimulated by HT. Elevated [CO₂] significantly reduced IE in both leaf types, whereas it increased ME in newly-emerged leaves only. In newly-emerged leaves, elevated [CO₂] decreased photosynthesis and altered the chloroplast ultrastructure and membrane integrity. These harmful effects were amplified by HT. HT did not cause any unfavorable effects in pre-existing leaves, which were characterized by inherently higher IE rates. We conclude that: (1) these results further prove the isoprene's putative thermo-protective role of membranes; (2) HT may likely outweigh the inhibitory effects of elevated [CO₂] on IE in the future.     

Pelagic-benthic coupling in a subtidal system of the North-Western Mediterranean

Suspended particulate matter, zooplankton, and macrobenthos dynamics were investigated in a shallow area of the Ligurian Sea (north-west Mediterranean) characterized by wide temporal variability over an annual cycle. As indicated by multivariate analyses, the seasonal dynamics can be summarized as follows: (1) a late winter-early spring phytoplankton bloom followed by high zooplankton and macrobenthos densities during the spring months; (2) low-quality particulate suspended matter in summer, and an increase in the importance of zooplankton taxa with a wide range of feeding strategies, a decrease in macrofaunal abundance, and an increase in deposit-feeders and predators; and (3) a second phytoplankton bloom in autumn, followed by an increase in copepod density and a low macrofaunal abundance. In conclusion, pelagic and benthic communities in the coastal area of the Ligurian Sea mainly seem to be controlled bottom-up. Our results suggest that the quality of the particulate organic matter may play an important role in determining the temporal changes of both plankton and benthic assemblages, while the direct influence of other environmental features (such as sediment grain size) is relevant only for some macrobenthic taxa (e.g. crustaceans).     

Phytoplankton photosynthetic activity and growth rates in the NW Adriatic Sea

Taxonomic composition, biomass, primary production and growth rates of the phytoplankton community were studied in two stations in the NW Adriatic Sea on a seasonal basis, in areas characterized by differing hydrological and trophic conditions. The main differences between the two stations were quantitative rather than qualitative, most phytoplankton species being common to both stations. The effects of differing nutrient concentrations and plume spreading were evident. Biomass and primary production rates were significantly higher in the coastal station (S1), and the phytoplankton distribution in the water column was markedly stratified in S1 and more even in the offshore station (S3). However, chlorophyll a specific production, potential growth rate and production efficiencies were very similar in both stations, even when phosphorus concentrations were limiting. A discrepancy between potential and actual growth rate was observed: as a feature common to both stations, comparisons between potential and actual growth rates revealed that little carbon produced by phytoplankton accumulated as algal biomass; therefore, very high loss rates were estimated.     

Land Management Versus Natural Factors in Land Instability: Some Examples in Northern Spain

The objective of this work is to test a hypothesis formulated on the basis of former results which considers that there might be a “global geomorphic change,” due to activities related to land management and not determined by climate change, which could be causing an acceleration of geomorphic processes. Possible relationships between some geomorphic processes related to land instability (landslides or sediment generation) and potential triggering factors are analyzed in study areas in northern Spain. The analysis is based on landslide inventories covering different periods, as well as the determination of sedimentation rates. Temporal landslide and sedimentation rate trends are compared with different indicators of human activities (land-use change, logging, forest fires) and with potential natural triggers (rainfall, seismicity). The possible influence of the road network in the distribution of landslides is also analyzed. Results obtained show that there is a general increase of both landslide and sedimentation rates with time that cannot be explained satisfactorily by observed rainfall trends and even less by seismicity. Land-use change appears to be by far the main factor leading to land instability, with some changes producing up to a 12-fold increase of landslide rate. A relationship between road network and the spatial distribution of landslides has also been observed. These results do confirm the existence of an acceleration of geomorphic processes in the region, and also suggest that climate-related factors play a limited role in the changes observed.