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Jože Kotnik Milena Horvat Emmanuel Tessier Nives Ogrinc Mathilde Monperrus David Amouroux Vesna Fajon Darija Gibičar Suzana Žižek Francesca Sprovieri Nicola Pirrone 《Marine Chemistry》2007
Mercury speciation and its distribution in surface and deep waters of the Mediterranean Sea were studied during two oceanographic cruises on board the Italian research vessel URANIA in summer 2003 and spring 2004 as part of the Med Oceaneor and MERCYMS projects. The study included deep water profiles of dissolved gaseous Hg (DGM), reactive Hg (RHg), total Hg (THg), monomethyl Hg (MeHg) and dimethyl Hg (DMeHg) in open ocean waters. Average concentrations of measured Hg species were characterized by seasonal and spatial variations. Overall average THg concentrations ranged between 0.41 and 2.65 pM (1.32 ± 0.48 pM) and were comparable to those obtained in previous studies of the Mediterranean Sea. A significant fraction of Hg was present as “reactive” Hg (average 0.33 ± 0.32 pM). Dissolved gaseous Hg (DGM), which consists mainly of Hg0, represents a considerable proportion of THg (average 20%, 0.23 ± 0.11 pM). The portion of DGM typically increased towards the bottom, especially in areas with strong tectonic activity (Alboran Sea, Strait of Sicily, Tyrrhenian Sea), indicating its geotectonic origin. No dimethyl Hg was found in surface waters down to the depth of 40 m. Below this depth, its average concentration was 2.67 ± 2.9 fM. Dissolved fractions of total Hg and MeHg were measured in filtered water samples and were 0.68 ± 0.43 pM and 0.29 ± 0.17 pM for THg and MeHg respectively. The fraction of Hg as MeHg was in average 43%, which is relatively high compared to other ocean environments. The concentrations reported in this study are among the lowest found in marine environments and the quality of analytical methods are of key importance. Speciation of Hg in sea water is of crucial importance as THg concentrations alone do not give adequate data for understanding Hg sources and cycling in marine environments. For example, photoinduced transformations are important for the presence of reactive and elemental mercury in the surface layers, biologically mediated reactions are important for the production/degradation of MeHg and DGM in the photic zones of the water column, and the data for DGM in deep sea indicate the natural sources of Hg in geotectonicaly active areas of the Mediterranean Sea. 相似文献
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This paper examines how bilateral ties between developed (home) countries and developing (host) countries influence the location of Clean Development Mechanism projects (CDMs). With the home-host country pair as the unit of analysis (2,058 country-pairs), we employ a logistic regression model to analyze decisions of home countries in selecting the location for their CDMs. We are most interested in examining how home countries’ familiarity with the host country influences CDM location decisions. The familiarity factors are: (1) colonial history; (2) bilateral trade; and (3) bilateral aid. Using a binary logistical model, we find that that bilateral familiarity factors strongly influence CDM location decisions. Further, with respect to host country characteristics, we find that total carbon dioxide emissions and UNFCCC specific domestic institutions influence CDM location decisions, but not general investment institutions or high carbon intensity of host country economies. 相似文献
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Carbon and nitrogen isotope composition of particulate organic matter in relation to mucilage formation in the northern Adriatic Sea 总被引：1，自引：0，他引：1
J. Faganeli N. Ogrinc N. Kovac K. Kukovec I. Falnoga P. Mozetic O. Bajt 《Marine Chemistry》2009,114(3-4):102-109
Carbon and nitrogen stable isotope ratios of particulate organic matter (POM) were studied approximately weekly during spring and summer 2003 and 2004 in the Gulf of Trieste (northern Adriatic Sea) in order to track the temporal variations and differences between two years. In parallel, particulate organic carbon (POC) and particulate nitrogen (PN), phytoplankton biomass (chlorophyll a), and N and P nutrients were monitored. All studied parameters, especially N and P nutrients and chlorophyll a, showed higher concentrations and larger variability in spring 2004. As a consequence the macroaggregates were produced in late spring 2004. The C and N isotope composition of POM was not directly linked to phytoplankton biomass dynamics. The δ13CPOC values covaried with temperature. In 2004, δ13CPOC variations followed the δ15NPN values as well as the δ13CDIC values which were probably more dependent on the photosynthetic use of 12C. Variations in δ15NPOM values were most probably the consequence of variations in N nutrient sources used in phytoplankton assimilation. The significant correlation between δ15NPN values and nitrate concentrations in 2004 implies intense nitrate assimilation in the presence of higher nitrate concentration. This suggests nitrate as the key nutrient in the »new primary production«, later producing macroaggregates with a mean δ13C and δ15N values of − 19‰ and 5‰, respectively. A low fractionation factor ε, < 1‰, lower than that reported in other marine and lacustrine systems, was found probably to be a consequence of distinct phytoplankton species, i.e. several classes of autotrophic nanoflagellates, and specific growth conditions present in the Gulf of Trieste. The tentative use of C isotope composition of POM revealed a higher contribution of allochthonous organic matter in 2004 compared to 2003 due to higher riverine inflow. 相似文献
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Hydrogeochemical and Stable Isotope Characteristics of the River Idrijca (Slovenia), the Boundary Watershed Between the Adriatic and Black Seas 总被引：1，自引：0，他引：1
The hydrogeochemical and isotope characteristics of the River Idrijca, Slovenia, where the world’s second largest mercury
(Hg) mine is located, were investigated. The River Idrijca, a typical steep mountain river, has an HCO3
−–Ca2+–Mg2+ chemical composition. Its Ca2+/Mg2+ molar ratio indicates that dolomite weathering prevails in the watershed. The River Idrijca and its tributaries are oversaturated
with respect to calcite and dolomite. The pCO2 pressure is up to 13 times over atmospheric pressure and represents a source of CO2 to the atmosphere. δ18O values in river water indicate primary control from precipitation and enrichment of the heavy oxygen isotope of infiltrating
water recharging the River Idrijca from its slopes. The δ13CDIC values range from −10.8 to −6.6‰ and are controlled by biogeochemical processes in terrestrial environments and in the stream:
(1) exchange with atmospheric CO2, (2) degradation of organic matter, (3) dissolution of carbonates, and (4) tributaries. The contributions of these inputs
were calculated according to steady state equations and are estimated to be—11%:19%:30%:61% in the autumn and 0%:26%:39%:35%
in the spring sampling seasons. 相似文献
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Lisbeth Lolk Johannsen Nives Zambon Peter Strauss Tomas Dostal Martin Neumann David Zumr 《水文科学杂志》2020,65(4):524-535
ABSTRACTOptical disdrometers can be used to estimate rainfall erosivity; however, the relative accuracy of different disdrometers is unclear. This study compared three types of optical laser-based disdrometers to quantify differences in measured rainfall characteristics and to develop correction factors for kinetic energy (KE). Two identical PWS100 (Campbell Scientific), one Laser Precipitation Monitor (Thies Clima) and a first-generation Parsivel (OTT) were collocated with a weighing rain gauge (OTT Pluvio2) at a site in Austria. All disdrometers underestimated total rainfall compared to the rain gauge with relative biases from 2% to 29%. Differences in drop size distribution and velocity resulted in different KE estimates. By applying a linear regression to the KE–intensity relationship of each disdrometer, a correction factor for KE between the disdrometers was developed. This factor ranged from 1.15 to 1.36 and allowed comparison of KE between different disdrometer types despite differences in measured drop size and velocity. 相似文献
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The relative contributions of dolomite to calcite weathering related to riverine fluxes are investigated on a highly resolved spatial scale in the diverse watersheds of Slovenia, which previous work has shown have some of the highest carbonate-weathering intensities in the world and suggests that dolomite weathering is favored over limestone weathering in mixed carbonate watersheds. The forested Sava and So?a River watersheds of Slovenia with their headwaters in the Julian Alps drain alpine regions with thin soils (<30 cm) and dinaric karst regions with thicker soils (0 to greater than 70 cm) all developed over bedded Mesozoic carbonates (limestone and dolomite), and siliclastic sediments is the ideal location for examining temperate zone carbonate weathering. This study extends previous work, presenting geochemical data on source springs and documenting downstream geochemical fluctuations within tributaries of the Sava and So?a Rivers. More refined sampling strategies of springs and discrete drainages permit directly linking the stream Mg2+/Ca2+ ratios to the local bedrock lithology and the HCO3 ? concentrations to the relative soil depths of the tributary drainages. Due to differences in carbonate source lithologies of springs and tributary streams, calcite and dolomite weathering end members can be identified. The Mg2+/Ca2+ ratio of the main channel of the Sava River indicates that the HCO3 ? concentration can be attributed to nearly equal proportions by mass of dolomite relative to calcite mineral weathering (e.g., Mg2+/Ca2+ mole ratio of 0.33). The HCO3 ? concentration and pCO2 values increase as soil thickness and alluvium increase for discrete spring samples, which are near equilibrium with respect to calcite. Typically, this results in approximately 1.5 meq/l increase in HCO3 ? from the alpine to the dinaric karst regions. Streams in general do not change in HCO3 ?, Mg2+/Ca2+, or Mg2+/HCO3 ? concentrations down course, but warming and degassing of CO2 produce high degrees of supersaturation with respect to calcite. Carbonate-weathering intensity (mmol/km2-s) is highest within the alpine regions where stream discharge values range widely to extreme values during spring snowmelt. Overall, the elemental fluxes of HCO3 ?, Ca2+, and Mg2+ from the tributary watersheds are proportional to the total water flux because carbonates dissolve rapidly to near equilibrium. Importantly, dolomite weathers preferentially over calcite except for pure limestone catchments. 相似文献
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Nives Grasso Andrea Maria Lingua Maria Angela Musci Francesca Noardo Marco Piras 《Natural Hazards》2018,90(2):623-637
Every year, there are almost 50,000 forest fires in Europe (127/day), which have burned an area equal to more than 450,000 ha. An effective management of forest fires is therefore fundamental in order to reduce the number of the fires and, especially, the related burned areas, preserving the environment and saving human lives. However, some problems still exist in the structure of information and in the harmonization of data and fire management procedures among different European countries. Pursuing the same interoperability aims, the European Union has invested in the development of the INSPIRE Directive (Infrastructure for Spatial Information in Europe) to support environmental policies. Furthermore, the EU (European Union) is currently working on developing ad hoc infrastructures for the safe management of forests and fires. Moving from this premises and following an analysis of the state of the art of information systems for forest fire-fighting, in the light of the end-user requirements, the paper presents the INSPIRE—compliant design of a geographical information system, implemented using open-source platforms. 相似文献
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Phosphorus regeneration and burial in near-shore marine sediments (the Gulf of Trieste, northern Adriatic Sea) 总被引：1，自引：0，他引：1
According to bioassay studies and high dissolved nutrient N/P ratios in the seawater column, phosphorus (P) is thought to control marine productivity in the northern Adriatic Sea. P in near-shore marine sediments of the Gulf of Trieste, the northernmost part of the Adriatic Sea, was investigated using pore water P distributions, and benthic P flux studies under oxic and anoxic conditions. The data show that P regeneration is up to three-fold more extensive in sediments overlain by oxygen-depleted waters and proceeds in parallel with Fe and Mn enhanced benthic fluxes. It appears from the incubation experiments that degradation of sedimentary organic matter is the main contribution to the flux of P at the sediment–water interface, while the release of phosphate adsorbed on the iron oxide surface is of minor importance.It appears that about 50% of P in the Gulf of Trieste is retained within in the sediments, probably bonded to clay minerals and carbonate grains or precipitated as fluoroapatite. In these sediments total P (Ptot) is preserved preferentially over organic C (Corg). P regenerated from surficial sediments contributes about 1/3 of the P that is assimilated by benthic microalgae. The phytoplankton P requirement should be entirely supplied from fresh-water sources. These results suggest that oxygen depletion in coastal areas caused by eutrophication enhances P regeneration from sediments, providing the additional P necessary for increased biological productivity. The development of anoxic bottom waters in coastal areas enhances the recycling of P, exacerbating the nutrient requirement in the area. A geochemical record of P burial in a longer sedimentary sequence revealed an increasing trend of Ptot and organic P (Porg) contents occurring approximately 50 years BP (after 1950), probably due to increasing use of inorganic fertilizers and detergents in the area. 相似文献