Effects of the physical properties of water masses on microbial activity during an Ice Shelf Water overflow in the central Ross Sea

During the 1997-98 Italian Expedition to Antarctica a five-day mesoscale experiment was carried out on the continental shelf-break in the central Ross Sea. This area is oceanographically characterized by shelf/slope interactions, through intense mixing processes, between the Circumpolar Deep Water (CDW) and the Ice Shelf Water (ISW), coming from beneath the Ross Ice Shelf and spilling over the shelf edge. The export of dense shelf waters is of crucial importance not only for the mass balance of the basin, but also for carbon export from the upper layers into the abyssal ones. The study investigated how the ISW interactions with the CDW may influence bacterial metabolism during an ISW downslope event. In particular, what effect does this have on the bacterial activities related to the utilization and transformation of the organic carbon substrate (ectoenzymatic activities, carbon production, growth rate) within the ISW and the CDW cores? Our data show that in the CDW the metabolic response was to increase the biomass and enzymes were less active due to a higher nutritional value for the substrate. In the ISW the bacterial metabolic activity shifted towards degradative processes. These results suggest differences in the quality of the organic carbon pool with a greater concentration of labile organic matter in the CDW and of low-degradable compounds in the ISW. The use of microbial parameters seems to be very promising in the evaluation of the carbon export during mixing processes, when the refractory fraction of the organic carbon pool might play a key role

Getting Your Work Published: An AFS Professional Development Lunchtime Roundtable

This document reports on a professional development workshop for graduate students and new professionals in the field of folklore studies sponsored by the AFS at its 2005 annual meeting in Atlanta. The roundtable leaders were: Harris M. Berger and Giovanna P. Del Negro – Texas A&M University; incoming co-editors, Journal of American Folklore and Judy McCulloh – Executive Editor, University of Illinois Press.The Folk and Traditional Arts Program of the National Endowment for the Arts provided funding for this workshop

Approaching the seismogenic source of the Calabria 8 September 1905 earthquake: New geophysical, geological and biochemical data from the S. Eufemia Gulf (S Italy)

Recognizing the seismogenic source of major historical earthquakes, particularly when these have occurred offshore, is a long-standing issue across the Mediterranean Sea and elsewhere. The destructive earthquake (M ~7) that struck western Calabria (southern Italy) on the night of 8 September 1905 is one such case. having various authors proposed a seismogenic source, with apparently diverse hypotheses and without achieving a unique solution. To gain novel insight into the crustal volume where the 1905 earthquake took place and to seek a more robust solution for the seismogenic source associated with this destructive event, we carried out a well-targeted multidisciplinary survey within the Gulf of S. Eufemia (SE Tyrrhenian Sea), collecting geophysical data, oceanographic measurements, and biological, chemical and sedimentary samples. We identified three main tectonic features affecting the sedimentary basin in the Gulf of S. Eufemia: 1) a NE-SW striking, ca. 13-km-long, normal fault, here named S. Eufemia Fault; 2) a WNW-striking polyphased fault system; and 3) a likely E-W trending lineament. Among these, the normal fault shows evidence of activity witnessed by the deformed recent sediments and by its seabed rupture along which, locally, fluid leakage occurs. Features in agreement with the anomalous distribution of prokaryotic abundance and biopolymeric C content, resulted from the shallow sediments analyses. The numerous seismogenic sources proposed in the literature during the past 15 years make up a composite framework of this sector of western Calabria, that we tested against a) the geological evidence from the newly acquired dataset, and b) the regional seismotectonic models. Such assessment allows us to propose the NE-SW striking normal fault as the most probable candidate for the seismogenic source of the 1905 earthquake. Re-appraising a major historical earthquake as the 1905 one enhances the seismotectonic picture of western Calabria. Further understanding of the region and better constraining the location of the seismogenic source may be attained through integrated interpretation of our data together with a) on-land field evidence, and b) seismological modeling

Bauman's Verbal Art and the Social Organization of Attention: The Role of Reflexivity in the Aesthetics of Performance

In Richard Bauman's landmark study Verbal Art as Performance, reflexivity plays a small but important role. Combining ideas from Verbal Art with insights from phenomenology, this article uses the concept of reflexivity to re-examine basic facets of expressive interaction and explores the structure of intersubjectivity in performance. Field data on American heavy metal music and the promenade of central Italy are used to reveal the crucial role that reflexivity plays in the aesthetics of performance

Discrete derivatives and symmetries of difference equations

We show on the example of the discrete heat equation that for any given discrete derivative we can construct a nontrivial Leibniz rule suitable to find the symmetries of discrete equations. In this way we obtain a symmetry Lie algebra, defined in terms of shift operators, isomorphic to that of the continuous heat equation.Comment: submitted to J.Phys. A 10 Latex page

Seismic-induced accelerations detected by two parallel gravity meters in continuous recording with a high sampling rate at Etna volcano

We analyse a microgravity data set acquired from two spring LaCoste & Romberg gravity meters operated in parallel at the same site on Etna volcano (Italy) for about two months (August – September 2005). The high sampling rate acquisition (2Hz) allowed the correlation of short-lasting gravity fluctuations with seismic events. After characterizing the oscillation behavior of the meters, through the study of spectral content and the background noise level of both sequences, we recognized fluctuations in the gravity data, spanning a range of periods from 1 second to about 30 seconds dominated by components with a period of about 15 ÷ 25 seconds, during time intervals encompassing both local seismic events and large worldwide earthquakes. The data analyses demonstrate that observed earthquake-induced gravity fluctuations have some differences due to diverse spectral content of the earthquakes. When local seismic events which present high frequency content excite the meters, the correlation between the two gravity signals is poor (factor < 0.3). Vice versa, when large worldwide earthquakes occur and low frequency seismic waves dominate the ensuing seismic wavefield, the resonance frequencies of the meters are excited and they react according to more common features. In the latter case, the signals from the two instruments are strongly correlated to each other (up to 0.9). In this paper the behaviors of spring gravimeters in the frequency range of the disturbances produced by local and large worldwide earthquakes are presented and discussed

Sink or swim? Modernization of mussel farming methods may negatively impact established seabird communities

Marine aquaculture is the fastest growing sector of global food production and is projected to increase to meet future demand. Expansion and modernization of cultivation methods are needed to reach this target but a cost-benefit evaluation for biodiversity conservation is required to achieve sustainable aquaculture practices. We assess drivers of avian richness and abundance in a long-established seabird community present in a series of longline mussel farms in Italy and in response to a recent modernization process in the farming methodology. Over 2 years (24 surveys) we detected a remarkable diversity (15 species in 5 families) and abundance (n = 5858) of birds, of which 40% (n = 6) are regarded as species of international conservation importance. Our models highlighted that the strongest driver explaining variation in abundance and richness across sites was the type of buoy and the associated cultivation method applied. The older and fast-declining double headrope design, offered greater stability for birds to rest. Conversely, the newer and mechanizable single headrope design dominant method in our study site and projected to replace the older system, was unsuitable for birds. Our findings confirm the function of mussel farms as a sort of marine protected area where low anthropogenic disturbance, higher prey availability and suitable artificial structures promote the establishment of seabird communities with minimal impacts on harvest. However, we suggest that potential modernization of farming methods, important to meet future human demand, needs to be carefully assessed and compensated for, particularly where long-established seabird communities have formed in response to such practices

Interactions between free-living nematodes and benthic diatoms: insights from the Gulf of Trieste (northern Adriatic Sea)

From July 2010 to July 2012, free-living nematodes were investigated in terms of abundance, genera and trophic composition at the long term St. C1 (depth 18 m), located in the Gulf of Trieste (northern Adriatic Sea). The integration of these results with environmental (e.g. sediment grain-size, Biopolymeric C and Chl a) and biological variables (benthic diatom biomass and composition) collected synoptically with nematodes, allowed to clarify the linkage between these organisms and another ecosystem component, i.e. benthic diatoms. The observed peaks of nematode abundance in summer samplings were ascribable almost exclusively to piercing nematodes that feed on microalgae (Chromadoridae and, among them, Ptycholaimellus) and were concomitant with the highest numbers of benthic diatoms. DISTLM outputs further corroborated this interaction by indicating Chl a, i.e. a proxy of benthic diatoms, as the only environmental variable that significantly shaped nematode assemblage over the 2-year period. This linkage was not explained only quantitatively (i.e. more diatoms supported more nematodes) but also qualitatively. During winter, in fact, the presence of heavily silicified diatoms co-occurred with nematode minima and the lowest percentage of piercing organisms, suggesting an overall minor ability of the assemblage in using this feeding strategy. In a benthic ecosystem functioning point of view, the observed seasonal pattern of variation in both nematodes and benthic diatoms suggests that more of the energy flowing to nematodes during the summer derives directly from benthic diatom primary production while in the winter this linkage is less important.</div