Endemism and dispersal: comparative phylogeography of three surgeonfishes across the Hawaiian Archipelago

To evaluate the hypothesis that a general correlation exists between species range size and dispersal ability, we surveyed mitochondrial cytochrome b sequence variation in three surgeonfish species with vastly different ranges: Ctenochaetus strigosus, Hawaiian endemic, N = 531; Zebrasoma flavescens, North Pacific, N = 560; Acanthurus nigrofuscus, Indo-Pacific, N = 305. Collections were made throughout the 2,500 km expanse of the Hawaiian Archipelago and adjacent Johnston Atoll. Analyses of molecular variance demonstrate that all three species are capable of maintaining population connectivity on a scale of thousands of km (all species global Φ_ST = NS). However, rank order comparison of pairwise Φ_ST results and Exact test P-values revealed modest but significantly different patterns of gene flow among the three species surveyed, with the degree of genetic structure increasing as range size decreases (P = 0.001). These results are consistent with mtDNA surveys of four additional Hawaiian reef fauna in which a wide-spread Indo-Pacific species exhibited genetic homogeneity across the archipelago, while three endemics had significant population subdivision over the same range. Taken together, these seven cases invoke the hypothesis that Hawaii’s endemic reef fishes evolved from species with reduced dispersal ability that, after initial colonization, could not maintain contact with parent populations. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

2019年锡林郭勒盟肉羊天气指数型保险浅析——以内蒙古西乌珠穆沁旗为例

天气指数型保险是一种创新型保险,肉羊天气指数型保险以牲畜草料为保险标的,为牧民提供因旱灾、雪灾所造成的肉羊饲养成本增长及因天气灾害致损的保险保障和风险对冲,即每当天气达到气象灾害标准时统一按投保合同中数量进行赔付.同时,天气指数型保险的实施也大大降低了保险公司查勘定损的成本和被保险人道德风险的危害.2019年,肉羊天气...     

缓释型化学氧化剂在地下水DNAPLs污染修复中的应用研究进展

重质非水相有机污染物具有高密度、高毒性、低水溶性和高界面张力的特性,在自然条件下难以降解.缓释型化学氧化剂可以控制反应性化合物的释放,减少氧化剂的非选择性消耗,在地下水低渗透含水层DNAPLs(重非水相液体,dense nonaqueous-phase liquids)污染修复中有巨大的发展潜力.本文通过大量的文献调研,综述了缓释型化学氧化剂的制备方法及其在DNAPLs污染修复中的应用,梳理和总结了高锰酸盐、碱土金属过氧化物、过硫酸盐3类代表性缓释氧化剂的制备方法及其在修复低渗透含水层重非水相有机污染的应用研究现状,并对未来研究提出了建议.     

氮肥与DCD配施对棚室黄瓜土壤NH3挥发损失及N2O排放的影响

以传统水氮管理为对照,进行了优化水氮管理条件下氮肥与DCD配施对大棚黄瓜土壤氨挥发损失及氧化亚氮排放的影响研究.试验结果表明,与传统水氮管理相比,优化水氮管理减少了氮肥用量及灌水量,但黄瓜产量并没有降低.各水氮处理的NH3挥发速率峰值出现在施肥灌水后的第3d,添加DCD的各优化水氮处理与传统水氮处理相比,土壤氨挥发累积量分别减少55.97%、43.68%、66.47%,4次追肥后W2N2+DCD、W2N3+DCD和W2N4+DCD的氨挥发速率峰值与累积量变化范围较小.不同水氮处理的N2O排放通量的峰值均出现在施肥灌水后的第4d,各追肥时期W2N2+DCD、W2N3+DCD和W2N4+DCD处理,土壤N2O排放通量峰值与N2O累计排放量均显著低于传统水氮处理W1N1,并且3个处理之间不存在显著差异,充分表明优化水氮管理中将氮肥与DCD配施对减少N2O排放起到了显著作用.     

Modulation of the DNA repair system and ATR-p53 mediated apoptosis is relevant for tributyltininduced genotoxic effects in human hepatoma G2 cells

The toxic effects of tributyltin (TBT) have been extensively documented in several types of cells, but the molecular mechanisms related to the genotoxic effects of TBT have still not been fully elucidated. Our study showed that exposure of human hepatoma G2 cells to 1-4 μmol/L TBT for 3 hr caused severe DNA damage in a concentration-dependent manner. Moreover, the expression levels of key DNA damage sensor genes such as the replication factor C, proliferating cell nuclear antigen and poly (ADP-ribose) polymerase-1 were inhabited in a concentration-dependent manner. We further demonstrated that TBT induced cell apoptosis via the p53-mediated pathway, which was most likely activated by the ataxia telangiectasia mutated and rad-3 related (ATR) protein kinase. The results also showed that cytochrome c, caspase-3, caspase-8, caspase-9, and the B-cell lymphoma 2 were involved in this process. Taken together, we demonstrated for the first time that the inhibition of the DNA repair system might be more responsible for TBT-induced genotoxic effects in cells. Then the generated DNA damage induced by TBT initiated ATR-p53-mediated apoptosis.     

Nitrogen and phosphorus removal comparison between periphyton on artificial substrates and plant-periphyton complex in floating treatment wetlands

Environmental Science and Pollution Research - Artificial substrates (ASs) and floating treatment wetlands (FTWs) have been widely used in the treatment of polluted surface water. In fact,...     

Enhanced removal of Cr(Ⅵ) by biochar with Fe as electron shuttles

Biochar is extensively used as an effective soil amendment for environmental remediation.In addition to its strong contaminant sorption capability, biochar also plays an important role in chemical transformation of contaminant due to its inherent redox-active moieties.However, the transformation efficiency of inorganic contaminants is generally very limited when the direct adsorption of contaminants on biochar is inefficient. The present study demonstrates the role of Fe ion as an electron shuttle to enhance Cr(Ⅵ) reduction by biochars. Batch experiments were conducted to examine the effects of Fe(Ⅲ) levels,pyrolysis temperature of biochar, initial solution pH, and biochar dosage on the efficiency of Cr(Ⅵ) removal. Results showed a significant enhancement in Cr(Ⅵ) reduction with an increase in Fe(Ⅲ) concentration and a decrease of initial pH. Biochar produced at higher pyrolysis temperatures(e.g., 700°C) favored Cr(Ⅵ) removal, especially in the presence of Fe(Ⅲ), while a higher biochar dosage proved unfavorable likely due to the agglomeration or precipitation of biochar. Speciation analysis of Fe and Cr elements on the surface of biochar and in the solution further confirmed the role of Fe ion as an electron shuttle between biochar and Cr(Ⅵ). The present findings provide a potential strategy for the advanced treatment of Cr(Ⅵ) at low concentrations as well as an insight into the environmental fate of Cr(Ⅵ) and other micro-pollutants in soil or aqueous compartments containing Fe and natural or engineered carbonaceous materials.     

借鉴国外经验,推广热电联产联供

1 德国热电联产联供概况 德国的电力市场构成比较复杂,从国家到地方大约有1000家电力公司在运行。其中9家跨地区的大公司控制着全国大约85％的发电量和大部分跨地区的电力输送,有些小的电力公司和地方电力公司从这些大公司购买电力。在发展热电联产过程中存在着:电力价格持续走低,投资回收期偏长,电厂建设在环保方面的许可程序复杂等发展障碍。但德国政府从减少温室气体排放和减少核电量的环保角度出发,鼓励发展热电联产;再加上天然气价格比较便宜,以及欧盟倡导能源市场解放运动对德国的影响,德国在欧盟中热电联产发展处于中上水平,其热电联产的发电量占全国总发电量的14％,总装机容量超过22000MW。     

全球变暖和人类居住地地域性变化的影响:鸟类越冬分布的转移

20世纪末,在美国马萨诸塞州的科德角,由于全球变暖的加剧,鸟类越冬出现了向北迁移的现象,这种北移与全球气温异常和当地冬季最低气温上升是分不开的.这一现象以及最近的其它研究结果都表明:最近的20年期间,全球变暖已造成规模大、范围广的生物地理意义上的变化,并对地球生态系统和人类构成了潜在的威胁.由于城市扩展引起的地方生境的变化主要对栖息地偏北的森林鸟类产生影响.在科德角,当地居民居住地扩大对鸟类栖息地分布的影响,在21世纪初,尚不及温室效应的影响大,但是,如果城市继续扩大,也许其影响会不亚干全球变暖.