Search results for "ecological modeling"
showing 10 items of 292 documents
Swimming pool water--fractionation and genotoxicological characterization of organic constituents.
2005
Swimming pool water treatment in general includes flocculation, sand filtration, and subsequent disinfection with chlorine. The continuous chlorination and input of organic material by bathers in combination with recirculation of the pool water leads to an accumulation of disinfection by-products (DBPs) in the water. Several DBPs have been identified as human carcinogens and are thought to cause allergic asthma. Therefore, the elimination of DBPs is one major aim of pool water treatment. Using membrane filtration as an alternative treatment technology, DBPs can be removed more efficiently than with conventional treatment. In this study membrane filtration and genotoxicity testing were appli…
Testing the effects of temporal data resolution on predictions of the effects of climate change on bivalves
2014
a b s t r a c t The spatial-temporal scales on which environmental observations are made can significantly affect our perceptions of ecological patterns in nature. Understanding potential mismatches between environmen- tal data used as inputs to predictive models, and the forecasts of ecological responses that these models generate are particularly difficult when predicting responses to climate change since the assumption of model stationarity in time cannot be tested. In the last four decades, increases in computational capacity (by a factor of a million), and the evolution of new modeling tools, have permitted a corresponding increase in model complexity, in the length of the simulations,…
Variation in spawning time promotes genetic variability in population responses to environmental change in a marine fish.
2015
Common-garden experiments suggest that the response of Atlantic cod larvae to temperature differs among populations that spawn at different times of year. Populations appear to be adapted to the temperatures experienced during the larval stage at a small spatial scale, despite a lack of physical barriers to gene flow.
Technical assessment and evaluation of environmental models and software: Letter to the Editor
2011
International audience; This letter details the collective views of a number of independent researchers on the technical assessment and evaluation of environmental models and software. The purpose is to stimulate debate and initiate action that leads to an improved quality of model development and evaluation, so increasing the capacity for models to have positive outcomes from their use. As such, we emphasize the relationship between the model evaluation process and credibility with stakeholders (including funding agencies) with a view to ensure continued support for modelling efforts. Many journals, including EM&S, publish the results of environmental modelling studies and must judge the w…
smatr 3 - an R package for estimation and inference about allometric lines
2011
Summary 1. The Standardised Major Axis Tests and Routines (SMATR) software provides tools for estimation and inference about allometric lines, currently widely used in ecology and evolution. 2. This paper describes some significant improvements to the functionality of the package, now available on R in smatr version 3. 3. New inclusions in the package include sma and ma functions that accept formula input and perform the key inference tasks; multiple comparisons; graphical methods for visualising data and checking (S)MA assumptions; robust (S)MA estimation and inference tools.
Recent trends in solar exergy and net radiation at global scale
2012
Abstract The availability during the last decades of remotely sensed images and global climatic data allow us to analyse the “Earth system” as a whole in order to develop concepts for global environmental management. This system can be considered a complex, dissipative, dynamic entity, far from thermodynamic equilibrium ( Schellnhuber, 1999 ). Energy balance has been considered for many decades to understand the functioning of ecosystems, the biosphere or the Earth planet as a whole, but it is also possible to study our planet from a thermodynamic point of view. In this letter we analyse recent trends in solar exergy and net radiation at global scale during the period 1980–2010, distinguish…
Automatic image-based identification and biomass estimation of invertebrates
2020
1. Understanding how biological communities respond to environmental changes is a key challenge in ecology and ecosystem management. The apparent decline of insect populations necessitates more biomonitoring but the time-consuming sorting and expert-based identification of taxa pose strong limitations on how many insect samples can be processed. In turn, this affects the scale of efforts to map and monitor invertebrate diversity altogether. Given recent advances in computer vision, we propose to enhance the standard human expert-based identification approach involving manual sorting and identification with an automatic image-based technology. 2. We describe a robot-enabled image-based ident…
The headstarting technique is an ineffective method for conservation of the European pond turtle – elasticity analysis
2008
The European pond turtle ( Emys orbicularis ) is endangered in many areas within its distribution range. Thus, protection programmes for the turtle populations are in place. However, the efficiency of some techniques (including a highly manipulative one - headstarting) is questionable. Elasticity analysis was conducted using the life history data gathered in central Poland during the period 1986 - 2002. The analysis revealed that headstarting is a fairly ineffective method. The most effective methods are those that protect adult individuals. Thus, methods that can sustain a decreasing adult mortality rate should be recommended for turtle conservation.
Optimization of the coagulation–flocculation treatment: influence of rapid mix parameters
1999
[EN] Turbid waters, containing suspended and colloidal particles, are normally treated by coagulation–flocculation followed by clarification; the process usually consists of the rapid dispersal of a coagulant into the raw water followed by an intense agitation commonly defined as rapid mixing. Rapid mixing is influenced by chemical and physical parameters and the final result of the whole treatment depends on this step. The study focused on the most important parameters of rapid mix design: velocity gradient and rapid mix time. Wastewaters from a tannery processing stored ovine hides were treated with aluminium(III) or iron(III) salts. Experimental results indicate that rapid mix time has a…
Comparative study of laboratory-scale thermophilic and mesophilic activated sludge processes.
2005
Laboratory-scale mesophilic (20-35 degrees C) and thermophilic (55 degrees C) activated sludge processes (ASPs) treating diluted molasses wastewater were compared in effluent quality, removal of different COD fractions, sludge yield, floc size, and sludge settleability. The effect of polyaluminium chloride (PAC) with high cationic charge on sludge settleability and effluent quality was also studied. In the ASPs, the hydraulic retention time was 12h in both processes, corresponding to a volumetric loading rate of 3.2+/-1.0 kg COD(filt) m(-3)d(-1). The mesophilic ASP gave 79+/-18% and 90+/-2% and the thermophilic ASP gave 50+/-6% and 67+/-11% total COD (COD(tot)) and GF/A-filtered COD (COD(fi…