Weakening climatic signal since mid-20th century in European larch tree-ring chronologies at different altitudes from the Adamello-Presanella Massif (Italian Alps)     

Anna Coppola  Giovanni Leonelli  Maria Cristina Salvatore  Manuela Pelfini  Carlo Baroni 《Quaternary Research》2012,77(3):344-354

Tree rings from temperature-limited environments are highly sensitive climate proxies, widely used to reconstruct past climate parameters for periods prior to the availability of instrumental data and to analyse the effect of recent global warming on tree growth. An analysis of the climatic signal in five high-elevation tree-ring width chronologies of European larch (Larix decidua Mill.) from the tops of five different glacial valleys in the Italian Central Alps revealed that they contain a strong summer-temperature signal and that tree-ring growth is especially influenced by June temperatures. However, a moving correlation function analysis revealed a recent loss of the June temperature signal in the tree-ring chronologies. This signal reduction primarily involves the two lowest-altitude chronologies. It is probable that the observed increasing importance of late-summer temperature for tree-ring growth over the past 50 yr is an effect of the lengthening growing season and of the variations in the climate/tree-ring relationship over time. All the chronologies considered, especially those at the highest altitudes, show an increasing negative influence of June precipitation on tree-ring growth. The climatic signal recorded in tree-ring chronologies from the Italian Central Alps varies over time and is also differentially influenced by climatic parameters according to site elevation.  相似文献   

Geochemical evidence of the 8.2 ka event and other Holocene environmental changes recorded in paleolagoon sediments,southeastern Brazil     

Alethéa E.M. Sallun  William Sallun Filho  Kenitiro Suguio  Marly Babinski  Simone M.C.L. Gioia  Benjamin A. Harlow  Wania Duleba  Paulo E. De Oliveira  Maria Judite Garcia  Cinthia Z. Weber  Sérgio R. Christofoletti  Camilla da S. Santos  Vanda B. de Medeiros  Juliana B. Silva  Maria Cristina Santiago-Hussein  Rosana S. Fernandes 《Quaternary Research》2012,77(1):31-43

The paleoclimatic record of Juréia Paleolagoon, coastal southeastern Brazil, includes cyclic and gradual changes with different intensities and frequencies through geological time, and it is controlled by astronomical, geophysical, and geological phenomena. These variations are not due to one single cause, but they result from the interaction of several factors, which act at different temporal and spatial scales. Here, we describe paleoenvironmental evidence regarding climatic and sea level changes from the last 9400 cal yr BP at the Juréia Paleolagoon — one of the main groups of protected South Atlantic ecosystems. Geochemical evidences were used to identify anomalies from multi-proxy analyses of a paleolagoon sediment core. The anomalies of centennial scale were correlated to climate and transgression–regression cycles from the Holocene period. Decadal scale anomalous oscillations in the Quaternary paleolagoon sediments occur between 9400 and 7500 cal yr BP, correlated with long- and short-term natural events, which generated high sedimentation rates, mainly between 8385 and 8375 cal yr BP (10 cm/yr). Our results suggest that a modern-day short-duration North Atlantic climatic event, such as the 8.2 ka event, could affect the environmental equilibrium in South America and intensify the South American Summer Monsoon.  相似文献   

Surveying the Townscape of Roman Ammaia in Portugal: An Integrated Geoarchaeological Investigation of the Forum Area     

Frank Vermeulen  Cristina Corsi  Morgan De Dapper 《Geoarchaeology》2012,27(2):123-139

Geoarchaeological research, integrating traditional excavations, and ground truthing with intensive geophysical surveys, aerial photography, and GIS‐based data processing, has revealed the full intramural plan of the abandoned Roman city of Ammaia in central Portugal. Although this multidisciplinary effort also focussed on understanding the town/territory relationships and the system of resource exploitation, this paper presents the most important results from fieldwork in the central monumental area of the town, the Roman Forum. Here, excavations, geomorphological survey, and an array of geophysical methods illuminate the long history of the site, from the first settlement and monument‐building phases in early Imperial times, to the ongoing post‐abandonment processes. This paper discusses some of the benefits of compiling these complementary data sets and proposes the use of a wide array of approaches in order to achieve full understanding of the complex topography and evolution of a classical urban site. It further demonstrates the need for effective stratigraphical control and geomorphological analysis of crucial areas revealed by high‐quality geophysics.  相似文献   

Redox state of subcontinental lithospheric mantle and relationships with metasomatism: insights from spinel peridotites from northern Victoria Land (Antarctica)     

Cristina Perinelli  Giovanni B. Andreozzi  Aida M. Conte  Roberta Oberti  Pietro Armienti 《Contributions to Mineralogy and Petrology》2012,164(6):1053-1067

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Ostreopsis cf. ovata bloom in the northern Adriatic Sea during summer 2009: ecology, molecular characterization and toxin profile     

Accoroni S  Romagnoli T  Colombo F  Pennesi C  Di Camillo CG  Marini M  Battocchi C  Ciminiello P  Dell'Aversano C  Dello Iacovo E  Fattorusso E  Tartaglione L  Penna A  Totti C 《Marine pollution bulletin》2011,62(11):2512-2519

Intense blooms of the benthic dinoflagellate Ostreopsis cf. ovata have occurred in the northern Adriatic Sea since 2006. These blooms are associated with noxious effects on human health and with the mortality of benthic organisms because of the production of palytoxin-like compounds. The O. cf. ovata bloom and its relationships with nutrient concentrations at two stations on the Conero Riviera (northern Adriatic Sea) were investigated in the summer of 2009. O. cf. ovata developed from August to November, with the highest abundances in September (1.3 × 10⁶ cells g⁻¹ fw corresponding to 63.8 × 10³ cells cm⁻²). The presence of the single O. cf. ovata genotype was confirmed by a PCR assay. Bloom developed when the seawater temperature was decreasing. Nutrient concentrations did not seem to affect bloom dynamics. Toxin analysis performed by high resolution liquid chromatography-mass spectrometry revealed a high total toxin content (up to 75 pg cell⁻¹), including putative palytoxin and all the ovatoxins known so far.  相似文献   

Coastal defence through low crested breakwater structures: jumping out of the frying pan into the fire?     

Munari C  Corbau C  Simeoni U  Mistri M 《Marine pollution bulletin》2011,62(8):1641-1651

The Adriatic coast of Punta Marina (Ravenna) is protected by 3-km long low crested breakwater structures (LCSs). Through a 3-years long multidisciplinar study, we assessed the impact of such defensive structures on environmental and biological condition. LCSs create pools where conditions are very different from the surrounding nearshore system. Mechanical disturbance by currents and waves varied greatly in intensity and frequency between seaward and landward sides of the structures. Sedimentary budget was positive at the landward side, but it was due to a gain on the seafloor and not on the emerged beach. The budget at seaward was negative. LCSs determine differences in benthic assemblages, alter the seasonal pattern of communities, and modify seasonal fluctuations of animal assemblages. Landward sheltered areas can be seen as “lagoonal island” surrounded by a “sea of marine habitat”. Differences in ecological quality status, obtained through M-AMBI, are due to the sum of these factors.  相似文献   

Pathogenic fungi: an unacknowledged risk at coastal resorts? New insights on microbiological sand quality in Portugal     

Sabino R  Veríssimo C  Cunha MA  Wergikoski B  Ferreira FC  Rodrigues R  Parada H  Falcão L  Rosado L  Pinheiro C  Paixão E  Brandão J 《Marine pollution bulletin》2011,62(7):1506-1511

Whilst the potential impact on beach users from microorganisms in water has received considerable attention, there has been relatively little investigation into microbial contaminants in sand. Thirty three beaches across Portugal were analyzed during a five year period (2006-2010) to determine the presence of yeasts, pathogenic fungi, dermatophytes, total coliforms, Escherichia coli and intestinal enterococci in sand.Our results showed that 60.4% of the samples were positive for fungi and that 25.2% were positive for the bacterial parameters. The most frequent fungal species found were Candida sp. and Aspergillus sp., whereas intestinal enterococci were the most frequently isolated bacteria. Positive associations were detected among analyzed parameters and country-regions but none among those parameters and sampling period.Regarding threshold values, we propose 15 cfu/g for yeasts, 17 cfu/g for potential pathogenic fungi, 8 cfu/g for dermatophytes. Eighty four cfu/g for coliforms, 250 cfu/g for E. coli, and 100 cfu/g for intestinal enterococci.  相似文献   

Effects of the 2003 European heatwave on the benthic community of a severe transitional ecosystem (Comacchio Saltworks, Italy)     

Munari C 《Marine pollution bulletin》2011,62(12):2761-2770

The summer of 2003 was the warmest summer in Europe since the 16th century. Its consequences on the fauna of a transitional ecosystem were studied through biodiversity, functional and ecological indicators, from summer 2002 to winter 2005. The heatwave caused considerable changes in the benthic community structure and relative composition, persisting in 2005. Animal assemblages switched from mollusc- to annelida-dominated. Biodiversity and functional indicators captured changes in community structure and composition, proving to be powerful tools to detect responses related to global warming. Ecological indicators rendered a monotonic response oscillating between bad and poor ecological status across the study period. The resilience of mollusc biocoenosis resulted limited with respect to other taxa, posing concerns about their conservation if, as predicted, the frequency of summers as hot as that of 2003 will progressively increase to become the norm at the end of this century.  相似文献   

Critical appraisal on the identification of Reference Conditions for the evaluation of ecological quality status along the Emilia-Romagna coast (Italy) using M-AMBI   总被引：1，自引：0，他引：1  

Paganelli D  Forni G  Marchini A  Mazziotti C  Occhipinti-Ambrogi A 《Marine pollution bulletin》2011,62(8):1725-256

According to the European Water Framework Directive, the ecological status (ES) of a water body is determined by comparing observation data with undisturbed Reference Conditions (RCs). Defining RCs is crucial when evaluating the ES of a water body as it strongly affects the final outcome of any index application. Identifying RCs by observing real sites is not feasible in many marine environments, such as the Emilia-Romagna coast (Italy, N-Adriatic Sea). We used a statistical approach on a large dataset to derive RCs for the application of the benthic index M-AMBI in this area. We then applied M-AMBI to samples collected along a gradient of presumed environmental disturbance. The results put 14.8% of the Emilia-Romagna samples in “High” ES, 60.2% in “Good”, 23.0% in “Moderate” and 2.0% in “Poor”, showing a spatial gradient of improving quality. These results are in agreement with the extensive ecological knowledge available for this area.  相似文献   

Geochemistry and arsenic behaviour in groundwater resources of the Pannonian Basin (Hungary and Romania)   总被引：1，自引：0，他引：1  

Helen A.L. Rowland  Enoma O. OmoregieRomain Millot  Cristina Jimenez  Jasmin Mertens  Calin BaciuStephan J. Hug  Michael Berg 《Applied Geochemistry》2011,26(1):1-17

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