Search results for "ecosystem"
showing 10 items of 1752 documents
An evaluation of a model ecosystem with DDT
1980
The reproducibility, variability, and reliability of a simple aquatic-terrtestrial model ecosystem experiment was tested with p,p'-DDT. The variation among the model replicates as well as within the units was studied by using hierarchal analysis of variance. the complete budget of the chemical was calculated and a theoretical transport model was constructed. The degradation and accumulation of DDT was followed by gas chromatographic residue analysis, which showed good reproducibility of the experimental design. The degradation of DDT in the model was similar to that found in the field, but the determination of concentration factors was questionable. The material balance tables revealed that…
A methodological approach for assessing businness investments in renewable resources from a circular economy perspective
2018
Abstract In this paper, we have analyzed a feasibility project for the realization of a biogas plant at a company in the viticulture sector located in south-central Sicily. Using engineering formulas, we identified the electrical power that the plant could produce using waste products created by the vineyard itself, examined the new and interesting opportunities that have arisen with the encouragement and development of biogas production in Italy, and then assessed the economic feasibility of the investment itself, considering an investment scheme of total capital self-financing. The possibility of using wastes from wine production comes from an in-depth study of the circular economy, that …
Valorization of Marine Waste: Use of Industrial By-Products and Beach Wrack Towards the Production of High Added-Value Products
2021
Biomass is defined as organic matter from living organisms represented in all kingdoms. It is recognized to be an excellent source of proteins, polysaccharides and lipids and, as such, embodies a tailored feedstock for new products and processes to apply in green industries. The industrial processes focused on the valorization of terrestrial biomass are well established, but marine sources still represent an untapped resource. Oceans and seas occupy over 70% of the Earth’s surface and are used intensively in worldwide economies through the fishery industry, as logistical routes, for mining ores and exploitation of fossil fuels, among others. All these activities produce waste. The other sou…
Risk Assessment of Toxicants to Pelagic Food-Webs: A Simulation Study
1991
For a generalized mathematical model of the pelagic compartment of a lake ecosystem we show that a small variance in input parameters may result in a large variance in predicted biomasses. Since input parameters for this kind of models always show a great variance, we conclude that deterministic prediction of biomass-trajectories is rather useless and demonstrate how stochastic analysis of the model may lead to a helpful risk analysis.
Gobio Genus Species Integrated Management System – Târnava Rivers Study Case (Transylvania, Romania)
2019
Abstract The lotic habitats quality indicative congeners species Gobio gobio, Gobio kessleri and Gobio albipinnatus populations’ dynamic in time (2004-2019) and space revealed a decreasing trend in these rivers ecological status. The ADONIS:CE tool has been used to build a backing management system model, based on these indicative fish species habitat needs, indicators for favourable conservation status, pressures and threats. This management system implementation in the field will favour the amelioration of lotic habitats and the ecological status recovering of two of the local fish species of conservative interest (G. kessleri and G. albipinnatus).
Flash-Floods Influence Macroinvertebrate Communities Distribution in Lotic Ecosystems
2019
Abstract Stream dwelling invertebrate populations are facing an ample array of stressors including the habitat imbalance caused by important floods. In this research we used a novel way to estimate the impact of floods upon the substrate, by utilising a remote variable named “flash-flood potential” (FFP), which accounts for the site slope and the average slope of the upstream catchment. The results showed that certain groups are sensitive to the influence of the FFP whereas other are not. We propose this remote variable as a surrogate for assessing stress imposed by floods and sediment scouring for lotic macroinvertebrates.
Species richness-standing crop relationship in stream bryophyte communities: patterns across multiple scales
2001
Summary 1 We tested for a unimodal (‘hump-backed’) relationship between species richness and standing crop at various spatial scales in stream bryophyte communities. Bryophyte species and their biomasses were determined from 20 to 25 quadrats in eight river and six stream sites in northern Finland. 2 Regression analyses revealed a quadratic relationship between richness and biomass in only two of the river sites and a positive correlation in one other. A quadratic relationship was detected in three stream sites and richness increased linearly with biomass in another. 3 We also tested for the hump-shaped pattern across individual stream boulders, representing an elevational gradient from con…
Evidence de l'adaptation des communautés microbiennes sédimentaires de rivière à la minéralisation du diuron: influence du ruissellement et de l'éros…
2010
International audience; Purpose Surface runoff and erosion are major drivers of pesticide transport from soils to rivers draining vineyard watersheds. A recent study showed that applications of diuron on vineyards and diuron dispersal could lead to microbial adaptation to diuron biodegradation from treated soils to the receiving hydrosystem. Given the limited knowledge on microbial adaptation to pesticide degradation in aquatic environments, we conducted a microcosm study designed to assess the impact of runoff and erosion processes on the adaptation of riverine-sediment microbial communities to diuron mineralization. Materials and methods The experimental laboratory set-up consisted in aqu…
Pleistocene allopatric differentiation followed by recent range expansion explains the distribution and molecular diversity of two congeneric crustac…
2021
AbstractPleistocene glaciations had a tremendous impact on the biota across the Palaearctic, resulting in strong phylogeographic signals of range contraction and rapid postglacial recolonization of the deglaciated areas. Here, we explore the diversity patterns and history of two sibling species of passively dispersing taxa typical of temporary ponds, fairy shrimps (Anostraca). We combine mitochondrial (COI) and nuclear (ITS2 and 18S) markers to conduct a range-wide phylogeographic study including 56 populations of Branchinecta ferox and Branchinecta orientalis in the Palaearctic. Specifically, we investigate whether their largely overlapping ranges in Europe resulted from allopatric differe…