Aerial surveys of manatees (<Emphasis Type="Italic">Trichechus manatus)</Emphasis> in Lee County,Florida<Emphasis Type="Italic">,</Emphasis> provide insights regarding manatee abundance and real time information for managers and enforcement officers

Conservation and management of the endangered Florida manatee is often centered on reducing mortality caused by watercraft collisions. Lee County, Florida, has led the state in watercraft-related mortality for eight of the last 10 years. This county is of particular concern as it contains important habitat for manatees, including extensive feeding grounds and an artificial warm-water refuge where more than 900 manatees have been recorded on a single day. Distributional aerial surveys were conducted from April 2007 through April 2009 over Lee County waters. Surveys yielded higher numbers of manatees than previously observed in this area. Using GIS methodology, kernel density analysis illustrated seasonal changes in distribution patterns and highlighted areas where manatees were most densely clustered. For example, during summer months, manatees were widely distributed throughout the survey area, with high-density areas associated with seagrass beds. During winter months, manatees were densely clustered at warm-water sites and over feeding grounds within close distance of these sites. These seasonal distribution patterns coincide well with speed zone designations. Counts and distributions of manatees were made available, almost immediately if necessary, to local marine law enforcement in an attempt to focus resources toward reducing manatee-watercraft collisions. Future studies should implement similar communication strategies to improve conservation efforts.     

Enhanced stability and dechlorination activity of pre-synthesis stabilized nanoscale FePd particles

Nanoscale zero-valent iron (NZVI) particles are promising materials for the in-situ remediation of a wide variety of source zone contaminants. This study presents the results of a systematic investigation of the stability of bimetallic FePd nanoparticle suspensions in water and their capability to degrade trichloroethylene (TCE) synthesized in the presence of various stabilizers (i.e., carboxymethyl cellulose (CMC), polyvinylpyrrolidone (PVP), and guar gum). Results indicate a dramatic improvement in FePd suspension stability when the stabilizer is present in the matrix during the nanoparticle synthesis step. Stability enhancement is controlled by iron nanoparticle/stabilizer electrostatic and steric interactions, which are a function of the molecular structure of the stabilizer. Stabilization mechanisms differed for each stabilizer with CMC and guar gum exhibiting the best nanoparticle suspension stability improvement. Results suggest that the complexation of iron precursors with the stabilizer, during synthesis, plays a key role in nZVI stability improvement. In case of guar gum, gelation during synthesis significantly increased suspension viscosity, enhancing suspension stability. The capability of these materials to degrade TCE was also investigated. Results demonstrated that when stabilizers were present in the matrix dechlorination rates increased significantly. FePd nanoparticles in CMC had the highest observed rate constant; however the highest surface area-normalized rate constant was obtained from FePd stabilized in PVP360K. Results from this study can be used to aid in the selection of appropriate iron nanoparticle stabilizers. Stabilizer selection should be assessed on a case by case basis as no stabilizer will meet the needs of all in-situ remediation applications.     

Role of extracellular compounds in Cd-sequestration relative to Cd uptake by bacterium Sinorhizobium meliloti

The role of bacterially derived compounds in Cd(II) complexation and uptake by bacterium Sinorhizobium meliloti wild type (WT) and genetically modified ExoY-mutant, deficient in exopolysaccharide production, was explored combining chemical speciation measurements and assays with living bacteria. Obtained results demonstrated that WT- and ExoY-strains excreted siderophores in comparable amounts, while WT-strain produced much higher amount of exopolysaccharides and less exoproteins. An evaluation of Cd(II) distribution in bacterial suspensions under short term exposure conditions, showed that most of the Cd is bound to bacterial surface envelope, including Cd bound to the cell wall and to the attached extracellular polymeric substances. However, the amount of Cd bound to the dissolved extracellular compounds increases at high Cd(II) concentrations. The implications of these findings to more general understanding of the Cd(II) fate and cycling in the environment is discussed.     

Effect of day time climatic conditions associated with different 2,4-D formulations on spray deposition and weed control

Abstract

The aim of this study was to evaluate the effect of time of the day and their associated climatic conditions on spray deposition of two 2,4-D formulations, as well as the influence on weed control. The experiment was installed in the field in complete randomized design. Treatments were arranged in factorial design 8?×?2, with 20 repetitions. First factor corresponded to different application time (1:00, 4:00, 7:00, 10:00, 13:00, 16:00, 19:00, and 22:00) with their respective climatic conditions. The second factor consisted of two formulations of 2,4-D applied at 776?g a.e. ha^?1 (2,4-D amine and 2,4-D choline salt with Colex-D? Technology) + glyphosate (816?g a.e. ha^?1). There was more spray deposition when 2,4-D choline formulation was used, and such differences were more evident for applications performed under adverse climatic conditions. More spray deposition was found in applications performed at times of day with more favorable temperature and humidity of the air conditions. Only the initial control of the evaluated species was affected by the time of application.     

Exploring the link between energy based taxes and economic growth

Environmental Economics and Policy Studies - This paper provides empirical evidence regarding the effect of energy based taxes on economic growth. The analysis is based on a panel dataset of 31...     

Passenger transport and CO2 emissions: What does the French transport survey tell us?

The aim of this article is to analyse CO₂ emissions caused by passenger transport in France: which socio-demographic groups travel, for what kinds of journey (local or long distance), how and why? Research focusing on the analysis of individual travel can improve the understanding of CO₂ emissions by identifying upstream socio-economic factors, and also enable a better assessment of the potential social impact of measures introduced to limit greenhouse gases due to transport.Calculations are based on the latest French national transport survey (1994). Distances covered and CO₂ emissions were estimated for each journey and for each surveyed individual. A socio-demographic characteristic typology was built and results were obtained through this analysis.If equity and accessibility issues are to be taken into account, planned policies cannot be of the same type if linked to mobility segments. An environmental tax system to limit CO₂ emission increases appears appropriate for long-distance trips. Results are more varied for local journeys, which are often more of a necessity. Nevertheless, income brackets, and measures concerning urban planning or the growth of new car fleets, seem more pertinent.     

I will not go,I cannot go: cultural and social limitations of disaster preparedness in Asia,Africa, and Oceania

While much work has been invested in addressing the economic and technical basis of disaster preparedness, less effort has been directed towards understanding the cultural and social obstacles to and opportunities for disaster risk reduction. This paper presents local insights from five different national settings into the cultural and social contexts of disaster preparedness. In most cases, an early warning system was in place, but it failed to alert people to diverse environmental shocks. The research findings show that despite geographical and typological differences in these locations, the limitations of the systems were fairly similar. In Kenya, people received warnings, but from contradictory systems, whereas in the Philippines and on the island of Saipan, people did not understand the messages or take them seriously. In Bangladesh and Nepal, however, a deeper cultural and religious reasoning serves to explain disasters, and how to prevent them or find safety when they strike.     

Pesticide pressure and fish farming in barrage pond in Northeastern France Part I: site characterization and water quality

Purpose

Fish farming in barrage pond is a rearing system commonly used worldwide. Obtaining good water quality is essential to improve sustainability of these ecosystems, both for health of fish consumers and environmental considerations. However, ponds are often located in agricultural landscape, but few study reports impact of pesticide pressure on these ecosystems. This study characterizes five sites in Northeastern France. This work establishes an initial framework for pesticide monitoring with the aim to improve understanding of the fate of pesticides in ponds.

Methods

This framework is based on surveys indicating managements and Geographical Information System (GIS) for five ponds and their watersheds (sites: C-0, C-25, C-45, C-75 and C-85) and completes with some analysis of a large spectrum of pesticide residues in surface waters.

Results

Watersheds show a gradient of crop proportion ranging from 0% to 82% of the watershed area, mainly rapeseed, wheat, barley and maize. Ponds were representative of local Northeastern France management. Many pesticides, and also nutrients, were measured in water with concentrations varying between sites and seasons. The sum of quantified molecules ranged from 0.17 ??g/l for site C-0 (March) to 8.81 ??g/l for site C-25 (October). Concentrations of metaldehyde, quinmerac, isoproturon and bentazon were sometimes above 1 ??g/l.

Conclusions

There is a strong connection between pond and watershed, due to water supply throughout the fish production cycle. Sites with small pond/big watershed are the most exposed to acute contamination a few days after spraying because water discharges are not diluted.