新型锰氧化菌株Pseudoxanthomonas mexicana S5-3-5X的分离及锰氧化机理研究

锰氧化微生物能催化氧化Mn^II生成锰氧化物（Mn^IV&III）,而生成的锰氧化物可强化水处理体系（如锰砂滤池、湿地）中的微量有机污染物降解及底泥中甲烷的厌氧氧化,因而受到广泛研究.从环境中分离出更多种属和生态位的锰氧化菌是生物强化环境中锰氧化过程的重要基础.依据锰氧化菌株对低浓度营养物的潜在偏好,本研究梯度稀释常用的锰氧化菌培养基（PYG培养基）,配置出5级营养物梯度浓度的培养基.相对于原培养基,从较低浓度的4级培养基中多分离出6个菌属的锰氧化菌株,提高了锰氧化菌株的分离效率.分离出的Pseudoxanthomonas（假黄色单胞菌属）菌属的锰氧化菌株（Pseudoxanthomonas mexicana S5-3_-5X）,属中文文献首次报道.研究发现该菌株能在环境常见条件（pH 6.0~7.8、低营养物浓度（如稀释5~625倍PYG培养基）、50 μmol·L^-1 ~1.6 mmol·L^-1的Mn^II浓度）生长并产生锰氧化活性;可以产生胞外超氧化物和锰氧化蛋白等锰氧化活性物质;基因组具有编码锰氧化模式菌株Pseudomonas putida GB-1的3个Mn^II氧化蛋白的同源基因,并且具有降解一些有机污染物的代谢通路.因此,该菌株具有较好的工程应用潜力.     

向家坝库区沉积物磷形态分布及释放风险

采用改进的连续提取法研究了向家坝库区沉积物中有机磷（OP）和无机磷（IP）的各赋存形态及分布特征,讨论了各形态磷的生物可利用性和释放风险.结果表明,向家坝库区沉积物总磷（TP）含量为388.9~616.4 mg·kg^-1,总体处于安全级别.库区沉积物磷形态以惰性碎屑态无机磷（De-P_i）和残渣态有机磷（Re-P_o）为主,两者共占TP质量分数的60%以上,呈上游高下游低的趋势,流域地质背景是主要的影响因素.以可交换态无机磷（Ex-P_i）、铝结合态无机磷（Al-P_i）、铁结合态无机磷（Fe-P_i）、可交换态有机磷（Ex-P_o）、铁铝结合态有机磷（Fe/Al-P_o）之和来估算生物可利用磷（BAP）,BAP/TP来评价沉积物中磷的释放风险,BAP含量为23.0~91.1 mg·kg^-1,BAP/TP为6.2%~17.1%.向家坝水库沉积物磷的释放风险较低.库区沉积物BAP储量为767.68 t,对向家坝水库上覆水磷浓度的潜在贡献为0.148 mg·L^-1,是导致未来库区水质恶化的重要因素 之一,应加强对库区内源磷的释放管理.     

2016~2020年上海市PM2.5化学组成特征和来源解析

2016~2020年在上海市区和郊区的6个点位开展了颗粒物系统性观测研究,分析了PM_2.5的质量浓度以及水溶性离子、有机碳/元素碳、无机元素等化学组分,并利用正矩阵因子分解模型对PM_2.5的来源进行了解析。结果表明,上海PM_2.5浓度水平呈现下降趋势,年均质量浓度依次为46,43,37,40,39μg/m³,表现为冬高夏低,西高东低的时空分布特征。有机物在PM_2.5中占比最高(30%~32%),不同年份和季节间的差异较小。二次无机离子(硫酸盐、硝酸盐和铵盐)的区域性特征明显,其中硝酸盐的占比在5a间升高最多,且在冬季污染过程中起到了关键作用。解析得到PM_2.5的来源有9类,分别为二次硝酸盐(30.6%)、二次硫酸盐(20.7%)、机动车(12.6%)、工业(8.0%)、生物质燃烧(7.7%)、扬尘(6.5%)、燃煤(5.8%)、海盐(4.8%)和船舶(3.2%)。机动车和船舶等移动源、秸秆焚烧和烟花爆竹燃放等生物质燃烧源的贡献浓度在研究期间呈现下降趋势,体现了相关治理措施的管控效果。     

秦皇岛市4种常见绿化植物滞尘效应研究

通过对秦皇岛市4种常见绿化植物的叶片滞尘量、单株滞尘能力及相关因素的研究,发现绿化植物单位叶面积的滞尘量最大可以相差2.5倍左右,树种叶片滞尘能力的大小排序为：国槐＞悬铃木＞金银木＞连翘,单株滞尘能力的大小排序为：悬铃木＞国槐＞金银木＞连翘;绿化植物的滞尘量与环境中粉尘含量成正比,树木滞尘能力还与叶片表面性状、叶面积指数及植物所处环境等因素有关。     

外来赤潮生物入侵现状及对赤潮灾害的影响研究

外来赤潮生物入侵加剧了我国近海海域的赤潮灾害。根据2004—2013年的数据统计,分别从赤潮生物优势种、频率、海域分布和赤潮面积4个方面分析了外来赤潮生物对我国近海赤潮灾害的影响,并着重从外来赤潮生物入侵早期预警系统建设、压舱水排放管理和赤潮灾害防治技术3个方面提出应对措施。     

Quantitative Determination of Rarity of Freshwater Fishes and Implications for Imperiled‐Species Designations

Abstract: Conserving rare species and protecting biodiversity and ecosystem functioning depends on sound information on the nature of rarity. Rarity is multidimensional and has a variety of definitions, which presents the need for a quantitative classification scheme with which to categorize species as rare or common. We constructed such a classification for North American freshwater fishes to better describe rarity in fishes and provide researchers and managers with a tool to streamline conservation efforts. We used data on range extents, habitat specificities, and local population sizes of North American freshwater fishes and a variety of quantitative methods and statistical decision criteria, including quantile regression and a cost‐function algorithm to determine thresholds for categorizing a species as rare or common. Species fell into eight groups that conform to an established framework for rarity. Fishes listed by the American Fisheries Society (AFS) as endangered, threatened, or vulnerable were most often rare because their local population sizes were low, ranges were small, and they had specific habitat needs, in that order, whereas unlisted species were most often considered common on the basis of these three factors. Species with large ranges generally had few specific habitat needs, whereas those with small ranges tended to have narrow habitat specificities. We identified 30 species not designated as imperiled by AFS that were rare along all dimensions of rarity and may warrant further study or protection, and we found three designated species that were common along all dimensions and may require a review of their imperilment status. Our approach could be applied to other taxa to aid conservation decisions and serve as a useful tool for future revisions of listings of fish species.     

Bumblebee Vulnerability: Common Correlates of Winners and Losers across Three Continents

Abstract:  It is widely agreed that in many parts of the world some bumblebee ( Bombus ) species have declined, and that this has often been driven by land-use changes that cause reductions in the abundance of food plants. There is much less agreement about how changes in food plants affect some bumblebee species more than others. We sought to identify which species' characteristics are generally associated with the relative winners and losers by comparing the 3 independent bumblebee faunas from parts of Britain, Canada, and China. Using available survey data, we assessed species characteristics, including competition with congeners, climatic specialization, proximity to climatic range edge, food specialization, phenology, body size, and range size. Results of our meta-analysis of correlations showed support for the hypotheses that decline susceptibility is generally greater for species that have greater climatic specialization, for species in areas where they occur closest to the edges of their climatic ranges, and for species that have queens that become active later in the year. The latter characteristic may render a species at a particular disadvantage when they have long colony cycles if there are losses of food plants in mid to late colony development.     

Interactions Among the Copper Species and Forms in Sea Water/Sediments and Copper Bioaccumulation in Oysters

Abstract

Earlier papers indicated that the first incident of green discoloration in oysters (Crassostrea gigas) and the mass mortality observed in 1986 along the Taiwan Erhjin Chi coastal area were caused by the higher contents of total copper and copper species (mainly bioavailable and free ion) in sea water. the copper in sea water would be sorbed by suspended matter and transferred to sediments, and the copper in the sediments would also be desorbed to sea water. Processes of copper adsorption and desorption are the major factors influencing the contents of total copper and copper species in sea water and sediments. in this study, the Erhjin Chi sediments were mixed with sea water by a shaker technique. When the mixture was shaken for one hour, analogous to tidal mixing in estuaries, only copper desorption from sediments was observed. If the shaking time is increased for more than 3 hours, the copper released from the sediments was resorbed to the remaining solid phases. the higher the contents of mud (91.71%) and total copper (701 mg kg^?1) in sediments, the higher the copper desorption rate (1.86 ppm hr^?1) and copper adsorption rate (0.50 ppm hr^?1) were observed. in sediments containing lower mud (0.80%) and lower copper (43.5 mg kg^?1), the copper desorption and adsorption rates were 0.83 ppm hr^?1 and 0.22 ppm hr^?1, respectively. the interactions among the total copper and copper species in sea water and sediments, chemical and ecological parameters, and copper bioaccumulation in oysters in the Erhjin Chi estuarine and coastal area are also discussed.     

Research On Zooplankton in the Gulf of Rapallo

Zooplankton samples, collected in autumn 1996 from two stations in the Gulf of Rapallo, Ligurian Sea (Rapallo Harbour and Prelo Bay, which is a more open site with lower human impacts) were analysed. at both stations, the community was dominated by copepods (mainly juveniles and adults of different species of Acartia and Oithona) and meroplankton (mainly polychaete larvae). Total zooplankton abundance in the harbour waters was significantly higher than in the nearby bay. the occurrence of Acartia grani in Rapallo Harbour and Pteriacartia josephinae in Prelo Bay is noteworthy, as they are reported for the first time in the Ligurian Sea, and A. grani has not previously been recorded to the Italian coastline. A three-day benthic chamber experiment aimed to quantify nutrient fluxes between the sediment and water column was performed in the Rapallo Harbour: the profound effects of confinement on the composition and abundance of zooplankton within the incubation chamber are discussed.     

Impact of Invasive Cane Toads on Australian Birds

Abstract: The cane toad (Bufo marinus), a large, toxic, American anuran, was introduced to Australia in 1935. Populations of many of Australia's reptiles (snakes, varanid lizards, crocodiles) and carnivorous mammals (dasyurid marsupials) have declined because these predators are killed by the toad's powerful toxins. In contrast to these well‐studied species, little is known about the cane toads impacts on Australian birds. We reviewed published and unpublished data on behavioral interactions between Australian avian predators and cane toads and collated distributional and dietary information to identify avian taxa potentially at risk from cane toad invasion. Cane toads are sympatric with 172 frog‐eating bird species in Australia, and an additional 8 bird species overlap with the predicted future range of the toad. Although many bird species thus are potentially at risk, behavioral observations suggest the risk level is generally low. Despite occasional reports of Australian birds being killed when they ingest cane toads, most birds either ignore toads or survive the predation event. The apparently higher tolerance of Australian birds to toad toxins, compared with Australian reptiles and marsupials, may reflect genetic exchange between Australian birds and Asian populations that encounter other bufonid species regularly and hence have evolved the capacity to recognize or tolerate this toxic prey.