Degradation of 1,1,2,2-tetrachloroethane and accumulation of vinyl chloride in wetland sediment microcosms and in situ porewater: biogeochemical controls and associations with microbial communities

The biodegradation pathways of 1,1,2,2-tetrachloroethane (TeCA) and 1,1,2-trichloroethane (112TCA) and the associated microbial communities in anaerobic wetland sediments were evaluated using concurrent geochemical and genetic analyses over time in laboratory microcosm experiments. Experimental results were compared to in situ porewater data in the wetland to better understand the factors controlling daughter product distributions in a chlorinated solvent plume discharging to a freshwater tidal wetland at Aberdeen Proving Ground, Maryland. Microcosms constructed with wetland sediment from two sites showed little difference in the initial degradation steps of TeCA, which included simultaneous hydrogenolysis to 112TCA and dichloroelimination to 1,2-dichloroethene (12DCE). The microcosms from the two sites showed a substantial difference, however, in the relative dominance of subsequent dichloroelimination of 112TCA. A greater dominance of 112TCA dichloroelimination in microcosms constructed with sediment that was initially iron-reducing and subsequently simultaneously iron-reducing and methanogenic caused approximately twice as much vinyl chloride (VC) production as microcosms constructed with sediment that was methanogenic only throughout the incubation. The microcosms with higher VC production also showed substantially more rapid VC degradation. Field measurements of redox-sensitive constituents, TeCA, and its anaerobic degradation products along flowpaths in the wetland porewater also showed greater production and degradation of VC with concurrent methanogenesis and iron reduction. Molecular fingerprinting indicated that bacterial species [represented by a peak at a fragment size of 198 base pairs (bp) by MnlI digest] are associated with VC production from 112TCA dichloroelimination, whereas methanogens (190 and 307 bp) from the Methanococcales or Methanobacteriales family are associated with VC production from 12DCE hydrogenolysis. Acetate-utilizing methanogens (acetotrophs) appear to be involved in the biodegradation of VC. The relative abundance of Methanosarcinaceae, the only methanogen group with acetotrophic members, doubled in microcosms in which degradation of VC was observed. In addition, molecular analyses using primers specific for known dehalorespiring bacteria in the Dehalococcoides and Desulfuromonas groups showed the presence of these bacteria in microcosm slurry from the site that showed the highest VC production and degradation. Determination of biogeochemical controls and microbial consortia involved in TeCA degradation is leading to a better understanding of the heterogeneity in biodegradation rates and daughter product distribution in the wetland, improving capabilities for developing remediation and monitoring plans.     

Incineration and human health

After pollutants from an incineration facility disperse into the air, some people close to the facility may be exposed directly through inhalation or indirectly through consumption of food or water contaminated by deposition of the pollutants from air to soil, vegetation, and water. For metals and other pollutants that are very persistent in the environment, the potential effects may extend well beyond the area close to the incinerator. Persistent pollutants can be carried long distances from their emission sources, go through various chemical and physical transformations, and pass numerous times through soil, water, or food.     

Bacteria on housefly eggs, Musca domestica, suppress fungal growth in chicken manure through nutrient depletion or antifungal metabolites

Female houseflies, Musca domestica (Diptera: Muscidae), lay their eggs in ephemeral resources such as animal manure. Hatching larvae compete for essential nutrients with fungi that also colonize such resources. Both the well-known antagonistic relationship between bacteria and fungi and the consistent presence of the bacterium Klebsiella oxytoca on housefly eggs led us to hypothesize (1) that K. oxytoca, and possibly other bacteria on housefly eggs, help curtail the growth of fungal resource competitors and (2) that such fungi indeed adversely affect the development of housefly larvae. Bacteria washed from housefly eggs significantly reduced the growth of fungi in chicken manure. Nineteen bacterial strains and ten fungal strains were isolated from housefly eggs or chicken manure, respectively. Co-culturing each of all the possible bacterium–fungus pairs revealed that the bacteria as a group, but no single bacterium, significantly suppressed the growth of all fungal strains tested. The bacteria's adverse effect on fungi is due to resource nutrient depletion and/or the release of antifungal chemicals. Well-established fungi in resources significantly reduced the number of larval offspring that completed development to adult flies. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Classification of different sustainable flood retention basin types

Using a revised version of a previously published expert classification system, a database of potential Sustainable Flood Retention Basins has been developed for Scotland. The research shows that the majority of small and former (often old) drinking water reservoirs are kept full and their spillways are continuously in operation. Utilising some of the available capacity to contribute to flood control could significantly reduce the costs of complying with the European Union Flood Directive. Furthermore, the application of a previously developed classification model for Baden in Germany for the Scottish data set showed a lower diversity for basins in Scotland due to less developed infrastructure. The classification system appears to be robust and has the potential, with minor modifications, to be applied across Europe. The principle value of this approach is a clear and unambiguous categorisation, based on standard variables, which can help to promote communication and understanding between stakeholders.     

21世纪可替代脊椎动物进行生态毒性测试的方法：过去二十年的发展和现状综述

替代脊椎动物进行化学物质和污染物危害评估的方法已成为越来越重要的需求。现在首先要考虑的是当启动一个脊椎动物生态毒性测试,必须确保不必要的脊椎动物生物的使用尽可能最小化。对于一些监管目的,脊椎动物的使用对环境风险评估(ERA)已经被禁止,而在其他情况下生物测试的数量已经大大减少了,或者测试程序严格精简了。然而,想要获得能够完全替代脊椎动物提供环境危害数据的方法仍有很长的路要走。动物替代品的发展不仅仅是基于道德的考虑,也可以降低执行脊椎动物生态毒性测试的成本以及在某些情况下能够提供更好的信息旨在改进环境风险评估。本文集中综述了在过去的几十年里生态毒性评估替代方法所发生的重大的进展。
精选自Adam Lillicrap, Scott Belanger, Natalie Burden, David Du Pasquier, Michelle R. Embry, Marlies Halder, Mark A. Lampi, Lucy Lee, Teresa Norberg-King, Barnett A. Rattner, Kristin Schirmer, Paul Thomas. Alternative approaches to vertebrate ecotoxicity tests in the 21st century: a review of developments over the last two decades and current status. Environmental Toxicology and Chemistry: Volume 35, Issue 11, pages 2637–2646, November 2016. DOI: 10.1002/etc.3603
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3603/full
     

Sounds associated with the reproductive behavior of the black grouper (Mycteroperca bonaci)

Passive acoustic and synchronous video recordings were made at two spawning aggregation sites to study the sounds associated with reproductive behaviors of Mycteroperca bonaci. A characteristic sound was produced during courtship displays involving behaviors commonly observed for groupers of this genus at aggregations. The sound has a short pulsing section followed by a longer tonal portion with a mean peak frequency below 100 Hz. Courtship-associated sounds were quantified over one spawning season at Mona Island, Puerto Rico. Most of the daily sound production occurred during a period of 2 h prior to sunset. The highest rates of sound production lasted for a period of 10 days with lunar periodicity over three consecutive months coincident with the reported season of reproduction. Passive acoustics provide a tool to measure the variability of the reproductive activity of M. bonaci over time and may provide a method to evaluate current strategies designed to protect multi-species spawning aggregations that are critical for the recovery of threatened groupers.     

Sedentary or mobile? Variability in space and depth use of an exploited coral reef fish

Movement of fishes defines the distribution and abundance of populations and occurs on a range of spatial and temporal scales. To successfully parameterise assessments and design management strategies for exploited fish populations, knowledge and consideration of their movement patterns are essential. Since the efficacy of management approaches vary depending on the sedentary or mobile nature of the target species, presence, space use and depth utilisation were examined to understand the movement patterns of redthroat emperor Lethrinus miniatus. Sixty individuals were monitored for up to 12 months in an acoustic array comprising three coral reefs, and variation in space use and movement patterns was observed among 26 individuals. Half of the individuals were recorded only in proximity of one receiver along the reef edge, while the other half were detected at multiple receivers and used horizontal areas of approximately 4 km². Periods of non-detection and lower detection frequency at night (χ ₁ ²  = 342.157, P < 0.001) indicated individuals may move away from the monitored reef edge to the adjacent sandy habitat, but most movements outside the array remain unknown. Long-distance movement was recorded for one individual, recaptured ~160 km from the release location. Generally, no trends in depth use were apparent, L. miniatus inhabited a variety of depths, which were not related to individual size or time of day, yet some effect of month was evident. Variation in movement among adult L. miniatus indicates that while some individuals undergo broader-scale movement, spatial closures that cover individual reefs (>4 km²) could provide protection from fishing for the proportion of the population that displayed high site fidelity and moderate-sized activity spaces (over a period of up to 12 months).     

Growing of trees in home-gardens by rural households in the Eastern Cape and Limpopo Provinces,South Africa

Trees provide a wide range of goods and services to rural households which, when incorporated into their livelihood strategies, help reduce their vulnerability to adversity. Governments and policy makers often ignore the contribution made by trees and consequently resources are focussed on cash crops and livestock. Villagers in the Eastern Cape and Limpopo Province, South Africa utilise a range of trees from home-gardens for various purposes, although predominantly for fruit and shade. Trees are either planted or actively retained in households' home-gardens. There were noticeable differences between the villages in the Eastern Cape and those in Limpopo Province, particularly with respect to the overall density of trees per hectare and the number of species per household, both being significantly greater in Limpopo Province. The five most preferred species were listed for each village, revealing a preference for exotic fruit trees in Limpopo Province and a mix of exotic fruit trees and shade trees in the Eastern Cape. Households also retained useful indigenous species, predominantly fruit-bearing species. A range of factors constrain tree growing in home-gardens and households engage in practices to grow and maintain their trees. Not all of these constraints and practices were significantly different between the various localities.     

Sperm storage reflects within- and extra-pair mating opportunities in a cooperatively breeding bird

In passerine birds, storage and maturation of sperm takes place in the cloacal protuberance (CP), an external swelling of the reproductive organ. The considerable variation in CP size among species is presumed to be a consequence of varying levels of sperm-competition, but whether individual variation in CP size within a species also reflects sperm competition is not well established. Here, we study temporal variation in male CP size in relation to within-pair and extra-pair mating opportunities and cuckoldry risk in purple-crowned fairy-wrens Malurus coronatus. This is a socially monogamous cooperatively breeding passerine that can breed year-round and has low levels of extra-pair paternity (in 6?% of broods). We show that male CP size sharply increased a few weeks before, and rapidly regressed after his partner laid eggs, consistent with a cost of its maintenance and/or sperm production. Surprisingly, despite low levels of extra-pair paternity, CP size of non-breeding and pre-breeding males was positively correlated with the number of breeding females in the population, suggesting that CP size is sensitive to extra-pair mating opportunities. However, CP sizes do not seem to reflect cuckoldry risk: CP size of dominant males was unaffected by the presence of a subordinate that was unrelated to the dominant female, although those subordinates occasionally sire offspring, and had a larger CP than subordinates living with their mother. Our results suggest that, even in a species with low levels of extra-pair paternity, individual investment in sperm storage reflects both within-pair and, albeit to lesser extent, extra-pair mating opportunities.     

Maternal allocation of lipid classes and fatty acids with seasonal egg production in Atlantic cod (Gadus morhua) of wild origin

A suite of characteristics is often used to assess egg quality as these properties potentially play important roles in progeny survival and growth. Our objective was to assess egg characteristics including lipid biocomposition of an iteroparous, batch-spawning teleost of wild origin. Maternal allocation to egg number was generally dome-shaped (5 of 8 females) and egg size declined over the breeding season for eight breeding pairs of wild Atlantic cod (Gadus morhua) (n = 43 batches). Egg lipid composition ranged considerably among females and between egg batches within females (e.g., phospholipids 40–86 %; polar 47–87 % and neutral lipids 15–52 % of total lipids; polyunsaturated fatty acids 16–50 % of total fatty acids). Principal component analyses revealed significant inter-relationships among maternal traits, batch sequence and fecundity, and egg size and composition. Seasonal trends with regard to lipid deposition were variable; three females showed consistent declines in lipid parameters (μg egg⁻¹) with both batch number and egg diameter, one female showed consistent increase and the four remaining females showed no trend. The three females that exhibited seasonal declines in egg lipid content were characterized as having high fertilization success (>75 %). Our findings highlight the variability in lipid allocation to eggs of batch spawners of wild origin and characterize the composition of endogenous reserves available during embryogenesis and yolk sac larval stages.