Taxonomic versus trophic structure of mesozooplankton: a seasonal study of species succession and stable carbon and nitrogen isotopes in a coastal upwelling ecosystem   总被引：2，自引：0，他引：2  

Bode  Antonio; Alvarez-Ossorio  Maria Teresa 《ICES Journal of Marine Science》2004,61(4):563-571

  相似文献   

Modelling of natural and synthetic polyelectrolyte interactions in natural waters by using SIT, Pitzer and Ion Pairing approaches     

Francesco Crea  Alba Giacalone  Antonio Gianguzza  Daniela Piazzese  Silvio Sammartano   《Marine Chemistry》2006,99(1-4):93

In this paper SIT and Pitzer models are used for the first time to describe the interactions of natural and synthetic polyelectrolytes in natural waters. Measurements were made potentiometrically at 25 °C in single electrolyte media, such as Et₄NI and NaCl (for fulvic acid 0.1 < I /mol L^− 1 < 0.75), and in a multi-component medium simulating the composition of natural waters at a wide range of salinities (for fulvic and alginic acids: 5 < S < 45) with particular reference to sea water [Synthetic Sea Water for Equilibrium studies, SSWE]. In order to simplify calculations, SSWE was considered to be a “single salt” BA, with cation B and anion A representing all the major cations (Na⁺, K⁺, Mg²⁺, Ca²⁺) and anions (Cl⁻, SO₄²⁻) in natural sea water, respectively. The ion pair formation model was also applied to fulvate and alginate in artificial sea water by examining the interaction of polyanions with the single sea water cation. Results were compared with those obtained from previous speciation studies of synthetic polyelectrolytes (polyacrylic and polymethacrylic acids of different molecular weights). Results indicate that the SIT, Pitzer and Ion Pairing formation models used in studies of low molecular weight electrolytes may also be applied to polyelctrolytes with a few simple adjustments.  相似文献   

Land inputs,behaviour and contamination levels of copper in a ria estuary (NW Spain)     

Cobelo-García A  Prego R 《Marine environmental research》2003,56(3):403-422

Copper concentrations were measured in the sediments and dissolved phase of the water column in the Lérez Estuary (Pontevedra Ria, Galicia), NW Spain, and in the freshwater-sewage inputs to the estuary. Dissolved copper fluxes in the estuary were quantified. Results show that the freshwater end-member in the Lérez Estuary has minimal copper contamination ([Cu](Dissolved)=7+/-4 nM, Sediment Enrichment Factor=1) and the source of dissolved copper inputs is localized in the saline end-member ([Cu](Dissolved)=20-55 nM, Sediment Enrichment Factor=6-7). A non-conservative behaviour of dissolved copper showing a net addition during estuarine mixing was observed. The budgetary calculations and the copper sediment distribution suggest that the major copper input to the estuary-ria system is located at the Marín-Placeres transect, playing an important role in the net addition of copper within the estuarine mixing. The importance of upwelling in the renewal of the Galician coastal waters and dilution of continental inputs is discussed.  相似文献   

Some Aspects of Fluorite and Vaterite Precipitation in Marine Environments*     

Karl J. Wittmann  Antonio P. Ariani 《Marine Ecology》1996,17(1-3):213-219

Abstract. Mysid shrimps of the genus Schistornysis precipitate either fluorite (CaF₂; S. spiritus) or vaterite (CaCO3; S. assimilis) for the formation of static bodies (statoliths). In S. assirnilis, 2.44 μg calcium and 3.66 μg carbonate are precipitated for each statolith. This corresponds to 69 mg or 30 mg ambient water, respectively, using the ion content of seawater for stoichiometrical comparison. Concentmtion factors of calcium or carbonate in relation to equivalent amounts of ambient water in the statocyst cavity are 760 or 3100, respectively. In S. spiritus, 3.79 μg calcium and 3.60 μg fluoride are precipitated. This corresponds to 9.3 mg or 2788 mg ambient water, respectively. Concentration factors with respect to statocyst water mass are 610 or 183.000. respectively. Ile high fluoride accumulation for the formation of statoliths alone contributes to a fluoride content of 4500 ppm with respect to body dry weight A minimum estimate for the role of mysids in the global fluoride cycle suggests that at least 62,000 tons of fluoride are bound in mysid statoliths. Due to rapid turnover of about seven days, mysid fluorite statoliths are a crucial factor by contributing to a turnover of at most 570,000 years for overall fluoride in the oceanic system.  相似文献   

Seasonal variation and structure of a decapod (Crustacea) assemblage living in a Caulerpa prolifera meadow in Cádiz Bay (SW Spain)     

Inmaculada Lpez De La Rosa  Antonio Rodríguez  J. Enrique García Raso 《Estuarine, Coastal and Shelf Science》2006,66(3-4):624-633

The decapod taxocoenosis living in shallow muddy bottoms with the green algae Caulerpa prolifera was studied monthly between February 1994 and January 1996 in the Inner Bay of Cádiz (SW Spain). More than 32,000 specimens belonging to 35 species were collected. Six species were dominant (representing the 85.8% of the total number of specimens), but the structure of the taxocoenosis was regulated by the Hippolyte species, Sicyonia carinata, Palaemon adspersus and Liocarcinus arcuatus. There was no significant qualitative difference between years. There was no clear change in the dominance of groups of species during the year, as happened in the outer Bay. This is probably due to the sheltered character of the area and the more stable and dense vegetal cover, but some seasonal differences were found.The benthic characteristics of the Inner Bay of Cádiz, such as shallow soft bottoms of fine and muddy sediments and the presence of macrophytes (seagrasses and seaweeds) might be key factors influencing the composition and structure of the general and seasonal decapod assemblage. In spite of human impacts on the bay (e.g. aquaculture activities, sewage), the values of the diversity, equitability and richness indexes appeared stable over time (higher than those found in outer adjacent areas) and no significant differences between years were found.  相似文献   

Settlement and primary succession in a shallow submarine cave: spatial and temporal benthic assemblage distinctness   总被引：1，自引：0，他引：1  

Francesco Denitto  Antonio Terlizzi  & Genuario Belmonte 《Marine Ecology》2007,28(S1):35-46

  相似文献   

Sources and transfer of organic matter in food webs of a Mediterranean coastal environment: Evidence for spatial variability   总被引：4，自引：0，他引：4  

Salvatrice Vizzini  Antonio Mazzola 《Estuarine, Coastal and Shelf Science》2006,66(3-4):459-467

The spatial variability in the food web structure of a Mediterranean semi-enclosed coastal environment (Stagnone di Marsala, Italy) was investigated using stable carbon and nitrogen isotopes. Organic matter sources and consumers were sampled in two locations with different environmental features (e.g. hydrodynamic regime, open-sea influence, vegetal coverage). Overall more ¹³C-enriched and ¹⁵N-depleted values were found in the central location than in the southern for organic matter sources and consumers. Pelagic consumers (zooplankton and juveniles of transient fish) showed slight spatial differences and in both locations seemed to depend on phytoplankton as the ultimate energy source. In contrast, benthic consumers (epifauna and resident fish) exhibited remarkable differences between locations. Spatial differences in organic matter sources were smaller than in benthic consumers and thus consumers presumably exploited different ultimate organic matter sources in the two locations. Sedimentary organic matter and epiphytes appeared to be the main primary producers transferred within the food web in both locations, and seagrasses seemed to play a non-negligible trophic role in the central location. The results of this paper corroborate the finding food webs are characterised by high spatial variability even on a small spatial scale and environmental heterogeneity more than primary production that seems to influence the trophic role of autotrophs.  相似文献   

The PAH composition of surface sediments from Stagnone coastal lagoon, Marsala (Italy)   总被引：2，自引：0，他引：2  

Loredana Culotta  Concetta De Stefano  Antonio Gianguzza  Maria Rosaria Mannino  Santino Orecchio   《Marine Chemistry》2006,99(1-4):117

This paper examines the presence, distribution, nature and sources of 22 Aromatic Hydrocarbons (PAHs), which are important environmentally and toxicologically, in sediments from the Stagnone coastal lagoon at Marsala (Italy). Analysis was performed by gas chromatography/mass spectrometry (GC/MS) with selected ion monitoring (SIM). The total concentration of polycyclic aromatic hydrocarbons ranged from 72 to 18381 μg/kg of dry matrix. The relative standard deviation (RSD) of the replicates on the concentrations of individual compounds ranged from 5% to 20%. The accuracy of method was estimated by analyzing “blank” samples added of known quantities of analytes and the recover percentage was 88 ± 9%. The detection limit (LOD) of analytical procedure was less than 0.2 μg/kg d.w. for all analytes. The quantification limit (LOQ) of analytical procedure was less than 0.7 μg/kg d.w.The resulting distributions and weight ratios of specific compounds are discussed in terms of sampling location and origin of organic matter. A comparison with other studies of total PAHs suggests that the levels are within the concentration ranges already reported by other authors. From an eco-toxicological point of view, total PAH concentrations at seven out of the eight sites studied represent a relatively clean environment when compared to other sites.Organic matter content and PAH concentrations were found to be correlated and the compounds present in Stagnone sediments were shown to be mainly of pyrolitic origin, while a negligible quantity of PAHs may derive from biogenic sources since all the sediments contain perylene traces. There is no evidence of coal-tar contamination.Cluster analysis was carried out in order to discriminate between different PAH origins.  相似文献   

Variations of Hydrochemical Features in the Coastal Waters of Monte Conero: 1982–1990     

Mauro Marini  Paola Fornasiero  Antonio Artegiani 《Marine Ecology》2002,23(S1):258-271

Abstract. This paper briefly summarises research carried out in 1982–1990 in the coastal area off Monte Conero, SW northern Adriatic Sea. Oceanographic data on temperature, salinity, oxygen saturation, nutrients (nitrates, silicates and orthophosphates), and chlorophylls were collected to characterise this coastal ecosystem in view of the setting up of the "Costa del Monte Conero" protected marine area.
Towards the coast the physical and chemical parameters exhibited a seasonal periodicity.
Temperature showed a clear annual periodicity with a certain interannual variability; this also holds true for oxygen saturation, with peaks in March and minima in September, though without hypoxic events.
Nutrient concentrations peaked at the surface layer at the coastal station from December to March (nitrates: 35–50 μmol 1⁻¹; silicates: 22–70 μmol 1⁻¹; orthophosphates: 0.37–0.54 μmol 1⁻¹) and minima in summer (Jul-Aug) on surface and bottom (0–12μmol 1⁻¹, 0–18.5 μmol 1⁻¹, and 0–0.15 μmol 1⁻¹, respectively). From 1988 to 1990 nutrient peaks were lower and coastal salinity exceed 33, with nitrates below 16 μmol 1⁻¹, silicates below 8 μmol 1⁻¹, and orthophosphates less than 0.2 μmol 1⁻¹.
In the coastal area of Senigallia, 40 km to the north, where the influence of the coastal current that carries the river inflows to the south is stronger, the seasonal cycle was similar, albeit with higher values for nutrients and chlorophylls.  相似文献   

Metal distributions and their fluxes at the coastal boundary of a semi-enclosed ria     

Antonio Cobelo-García  Ricardo Prego  Maite DeCastro 《Marine Chemistry》2005,97(3-4):277-292

Water column samples have been collected in the outer channel of the Ferrol Ria (NW Spain) during four occasions over a tidal cycle. The objective was to study the exchange of dissolved and particulate Cd, Cu, Pb and Zn and particulate Al, Fe and Si between the ria and the adjacent coastal waters. This study provides the first extensive dataset on dissolved and particulate metal concentrations in the water column of a Galician ria. Typical concentrations of dissolved Cd (96 ± 31 pM), Cu (8 ± 4 nM), Pb (270 ± 170 pM) and Zn (21 ± 10 nM) were similar than in other European Atlantic shelf and coastal waters. The fraction of metals in the particulate phase followed the trend: Pb > Cu Zn > Cd. The outgoing water from the ria was enriched in dissolved and particulate Cu, Pb and Zn compared with incoming waters, whereas Cd concentrations were similar for both waters. The suspended particulate matter was composed of a mixture of marine and continental material. The latter end-member was found to arise from the metal-rich ria bed sediments, which is diluted by the dominant metal-poor marine end-member. The net output flux of Cu from the channel is balanced by the freshwater inputs to the ria, and the net Zn flux gave a positive output to coastal waters. For Pb, the net flux to the coastal waters is less than that input from the rivers, as a result of its particle reactivity and deposition in sediments. On the contrary, a net input flux of dissolved Cd from coastal waters was observed, highlighting the oceanic source of this metal in the Galician rias. Results from the budget calculations are in agreement with the differential geochemical behavior of these elements in coastal waters.  相似文献