1,720,974 research outputs found
Comunità microbica delle vermicolazioni provenienti da cavità carsiche e il suo ruolo nella loro formazione
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Sediment and water geochemistry shedding light on ecohydrology and anthropogenic impacts in Pertosa-Auletta Cave
No full textShedding light on vermiculations: a key step towards their conservation
No full textCaves are hostile environments for life development, due to the prohibitive abiotic factors. However, they host interesting ecological niches for extremophiles, perfectly adapted and specialized. They, in turn, might contribute to the formation processes of the cave and other structures, like vermiculations, enigmatic and still little known deposits, found worldwide on rock surfaces of underground environments.
This study, through an interdisciplinary approach, aimed to characterize vermiculations from Pertosa-Auletta Cave (southern Italy), understanding their genesis and nature, indispensable to actuate a protection plan of these singular biosignature.
XRD pointed out that they, apart from their colors and morphologies, are mainly composed of calcite, with a lower content of quarts and traces of clay minerals. Elemental analysis showed wide variations in Al, Ba, Ca, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, S, Si, Sr, Ti, V and Zn concentrations. NGS analysis highlighted that they swarm of microbial life (Proteobacteria, 48.0%; Acidobacteria, 11.6%; Actinobacteria, 7.1%; Nitrospirae, 5.8%; Firmicutes, 4.3%; Planctomycetes, 3.2%; Chloroflexi, 1.9%; Gemmatimonadetes, 1.1%; Archaea, 0.1%) and a significant percentage of it (13.1%) is likely not yet classified. Also microscopic surveys (CLSM and FE-SEM) revealed the presence of biological evidences, strengthening the hypothesis of a key role of microorganisms in their genesis and development
Geochemical characterization of clastic sediments sheds light on energy sources and on alleged anthropogenic impacts in cave ecosystems
Full text linkCaves are usually oligotrophic ecosystems, where the organic matter represents a limiting factor to the hypogeal community and sediments are often a significant energy source. With a view to identifying the energy input influencing the ecological processes occurring in caves, as well as the potential alteration sources of the natural equilibriums, geochemical features of several typologies of clastic sediments from the Pertosa-Auletta Cave (Italy) were investigated. The collected sediments, analyzed for a number of chemical (organic matter, Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Si, Sr, Ti, V, Zn concentrations) and mineralogical (quartz, calcite, dolomite, clay minerals) characteristics, showed a different composition. Overall, their origin is supposed to be allochthonous, related to the important fluviokarst activities interesting the cave in the past, whereas the abundance of calcitic and dolomitic compounds can be autochthonous, being the carbonate the main host rock. The highest concentrations of organic matter, together with C, Cu, Mo, N, P, Pb, S and Zn, highlighted in one sample composed mainly of bats guano, revealed an important bioavailable energy input as well as a pollutant accumulation, mainly of anthropogenic origin
Characterization of soil microalgae and cyanobacteria in a differentially managed olive orchard
No full textEarthworms as ecological engineers enhancing the physico-chemical soil properties
No full textEarthworms represent the most relevant component of the soil macrofauna for their capacity to improve the soil fertility and quality, playing a crucial ecological role in maintaining its health through the bioturbation and microbial interactions processes, which increase the porosity and aeration, as well as the nutrients availability. This work aims to shed light on the epigeic earthworms (Eisenia sp.) effects on the development of two plant species (Brassica oleracea, broccoli; Vicia faba; faba bean), by changes in the soil chemico-physical properties induced by them. Using mesocosm techniques, plants were grown outdoors for four months with or without earthworms. Earthworms abundance and soil chemico-physical properties (temperature and water content throughout the experiment; macroporosity, water holding capacity, pH, organic carbon and total nitrogen at the beginning and at the end of the trial; bioturbation) were determined. Plants morphometric parameters were also measured at the end of the experiment. Earthworms’ number and total weight doubled during the trial. They induced changes in the soil chemico-physical properties. Their presence increased the soil macroporosity (+16%, mean value) and water holding capacity (+9%, mean value), as well as the bioturbation level. A significant decrease of soil organic carbon in presence of earthworms on both species were detected at the end of experiment, probably related to the higher organic matter mineralization processes; whereas the significantly higher total nitrogen in the controls of both species compared to the treatments with earthworms suggested that they can promote the readily available N uptake by roots. Finally, earthworms significantly improved the shoots and roots growth of both species. These results confirm earthworms soil enhancing and plant growth supporting action, useful to make more sustainable the soil management in agroecosystems
Controlling lampenflora, the green disease of show caves
No full textArtificial lighting in show caves causes the growth of green photosynthetic biofilms, called lampenflora, on rock surfaces. This represents a worrisome ecological problem in caves as these biofilms cause aesthetical, physical and chemical damages on the rock substrates. Finding an efficient eco-friendly control method is now a priority to carry out a sustainable management of cave tourism. In this study we assessed the efficacy of three growth-control methods in Pertosa-Auletta limestone Cave (Italy). Reflectance spectra showed that the lampenflora is able to reflect only the near-infrared, absorbing all the visible light frequencies, likely due to its capability to produce secondary accessory pigments or to the mixotrophic metabolism of some cyanobacterial species. Filamentous organisms, knotted with minerals, promote rock corrosion and the precipitation of carbonate secondary minerals. Treatment of lampenflora with NaClO (commercial bleach) demonstrated its long-term efficacy in disinfection and cleaning of the surfaces, whereas the H2O2 (oxygenated water) revealed a recovery of the biofilms after three months and corrosive effects on the underlying carbonate bedrock. Both the chemical treatments eliminated the photoautotrophs, but not Proteobacteria and Bacteroidetes bacterial phyla, and, among the Eukaryotes, Apicomplexa and Cercozoa. UVC lighting showed no effects on lampenflora with the protocol used in such work
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