Application of a Random Forest algorithm to predict spatial distribution of the potential yield of Ruditapes philippinarum in the Venice lagoon, Italy

We present a modelling framework that combines machine learning techniques and Geographic Information Systems to support the management of an important aquaculture species, Manila clam (Ruditapes philippinarum). We use the Venice lagoon (Italy), the first site in Europe for the production of R. philippinarum, to illustrate the potential of this modelling approach. To investigate the relationship between the yield of R. philippinarum and a set of environmental factors, we used a Random Forest (RF) algorithm. The RF model was tuned with a large data set (n = 1698) and validated by an independent data set (n = 841). Overall, the model provided good predictions of site-specific yields and the analysis of marginal effect of predictors showed substantial agreement among the modelled responses and available ecological knowledge for R. philippinarum. The most influent environmental factors for yield estimation were percentage of sand in the sediment, salinity, and water depth. Our results agree with findings from other North Adriatic lagoons. The application of the fitted RF model to continuous maps of all the environmental variables allowed estimates of the potential yield for the whole basin. Such a spatial representation enabled site-specific estimates of yield in different farming areas within the lagoon. We present a possible management application of our model by estimating the potential yield under the current farming distribution and comparing it to a proposed re-organization of the farming areas. Our analysis suggests a reduction of total yield is likely to result from the proposed re-organization.     

Sampling approaches to predict urban street noise levels using fixed and temporary microphones

Requirements for static (prediction of L(den) and diurnal averaged noise pattern) and dynamic (prediction of 15 min and 60 min evolution of L(Aeq) and statistical levels L(A90,)L(A50) and L(A10)) noise level monitoring are investigated in this paper. Noise levels are measured for 72 consecutive days at 5 neighboring streets in an inner-city noise measurement network in Gent, Flanders, Belgium. We present a method to make predictions based on a fixed monitoring station, combined with short-term sampling at temporary stations. It is shown that relying on a fixed station improves the estimation of L(den) at other locations, and allows for the reduction of the number of samples needed and their duration; L(den) is estimated with an error that does not exceed 1.5 dB(A) to 3.4 dB(A) according to the location, for 90% of the 3 × 15 min samples. Also the diurnal averaged noise pattern can be estimated with a good accuracy in this way. It was shown that there is an optimal location for the fixed station which can be found by short-term measurements only. Short-term level predictions were shown to be more difficult; 7 day samples were needed to build models able to estimate the evolution of L(Aeq,60min) with a RMSE ranging between 1.4 dB(A) and 3.7 dB(A). These higher values can be explained by the very pronounced short-term variations appearing in typical streets, which are not correlated between locations. On the other hand, moderately accurate predictions can be achieved, even based on short-term sampling (a 3 × 15 minute sampling duration seems to be sufficient for many of the accuracy goals set related to static and dynamic monitoring). Finally, the method proposed also allows for the prediction of the evolution of statistical indicators.     

Bioaccumulation Dynamic by Crassostrea gigas Oysters of Viruses That Are Proposed as Surrogates for Enteric Virus Contamination in Environmental Samples

Food and Environmental Virology - Oysters are filter-feeders and retain sewage-derived pathogens in their organs or tissues. Since most enteric viruses involved in outbreaks cannot grow in cell...     

Insights into the Porretta Terme (northern Apennines,Italy) hydrothermal system revealed by geochemical data on presently discharging thermal waters and paleofluids

Environmental Geochemistry and Health - This study focuses on the geochemical features of the presently discharging thermal and cold springs and on paleofluids from the upstream portion of the Reno...     

The tolerance of grapevine rootstocks to copper excess and to the use of calcium and phosphorus to mitigate its phytotoxicity

Environmental Science and Pollution Research - High soil copper (Cu) concentrations in vineyards can cause phytotoxicity to grapevine rootstocks. In order to mitigate toxicity, the use of grapevine...     

Reuse of residues arising from lead batteries recycle: a feasibility study

The performance of products arising from the stabilization/solidification of slags from lead batteries recycle into a Portland cement matrix has been evaluated not only in order to get a stabilized waste to be disposed of according to the current legislation, but also to obtain a recyclable material, with both economic and environmental benefits. Under this respect a detailed characterization of raw slags has been performed and different slag-cement samples have been prepared by varying the slag content. The parameters related to the cementation process have been evaluated and a series of tests on the final waste forms have been carried out, aimed at assessing both mechanical performance and leaching behaviour. In spite of the acceptable values for flexural, compressive and tensile strength, however, the high release of lead from the solidification products seems to be a limiting factor for a reusable material. While explanations of such phenomenon are given (high alkalinity of Portland cement; early "doping" of cementitious components by lead in the amorphous state), the main conclusion of the research work is that further efforts should be addressed to the adoption of a different or a modified incorporation matrix.     

Farmers' Motivations for Adopting Conservation Practices along Riparian Zones in a Mid-western Agricultural Watershed

In the agricultural Mid-west, riparian corridors are vital for protecting biodiversity and water quality. The cumulative management decisions of hundreds of private landowners have a tremendous impact on this riparian zone. This study of 268 farmers in a typical Mid-western watershed in Michigan looked at farmer's motivations for adopting conservation practices, their current management practices along their rivers and drains as well as their future management plans. The results of the study showed that farmers are intrinsically motivated to practise conservation by such factors as their attachment to their land, rather than by motivations such as receiving economic compensation. Farmers are also likely to engage in conservation practices that make their farm appear well-managed. Furthermore, those farmers with strong intrinsic motivations were likely to adopt conservation practices that protect streams, such as maintaining a woody vegetative buffer or practicing no-till farming. This study shows that protecting riparian resources in agricultural watersheds requires strategies for conservation that respect farmers' attachment to their land and their desire to practise good stewardship.