沉积型微生物燃料电池对 模拟湖泊水中磷的去除

沉积型微生物燃料电池(SMFC)是借助于沉积物中具有电化学活性微生物的催化作用,氧化沉积物中有机物以获得电能的一种装置,它具有用于淡水水体的原位修复的潜力.以湖泊底泥为阳极底物,含磷模拟配水为阴极液,构建了SMFC系统,研究了其产电性能及其对水中总磷去除的影响.结果表明,构建的SMFC系统可成功产电,运行22 d后输出电压达到最大值0.28 V(外电阻为1 000Ω).稳定运行期间,底泥烧失量由4.42%降低至1.91%;底泥氧化还原电位显著提高,由初始的-254 m V上升至-183 m V;溶液p H由初始的6.02上升至7.34;水中总磷浓度由10 mg/L降低至0.13 mg/L,这可能与SMFC使底泥电位、p H升高有关.     

沉积物燃料电池阳极区纤维素分解菌群筛选及酶学特性

以沉积型微生物燃料电池(SMFC)的阳极区为筛选源,通过电化学的方法,经过对菌群的富集培养,分别从电极上、电极近端以及电极远端筛选得到3组纤维素分解混合菌群。通过对3组菌群滤纸降解特性的研究表明,距离电极越近,滤纸酶活活性越高,最高可达56.8 U,电极上的菌群分解产物的含糖量是电极远端的含糖量1.67倍,3组菌群的酶反应环境偏酸性,耐热性能比较好;距离电极越近,对Ca2+浓度的耐受性越强,Mg2+对酶促反应有促进作用,由此可以看出,距离电极越近,其降解纤维素能力越高。     

微生物燃料电池处理剩余污泥及其产电特性

针对目前存在的剩余污泥处理问题,采用沉积型微生物燃料电池(SMFC)处理二沉池剩余污泥,考察了不同条件下其产电特性及污泥减量化情况.SMFC运行一个周期(60 d),无表面曝气,不投加缓冲溶液的条件下获得最大功率密度可达9.45 W/m3;表面曝气和投加缓冲溶液均可提高SMFC的产电性能.闭路运行SMFC一个周期后,TCOD、TSS、VSS去除率均显著高于开路状态,且底物中投加氧化物可以提高有机物的去除率.微生物燃料电池可以用来实现剩余污泥的减量,并同时产生电能.     

Rare earth elements in hydrothermal fluids from Kueishantao, off northeastern Taiwan: Indicators of shallow-water, sub-seafloor hydrothermal processes

The rare earth element (REE) geochemistry of hydrothermal vent systems has been investigated intensively, but few studies have been carried out on marine shallow-water hydrothermal systems like that at Kueishantao. Here we present novel data sets of REE in hydrothermal fluids from Kueishantao, off northeastern Taiwan. The total REE (ΣREE) concentrations of yellowish fluids are similar to those of whitish fluids, 813–1212 ng/L, and are significantly higher than that of ambient seawater. The yellowish fluids have chondrite-normalized REE (REEN) distribution patterns with slight convex-downward curvatures at Eu; and the REE patterns of the whitish fluids are smooth at Eu, which is related to the lower temperature and more oxidizing conditions. The Kueishantao hydrothermal fluids are slightly enriched in light REE (La-Nd) relative to the heavy REE (Gd-Lu). The behaviors of REE in both yellowish and whitish fluids are affected by the short time of water-rock interaction. The REE distributions in the yellowish fluids are also affected by very low pH (2.81 and 2.29), boiling of the fluid and precipitation of native sulfur. In the whitish fluids, adsorption by small particles and formation of REE-chloride complexes has played a role in the distribution of REE.     

鄂尔多斯盆地南部延长组湖相水道-朵状体浊积扇沉积模式

为研究鄂尔多斯盆地上三叠统延长组深湖重力流的沉积特征及其沉积模式,利用钻井岩心,周缘野外露头及钻井测井资料,识别出深水区的块状砂岩、具撕裂屑块状砂岩、平行层理砂岩、沙纹交错层理粉砂岩、同生变形构造粉砂岩、水平层理粉砂岩、块状泥岩等7种岩相类型,代表了浊流沉积(高密度、低密度)、碎屑岩、滑塌岩、深水原地沉积等成因类型;其...     

微生物间歇发酵比生长速率辨识及优化算法

根据微生物间歇发酵甘油生产1,3-丙二醇过程的特征及动态行为,建立了能够更好地描述微生物间歇发酵过程的含控制函数和参数的动力系统,证明了该系统的一些性质.以实验数据和计算值之间误差平方和最小为性能指标,建立了系统辨识模型.根据微生物生长特点,采用离散化方法将系统辨识模型转化为一个参数辨识问题.最后,构造了改进的粒子群算法求解.数值结果表明实验观测值和计算值之间的相对误差比已有研究结果降低了6%~16%,该系统能更好地模拟间歇发酵过程.     

轮叶黑藻对不同底质和密度的可塑性响应

为研究沉水植物对环境因子的生长可塑性,开展了轮叶黑藻在两种底质(沙,泥 沙)和3种初始密度(3.9,15株/钵)条件下的生长响应研究.结果表明:与沙质底质相比,泥沙底质显著增大了植物的株高和茎粗,但减少植物对根的生物量分配(P<0.05);较小密度促进了植物向茎的生物量分配,但减小了叶生物量的比例(P<0.05).在沙质底质上,高密度下植物生长较好,表现出有较大的相对生长速率和生物量(P<0.05),但在泥沙底质上趋势相反,高密度下植物生长较慢(P<0.05);高密度时,植物在沙质底质上生长较好(P<0.05),当密度较小时,则在泥沙底质上生长较好(P<0.05).底质和密度存在交互作用,两者共同影响植物的生长,即轮叶黑藻在不同底质下,对密度有不同的生长响应,而密度不同时,又对不同底质有不同生长响应.结果表明.要成功构建沉水植被,密度和底质类型应综合考虑,依据底质特点合理安排植物密度.     

Stoichiometry and turnover in single, functioning membrane protein complexes

Many essential cellular processes are carried out by complex biological machines located in the cell membrane. The bacterial flagellar motor is a large membrane-spanning protein complex that functions as an ion-driven rotary motor to propel cells through liquid media. Within the motor, MotB is a component of the stator that couples ion flow to torque generation and anchors the stator to the cell wall. Here we have investigated the protein stoichiometry, dynamics and turnover of MotB with single-molecule precision in functioning bacterial flagellar motors in Escherichia coli. We monitored motor function by rotation of a tethered cell body, and simultaneously measured the number and dynamics of MotB molecules labelled with green fluorescent protein (GFP-MotB) in the motor by total internal reflection fluorescence microscopy. Counting fluorophores by the stepwise photobleaching of single GFP molecules showed that each motor contains approximately 22 copies of GFP-MotB, consistent with approximately 11 stators each containing two MotB molecules. We also observed a membrane pool of approximately 200 GFP-MotB molecules diffusing at approximately 0.008 microm2 s(-1). Fluorescence recovery after photobleaching and fluorescence loss in photobleaching showed turnover of GFP-MotB between the membrane pool and motor with a rate constant of the order of 0.04 s(-1): the dwell time of a given stator in the motor is only approximately 0.5 min. This is the first direct measurement of the number and rapid turnover of protein subunits within a functioning molecular machine.     

特质波动率、换手率与预期收益关系

运用时间序列分析方法考察特质波动率和换手率对横截面预期收益解释能力之间的区别与联系,采用法马和弗伦奇的组合设计和因子构造方法控制相关因素对预期回报的影响。结果显示,控制换手率会减弱特质波动率对收益回报的解释能力,这种影响是由于换手率与特质波动率之间的相关性造成的;换手率风险溢价主要体现在高特质波动率的组合中,特质波动率风险溢价也主要体现在高换手率组合;卖空限制和投资者异质信念差异导致的投机性交易泡沫可以解释实证结果。     

JD37复合微生物肥料对小白菜、蕹菜生长及品质的影响

JD37复合微生物肥料主要由本实验室筛选出的一株植物根际促生细菌JD37与蚯蚓粪组成,该肥料对小白菜与蕹菜具有显著的促生作用.盆栽试验中,小白菜全株鲜重增加了45.6%,蕹菜全株鲜重增加了45%;大棚种植试验中,小白菜产量增加18.2%;蕹菜产量增加107.4%.在对两种蔬菜进行品质检测后发现,JD37复合微生物肥料组和化肥组的抗坏血酸含量无显著差异,可溶性蛋白含量中,JD37复合微生物肥料组要优于化肥组;亚硝酸盐含量中,JD37复合微生物肥料组为化肥组的一半,说明该肥料能有效降低两种蔬菜的亚硝酸盐含量.本实验为JD37复合微生物肥料的进一步实践应用奠定了基础.     

中国煤中汞的含量、分布与赋存状态研究

在测试分析中国皖北矿区6个煤矿81个煤样品中汞含量的基础上,结合国内外文献资料中报道的1 712个中国煤样品中汞的数据,对中国煤中汞的含量、分布、赋存状态及燃煤引起的汞的环境污染进行了分析和探讨。通过研究得出:中国煤中汞的平均含量为0.20 mg/kg,高于世界煤中汞的平均值(0.10 mg/kg),接近美国煤中汞的平均值(0.17 mg/kg);由于沉积环境及成煤过程中各种地质因素的综合影响,汞在中国不同地区、不同成煤时代以及不同变质程度煤中的含量差异较大;高硫煤中的汞与硫化物关系密切,主要赋存在黄铁矿中;硫化物结合态和有机结合态是低硫煤中汞的主要存在形态;岩浆活动对煤中汞的含量分布与赋存状态有明显影响;煤中汞的赋存状态与煤中汞的释放、毒性有着重要的关系,中国巨大的煤炭消耗量,已引起大量的汞排放,控制燃煤过程中汞的排放是今后环境保护的重要内容之一。     

秸秆生物炭及秸秆对大豆生长及土壤微生物活性的影响

为了明确不同秸秆利用方式对作物生长及土壤微生物的影响,采用盆栽试验,研究秸秆直接添加和秸秆生物炭添加对大豆生长状况、根际土壤有机碳及微生物群落功能多样性的影响.结果表明:秸秆生物炭添加(MB和WB)能有效提高大豆盛花期地下生物量.秸秆直接添加(M和W)能显著增加大豆花期根际土壤有机碳的含量,玉米秸秆直接添加处理(M)下的有机碳含量最高,为21.15 mg/g.大豆成熟期,秸秆生物炭添加处理(MB和WB)下土壤有机碳含量较空白处理(CK)显著增加,玉米秸秆添加处理(M)下根际土壤有机碳含量显著高于小麦秸秆添加处理(W).不同秸秆利用方式下大豆根际土壤平均颜色变化率(AWCD)随时间延长而增加,MB和WB处理较M和W处理能显著提高成熟期大豆根际土壤AWCD值.因此,可利用秸秆生物炭添加改善大豆根际土壤微生物活性,提高土壤碳贮量.     

复合微生物肥料替代部分复合肥对花生生长及根际土壤微生物和理化性质的影响

通过田间小区试验,研究了不同比例的复合微生物肥料替代复合肥对花生根际土壤环境及产量的影响。结果显示,与常规施肥（100%复合肥）相比,复合微生物肥料替代量在30%~70%范围内,显著提高了苗期和成熟期花生根际土壤细菌、真菌和放线菌总量,且根际细菌和放线菌数随生育期的推移提高比例逐渐升高,而真菌数的变化趋势与之相反。同时,显著提高了苗期土壤过氧化氢酶、脱氢酶、中性磷酸酶和蔗糖酶活性,而替代量为50%和70%时降低了土壤脲酶活性,到成熟期不同替代配比均降低了土壤脲酶和蔗糖酶活性,提高了土壤脱氢酶活性,进而降低了苗期和结荚期土壤碱解氮含量而提高了全氮含量,也提高了各生育期土壤有机质和速效钾含量以及结荚期和成熟期土壤有效磷含量。当替代量为50%时,产量提高了5.23%,最终实现了养地增产的效果。     

Coexistence and relative abundance in forest trees

Contemporary acceleration of biodiversity loss makes increasingly urgent the need to understand the controls of species coexistence. Tree diversity in particular plays a pivotal role in determining terrestrial biodiversity, through maintaining diversity of its dependent species and with them, their predators and parasites. Most theories of coexistence based on the principle of limiting similarity suggest that coexistence of competing species is inherently unstable; coexistence of competitors must be maintained by external forces such as disturbance, immigration or 'patchiness' of resources in space and time. In contrast, storage theory postulates stable coexistence of competing species through temporal alternation of conditions favouring recruitment of one species over the other. Here we use storage theory to develop explicit predictions for relative differences between competitors that allow us to discriminate between coexistence models. Data on tree species from a primary forest on the Mexican Pacific coast support a general dynamic of storage processes determining coexistence of similar tree species in this community, and allow us to reject all other theories of coexistence.     

压力对采油微生物生长代谢的影响

影响微生物提高原油采收率技术的油藏环境因素主要包括压力、温度、矿化度和pH值等.以葡萄糖为主要碳源,对河口采油厂沾3x24井产出水中的内源微生物进行高压(10 MPa)和常压下的静态激活试验,对培养前后的微生物群落结构、代谢产生的低分子有机酸及表面张力进行检测.结果表明:微生物在不同压力下的生长代谢有较大的差异,压力不仅显著影响微生物群落的结构,而且影响微生物的生长代谢活性和速度,以及整体群落的代谢方式;与高压相比,常压下微生物种类较多,丰度较高,代谢高峰提早14 d,变化周期较短.     

黄浦江河口水沙输运机制研究

受潮汐影响的弯道泥沙输运表现出与径流弯道不一样的现象.本文运用通量分解机制法,以黄浦江河口大潮期间实测水文资料为基础,对黄浦江河口受潮汐影响的弯曲河道水沙输运进行机制分析.结果表明,黄浦江河口水沙输运受弯道环流影响可分为纵向输运和横向输运.纵向水体潮周期净输运因径流作用指向口外,泥沙潮周期净输运因潮泵输运大于平流输运指向口内.潮周期横向水体净输运和泥沙净输运均指向凸岸,其中横向水体输运以欧拉输运为主,横向泥沙属于以平流项为主.通过比较水量输运的纵横比和泥沙输运的纵横比可得黄浦江河口大潮期间水量潮周期横向净输运大于纵向,泥沙是纵向大于横向.说明潮泵输运在黄浦江河口大潮期间起主导作用.     

裸地休闲和春小麦生长条件下土壤微生物量和土壤有机质动态研究

不同作物栽培管理措施对土壤微生物量和土壤有机质对农业持续性耕作的影响非常重要.研究结果表明,各处理间pH、容重和含水量无显著差异.尽管春小麦地的土壤有机碳和微生物碳质量分数比休闲地土壤的高,但是休闲地土壤的全氮、微生物氮、微生物碳的质量分数与有机碳的质量分数的比值与微生物氮与全氮的质量分数却都显著高于春小麦地的.     

长春市土壤重金属化学形态与土壤微生物量、微生物商和代谢商之间的关系

通过样品采集和室内分析相结合的方法研究了长春市城市土壤重金属化学形态与土壤微生物量、微生物商和代谢商之间的关系,以及土壤理化性质对重金属形态与土壤微生物量、微生物商和代谢商之间关系的影响.实验结果表明:城市土壤环境的空间异质性是引起城市土壤微生物参数的空间分异性的主要原因.长春市土壤重金属(Pb、Cd、Cu、Zn和Ni)不同的化学形态对土壤微生物量、微生物商和代谢商的影响明显不同,且土壤理化性质对它们之间关系的影响比较显著.采用重金属化学形态与微生物学指标相结合的方法评价长春市土壤重金属污染状况时,应该剔除土壤理化性质的影响.可以选择碳氮比与有机结合态Ni含量相结合的方法评价长春市土壤重金属污染状况或者确定重金属污染的临界浓度.     

Neutral theory and relative species abundance in ecology

The theory of island biogeography asserts that an island or a local community approaches an equilibrium species richness as a result of the interplay between the immigration of species from the much larger metacommunity source area and local extinction of species on the island (local community). Hubbell generalized this neutral theory to explore the expected steady-state distribution of relative species abundance (RSA) in the local community under restricted immigration. Here we present a theoretical framework for the unified neutral theory of biodiversity and an analytical solution for the distribution of the RSA both in the metacommunity (Fisher's log series) and in the local community, where there are fewer rare species. Rare species are more extinction-prone, and once they go locally extinct, they take longer to re-immigrate than do common species. Contrary to recent assertions, we show that the analytical solution provides a better fit, with fewer free parameters, to the RSA distribution of tree species on Barro Colorado Island, Panama, than the lognormal distribution.