Consequences of Embryonic UV-B Exposure for Embryos and Tadpoles of the Plains Leopard Frog

Abstract: In organisms with complex life cycles, understanding the effects of environmental change requires investigating the possibility that the effect of such change on one stage will have consequences for other stages. We investigated the effects of embryonic exposure to UV-B radiation on embryo and tadpole development of the plains leopard frog (   Rana blairi ). Embryos were exposed to sunlight filtered to provide two levels of UV-B exposure (e.g., at 310 nm: high exposure is approximately 84% transmittance and low exposure is approximately 58% transmittance). Hatching success of embryos exposed to different UV-B levels did not differ. Tadpoles resulting from exposed embryos were raised at three densities. Growth and development were slower in tadpoles exposed to higher UV-B levels as embryos. Density negatively affected growth and development. Survivorship did not differ among UV-B or density treatments. Our results suggest that even if lethal effects are not exhibited at one stage, sublethal effects may manifest themselves at other stages, possibly affecting the long-term success of exposed individuals and populations.     

Research priorities for coordinating management of food safety and water quality

Efforts to exclude disease organisms from farms growing irrigated lettuce and leafy vegetables on California's central coast are conflicting with traditionally accepted strategies to protect surface water quality. To begin resolving this dilemma, over 100 officials, researchers, and industry representatives gathered in April 2007 to set research priorities that could lead to effective co-management of both food safety and water quality. Following the meeting, research priorities were refined and ordered by way of a Delphi process completed by 35 meeting participants. Although water quality and food safety experts conceptualized the issues differently, there were no deep disagreements with respect to research needs. Top priority was given to investigating the fate of pathogens potentially present on farms. Intermediate priorities included characterizing the influence of specific farm management practices on food safety and improving our understanding of vector processes. A scientific subdiscipline focusing on competing risks is needed to characterize and resolve conflicts between human and environmental health.     

Fishers,Farms, and Forests in Eastern North America

The fisher (Martes pennanti) has recently recovered from historic extirpations across much of its geographic range. There are at least five explanations for the recovery of the fisher, including changes in the amount of habitat, the suitability of habitat, trapping pressure, societal attitudes toward predators, and climate. We evaluated a recovering fisher population in Ontario to test two conditions we viewed as necessary to support the hypothesis that fisher populations have increased due to an increase in the amount of forested land. First, we tested whether the amount of forested land has increased. Second, we tested whether contemporary fisher abundance (and therefore habitat quality) was related to the amount of forest. Topographic maps showed that the proportion of forested land in the study area had increased by 1.9% per decade since 1934 and 3.3% per decade since 1959, likely as a result of land conversion from agricultural uses. Overall the proportion of the study area that was forested increased from 29% to 40% during 1934 to 1995. Census data from the region indicated that there had been a decline in the amount of land area being farmed during the last 50 years. Recent livetrapping data showed that fisher abundance was positively related to the proportion of landscapes that were forested. Based on our results, we could not reject the hypothesis that an increase in the amount of forested land has contributed to the recovery of fisher populations.     

Removal of humic acid using TiO2 photocatalytic process--fractionation and molecular weight characterisation studies

The photocatalytic removal of humic acid (HA) using TiO₂ under UVA irradiation was examined by monitoring changes in the UV₂₅₄ absorbance, dissolved organic carbon (DOC) concentration, apparent molecular weight distribution, and trihalomethane formation potentials (THMFPs) over treatment time. A resin fractionation technique in which the samples were fractionated into four components: very hydrophobic acids (VHA), slightly hydrophobic acids, hydrophilic charged (CHA) and hydrophilic neutral (NEU) was also employed to elucidate the changes in the chemical nature of the HA components during treatment. The UVA/TiO₂ process was found to be effective in removing more than 80% DOC and 90% UV₂₅₄ absorbance. The THMFPs of samples were decreased to below 20 μg l⁻¹ after treatments, which demonstrate the potential to meet increasingly stringent regulatory level of trihalomethanes in water. Resin fractionation analysis showed that the VHA fraction was decreased considerably as a result of photocatalytic treatments, forming CHA intermediates which were further degraded with increased irradiation time. The NEU fraction, which comprised of non-UV-absorbing low molecular weight compounds, was found to be the most persistent component.     

Preliminary investigation on the environmental occurrence and effects of antibiotics used in aquaculture in Italy

A preliminary investigation has been carried out on the occurrence and effects of antibiotics used in Italian aquaculture with the objective of identifying priorities for monitoring programmes. According to the information available on the most pertinent and diffuse fish diseases and their related therapies, the presence of flumequine and oxytetracycline in sediments sampled from two trout farms and three sea-bass farms and in their surrounding environments was selected for an analytical investigation. The concentrations of oxytetracycline and flumequine varied up to a maximum of 246.3 and 578.8 microg/kg d.w., respectively. Flumequine was seen to have the highest toxicity in a bioluminescence assay with EC50 values varying within the range of 12-15 mg/l, while the EC50 values for oxytetracycline were within the range of 121-139 mg/l. The results of the present study indicate flumequine and oxytetracycline as priority chemicals to be monitored for possible environmental side effects of aquaculture in Italy. Apart from peak concentrations the chronic presence of flumequine and oxytetracycline in sediments both inside and outside farms should also be considered. In spite of the potential risks related to the use of antibiotics, the concentrations found in the sediments of the studied fish farms are significantly lower than those found in other areas.     

Stability of pentobarbital in soil

Intravenous injection of barbiturates, particularly pentobarbital (5-ethyl-5-pentan-2-yl-1,3-diazinane-2,4,5-trione), is a widely used method to euthanize large animals such as horses. However, one concern with this method is the fate of pentobarbital after the disposal of the carcass. As tissues decompose, pentobarbital may leach into the soil and from there migrate to groundwater. A method using methanol extraction, solid phase concentration, and liquid chromatography (LC/MS) has been developed to measure pentobarbital in soils. Recovery of pentobarbital from soil averaged approximately 85% from different soil types including topsoil, potting soil, sand, stall sweepings, and loam. The method was capable of detecting pentobarbital levels of 0.1 ppm. A calibration curve was constructed with a linear range of 1 ppm to 100 ppm. The limit of quantification was 0.5 ppm. The rate of degradation of pentobarbital in sand, topsoil, and potting soil was measured over a 17-week period. At the end of week 17, approximately 17% of the pentobarbital remained in the sand, 19% remained in the topsoil, and 10% remained in the potting soil. While there was a significant decrease in the pentobarbital recovered from the soil, there were still detectable amounts of pentobarbital present in the soil after 17 weeks. To determine the importance of bacterial degradation, the three soil types were autoclaved before addition of pentobarbital. After autoclaving, no degradation of pentobarbital was observed in sand and one topsoil sample, while there was no difference in the degradation of pentobarbital in autoclaved potting soil versus potting soil that had not undergone autoclaving.     

Effects of urbanization on the population structure of freshwater turtles across the United States

Landscape‐scale alterations that accompany urbanization may negatively affect the population structure of wildlife species such as freshwater turtles. Changes to nesting sites and higher mortality rates due to vehicular collisions and increased predator populations may particularly affect immature turtles and mature female turtles. We hypothesized that the proportions of adult female and immature turtles in a population will negatively correlate with landscape urbanization. As a collaborative effort of the Ecological Research as Education Network (EREN), we sampled freshwater turtle populations in 11 states across the central and eastern United States. Contrary to expectations, we found a significant positive relationship between proportions of mature female painted turtles (Chrysemys picta) and urbanization. We did not detect a relationship between urbanization and proportions of immature turtles. Urbanization may alter the thermal environment of nesting sites such that more females are produced as urbanization increases. Our approach of creating a collaborative network of scientists and students at undergraduate institutions proved valuable in terms of testing our hypothesis over a large spatial scale while also allowing students to gain hands‐on experience in conservation science.     

The connection between urbanization and carbon emissions: a panel evidence from West Africa

Environment, Development and Sustainability - This study examined the nexus between urbanization and carbon emissions in West Africa. Second-generation econometric techniques that are robust to...     

Sanitation entrepreneurship in rural Indonesia: a closer look

Enterprises are playing increasing roles in facilitating access to sanitation products and services in Indonesia and other developing economies. This study investigated the factors affecting the sustainability of sanitation enterprises in rural Indonesia. Interviews with 33 organisations representing sanitation enterprises, associations of sanitation enterprises, national and international civil society organisations (CSOs), donor organisations and national and local government agencies were conducted to explore different stakeholder perceptions about enterprise roles. The research revealed factors specific to the sanitation entrepreneurs themselves, such as their skills, entrepreneurial traits, pro-social motivations and intrinsic motivations, as well as factors within their enabling environment. Insufficient customer demand, inadequate capacity building opportunities, lack of financing options for entrepreneurs and their customers, and limited government support were observed to undermine sanitation enterprise success. Industry associations were found to be a useful intermediary support mechanism, particularly in the absence of significant government support for enterprises. However, such associations could also stifle innovation, and their role needs to be carefully developed, including financially sustainable models for such associations. This study has implications for how governments and CSOs in Indonesia and elsewhere might best support the role of enterprises and entrepreneurship towards improved sanitation outcomes.     

Colonies of Cliff Swallows on Highway Bridges: A Source of Escherichia coli in Surface Waters1

Sejkora, Patrick, Mary Jo Kirisits, and Michael Barrett, 2011. Colonies of Cliff Swallows on Highway Bridges: A Source of Escherichia coli in Surface Waters. Journal of the American Water Resources Association (JAWRA) 47(6):1275–1284. DOI: 10.1111/j.1752‐1688.2011.00566.x Abstract: Animals, such as birds, are a source of fecal indicator bacteria and pathogens in the environment. Our objective was to determine whether a colony of cliff swallows nesting underneath a bridge would yield a measurable increase in fecal indicator bacteria (specifically Escherichia coli) in the underlying creek. When the swallows were absent, dry‐weather concentrations of E. coli upstream and downstream of the bridge (in Austin, Texas) were below the Texas contact recreation criteria. When the swallows were present, dry‐weather geometric‐mean E. coli concentrations increased significantly from upstream (43 most probable number [MPN]/100 ml) to downstream (106 MPN/100 ml) of the bridge. One exceedance and one near‐exceedance of the Texas single‐sample contact recreation criterion were observed during the swallows’ nesting phase. When the swallows were present, the downstream E. coli geometric‐mean concentration in storm events (875 MPN/100 ml) was significantly higher than the upstream concentration (356 MPN/100 ml), suggesting that runoff flushes swallow feces from the ground into the creek. Although the loading of E. coli from cliff swallows nesting under bridges can be significant (e.g., dry‐weather loading of 3.1 × 10⁸ MPN/day/nest), the zoonotic potential of the cliff swallow must be examined to determine the risk to human health from contact recreation in waters contaminated with cliff swallow feces.