Client preferences by Caribbean cleaning gobies: food,safety or something else?

Predation risk is amongst the most pervasive selective pressures influencing behaviour and animals have been repeatedly shown to trade-off foraging success for safety. We examined the nature of this trade-off in cleaning symbioses amongst Caribbean coral reef fishes. We predicted that cleaning gobies (Elacatinus evelynae and Elacatinus prochilos) should prefer fish clients that pose a low risk of predation (e.g. herbivores) over clients that may have more ectoparasites but pose a higher risk (e.g. piscivores). Our field observations revealed that cleaners did clean preferentially client species with more parasites but predatory and non-predatory clients had similar ectoparasite loads. Despite the lack of a foraging advantage for inspecting predators, cleaners did not avoid risky clients. On the contrary, a larger proportion of visiting predators than non-predators was inspected, gobies initiated more interactions with predatory clients, and predators were attended to immediately upon arrival at cleaning stations. This preferential treatment of dangerous clients may allow the rapid identification of cleaners as non-prey item or may be due to the effect of predators on the rest of the cleaners’ clientele, which avoided cleaning stations whilst predators were present. Dealing with potentially risky clients may allow gobies to regain access to their main food source: non-predatory clients.     

Charging for Nature: Marine Park Fees and Management from a User Perspective

User fees can contribute to the financial sustainability of marine protected areas (MPAs), yet they must be acceptable to users. We explore changes in the fee system and management of Bonaire National Marine Park (BNMP) from the perspective of users. Responses from 393 tourists indicated that 90% were satisfied with park conditions and considered current user fees reasonable. However, only 47% of divers and 40% of non-divers were prepared to pay more. Diver willingness-to-pay (WTP) appears to have decreased since 1991, but this difference could be due in part to methodological differences between studies. Although current fees are close to diver maximum stated WTP, revenues could potentially be increased by improving the current fee system in ways that users deem acceptable. This potential surplus highlights the value of understanding user perceptions toward MPA fees and management.     

Probabilistic intake assessment of multiple compounds as a tool to quantify the nutritional-toxicological conflict related to seafood consumption

Seafood represents a natural source of valuable nutrients (e.g., long chain omega-3 poly-unsaturated fatty acids (LC n-3 PUFAs), vitamin D, and iodine), but the favourable health perception is troubled by the presence of contaminants (e.g., PCBs, dioxin-like compounds, and (methyl) mercury (MeHg)). This dualism forms the basis for an important public health conflict. The objective of this study was to calculate and evaluate the simultaneous intake of multiple beneficial and harmful compounds (LC n-3 PUFAs, vitamin D, iodine, (Me)Hg, PCBs, and dioxin-like compounds) via seafood consumption in Belgium. A methodology and a software module were developed for executing probabilistic assessments of the simultaneous intake of multiple compounds leading to better insight in the problematic nature of food items involving both health benefits and risks. The simulations concerning seafood consumption in Belgium predicted that, as far as only seafood consumption is concerned, the considered populations do not reach a sufficiently high intake for the three nutrients considered (LC n-3 PUFAs, vitamin D, and iodine). Regarding the contaminants, (Me)Hg contamination of seafood on the Belgian market does not seem to be an issue of major toxicological concern. In contrast, for dioxin-like compounds the tolerable daily intake is reached by people with high seafood consumption.     

Evaluation of the exposure methodology for risk-benefit assessment of seafood consumption

This study evaluated the methodology of using existing, international data to calculate the intake of nutrients and contaminants via seafood consumption on a national level. This was done by combining French seafood consumption data with two different datasets. The results showed that a significant correlation was found between the results obtained by using different data sets and that a high percentage of the population was classified in the same category (above or below the intake reference values). As such, the general conclusion that can be drawn from the results: 'whether a part of the population does exceed the toxicological reference values for certain contaminants and whether a part of the population does not reach the recommended intake for certain nutrients' remains the same for the two approaches. Therefore, it can be concluded that the existing, international probability distributions are useful when aiming to perform a cost-effective risk benefit evaluation of seafood consumption on national or regional level. When this evaluation does indicate that more detailed results are needed because a certain health risk exists, it can be decided that it is worth to spend more time and money for the analyses of national samples in order to collect more detailed results.     

Remediation technologies using cyclodextrins: an overview

Nowadays, the human activity and the modern way of life are responsible for the increase of the environmental pollution. Industrial processes generate a variety of molecules that may pollute air, water, and soils due to negative impacts for ecosystems and humans. The development of innovative remediation technologies has thus emerged as a significant environmental priority. Within this scope, supramolecular chemistry, which is a recent discipline, could provide solutions. In particular, cyclodextrins (CDs) are a family of cyclic oligosaccharides having a low-polarity cavity in which organic compounds of appropriate shape and size can form inclusion complexes. This unique property makes them suitable for application in environmental protection. Here, we review the use of cyclodextrins and cyclodextrin derivatives in remediation technologies. Accordingly, the present review shows the advantages of using CDs in soil, groundwater, wastewater, and atmosphere remediation. Resulting processes are highly versatile, since the complexing ability of CD is applicable to a wide range of pollutants. They may also been referred to green processes, according to the CD innocuity. Moreover, as inclusion phenomena correspond to reversible equilibriums, a major trend in the CD environmental application field is to develop methods, which combine supramolecular chemistry and irreversible processes, as advanced oxidation or biodegradation. Such processes might lead to a complete remediation of pollutants and eventually to the CD recycling.     

Nitrate Leaching From a Mountain Forest Ecosystem with Gleysols Subjected to Experimentally Increased N Deposition

Nitrate leaching was measured over seven years of nitrogen (N) addition in a paired-catchment experiment in Alptal, central Switzerland (altitude: 1200 m, bulk N deposition: 12 kg ha^-1 a^-1). Two forested catchments (1500 m² each) dominated by Picea abies) were delimited by trenches in the Gleysols. NH₄NO₃ was added to one of the catchments using sprinklers. During the first year, the N addition was labelled with ¹⁵N. Additionally, soil N transformationswere studied in replicated plots. Pre-treatment NO₃ ^--N leaching was 4 kg ha^-1 a^-1 from both catchments, and remained between 2.5 and 4.8 kg ha^-1 a^-1 in the control catchment. The first year of treatment induced an additional leaching of 3.1 kg ha^-1, almost 90% of which was labelled with ¹⁵N, indicating that it did not cycle through the large N pools of the ecosystem (soil organic matter and plants). These losses partly correspond to NO₃ ^- from precipitation bypassing the soil due to preferential flow. During rain or snowmelt events, NO₃ ^- concentration peaks as the water table is rising, indicating flushing from the soil. Nitrification occurs temporarily along the water flow paths in the soil and can be the source of NO₃ ^- flushing. Its isotopic signature however, shows that this release mainly affects recently applied N, stored only between runoff events or up to a few weeks. At first, the ecosystem retained 90% of the added N (2/3 in the soil), but NO₃ ^- losses increased from 10 to 30% within 7 yr, indicating that the ecosystem became progressively N saturated.     

Bearded seal males perceive geographic variation in their trills

Geographic variation in animal vocalisations, ranging from micro- to macro-variations, has now been widely documented. These dialects can impair communication between separated groups or populations and thus may play a role in speciation processes. Although the existence of geographical variation has been already shown in some pinnipeds species, the extent to which individuals perceive it is poorly understood. Here, we studied this question in the bearded seal Erignatus barbatus, a species found across different arctic regions. As in other phocids, bearded seal males emit sophisticated acoustic displays while defending an aquatic territory during the breeding season. First, we used playbacks to demonstrate that the trill has a function in territorial defence. Second, we used synthetic trills from two distinct populations (Nunavut and Greenland), to show that bearded seal males perceived the geographic variation in the trills. Males from Greenland responded more strongly to trills from local males than those from a distant area (Nunavut). This study provides the first experimental evidence that phocid males can perceive geographic variation in their vocalisations. Acoustic analyses combined with playback experiments can help to identify distinct populations in bearded seals. This may then provide information on both strength and scale of breeding site fidelity in this and potentially other species.     

TBT and TPhT persistence in a sludged soil

The persistence of tributyltin (TBT) and triphenyltin (TPhT) in soils was studied, taking into consideration the quantity of sewage sludge, TBT and TPhT concentrations in soil as well as the soil pH. The organotin compounds (OTC) were introduced into the soil via a spiked urban sludge, simulating agricultural practise. OTC speciation was achieved after acidic extraction of soil samples followed by gas chromatography–pulsed flame photometric analysis (GC–PFPD). Leaching tests conducted on a spiked sludge showed that more than 98% of TBT are sorbed on the sludge. TBT persistence in soil appeared to depend on its initial concentration in sludge. Thus, it was more important when concentration is over 1000 μg(Sn) kg⁻¹ of sludge. More than 50% of the initial TBT added into the soil were still present after 2 months, whatever the experimental conditions. The main degradation product appeared to be dibutyltin. About 90% of TPhT were initially sorbed on sludge, whatever the spiking concentration in sludge was. However, TPhT seemed to be quantitatively exchangeable at the solid/liquid interface, according to the leaching tests. It was also significantly degraded in sludged soil as only about 20% of TPhT remain present after 2 months, the monophenyltin being the main degradation product. pH had a significant positive effect on TBT and particularly TPhT persistence, according to the initial amounts introduced into the soil. Thus, at pH over 7 and triorganotin concentration over 100 μg(Sn) kg⁻¹, less than 10% of TBT but about 60% of TPhT were degraded. When the sludge was moderately contaminated by triorganotins (typically 50 μg(Sn) kg⁻¹ in our conditions) the pH had no effect on TBT and TPhT persistence.     

Inverse modeling of BTEX dissolution and biodegradation at the Bemidji, MN crude-oil spill site

The U.S. Geological Survey (USGS) solute transport and biodegradation code BIOMOC was used in conjunction with the USGS universal inverse modeling code UCODE to quantify field-scale hydrocarbon dissolution and biodegradation at the USGS Toxic Substances Hydrology Program crude-oil spill research site located near Bemidji, MN. This inverse modeling effort used the extensive historical data compiled at the Bemidji site from 1986 to 1997 and incorporated a multicomponent transport and biodegradation model. Inverse modeling was successful when coupled transport and degradation processes were incorporated into the model and a single dissolution rate coefficient was used for all BTEX components. Assuming a stationary oil body, we simulated benzene, toluene, ethylbenzene, m,p-xylene, and o-xylene (BTEX) concentrations in the oil and ground water, respectively, as well as dissolved oxygen. Dissolution from the oil phase and aerobic and anaerobic degradation processes were represented. The parameters estimated were the recharge rate, hydraulic conductivity, dissolution rate coefficient, individual first-order BTEX anaerobic degradation rates, and transverse dispersivity. Results were similar for simulations obtained using several alternative conceptual models of the hydrologic system and biodegradation processes. The dissolved BTEX concentration data were not sufficient to discriminate between these conceptual models. The calibrated simulations reproduced the general large-scale evolution of the plume, but did not reproduce the observed small-scale spatial and temporal variability in concentrations. The estimated anaerobic biodegradation rates for toluene and o-xylene were greater than the dissolution rate coefficient. However, the estimated anaerobic biodegradation rates for benzene, ethylbenzene, and m,p-xylene were less than the dissolution rate coefficient. The calibrated model was used to determine the BTEX mass balance in the oil body and groundwater plume. Dissolution from the oil body was greatest for compounds with large effective solubilities (benzene) and with large degradation rates (toluene and o-xylene). Anaerobic degradation removed 77% of the BTEX that dissolved into the water phase and aerobic degradation removed 17%. Although goodness-of-fit measures for the alternative conceptual models were not significantly different, predictions made with the models were quite variable.