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- Bartoli, M., et al.
(författare)
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Denitrification, Nitrogen Uptake, and Organic Matter Quality Undergo Different Seasonality in Sandy and Muddy Sediments of a Turbid Estuary
- 2021
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Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- The interaction between microbial communities and benthic algae as nitrogen (N) regulators in poorly illuminated sediments is scarcely investigated in the literature. The role of sediments as sources or sinks of N was analyzed in spring and summer in sandy and muddy sediments in a turbid freshwater estuary, the Curonian Lagoon, Lithuania. Seasonality in this ecosystem is strongly marked by phytoplankton community succession with diatoms dominating in spring and cyanobacteria dominating in summer. Fluxes of dissolved gas and inorganic N and rates of denitrification of water column nitrate (D-w) and of nitrate produced by nitrification (D-n) and sedimentary features, including the macromolecular quality of organic matter (OM), were measured. Shallow/sandy sites had benthic diatoms, while at deep/muddy sites, settled pelagic microalgae were found. The OM in surface sediments was always higher at muddy than at sandy sites, and biochemical analyses revealed that at muddy sites the OM nutritional value changed seasonally. In spring, sandy sediments were net autotrophic and retained N, while muddy sediments were net heterotrophic and displayed higher rates of denitrification, mostly sustained by D-w. In summer, benthic oxygen demand increased dramatically, whereas denitrification, mostly sustained by D-n, decreased in muddy and remained unchanged in sandy sediments. The ratio between denitrification and oxygen demand was significantly lower in sandy compared with muddy sediments and in summer compared with spring. Muddy sediments displayed seasonally distinct biochemical composition with a larger fraction of lipids coinciding with cyanobacteria blooms and a seasonal switch from inorganic N sink to source. Sandy sediments had similar composition in both seasons and retained inorganic N also in summer. Nitrogen uptake by microphytobenthos at sandy sites always exceeded the amount loss via denitrification, and benthic diatoms appeared to inhibit denitrification, even in the dark and under conditions of elevated N availability. In spring, denitrification attenuated N delivery from the estuary to the coastal area by nearly 35%. In summer, denitrification was comparable (similar to 100%) with the much lower N export from the watershed, but N loss was probably offset by large rates of N-fixation.
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- Rota, E., et al.
(författare)
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Mitochondrial evidence supports a Nearctic origin for the spreading limicolous earthworm Sparganophilus tamesis Benham, 1892 (Clitellata, Sparganophilidae)
- 2016
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Ingår i: Contributions to Zoology. - : Brill. - 1383-4517 .- 1875-9866. ; 85:1, s. 113-119
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Tidskriftsartikel (refereegranskat)abstract
- We analysed samples of Sparganophilus taken at the corners of its distribution area in Europe (UK, Germany and Italy). No mitochondrial genetic divergence within and amongst them was found, neither in COI nor in 16S. Further, the COI haplotype was also identical to two sequences from Ontario, Canada in the Barcoding of Life Data System (BOLD) database. Our European COI and 16S sequences showed only minimal differentiation (only 1 or 2 substitutions) from specimens newly collected in Illinois and Washington states (USA), as well as from a COI haplotype from Tennessee (USA) in BOLD. An additional COI haplotype from Illinois (found in BOLD) is 2.1% different from the other haplotypes but clearly belongs to the same lineage of Sparganophilus. This geographically broad but genetically compact group fits the morphological diagnosis of S. tamesis Benham, 1892 as revised by Jamieson (1971) and is seen as evidence that all European populations 1) belong to the same species, 2) derive from a recent introduction, 3) are con specific with the most widespread species of Sparganophilus in North America, and that 4) S. tamesis is a senior synonym of S. eiseni Smith, 1895. The single European haplotype does not refute the possibility of its spread from a single introduced source population.
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- Shanmugam, V., et al.
(författare)
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Potential natural polymer-based nanofibres for the development of facemasks in countering viral outbreaks
- 2021
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Ingår i: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 138:27
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Tidskriftsartikel (refereegranskat)abstract
- The global coronavirus disease 2019 (COVID-19) pandemic has rapidly increased the demand for facemasks as a measure to reduce the rapid spread of the pathogen. Throughout the pandemic, some countries such as Italy had a monthly demand of ca. 90 million facemasks. Domestic mask manufacturers are capable of manufacturing 8 million masks each week, although the demand was 40 million per week during March 2020. This dramatic increase has contributed to a spike in the generation of facemask waste. Facemasks are often manufactured with synthetic materials that are non-biodegradable, and their increased usage and improper disposal are raising environmental concerns. Consequently, there is a strong interest for developing biodegradable facemasks made with for example, renewable nanofibres. A range of natural polymer-based nanofibres has been studied for their potential to be used in air filter applications. This review article examines potential natural polymer-based nanofibres along with their filtration and antimicrobial capabilities for developing biodegradable facemask that will promote a cleaner production.
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- Zilius, M., et al.
(författare)
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Role of crab holobionts in benthic N cycling in mangroves with different trophic status
- 2023
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Ingår i: Marine Ecology Progress Series. - 0171-8630. ; 712, s. 87-99
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Tidskriftsartikel (refereegranskat)abstract
- Microbial dinitrogen (N-2) fixation and intense bioturbation by macrofauna can contribute to reduce nitrogen (N) limitation in mangrove systems. In particular, crabs are important ecosystem engineers that rework sediments, redistribute organic matter, accelerate nutrient cycling and shape microbial communities in mangrove sediments. Hosting functionally diverse microbial communities, crabs form a discrete ecological unit (a holobiont). In this study, we report rates of respiration, inorganic N fluxes, net N-2 fixation, denitrification and dissimilatory nitrate reduction to ammonium (DNRA) measured in the fiddler crab Leptuca thayeri and sesarmid crab Armases rubripes holobionts, which are dominant in oligotrophic and eutrophic mangrove systems of southeast Brazil, respectively. We measured lower biomass-specific rates of respiration and ammonium (NH4+) production for the larger L. thayeri compared to A. rubripes, with very different molar ratios of O-2 respiration to NH4+ production (152:1 vs. 20:1, respectively). This suggests a size-metabolism relationship, different food quality or different coupling of N excretion and assimilation by the crab holobionts in the 2 systems. Both crab holobionts contributed to net denitrification and DNRA, with faster N cycling in A. rubripes in the eutrophic system. Net N-2 fixation was also detected, with nearly 4-fold higher rates in A. rubripes compared to L. thayeri. Overall, our results illustrate active and complex N cycling associated with the 2 dominant crab holobionts and highlight their potential and overlooked role as important conduits of fixed N, which may double N-2 fixation rates in the mangrove's rhizosphere.
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- Bartoli, A., et al.
(författare)
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Coupling economic and GHG emission accounting models to evaluate the sustainability of biogas policies
- 2019
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier. - 1364-0321 .- 1879-0690. ; 106, s. 133-148
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study is to evaluate and quantify the impacts of different biogas and related policies on the agricultural sector as well as their performance in terms of climate change mitigation and associated costs. To do so we coupled the partial equilibrium approach simulating the market clearing process with the perspective of Life Cycle Assessment of GHG applying it to the well-documented Lombardy case. Results show that the recent Italian biogas policy – prompting manure utilization and reducing the average subsidy per kWh – effectively increased the environmental sustainability of the system, which only now seems able to counteract global warming. Synergies are observed when the recent Common Agricultural Policy greening reform is simultaneously considered by the model.
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