Dependency of Antarctic zooplankton species on ice algae‐produced carbon suggests a sea ice‐driven pelagic ecosystem during winter

How the abundant pelagic life of the Southern Ocean survives winter darkness, when the sea is covered by pack ice and phytoplankton production is nearly zero, is poorly understood. Ice‐associated (“sympagic”) microalgae could serve as a high‐quality carbon source during winter, but their significance in the food web is so far unquantified. To better understand the importance of ice algae‐produced carbon for the overwintering of Antarctic organisms, we investigated fatty acid (FA) and stable isotope compositions of 10 zooplankton species, and their potential sympagic and pelagic carbon sources. FA‐specific carbon stable isotope compositions were used in stable isotope mixing models to quantify the contribution of ice algae‐produced carbon (α_Ice) to the body carbon of each species. Mean α_Ice estimates ranged from 4% to 67%, with large variations between species and depending on the FA used for the modelling. Integrating the α_Ice estimates from all models, the sympagic amphipod Eusirus laticarpus was the most dependent on ice algal carbon (α_Ice: 54%–67%), and the salp Salpa thompsoni showed the least dependency on ice algal carbon (α_Ice: 8%–40%). Differences in α_Ice estimates between FAs associated with short‐term vs. long‐term lipid pools suggested an increasing importance of ice algal carbon for many species as the winter season progressed. In the abundant winter‐active copepod Calanus propinquus, mean α_Ice reached more than 50% in late winter. The trophic carbon flux from ice algae into this copepod was between 3 and 5 mg C m^?2 day^?1. This indicates that copepods and other ice‐dependent zooplankton species transfer significant amounts of carbon from ice algae into the pelagic system, where it fuels the food web, the biological carbon pump and elemental cycling. Understanding the role of ice algae‐produced carbon in these processes will be the key to predictions of the impact of future sea ice decline on Antarctic ecosystem functioning.     

Pollution risk assessment based on source apportionment in a groundwater resource area,NE China

Pollution risk assessment of a groundwater resource area is instrumental in contributing to groundwater protection. This study considered the evaluation results of source apportionment by combining a principal component analysis (PCA) with a factor analysis (FA) to identify potential risk sources. The vulnerability was evaluated using a DRASTIC model as the main pollution pathway, and groundwater quality as a pollution receptor, in order to validate the risk of pollution in a typical groundwater resource area of northeastern China. Results showed that four principal potential pollution sources were point source pollution such as water-rock interaction, dissolution of iron and manganese bearing minerals due to geological processes, non-point source pollution of nitrogen such as agriculture fertilizers, and organic pollution resulting from domestic and industrial wastewater. A “high” and “relatively high” pollution risk occurred mainly at the northwestern and southeastern edges of the region, respectively, with a widely distributed “moderate” pollution risk over the majority of the study area, and a “relatively low” and “low” pollution risk located mainly in the central of the Limin Groundwater Resources area, which showed that the potential pollution sources, especially due to human activity, have significantly changed the distribution of pollution risk in groundwater resource areas.     

Effect of different dietary energy and protein sources on antioxidant status,fresh yolk fatty acid profile and microstructure of salted yolks in laying ducks

The study investigated whether different dietary energy and protein sources affect laying performance, antioxidant status, fresh yolk fatty acid profile and quality of salted yolks in laying ducks. In all, 360 19-week-old Longyan ducks were randomly assigned to four diets in a factorial arrangement (2×2). The four diets consisted of two energy sources, corn (CO) or sorghum (SO) and two protein sources, soybean meal (SM) and rapeseed meal with corn distillers dried grains with solubles (RMD), and each treatment contained six replicates of 15 birds each. The experimental diets were isocaloric (metabolizable energy, 10.84 MJ/kg) and isonitrogenous (CP, 17%). The results showed that egg production, average egg weight, egg mass and feed conversion ratio were not affected by diets (P>0.05). Plasma contents of reduced glutathione (GSH), GSH/oxidized glutathione and total antioxidant capacity were lower (P<0.05) in ducks fed the RMD diets compared with those fed SM diets with a substantial increase (P=0.006) in plasma content of malondialdehyde (MDA). Egg yolks from ducks fed SO diets had higher proportions of polyunsaturated fatty acids (PUFA) and lower saturated and monounsaturated fatty acids compared with CO diets (P<0.001). Similarly, ducks fed RMD diets had a higher content of PUFA and n-6/n-3 ratio in fresh yolks (P<0.001), and increased salted yolk MDA, carbonylated proteins content and incidence of hard salted yolks (P<0.05) compared with SM diets. Scanning electron microscopy showed that salted yolks contained rougher polyhedral granules and fewer fat droplets, and were surrounded with a layer of bunchy fibers in ducks fed SO+RMD than those fed CO+SM diet. In conclusion, the current study showed that feeding laying ducks with diets containing SO or RMD reduced antioxidant capacity and increased egg yolk concentrations of PUFA. It appeared that egg yolks from ducks fed these diets were more sensitive to lipid peroxidation and protein oxidation during salting, and reduced the quality of salted yolks.     

Sources of organic carbon in the littoral of Lake Gooimeer as indicated by stable carbon isotope and carbohydrate compositions

The relative importance of potential carbon sources in the littoral of Lake Gooimeer, a lake in the centre of the Netherlands, was studied using a combination of ¹³C/¹²C-ratio analysis and carbohydrate composition analysis. The littoral is covered on the land side by a 80 m wide Phragmites australis bed. Potential carbon sources were macrophyte litter, seston and benthic algae. Samples of potential carbon sources, sediments and benthic macrofauna from inside and outside the bed were analyzed for their¹³C/¹²C-ratio and some for their carbohydrate composition. Results indicate that inside the bed, macrophyte litter was the main source of carbon for both the sediment organic matter and the benthic macrofauna, and that algal material was of minor importance. Outside the bed, production by benthic algae was the main carbon source, with seston as a second source. No macrophyte derived material could be detected outside the reed bed.Abbreviations DOC (Dissolved Organic Carbon) - SOM (Sediment Organic Matter)     

Opportunistic Properties of Nosema algerae (Microspora), a Mosquito Parasite, in Immunocompromised Mice

ABSTRACT. In the last ten years microspordia have been recognized as opportunistic pathogens in AIDS patients. The sources of infection and the mechanisms of transmission of these organisms in humans are mostly uncertain. Transmission of invertebrte microsporidia to mammals is normally considered impossible, temperature being a limiting factor for development. Mice treated with cortisone acetate and with cyclosporin A, respectively, as well as athymic mice were injected intravenously, intranasally, perorally and subcutaneously with spores of Nosema algerae , a microsporidian species of culicine mosquitoes. No infection could be detected in tissue samples of cortisone acetate and cyclosporin A treated mice. However, the experimental inoculation of spores into the tail and foot of athymic mice caused severe infection in skeletal muscles and the connective tissue. In some tails, nerve tissue and bone marrow were also infected. Vegetative stages and spores were seen in direct contact to host cell cytoplasma. For the first time the prolonged and progressive development of an invertebrate microsporidium in a mammalian host is shown. The possibility of invertebrate microsporidia as a source of human microsporidiosis should now be taken into consideration.     

Method for Setting Environmental Targets in Product Development: Incorporating Use‐Phase Impact by Subsystem

In order to address environmental aspects during redesign, the product specification must include related targets that are reachable and challenging. To do so, this article presents a stepwise approach for combining benchmarking information and component impact, out of life cycle assessment (LCA) scaling. This approach requires allocating environmental impacts to each subsystem, which is not commonly done for some life cycle phases in LCAs, most particularly for use phases. This article includes a methodology for allocating such impacts. The underlying criterion is avoiding complex calculations, to make the method more agile. This methodology is presented in a full case study of a complex product: a knuckle boom crane. The case study results in the percentage of impact reduction needed to meet the market average or best competitors. In particular, the results show that the cylinders of the crane have a high contribution to environmental impact, not only because of their weight, but also because of the active power consumed to activate them.     

元阳梯田水源区旱冬瓜水分来源

旱冬瓜(Alnus nepalensis)是元阳梯田水源区的优势树种之一,其作为一种速生树种被发展为当地居民重要的薪炭林和经济林,树种的生长发育和地理分布受到水分制约,其吸收水分和水分利用的变化将会直接影响森林生态系统的水循环。该研究于2014年5－11月间进行,研究时段内累计降雨1262 mm,地下水δD 值在－71‰~－53‰范围,δ18 O 在－10.6‰~－7.0‰范围,受环境因子的影响很小,基本上保持常年稳定。土壤水是可供树种直接吸收利用的水源,基于氢氧稳定同位素技术,对比元阳梯田水源区旱冬瓜树种茎干水δD 和其林地不同深度土壤水δD 的同位素组成情况,结合不同深度土壤含水量,定性分析判断旱冬瓜对土壤水的利用,结果表明旱冬瓜旱季利用的土壤水主要分布在40 cm 土层附近,而雨季利用的土壤水范围较广,分布在0~60 cm 的土层。利用多元线性混合模型 IsoSource 软件定量分析旱冬瓜对土壤水和地下水的利用,结果表明：旱冬瓜水分来源分布较广,各土层土壤水和地下水均有贡献,雨季旱冬瓜主要利用0~60 cm 深土壤水,其中雨后旱冬瓜绝大部分水分来源于0~10 cm 的土壤水分,利用比例为66％~73％;其它时间主要利用40~60 cm 的土壤水,贡献率高达73％;旱季旱冬瓜的绝大部分水分来源于地下水,对地下水的利用比例为18％~68％,同时,40~60 cm 的土壤水也是其重要的水源。从不同时间尺度考察旱冬瓜对土壤水和浅层地下水的需求,更加准确地认识元阳梯田水源区不同森林类型优势树种的水分来源,为梯田森林生态系统经营与维护以及梯田的可持续发展提供了理论依据。     

Human health risk assessment and source diagnosis of polycyclic aromatic hydrocarbons (PAHs) in the corn and agricultural soils along main roadside in Changchun,China

This work was to investigate distribution characteristics, human health risk assessment, and possible sources of 16 priority polycyclic aromatic hydrocarbons (PAHs) in corn and surface soils of farmlands along main roadside in Changchun City, Jilin Province, China. Total concentrations of 16 PAHs ranged from 1572.4 to 4390.2 µg/kg with a mean value of 2954.9 µg/kg in soils and from 219.9 to 627 µg/kg with a mean value of 362µg/kg in corn. Light-molecular-weight PAHs (2–3 rings) concentration was dominant in soils, accounting for 51%, whereas high-molecular-weight PAHs (5–6 rings) concentration was highest in corn, accounting for 48%. The results of plant concentration factor indicated that high-molecular-weight PAHs have greater mobility. To evaluate potential risk to human health, hazard index (HI) and risk index (RI) were employed. The values of HI for corn and soils were both smaller than 1, indicating that exposure of PAHs posed no or little potential risk to local residents. The fact that values of RI for corn and soils were smaller than 1 × 10^–4 suggested that exposure of PAHs posed no or little cancer risk to local residents. The possible sources of PAHs in corn and soils were both identified as mixture patterns of pyrogenic and petrogenic sources.     

A Novel Sustainable Flour Derived Hierarchical Nitrogen‐Doped Porous Carbon/Polyaniline Electrode for Advanced Asymmetric Supercapacitors

Hierarchically porous nitrogen‐doped carbon (HPC)/polyaniline (PANI) nanowire arrays nanocomposites are synthesized by a facile in situ polymerization. 3D interconnected honeycomb‐like HPC was prepared by a cost‐effective route via one‐step carbonization using urea and alkali‐treated wheat flour as carbon precursor with a high specific surface area (1294 m² g^?1). The specific capacitances of HPC and HPC/PANI (with a surface area of 923 m² g^?1) electrode are 383 and 1080 F g^?1 in 1 m H₂SO₄, respectively. Furthermore, an asymmetric supercapacitor based on HPC/PANI as positive electrode and HPC as negative electrode is successfully assembled with a voltage window of 0–1.8 V in 1 m Na₂SO₄ aqueous electrolyte, exhibiting high specific capacitance (134 F g^?1), high energy density (60.3 Wh kg^?1) and power density (18 kW kg^?1), and excellent cycling stability (91.6% capacitance retention after 5000 cycles).