Labile, recalcitrant and stable soil organic carbon: comparison of agronomic management in a vineyard of Trentino (Italy)

The intensive exploitation of agricultural land has caused a depletion of soil organic carbon (SOC) and a decline in soil fertility, with a consequent decrease in the productivity of agroecosystems, also contributing to atmospheric GHG emissions. The ability of soil to storage organic carbon (OC) depends on its persistence and susceptibility to decomposition. SOC is generally partitioned into fractions differing in protection mechanisms and in turn decomposability. This study aimed to compare the OC pool repartition in soils managed with three different fertilization practices (mineral – CONV, manure – ORGM and green manure – ORG-GM) during a medium-term trial in vineyard, in order to understand the best solution in increasing C sequestration. The OC fractionation by acid hydrolysis allowed separating three fractions of OC: a labile, quickly mineralizable pool, a recalcitrant pool with a slower turnover and a stable pool protected by microbial attack. The results showed that the periodic application of organic matrices (manure and green manure), although did not increase total OC, enriched the soil along time with readily available OC, thus promoting the release of nutrients. Green manure has also been shown to promote the accumulation of stabilized OC, able to improve the structure of the soil and, therefore, its fertility

A Synthetic Quality Index to Evaluate the Functional Stability of Soil Microbial Communities After Perturbations

[Abstract] Soil stability includes both resistance, the ability to withstand a perturbation or stress, and resilience, the ability to recover to pre perturbation levels. The functional stability of soil microbial communities is of paramount importance for the ecosystem functioning. We investigated the differences in the stability (resistance and resilience) of three enzyme activities (hydrolytic, laccase and peroxidase) in three different forest (holm oak, black pine and beech) soils after addition of PAHs (phenanthrene, pyrene and benzo[a]pyrene) with different molecular weights. Furthermore, we proposed a new soil quality index (MAI) based on the measured enzyme activity values, useful to quantify the ecological impact of soil perturbations (PAH exposure in our case). The degradation rates of different PAHs follow their complexity, slowing with increasing of PAH molecular weight in all soil types. Moreover, we found higher microbial resistance to PAH perturbation in “broad scale” enzyme activity (hydrolase), in respect to the two “narrow-niche” enzyme activities (laccase and peroxidase). The results demonstrate a higher functional stability in soils with a higher content of recalcitrant organic matter (soil under pine), compared to soils with higher content of labile organic matter (soil under holm oak). In particular, laccase activity is less affected by phenanthrene and pyrene addition in soil under pine; peroxidase activity shows a higher resistance and resilience in soil under beech for all PAHs added. Resistance and/or resilience to PAH contamination, observed for hydrolytic functional stability in the three soils, is mainly due to the high diversity of enzymes expressing this type of catalytic activity

Wilson Disease Protein ATP7B Utilizes Lysosomal Exocytosis to Maintain Copper Homeostasis

SummaryCopper is an essential yet toxic metal and its overload causes Wilson disease, a disorder due to mutations in copper transporter ATP7B. To remove excess copper into the bile, ATP7B traffics toward canalicular area of hepatocytes. However, the trafficking mechanisms of ATP7B remain elusive. Here, we show that, in response to elevated copper, ATP7B moves from the Golgi to lysosomes and imports metal into their lumen. ATP7B enables lysosomes to undergo exocytosis through the interaction with p62 subunit of dynactin that allows lysosome translocation toward the canalicular pole of hepatocytes. Activation of lysosomal exocytosis stimulates copper clearance from the hepatocytes and rescues the most frequent Wilson-disease-causing ATP7B mutant to the appropriate functional site. Our findings indicate that lysosomes serve as an important intermediate in ATP7B trafficking, whereas lysosomal exocytosis operates as an integral process in copper excretion and hence can be targeted for therapeutic approaches to combat Wilson disease

Polymer functionalized nanocomposites for metals removal from water and wastewater: An overview

Pollution by metal and metalloid ions is one of the most widespread environmental concerns. They are non-biodegradable, and, generally, present high water solubility facilitating their environmental mobilisation interacting with abiotic and biotic components such as adsorption onto natural colloids or even accumulation by living organisms, thus, threatening human health and ecosystems. Therefore, there is a high demand for effective removal treatments of heavy metals, making the application of adsorption materials such as polymer-functionalized nanocomposites (PFNCs), increasingly attractive. PFNCs retain the inherent remarkable surface properties of nanoparticles, while the polymeric support materials provide high stability and processability. These nanoparticle-matrix materials are of great interest for metals and metalloids removal thanks to the functional groups of the polymeric matrixes that provide specific bindings to target pollutants. This review discusses PFNCs synthesis, characterization and performance in adsorption processes as well as the potential environmental risks and perspectives. (C) 2016 Elsevier Ltd. All rights reserved

On the Capability of the Epigeous Organs of Phragmites australis to Act as Metal Accumulators in Biomonitoring Studies

With a view of shedding light on the accumulation capability of the epigeous organs of common reed (Phragmites australis), employed worldwide in metal biomonitoring, an accumulation study of Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn was performed, focusing on leaves belonging to different whorls and culms. To this end, in five sampling sites on the littoral zone of the volcanic Lake Averno (Italy), and in one occasion (autumn) before plant senescence, leaves of different ages and culms were collected and analyzed for metal concentrations. In terms of the suitability for biomonitoring, culms demonstrated poor performances in relation to the low metal accumulation and the difficulties in sampling and processing, whereas leaves proved their effectiveness in highlighting whole plant exposure. Since the accumulation degree of Cr, Cu, Fe and Zn is unaffected by leaf age, the pooling of leaves from different whorls is advisable to improve the representativeness of samplings. This strategy becomes mandatory in the case of Ni, the non-monotonic age-dependent variations of which would affect the derivation of contamination gradients otherwise. For Mn, Cd and Pb, the accumulation patterns strictly dependent on age can instead be exploited in selecting the sensitivity of biomonitoring by focusing on the organs where they are preferentially accumulated: old leaves for Mn and young leaves for Cd and Pb

Lampenflora growth-control: the challenge of the show caves

Show caves are subjected to tourist adaptations, often with negative consequences on the ecological equilibria of the system. Among the worst problems, photosynthetic biofilms, called “lampenflora”, can develop on surfaces due to the artificial lighting system, covering with green patinas every lit rocks, included speleothems, such as the still few known vermiculations. They implement biodeteriorations processes on surfaces, damaging them irreversibly. The aim of this study was to investigate the efficacy of lampenflora growth-control strategies, carried out monthly using chemical (15% hydrogen peroxide2 or commercial bleach) and physical (UV-C) remedies, on surfaces with and without vermiculations. The tests were performed in the tourist trail of the Pertosa-Auletta Cave (southern Italy), lit and frequented by human beings, analyzing, before and after the treatments, the chlorophyll fluorescences (MINI-PAM, Walz), an in situ non-destructive method representing a proxy of the biofilms photosynthetic activities. The results highlighted an evident reduction of the lampenflora photosynthetic activity already after the 1st treatment. Before every actions, the dark-adapted surfaces, with and without vermiculations, displayed Fv/Fm values between 0.766-0.713 and 0.710-0.663, respectively. After chemical treatments, using H2O2 or commercial bleach, the maximal PSII photochemical efficiency was close to 0, showing an almost complete reduction of the photosynthetic activity. Such values have been maintained until the 2nd treatment, in pre- and post phase. After three months without treatments due to the pandemic lockdown closure of the show cave, there was a slight recovery of lampenflora on the surfaces treated with H2O2, immediately stopped after the 3rd treatment. No effect occurred on the surfaces treated with UV-C, probably in relation to the low frequency of treatments (one night) in a month

Usefulness of different vascular plant species for passive biomonitoring of Mediterranean rivers

Choosing native vascular plants as nutrient and toxic element accumulators for passive biomonitoring of urban river quality is not an easy task in Mediterranean rivers, due to the particular climate determining high variations in river hydrology. To identify potential biomonitors for this area, the roots of seven species (Angelica sylvestris, Apium nodiflorum, Tradescantia fluminensis, Nasturtium officinale, Persicaria lapathifolia, Arctium lappa, Typha latifolia), growing in seven sites along the River Irno (Southern Italy), were collected in July 2010 and analyzed regarding their capability to accumulate Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, V, and Zn through atomic absorption spectrometry. Notwithstanding the expected different accumulation degree among the species, they highlighted similar spatial contamination gradients, and all of them appeared suitable, alone or in combination, for river passive biomonitoring. A. nodiflorum, in particular, appeared the best biomonitor for the River Irno, where severe anthropogenic impacts were detected: high Cu and Cd contamination from vine cultivation in the upper stretch, and Pb, Zn, and Mn contamination in the medium stretch from airborne dusts coming from a cast iron foundry

Biomonitoring of freshwater ecosystems in the area of the “Cilento Vallo di Diano e Alburni” National Park (Italy)

The temporal and spatial variability in the chemical properties of freshwater ecosystems demand for novel approaches tackling the rapid changes induced by anthropogenic activities. The possible approaches can be divided into two classes: high resolution and integration strategies. The biomonitoring through accumulator organisms falls into the latter group and can be adopted in deriving time-integrated measures of environmental contamination and accurate spatial gradients. To accomplish these goals, the organisms should linearly accumulate pollutants in relation to the environmental concentrations, being able to live in the selected environments and be common, easily recognized and managed. In searching for better biomonitors matching these criteria, a large field biomonitoring study was performed in the area of two of the main freshwater ecosystems of the “Cilento Vallo di Diano e Alburni” National Park (Italy). Here a novel biomonitor of potentially toxic elements, the macrophytic alga Chara gymnophylla, was validated using a long-established biomonitor, the aquatic moss Fontinalis antipyretica, by exposing the species in purposely developed devices, enabling their floating at the water surface, for 21 days. The experimental setting allowed not only validating Ch. gymnophylla, but also deriving spatial concentration gradients of Al, As, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, S, Si, V and Zn, measured trough ICP-OES, in an area of exceptional natural value. The latter achievement relies on the analysis of the joint responses of biomonitors through novel data analyses, defining a reference framework for the biomonitorg of freshwater ecosystems