SUMMARY
Benthic‐algal distributions in the upper Illinois River basin, IL, U.S.A., were examined in relation to geology, land use, water chemistry and stream habitat using (detrended) (canonical) correspondence analysis, autecological metrics and indicator‐species analysis in order to identify the major environmental gradients influencing community variation.
Ionic composition and major nutrient [i.e. nitrogen (N) and phosphorus (P)] concentration of surface waters, salinity (Na‐Cl type), substratum type and physiognomic form of dominant species were primary factors contributing to variation in benthic‐algal assemblages of the basin. Basin geology was a significant contributing factor, but the explained variance associated with this factor was less than that related to land use.
Proportions of algal biomass consisting of cyanophytes, filamentous chlorophytes, halophilic diatoms and diatoms which utilize nitrogen heterotrophically were greater in eutrophic river segments than in less nutrient‐enriched segments. Composition of the benthic flora indicated meso‐eutrophic or eutrophic conditions throughout the basin; there were few diatoms indicative of hypertrophic waters. Shifts in diatom‐assemblage structure in response to nutrient loading provided an incomplete representation of the community‐response curve.
A weighted‐averages regression model based on total P and benthic‐algal abundances (all divisions included) yielded a highly significant correlation (r2 = 0.83) between species‐inferred [WA(tol)] and observed total P, with systematic bias (increased deviation of residuals) occurring only at concentrations greater than ∼ 1.0 mg L−1 total P. This result indicates that total P regression and calibration models can be predictable for a river basin receiving excessive loadings of phosphorus.
Research on loss & waste of food meant for human consumption (FLW) and its environmental impact typically focuses on a single or small number of commodities in a specific location and point in time. However, it is unclear how trends in global FLW and potential for climate impact have evolved. Here, by utilising the Food and Agriculture Organization's food balance sheet data, we expand upon existing literature. Firstly, we provide a differentiated (by commodity, country and supply chain stage) bottom-up approach; secondly, we conduct a 50-year longitudinal analysis of global FLW and its production-phase greenhouse gas (GHG) emissions; and thirdly, we trace food wastage and its associated emissions through the entire food supply were from developing economies, specifically China and Latin America -primarily from increasing losses in fruit and vegetables. Over the period examined, cumulatively such emissions added almost 68 Gt CO2e to the atmospheric GHG stock; an amount the rough equivalent of two years of emissions from all anthropogenic sources at present rates. Building up from the most granular data available, this study highlights the growth in the climate burden of FLW emissions, and thus the need to improve efficiency in food supply chains to mitigate future emissions.
Avoidable food losses and associated production-phase greenhouse gas emissions arising from application of cosmetic standards to fresh fruit and vegetables in Europe and the UK', Journal of Cleaner Production.
Most herbicides applied to crops are adsorbed by plants or transformed (degraded) in the soil, but small fractions are lost from fields and either move to streams in overland runoff, near surface flow, or subsurface drains, or they infiltrate slowly to ground water. Herbicide transformation products (TPs) can be more or less mobile and more or less toxic in the environment than their source herbicides. To obtain information on the concentrations of selected herbicides and TPs in surface waters of the Midwestern United States, 151 water samples were collected from 71 streams and five reservoir outflows in 1998. These samples were analyzed for 13 herbicides and 10 herbicide TPs. Herbicide TPs were found to occur as frequently or more frequently than source herbicides and at concentrations that were often larger than their source herbicides. Most samples contained a mixture of more than 10 different herbicides or TPs. The ratios of TPs to herbicide concentrations can be used to determine the source of herbicides in streams. Results of a two‐component mixing model suggest that on average 90 percent or more of the herbicide mass in Midwestern streams during early summer runoff events originates from the runoff and 10 percent or less comes from increased ground water discharge.
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