Effects of environmental methylmercury on the health of wild birds, mammals, and fish

Wild piscivorous fish, mammals, and birds may be at risk for elevated dietary methylmercury intake and toxicity. In controlled feeding studies, the consumption of diets that contained Hg (as methylmercury) at environmentally realistic concentrations resulted in a range of toxic effects in fish, birds, and mammals, including behavioral, neurochemical, hormonal, and reproductive changes. Limited field-based studies, especially with certain wild piscivorous bird species, e.g., the common loon, corroborated laboratory-based results, demonstrating significant relations between methylmercury exposure and various indicators of methylmercury toxicity, including reproductive impairment. Potential population effects in fish and wildlife resulting from dietary methylmercury exposure are expected to vary as a function of species life history, as well as regional differences in fish-Hg concentrations, which, in turn, are influenced by differences in Hg deposition and environmental methylation rates. However, population modeling suggests that reductions in Hg emissions could have substantial benefits for some common loon populations that are currently experiencing elevated methylmercury exposure. Predicted benefits would be mediated primarily through improved hatching success and development of hatchlings to maturity as Hg concentrations in prey fish decline. Other piscivorous species may also benefit from decreased Hg exposure but have not been as extensively studied as the common loon.     

Combustion characteristics of Malaysian municipal solid waste and predictions of air flow in a rotary kiln incinerator

Malaysia is in dire need of alternatives to landfilling for solid waste management. Recently, landfills have faced the problems of overfilling, overflowing of leachates leading to pollution of water resources, and uncontrolled dust emissions adversely affecting the local environment. With the rising cost of urbanization coupled with the high rate of waste generation, one possible method of waste treatment that is receiving particular attention by the government is incineration. Incineration of solid waste is rather new in Malaysia, with limited usage in handling small sources of waste generation such as the municipal solid waste (MSW) of resort islands; however, its potential in ameliorating the problems associated with solid waste treatment may make it an attractive alternative to landfill. This article presents the results of test runs conducted to investigate the performance of a locally designed and manufactured rotary kiln incinerator (RKI). The test runs were conducted using MSW collected from the Shah Alam municipality. The combustion efficiency was analyzed by looking at the temperature profiles and chemical species concentrations. To complement the combustion characteristics measurements, predictions of the air flow in the incinerator during the process were also investigated. The overall performance of the RKI suggests that it is suitable for treating MSW.     

Lysimeter Experiments to Investigate the Fate of Chemicals in Soils – Comparison of Five Different Lysimeter Systems

Several lysimeter scenarios and approaches exist to study the fate of agro-chemicals or contaminants from deposition in soil columns. In many systems just transport and leaching of the parent compound is followed, in some systems the leaching and transport of the metabolites is investigated as well. In more sophisticated lysimeter systems the volatilization and also the mineralization of the applied chemicals can be additionally monitored. Depending on the lysimeter system used and on the fact whether the applied chemicals are ¹⁴C-labeled or not, different results and various interpretations of the results might be achieved. Different lysimeter systems are described in this paper and a real dataset of a specific lysimeter experiment was transferred and evaluated in a virtual approach in the different lysimeter systems in order to show the advantages and disadvantages of the various systems.     

The Bias of Complementarity Hotspots toward Marginal Populations

Abstract: It has been suggested that using complementarity to identify networks of important areas for conserving biodiversity may preferentially select areas within the margins of species ranges. We tested this idea by examining the location of complementarity hotspots in relation to two measures of range core-periphery. The first measures patterns of aggregation among records within each species' range to identify areas within the core (i.e., areas with aggregated distributions) and periphery (i.e., areas with scattered distributions) of the range. The second measures spatial turnover among species to identify areas with a high density of range edges. For three selected groups of terrestrial vertebrates in Europe—mammals, birds, and herptiles—areas chosen based on complementarity were located within the margins of species' ranges more often than expected by chance. This pattern was consistent for the two measures of core-periphery we used. The bias of complementarity hotspots toward marginal populations is especially important for species with restricted range sizes. If extinctions are determined mainly by demographic factors, then selecting areas at the peripheries of species' ranges might be a poor option. But if extinctions are determined mainly by extrinsic factors, then peripheral populations might be important to ensure the long-term persistence of species.     

Molecular response of the sponge Suberites domuncula to bacterial infection

The aim of this study was the documentation of the molecular immune response of Suberites domuncula upon bacterial infection. Additionally, the bacteria that are naturally present in the sponge after prolonged aquarium maintenance were characterized. After 6 months of maintenance of S. domuncula in seawater aquaria, only one bacterial 16S rDNA sequence could be recovered, which belongs to the genus Pseudomonas. Concomitantly, morphologically uniform bacteria were found encapsulated in bacteriocytes. These findings indicate that certain bacteria, possibly of the genus Pseudomonas, are able to persist for long periods in host bacteriocytes. Subsequent to performing a previously established infection assay with S. domuncula, a potentially pathogenic Vibrio sp. was isolated from the tissues. Furthermore, the host tissue disintegrated and asexual propagation bodies (gemmules) were formed. In order to gain insights into the molecular events occurring after bacterial infection, the stress-response kinases, p38 protein kinase and JNK protein kinase, were analyzed. It is demonstrated that these two kinases are activated (phosphorylated) upon incubation of the tissue with the bacterial endotoxin lipopolysaccharide (LPS). Moreover, LPS strongly inhibits protein synthesis. It is concluded that there are many functionally different interactions between S. domuncula and bacteria and that the animal possesses mechanisms to differentiate between bacteria and to respond accordingly.     

Genetic, morphological, and chemical divergence in the sponge genus Latrunculia (Porifera: Demospongiae) from New Zealand

We undertook a comprehensive study of Latrunculia in New Zealand to determine the relationship between taxonomic, environmental, and chemical variation within the genus. Sponges were collected from five locations around New Zealand: Three Kings Islands, Tutukaka, Wellington, Kaikoura, and Doubtful Sound. Allozyme electrophoresis at nine polymorphic loci indicated that sponges from each geographic location were genetically distinct, and that they displayed genetic differences of the magnitude usually associated with reproductively isolated species (Nei's D between locations =0.375-2.476). Additionally, the comparisons revealed that the green and brown colour morphs of Latrunculia that are sympatric at Three Kings Islands and Kaikoura are distinct from each other, and that there are two genetic groups within the green sponges in Doubtful Sound. On the basis of genetic data we conclude that there are at least eight species of Latrunculia in New Zealand waters, not one to four as had been previously thought. Morphological comparisons of the eight genetic species based on skeletal characters (i.e. skeletal organisation of the choanosome, spicule composition, size, and geometry) indicated that the eight Latrunculia species fell into only two morphological groups that could be easily diagnosed on the basis of discorhabd type. Within these two primary morphological groups, skeletal characteristics among the eight species largely overlap and are not diagnostic. These findings emphasise the limitations of traditional taxonomic methods based solely on skeletal characters for distinguishing species of Latrunculia. However, multivariate analysis (MANOVA and CDA) based on six measured skeletal variables did reveal significant morphological variation among the species (Pillai's Trace=3.28, F=6.90, P<0.0001), supporting the division of the genus into eight species. Comparisons of chemical extracts from Latrunculia also showed that the amounts of five different bioactive compounds (discorhabdins A, B, C, D, and J) varied predictably among the eight species. This finding suggests that discorhabdin variation within Latrunculia, previously thought to be associated with intra-specific environmental variability, is more likely to reflect differences among species rather than phenotypic plasticity. Our results also highlight the importance of thorough taxonomic studies associated with marine natural products research to understand fully the variation in bioactive properties among individuals. The potential processes underlying the unusually high speciation rates in New Zealand Latrunculia that are indicated in our study are discussed.     

A Systematic Test of an Enterprise Strategy for Community-Based Biodiversity Conservation

Abstract: A commonly held belief is that if people can benefit financially from enterprises that depend on nearby forests, reefs, and other natural habitats, then they will take action to conserve and sustainably use them. The Biodiversity Conservation Network brought together conservation and development organizations and local communities to systematically test this hypothesis across 39 conservation project sites in Asia and the Pacific. Each project implemented one or more community-based enterprises such as setting up an ecotourism lodge, distilling essential oils from wild plant roots, producing jams and jellies from forest fruits, harvesting timber, or collecting marine samples to test for pharmaceutical compounds. Each project team collected the biological, enterprise, and social data necessary to test the network's hypothesis. We present the results of this test. We found that a community-based enterprise strategy can lead to conservation, but only under limited conditions and never on its own. We summarize the specific conditions under which an enterprise strategy will and will not work in a decision chart that can be used by project managers to determine whether this strategy might make sense at their site. We also found that an enterprise strategy can be subsidized and still create a net gain that pays for conservation. Based on our experiences, we recommend developing "learning portfolios" that combine action and research to test other conservation strategies.     

Regulation of ovary activation in worker honey-bees (Apis mellifera): larval signal production and adult response thresholds differ between anarchistic and wild-type bees

One-day-old anarchistic (selected for successful worker reproduction) and wild-type honey-bee workers were introduced into queenright colonies of honey-bees of two treatments. In treatment 1, all eggs and larvae were offspring of queens from an anarchistic line. In treatment 2, all eggs and larvae were offspring of wild-type queens. In both treatments, adult workers were wild type. This experimental arrangement was used to test the importance of larval genotype on ovary activation in young adult workers. After 12 days, the introduced bees were dissected to determine the frequency of ovary activation. In those colonies provided with wild-type brood, 0% of introduced wild-type bees and 16% of anarchistic bees had activated ovaries. In those colonies provided with anarchistic brood, 13% of introduced wild-type bees and 41% of anarchistic bees had activated ovaries. These results strongly support the hypothesis that selection for high levels of worker reproduction in anarchistic stocks has reduced the amount or composition of brood pheromones produced by larvae that normally signal workers to refrain from reproduction. They also suggest that anarchistic workers have a higher threshold for these signals than wild-type bees.     

The role of periodic boundary forcing in plankton pattern formation

We consider one and two-dimensional minimal models in plankton dynamics. The influence of oscillating boundary forcing functions as agents for triggering pattern formation is discussed. In particular it is found that in these conditions population waves arise for one dimensional models, while for two dimensional models, different amplitudes and frequencies in the boundary forcing generate definite patterns, mimicking the boundary term. This happens even though the model we investigate is very simple. The emergence of these features is an interesting metaphor for the fundamental biological problem of how pattern formation processes may be inevitable in natural heterogeneous ecosystems.     

High-frequency measurements reveal spatial and temporal patterns of dissolved organic matter in an urban water conveyance

Stormwater runoff in urban areas can contribute high concentrations of dissolved organic matter (DOM) to receiving waters, potentially causing impairment to the aquatic ecosystem of urban streams and downstream water bodies. Compositional changes in DOM due to storm events in forested, agricultural, and urban landscapes have been well studied, but in situ sensors have not been widely applied to monitor stormwater contributions in urbanized areas, leaving the spatial and temporal characteristics of DOM within these systems poorly understood. We deployed fluorescent DOM (FDOM) sensors at upstream and downstream locations within a study reach to characterize the spatial and temporal changes in DOM quantity and sources within an urban water conveyance that receives stormwater runoff. Baseflow FDOM decreased over the summer season as seasonal flows upstream transported less DOM. FDOM fluctuated diurnally, the amplitude of which also declined as the summer season progressed. During storms, FDOM concentrations were rapidly elevated to values orders of magnitude greater than baseflow measurements, with greater concentrations at the downstream monitoring site, revealing high contributions from stormwater outfalls between the two locations. Observations from custom, in situ fluorometers resembled results obtained using laboratory methods for identifying DOM source material and indicated that DOM transitioned to a more microbially derived composition as the summer season progressed, while stormwater contributions contributed DOM from terrestrial sources. Deployment of a mobile sensing platform during varying flow conditions captured spatial changes in DOM concentration and composition and revealed contributions of DOM from outfalls during stormflows that would have otherwise been unobserved.