Physical contact interactions with scleractinian corals in hard substrate communities

Shallow reefs are among the most diverse ecosystems, and their substrate is densely occupied by sessile organisms that frequently contact physically and interact mutually. Nevertheless, the relative importance of species abundance in shaping physical contacts in these ecosystems remains largely unknown. The aim of this study was to evaluate physical contact interactions, by using tools derived from the complex network theory, between hard corals and other benthic organisms in four areas along the Brazilian coast comprising coral reefs and rocky shores with different physical and biotic structures. It was also investigated whether interactions with corals occurred as expected by the abundance of the benthic organisms in each area, and whether corals belonging to families known as more aggressive interacted less with other organisms. In all areas, the abundance of both corals and contacting organisms directly influenced the abundance of interactions between benthic organisms, regardless of the physical or biological characteristics of the habitat and of the interacting organisms. In addition, coral species interacted more with the most abundant benthic group, the epilithic algal matrix, in all areas. Nevertheless, some evidence was found about biological mechanisms helping to explain the structure of the studied interactions, although to a lesser extent. The obtained networks presented high nestedness and connectance, but low modularity. These patterns indicate the low specificity of the studied interactions and reinforce the role of abundance as an important driver of contacts between sessile organisms in shallow hard bottom ecosystems.     

Lidar and the mobile Scene Modeler (mSM) as scientific tools for planetary exploration

With the continued success of the Mars Exploration Rovers and the return of humans to the Moon within the next decade, a considerable amount of research is being done on the technologies required to provide surface mobility and the tools required to provide scientific capability. Here, we explore the utility of lidar and the mobile Scene Modeler (mSM) - which is based on a stereo camera system - as scientific tools. Both of these technologies have been, or are being considered for, technological applications such as autonomous satellite rendezvous and rover navigation. We carried out a series of field tests at the 23 km diameter, 39 Ma, Haughton impact structure located on Devon Island in the Canadian Arctic. Several sites of geological interest were investigated, including polygonal terrain, gullies and channels, slump/collapse features, impact melt breccia hills, and a site of impact-associated hydrothermal mineralization. These field tests show that lidar and mSM provide a superior visual record of the terrain, from the regional (km) to outcrop (m to cm) scale and in 3-D, as compared to standard digital photography. Thus, a key strength of these technologies is in situ reconnaissance and documentation. Lidar scans also provide a wealth of geometric and structural information about a site, accomplishing the equivalent of weeks to months of manual surveying and with much greater accuracy than traditional tools, making this extremely useful for planetary exploration missions. An unexpected result of these field tests is the potential for lidar and mSM to provide qualitative, and potentially quantitative, composition information about a site. Given the high probability of lidar and mSM being used on future lunar missions, we suggest that it would be beneficial to further investigate the potential for these technologies to be used as science tools.     

Insights into Li and Li isotope cycling and sub-arc metasomatism from veined mantle xenoliths,Kamchatka

Harzburgitic xenoliths cut by pyroxenite veins from Avachinsky volcano, Kamchatka, are derived from the sub-arc mantle and record element transfer from the slab to the arc. Olivine and orthopyroxene in the harzburgites have Li isotopic compositions (δ⁷Li = +2.8 to +5.6) comparable to estimates of the upper mantle (δ⁷Li ~ +4 ± 2). The pyroxenite veins, which represent modal metasomatism and may therefore provide information about the metasomatic agent, have mantle-normalized trace element characteristics that suggest overprinting of their mantle source by an aqueous, slab-derived fluid. These include relative enrichments of Pb over Ce, U over Th and Sr over Nd. Li is enriched relative to the HREE, and ortho- and clinopyroxene from the veins are in Li elemental and isotopic equilibrium with each other and the surrounding harzburgite. Vein samples (δ⁷Li = +3.0 to +5.0) do not record a significant slab-derived δ⁷Li signature. These observations can be reconciled if slab Li diffusively re-equilibrates in the mantle wedge. Modeling demonstrates that Li equilibration of small (1–2 cm width) veins or melt conduits is achieved at mantle wedge temperatures within 10¹–10⁵ years. We conclude that strongly fractionated Li isotopic signatures cannot be sustained for long periods in the sub-arc mantle, at least at shallow (<70 km) depths. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Correlating Alpine glaciation with Adriatic sea‐level changes through lake and alluvial stratigraphy

We compare lake and alluvial stratigraphy along a frame connecting the southern Alpine foothills and the Adriatic Sea, with the aim of matching the effects of Alpine glaciation and sea‐level changes on sedimentation during the last glacial cycle. The palynostratigraphy of Lake Fimon provided proxies for regional vegetation and climate change and was coupled with sediment petrography, loss on ignition and magnetic susceptibility, disentangling alluvial phases from fluvioglacial activity related to culminations of the southeastern Alpine glaciers. The Fimon area was not reached by alluvial fans during the penultimate glacial maximum, nor by the sea transgression during the last interglacial, but a closed lake soon developed at the Eemian onset due to enhanced rainfall. Sea‐level fall at glacial inception triggered the entrenchment of the drainage network in the plain reaching the outer Fimon Basin. Slow aggradation, but no sign of fluvioglacial activity, lasted to 38.2 ± 1.45 cal. ka BP, when a major forest withdrawal took place, coeval to the spread of alluvial fans. By 27.5 ± 0.5 cal. ka BP the Fimon Basin was dammed by the Brenta outwash system. The main step of of forest recovery commenced at around (15.8) cal. ka BP, when apex trenching of the outwash fans was triggered by the glacier's decay. Copyright © 2011 John Wiley & Sons, Ltd.     

Assessing landslide exposure in areas with limited landslide information

Landslide risk assessment is often a difficult task due to the lack of temporal data on landslides and triggering events (frequency), run-out distance, landslide magnitude and vulnerability. The probability of occurrence of landslides is often very difficult to predict, as well as the expected magnitude of events, due to the limited data availability on past landslide activity. In this paper, a qualitative procedure for assessing the exposure of elements at risk is presented for an area of the Apulia region (Italy) where no temporal information on landslide occurrence is available. Given these limitations in data availability, it was not possible to produce a reliable landslide hazard map and, consequently, a risk map. The qualitative analysis was carried out using the spatial multi-criteria evaluation method in a global information system. A landslide susceptibility composite index map and four asset index maps (physical, social, economic and environmental) were generated separately through a hierarchical procedure of standardising and weighting. The four asset index maps were combined in order to obtain a qualitative weighted assets map, which, combined with the landslide susceptibility composite index map, has provided the final qualitative landslide exposure map. The resulting map represents the spatial distribution of the exposure level in the study area; this information could be used in a preliminary stage of regional planning. In order to demonstrate how such an exposure map could be used in a basic risk assessment, a quantification of the economic losses at municipal level was carried out, and the temporal probability of landslides was estimated, on the basis of the expert knowledge. Although the proposed methodology for the exposure assessment did not consider the landslide run-out and vulnerability quantification, the results obtained allow to rank the municipalities in terms of increasing exposure and risk level and, consequently, to identify the priorities for designing appropriate landslide risk mitigation plans.     

Late Neolithic vegetation history at the pile‐dwelling site of Palù di Livenza (northeastern Italy

The Late Neolithic pile‐dwelling of Palù di Livenza yielded archaeological remains typical of the Square Mouth Pottery and Lagozza Cultures. A palynological investigation reveals important changes in the vegetation due to anthropogenic pressure. Between ca. 6590 and 5960 cal. yr BP, dense oak wood forests with deciduous Quercus, Fagus and Corylus extended around the mire, with no signs of human impact. The establishment of the pile‐dwelling, dated to ca. 5960 cal. yr BP, led to a strong reduction of forests, reclamation of wetlands, and expansion of herbaceous communities, with cultivated species, infestant weeds, nitrophilous and ruderal herbs, pastures and meadows. According to AMS dates and previous archaeological chronologies, the pile‐dwelling persisted for about 700 years (from ca. 5960 to 5260 cal. yr BP). The history of the pile‐dwelling after ca. 5260 cal. yr BP cannot be reconstructed because of recent contamination of the top part of the section. Rarefaction analysis was applied to estimate changes of palynological richness through time: the highest E(T_n) (between 56 and 69 taxa) are contemporaneous with the local development of the pile‐dwelling. The comparison of pollen data with archaeobotanical evidence indicates that Fragaria vesca, Malus sylvestris, Papaver somniferum and Physalis alkekengi were gathered at some distance from the site and that Linum usitatissimum is strongly under‐represented in pollen samples. Crop cultivation can be estimated for a radius of several hundred metres around the mire. Palù di Livenza is significant in the context of Neolithic archaeobotany of northern Italy and neighbouring countries. Copyright © 2004 John Wiley & Sons, Ltd.     

Innovative monitoring tools for the complex spatial dynamics of river chemistry: case study for the Alpine region

Chemical reactions in aqueous geochemical systems are driven by nonequilibrium conditions, and their dynamics can be deduced through the distributional analysis (identification of probability laws) of complex compositional indices. In this perspective, compositional data analysis offers the possibility to investigate the behavior of the composition as a whole instead of isolated chemical species, with the awareness that multispecies systems are characterized by the simultaneous interactions among all their parts. We addressed this problem using D???1 isometric log-ratio coordinates describing the D compositional dataset of the river chemistry of the Alpine region (D number of variables), thus working in the \({{\mathbb{R}}^{D - 1}}\) statistical sample space. The D???1 coordinates were chosen using the decreasing variance criterion so that each one could provide information about different space–time properties for the investigated geochemical system. Coordinates dominated by heterogeneity appear to be able to capture regime shifts only on a long-time period and monitor processes on a very wide scale. On the other hand, coordinates characterized by lower variability present multimodality, thus capturing the presence of alternative states in the analyzed spatial domain also for the current time. Further developments are needed to determine the ranges of conditions for which variability and other statistics can be useful indicators of regime shifts on different time–space scales in geochemical systems.     

Geochemical thermodynamics of cadmium removal from water with limestone

Limestone-based material can reduce concentrations of cadmium below 0.001 mg/L (1 ppb) in water, resulting in > 99% removal efficiency. Thermodynamic constraints appear to be favorable for reactions involving the formation of otavite during cadmium removal. Thermodynamic values for these reactions yield a theoretical removal limit of 0.0015 mg/L or better for cadmium, in reasonable agreement with tests on laboratory and field samples that show cadmium removal at levels less than 0.001 mg/L.     

Summer larval fish assemblages in the Southern Tyrrhenian Sea (Western Mediterranean Sea)

The purpose of this paper was to study the community structure, in terms of species composition, abundance and spatial distribution, of fish larvae in a wide coastal area of Sicily facing the Southeastern Tyrrhenian Sea, extending for 2300 km² from Cape Cefalù to the west, to Cape Rasocolmo in the east. This study analyses how species are assembled in relation to an inshore–offshore gradient and also how environmental conditions, determined by surface circulation patterns occurring in the Central Mediterranean at the local scale, determine the distribution patterns. Samples from 39 stations were collected using a 60‐cm Bongo net during an ichthyoplanktonic survey carried out in June 2006. In all, 62 taxa, representing 32 families, were identified. Cyclothone braueri (59.6%), Engraulis encrasicolus (9.2%) Lampanyctus crocodilus (4.3%) and Lampanyctus pusillus (4.1%) were the most abundant species. The results showed that the highest abundance value (14830.6 fish larvae per 10 m² sea surface) was observed in the western part of the study area. MDS, SIMPER and CCA analyses revealed well defined groups of stations and assemblages of larvae in accordance with an inshore–offshore gradient. The results of this study could have implications for the management of marine resources because the investigated area has already been identified as a nursery area for many pelagic and coastal fishes and a natural habitat for many species of high commercial interest.