http://hdl.handle.net/2122/182 Tue, 21 May 2013 10:35:39 GMT 2013-05-21T10:35:39Z http://hdl.handle.net/2122/8702 Title: The use of non-invasive field techniques in the study of small topographically closed lakes: two case studies in Sicily (Italy) Authors: Madonia, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Cangemi, M.; Göttingen Zentrum Geowissenschaften, Abteilung Geobiologie, Universität Göttingen, Germany; Di Trapani, F. P.; Legambiente, Comitato regionale siciliano, Palermo, Italy Abstract: Small endhoreic (topografically closed) lakes represent a little percentage of continental waters but, in arid or sub-arid regions, they develop special ecosystems potentially prone to ecological involution due to climatic changes. The mandatory use of light, non-invasive field techniques is often required, especially in protected areas. In the present work the use of non-invasive techniques like GPS−based bathymetric and photographic surveys have been applied to the study of two lakes, Specchio di Venere and Sfondato (Sicily, southern Italy), both natural reserves. The comparison between historical surveys and modern GPS−based bathymetries highlighted the difficulty of using the former for the reconstruction of climatic-induced variations due to the low number of measurements (spatial aliasing). In particular, at the intracaldera Lake Specchio di Venere, a high resolution survey gave new insights into a peculiar geo-ecosystem whose evolution is driven by both volcanic phenomena and biomineralization processes. On the contrary, the morphology of Lake Sfondato floor is much more simple and driven only by the superimposition of a detrital sedimentation on the initial collapse that generated the lake. The comparison betweem direct measurements and estimated changes of lake level, carried out between February 2008 and October 2009 variations, allowed us to test different hypotheses of hydrological balances, leading to opposite conclusions with respect to previous studies and remarking the fundamental importance of direct measurements in the validation of theoretical hydrological models. Mon, 22 Apr 2013 22:00:00 GMT http://hdl.handle.net/2122/8702 2013-04-22T22:00:00Z http://hdl.handle.net/2122/8680 Title: The importance of methanotrophic activity in geothermal soils of Pantelleria island (Italy) Authors: D'Alessandro, W.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Gagliano, A.L.; Università di Palermo, Dipartimento DiSTeM; Quatrini, P.; Università di Palermo, Dipartimento STEBICEF; Parello, F.; Università di Palermo, Dipartimento DiSTeM Abstract: Methane is a major contributor to the greenhouse effect, its atmospheric concentration being more than doubled since the XIX century. Every year 22 Tg of methane are released to the atmosphere from several natural and anthropogenic sources. Natural sources include geothermal/volcanic areas but the estimation of the total methane emission from these areas is currently not well defined since the balance between emission through degassing and microbial oxidation within the soils is not well known. Microbial oxidation in soils contributes globally for about 3-9% to the removal of methane from the atmosphere and recent studies evidenced methanotrophic activity also in soils of volcanic/geothermal areas despite their harsh environmental conditions (high temperatures, low pH and high concentrations of H2S and NH3). Methanotrophs are a diverse group of bacteria that are able to metabolize methane as their only source of carbon and energy and are found within the Alpha and Gamma classes of Proteobacteria and within the phylum Verrucomicrobia. Our purpose was to study the interaction between methanotrophic communities and the methane emitted from the geothermally most active site of Pantelleria island (Italy), Favara Grande, whose total methane emission has been previously estimated in about 2.5 t/a. Laboratory incubation experiments with soil samples from Favara Grande showed methane consumption values of up to 9500 ng g-1 dry soil per hour while soils collected outside the geothermal area consume less than 6 ng g-1 h-1. The maximum consumption was measured in the shallowest part of the soil profile (1-3 cm) and high values (>100 ng g-1 h-1) were maintained up to a depht of 15 cm. Furthermore, the highest consumption was measured at 37 C, and a still recognizable consumption (>20 ng g-1 h-1) at 80 C, with positive correlation with the methane concentration in the incubation atmosphere. These results can be considered a clear evidence of the presence of methanotrophs that were investigated by culturing and culture-independent techniques. The diversity of proteobacterial methanotrophs was investigated by creating a clone library of the amplified methane mono-oxygenase encoding gene, pmoA. Clone sequencing indicates the presence of Gammaproteobacteria in the soils of Favara Grande. Enrichment cultures, on a mineral medium in a CH4-enriched atmosphere, led to the isolation of different strains that were identified as Methylocistis spp., which belong to the Alphaproteobacteria. The presence of Verrucomicrobia was detected by amplification of pmoA gene using newly designed primers. Soils from Favara Grande show therefore the largest spectrum of methanotrophic microorganisms until now detected in a geothermal environment. While the presence of Verrucomicrobia in geothermal soils was predictable due to their thermophilic and acidophilic character, the presence of both Alpha and Gamma proteobacteria was unexpected. Their presence is limited to the shallowest part of the soil were temperatures are lower and is probably favored by a soil pH that is not too low (pH 5) and their contribution to biological methane oxidation at Pantelleria is significant. Understanding the ecology of methanotrophy in geothermal sites will increase our knowledge of the role of soils in methane emissions in such environments. Sun, 07 Apr 2013 22:00:00 GMT http://hdl.handle.net/2122/8680 2013-04-07T22:00:00Z http://hdl.handle.net/2122/8195 Title: Impacts of natural and anthropogenic climate variations on North Pacific plankton in an Earth System Model Authors: Patara, L.; CMCC; Vichi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Masina, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Abstract: The impacts of natural atmospheric variability and anthropogenic climate change on the spatial distribution, seasonality, structure, and productivity of North Pacific plankton groups are investigated by means of an Earth System Model (ESM) that contains a plankton model with variable stoichiometry. The ESM is forced with observed greenhouse gases for the 20th century and with the Intergovernmental Panel on Climate Change A1B Emission Scenario for the 21st century. The impacts of the two main modes of variability – connected with the Aleutian Low (AL) strength and with the North Pacific Oscillation (NPO) – are considered. When the AL is strong, primary productivity and chlorophyll concentrations are higher in the central Pacific, the seasonality of plankton is enhanced, and the classical grazing chain is stimulated, whereas in the Alaskan Gyre the model simulates a chlorophyll decrease and a shift toward smaller phytoplankton species. A stronger NPO increases productivity and chlorophyll concentration at ∼45°N. In the anthropogenic climate change scenario, simulated sea surface temperature is 4 °C higher with respect to contemporary conditions, leading to reduced mixing and nutrient supply at middle-subpolar latitudes. The seasonal phytoplankton bloom is reduced and occurs one month earlier, the flow of carbon to the microbial loop is enhanced, and phytoplanktonic stoichiometry is nutrient-depleted. Primary productivity is enhanced at subpolar latitudes, due to increased ice-free regions and possibly to temperature-related photosynthesis stimulation. This study highlights that natural climate variability may act alternatively to strengthen or to weaken the human-induced impacts, and that in the next decades it will be difficult to distinguish between internal and external climate forcing on North Pacific plankton groups. Sat, 31 Dec 2011 23:00:00 GMT http://hdl.handle.net/2122/8195 2011-12-31T23:00:00Z http://hdl.handle.net/2122/7628 Title: The emergence of ocean biogeochemical provinces: a quantitative assessment and a diagnostic for model evaluation. Authors: Vichi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Allen, J. I.; PML; Masina, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Hardman-Mountford, N.; PML Abstract: The concept of ocean biogeochemical provinces is based on the observation that large ocean regions are characterized by coherent physical forcing and environmental conditions, which are eventually representative of macroscale ocean ecosystems. Biogeochemical models of the global ocean focus on simulating the coupling between prevalent physical conditions and the biogeochemical processes with the assumption that biological properties respond coherently to physics and therefore should produce such provinces as an emergent property. In this paper, we quantitatively assess the emergence of a reference set of predefined biogeochemical provinces in the available global data sets and propose a province‐based approach to the evaluation of one of the most comprehensive models of ocean biogeochemistry. Multivariate statistical tools were applied to model and observation data, verifying the existence, distinctiveness and reliability of the predefined provinces and quantifying the correlation of model results with observations at the global scale. The analysis of similarity between provinces shows that they are statistically separable in data and model output and therefore can be used as reliable metrics. The analyses indicate that provinces can be more easily distinguished in terms of their environmental features rather than using chlorophyll concentration. The characterization of provinces by means of chlorophyll values shows a significant overlap in both the Sea‐viewing Wide Field‐of‐view Sensor (SeaWiFS) data and the model. It is likely this is related to the choice of province boundaries based on coarse‐resolution mapped data, which are not necessarily the same as those derivable from high‐resolution satellite data. We also demonstrated through cluster analysis that the long‐term time series data collected at Joint Global Ocean Flux Study (JGOFS) stations are representative of environmental conditions of the respective province and can thus be used to evaluate model results extracted from that province. The method shows promise for helping to overcome problems with model verification due to under sampling of most ocean biogeochemical variables but also gives indications that unsupervised clustering may be required when more spatially resolved data and models are available. Fri, 31 Dec 2010 23:00:00 GMT http://hdl.handle.net/2122/7628 2010-12-31T23:00:00Z http://hdl.handle.net/2122/7625 Title: Impact of appendicularians on detritus and export fluxes: a model approach at Dyfamed site Authors: Berline, L.; LOB; Stemman, L.; LOB; Vichi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Lombard, F.; LOPB; Gorsky, G.; LOB Abstract: So far, the role of appendicularians in the biogeochemical cycling of organic matter has been largely overlooked. Appendicularians represent only a fraction of total mesozooplankton biomass, however these ubiquitous zooplankters have very high filtration and growth rates compared to copepods, and produce numerous fecal pellets and filtering houses contributing to export production by aggregating small marine particles. To study their quantitative impact on biogeochemical flux, we have included this group in the biogeochemical flux model, using a recently developed ecophysiological model. One-dimensional annual simulations of the pelagic ecosystem including appendicularians were conducted with realistic surface forcing for the year 2000, using data from the DyFAMed open ocean station. The appendicularian grazing impact was generally low, but appendicularians increased detritus production by 8% and export production by 55% compared to a simulation without appendicularians. Therefore, current biogeochemical models lacking appendicularians probably under, or misestimate the detritus and export production by omitting the pathway from small-sized plankton to fast sinking detritus. Detritus production and export rates are 60% lower than the estimates from mesotrophic sites, showing that appendicularians’ role is lower but still significant in oligotrophic environments. The simulated annual export at 200 m exceeds sediment trap values by 44%, suggesting an intense degradation during the sinking of appendicularian detritus, supported by observations made at other sites. Thus, degradation and grazing of appendicularian detritus need better quantification if we are to accurately assess the role of appendicularia in export flux. Fri, 31 Dec 2010 23:00:00 GMT http://hdl.handle.net/2122/7625 2010-12-31T23:00:00Z http://hdl.handle.net/2122/7104 Title: Societal need for improved understanding of climate change, anthropogenic impacts, and geo-hazard warning drive development of ocean observatories in European Seas Authors: Ruhl, H. A.; NOCS; Andrè, M.; UPC; Beranzoli, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Çagatay, M. N.; ITU; Colaço, A.; Univ. Azores; Cannat, M.; IPGP; Dañobeitia, J. J.; CSIC-UTM; Favali, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Géli, L.; IFREMER; Gillooly, M.; IMI; Greinert, J.; NIOZ; Hall, P. O. J.; Univ. Goteborg; Huber, R.; MARUM; Karstensen, J.; Univ. Kiel; Lampitt, R. S.; NOCS; Larkin, K. E.; NOCS; Lykousis, V.; HCMR; Mienert, J.; Univ. Tromsø; Miranda, J. M.; Univ. Lisboa; Person, R.; IFREMER; Priede, I. G.; Univ. Aberdeen; Puillat, I.; IFREMER; Thomsen, L.; Jacobs Univ. Bremen; Waldmann, C.; MARUM Abstract: Society’s needs for a network of in situ ocean observing systems cross many areas of earth and marine science. Here we review the science themes that benefit from data supplied from ocean observatories. Understanding from existing studies is fragmented to the extent that it lacks the coherent long-term monitoring needed to address questions at the scales essential to understand climate change and improve geo-hazard early warning. Data sets from the deep sea are particularly rare with long-term data available from only a few locations worldwide. These science areas have impacts on societal health and well-being and our awareness of ocean function in a shifting climate. Substantial efforts are underway to realise a network of open-ocean observatories around European Seas that will operate over multiple decades. Some systems are already collecting high-resolution data from surface, water column, seafloor, and sub-seafloor sensors linked to shore by satellite or cable connection in real or near-real time, along with samples and other data collected in a delayed mode. We expect that such observatories will contribute to answering major ocean science questions including: How can monitoring of factors such as seismic activity, pore fluid chemistry and pressure, and gas hydrate stability improve seismic, slope failure, and tsunami warning? What aspects of physical oceanography, biogeochemical cycling, and ecosystems will be most sensitive to climatic and anthropogenic change? What are natural versus anthropogenic changes? Most fundamentally, how are marine processes that occur at differing scales related? The development of ocean observatories provides a substantial opportunity for ocean science to evolve in Europe. Here we also describe some basic attributes of network design. Observatory networks provide the means to coordinate and integrate the collection of standardised data capable of bridging measurement scales across a dispersed area in European Seas adding needed certainty to estimates of future oceanic conditions. Observatory data can be analysed along with other data such as those from satellites, drifting floats, autonomous underwater vehicles, model analysis, and the known distribution and abundances of marine fauna in order to address some of the questions posed above. Standardised methods for information management are also becoming established to ensure better accessibility and traceability of these data sets and ultimately to increase their use for societal benefit. The connection of ocean observatory effort into larger frameworks including the Global Earth Observation System of Systems (GEOSS) and the Global Monitoring of Environment and Security (GMES) is integral to its success. It is in a greater integrated framework that the full potential of the component systems will be realised. Fri, 31 Dec 2010 23:00:00 GMT http://hdl.handle.net/2122/7104 2010-12-31T23:00:00Z http://hdl.handle.net/2122/6914 Title: Is the southeastern Adriatic Sea coastal strip an eutrophic area? Authors: Marini, M.; Institue of Marine Science, National Research Center; Grilli, F.; Institue of Marine Science, National Research Center; Guarnieri, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Burton, H. J.; University of Southern California, Los Angeles; Klajic, Z.; Institute of Marine Biology Kotor, Montenegro; Pinardi, N.; CIRSA, University of Bologna, Ravenna, Italy; Sanxhaku, M.; Institute of Hydrometeorology, Tirana, Albania Abstract: This study intends to understand and assess the effects of the discharge from the Buna/Bojana river delta watersheds on the eutrophic status of the southeastern Adriatic Sea, and contrast this area with the northwestern Adriatic region where the Po River dominates the freshwater discharge into the coastal ocean. We compare observations of inorganic nutrients, turbidity, and physical variables from the two regions and use numerical model results to characterize the physical circulation of the two areas. The area affected by the Po River discharge extends at least one hundred kilometers southward from the delta and approximately 20 km offshore. Maximum chlorophyll concentrations typically occur within the river plume. Similarly, in the southeastern Adriatic Sea, the Buna/Bojana River discharge extends northward along the coasts for approximately one hundred kilometers and contains a large maxima in the regional chlorophyll distribution. The two coastal areas tend to have opposing physical forcing processes: the Po River tends to be affected area by northerly to northeasterly winds that cause downwelling, whereas the Buna/Bojana River on the opposite side of the basin is typically characterized by northerly, upwelling favorable winds. However, during the study period, upwelling is not a dominant feature of the circulation and both the shelf slope current (SouthEastern Adriatic e SEAd current) and the along shore currents in the southeastern Adriatic Sea are northward. The along shore current probably dominated by the river runoff is here described for the first time and called the southeastern Shelf Coastal (SESC) current. Under these conditions, primary productivity is high in both regions leading us to conclude that river plume dynamics and the associated nutrient inputs determine the eutrophication status of the coastal strip, regardless of the circulation regime in the southeastern Adriatic Sea area. The Adriatic southeastern coastal area is an eutrophic area that is strongly affected by freshwater inputs particularly from the Buna/ Bojana River system. Tue, 20 Apr 2010 22:00:00 GMT http://hdl.handle.net/2122/6914 2010-04-20T22:00:00Z http://hdl.handle.net/2122/6871 Title: Challenges of modeling depth-integrated marine primary productivity over multiple decades: A case study at BATS and HOT Authors: Saba, V.; VIMS; Friedrichs, M.A.M.; VIMS; et al.; including; Vichi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Abstract: The performance of 36 models (22 ocean color models and 14 biogeochemical ocean circulation models (BOGCMs)) that estimate depth-integrated marine net primary productivity (NPP) was assessed by comparing their output to in situ 14C data at the Bermuda Atlantic Time series Study (BATS) and the Hawaii Ocean Time series (HOT) over nearly two decades. Specifically, skill was assessed based on the models' ability to estimate the observed mean, variability, and trends of NPP. At both sites, more than 90% of the models underestimated mean NPP, with the average bias of the BOGCMs being nearly twice that of the ocean color models. However, the difference in overall skill between the best BOGCM and the best ocean color model at each site was not significant. Between 1989 and 2007, in situ NPP at BATS and HOT increased by an average of nearly 2% per year and was positively correlated to the North Pacific Gyre Oscillation index. The majority of ocean color models produced in situ NPP trends that were closer to the observed trends when chlorophyll-a was derived from high-performance liquid chromatography (HPLC), rather than fluorometric or SeaWiFS data. However, this was a function of time such that average trend magnitude was more accurately estimated over longer time periods. Among BOGCMs, only two individual models successfully produced an increasing NPP trend (one model at each site). We caution against the use of models to assess multiannual changes in NPP over short time periods. Ocean color model estimates of NPP trends could improve if more high quality HPLC chlorophyll-a time series were available Thu, 31 Dec 2009 23:00:00 GMT http://hdl.handle.net/2122/6871 2009-12-31T23:00:00Z http://hdl.handle.net/2122/6870 Title: A dynamic Biologically-Active Layer for numerical studies of the sea ice ecosystem. Authors: Tedesco, L.; CMCC; Vichi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Haapala, J.; FMI; Stipa, T.; FMI Abstract: This work introduces a novel approach for the modelling and coupling of sea ice biology to sea ice physics. The central concept of the coupling is the definition of the Biologically Active Layer, which is the time-varying fraction of sea ice that is connected to the ocean via brine pockets and channels, and acts as a rich habitat for many microorganisms. A simple but comprehensive physical model of the sea ice thermohalodynamics is coupled to a novel sea ice microalgal model of growth in the framework of the Biogeochemical Flux Model. The physical model provides the key physical properties of the Biologically Active Layer and the biological model simulates the physiological and ecological response of the algal community to the physical environment. Numerical simulations of chl-a were compared with observations at two different ice stations, in the Baltic and off the coast of Greenland, showing that this new coupling structure is sufficiently generic to represent well the temporal and spatial distribution of sea ice algae during the whole ice season at both sites. This model implementation and coupling structure is viable as a new component of General Circulation Models, allowing for estimates of the role and importance of sea ice biology in the local and global carbon cycle. Thu, 31 Dec 2009 23:00:00 GMT http://hdl.handle.net/2122/6870 2009-12-31T23:00:00Z http://hdl.handle.net/2122/6838 Title: Questo caldo, caldo, caldo mondo Authors: Carapezza, M. L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; D'Addezio, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Ricci, T.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Barberi, F.; DSG, Univ. Roma Tre; Ranaldi, M.; DSG, Univ. Roma Tre Abstract: La mostra consente fin dal suo inizio di “entrare” nel mondo degli spettacolari fenomeni geotermici. Immagini di geyser, pozze di fango ribollente, fumarole, acque termali dai colori più improbabili, incrostazioni multicolori e affascinanti cristalli, provenienti da varie parti del mondo accompagneranno i visitatori alla scoperta delle caratteristiche naturalistiche del fenomeno. Ad arricchire l'esposizione iniziale curata da Vulcano Esplorazioni, un video con immagini raccolte in varie parti del pianeta, eccezionali campioni di minerali di origine idrotermale provenienti dal Museo di Storia Naturale di Milano e diorami esplicativi, in scala e ridotti. Ricostruzioni, schemi ed exhibit facilitano la comprensione del meccanismo fisico che scatena questi fenomeni. La parte scientifica, curata in particolare dall’INGV, ripercorre anche le esperienze pionieristiche di Larderello, ricostruendo il primo esperimento del 1904 di produzione di energia elettrica da vapore geotermico. Il percorso museale illustra anche il grande potenziale energetico presente soprattutto in Italia, il paese più caldo d'Europa, offerto dal calore della Terra, un’energia rinnovabile e pulita. L'esibizione termina con uno spettacolare filmato in 3D. Thu, 22 Oct 2009 22:00:00 GMT http://hdl.handle.net/2122/6838 2009-10-22T22:00:00Z