黄渤海海水中叶绿素a的分布特征及其环境影响因素

基于2013年夏、秋季和2014年春季黄渤海海域调查数据,分析了该海域叶绿素a的含量、分布特征及其环境影响因素(温度、盐度、pH值、溶解无机氮、硅酸盐、磷酸盐).结果表明:2013年夏、秋季和2014年春季,黄渤海海水中叶绿素a含量范围分别是0.918~9.287,1.477~6.435,1.837~5.966mg/L,平均浓度分别为3.527,3.467,3.524mg/L;夏季和春季叶绿素a含量略高,秋季叶绿素a含量最低且变化范围较小;渤海海域叶绿素a分布具有明显区域特征,其分布基本呈近岸高、中部海域低的分布趋势;将水质参数作为自变量输入支持向量机(SVM)中,GA-SVM算法拟合效果(R20.9)和精确度(MSE0.01)较好,不同水质参数对海水叶绿素a含量的影响相对重要性具有季节差异,夏季,对海水叶绿素a含量影响最重要是磷酸盐和温度;秋季,对于海水叶绿素a含量影响最重要是硅酸盐和盐度;春季,对于海水叶绿素a含量影响最重要的是盐度和溶解无机氮.所有调查季节,对于海水叶绿素a含量影响最重要的是盐度和磷酸盐.综合参数影响重要性,表明陆源输入是黄渤海海域叶绿素a含量的最重要影响因素.     

夏季热分层效应对典型岩溶水库水化学及溶解无机碳的影响

热分层导致水库内部水化学、水生生物分布等出现显著的分层特征,并影响了水库内部的生物地球化学循环过程.为掌握夏季热分层期岩溶水库水体理化性质和溶解无机碳变化过程及其影响因素,以岩溶地下水补给型水库广西上林县大龙洞水库为研究对象,于2015年6月沿水库流程方向在8个点位开展分层采样及监测.结果发现:(1)水库夏季存在明显的热分层现象,水体pH、电导率(Spc)等理化性质出现分层结构;(2)水体溶解氧(DO)与叶绿素a(Chl-a)浓度从表层至底层并没有呈现单一的递减趋势,而是在水面以下2.5 m或者5 m处达到最大值;(3)由表层至底层水体溶解无机碳(DIC)浓度整体上呈增加趋势,表层水体DIC平均浓度为2.03 mmol·L~(-1),底层平均浓度为4.18 mmol·L~(-1);其同位素(δ~(13)C_(DIC))在表水层偏正,在温跃层随水深增加逐渐偏负.分析认为:(1)由于夏季热分层效应,水库水体温度、水生生物的分布及新陈代谢的强度和方向在不同水层存在显著差异,致使水库水体理化性质、DIC均呈现垂向分层性特征;(2)DIC浓度变化在表水层主要受碳酸盐岩沉淀过程及浮游植物光合作用影响,进而影响水中DIC稳定同位素的分馏;在温跃层则主要由生物呼吸作用及有机质分解过程控制.     

黄河口无机碳输运过程对pH异常增高现象的响应

为研究黄河无机碳的输运过程及有效入海通量,通过对2004年至2006年黄河口汛期和非汛期淡水-海水混合过程中无机碳参数、溶解氧饱和度、叶绿素和NH⁺₄、 PO^3-₄的分析得出,黄河口低盐度区pH出现相对于淡水端异常增高现象,而恰在此区域DIC出现亏损现象,黄河口淡-咸水混合区域pH异常增高现象可以表征无机碳的沉降作用.淡咸水混合初期生物好氧呼吸作用的降低能够导致p_CO2的迅速降低是造成低盐度区pH出现相对于淡水端异常增高现象的主要原因.根据河口溶解物质的保守混合模型,发现混合过程中ΔDIC与ΔTA是1∶1的关系,表明DIC出现亏损是由于HCO^-₃清除造成的,汛期和非汛期黄河口无机碳的沉降作用能够清除输入到河口DIC总量的10%,即黄河口每年可清除1.21×10⁵ t河流输入的溶解无机碳,DIC的有效入海通量约为10.86×10⁵ t,通过评估,黄河流域风化作用吸收的大气CO₂量将有10%左右被河口无机碳沉降作用重新释放到大气中,而流域风化作用固定的CO₂在河口将有2.24×10⁵ t（以CO₂计）重新释放到大气中.     

猫跳河流域梯级水库夏-秋季节溶解无机碳（DIC）含量及其同位素组成的分布特征

于2007年7月(夏季)、10月(秋季)2次对猫跳河流域河流-水库水体样品进行了采集,分析其水化学组成特征,溶解无机碳(DIC)含量及其同位素组成,研究了猫跳河流域河流-水库的碳元素地球化学行为,目的是阐明梯级水库拦截后河流的碳元素含量和碳同位素(δ13CDIC)组成的分布特征.水体DIC及其同位素(1δ3CDIC)组成的总体特征为:DIC含量夏季低于秋季,夏季DIC含量为1.35~2.84 mmol/L,平均值为2.12 mmol/L,秋季DIC含量为2.03~3.98 mmol/L,平均值为2.67 mmol/L;1δ3CDIC值则相反,夏季较秋季偏正,其1δ3CDIC值流域夏季为-10.3‰~-5.1‰,平均值是-8.6‰,秋季为-13.0‰~-6.9‰,平均值为-9.0‰,表明夏季藻类光合作用优先富集12C,水体富集13C.夏季水库的DIC含量随着深度的加深而增大,而δ13CDIC值则随着深度的加深而偏负,表明表层水体受藻类生物作用影响较大,下层水体主要受有机质的降解影响.DIC含量从上游至下游呈逐渐降低的趋势,而δ13CDIC值从上游至下游呈逐渐偏负的趋势,表明河流受水坝拦截后河流水化学性质发生了改...     

闽北海域水体中溶解有机碳的时空变化及其影响因素

为探讨闽北海域水体中溶解有机碳（DOC）时空变化特征及其主要影响因素,于2015年8月、11月、2016年2月和5月对闽北海域环境进行调查,分析该海域DOC时空分布特征,并探讨DOC分布与Chl a、COD、AOU、营养盐、盐度等环境因子的关系。结果表明:2015~2016年闽北海域DOC的含量范围为0.32~2.78 mg/L,均值为1.19 mg/L;季节变化上,秋季>夏季>冬季>春季;空间分布上,整体呈现由近岸向远岸逐渐降低,由南向北逐渐升高的变化趋势,各季节略有差异。DOC与Chl a、COD以及盐度有较强的相关性,与AOU和营养盐的相关性不显著,不同季节影响DOC分布的主要环境因素存在一定差异。研究海域水体中DOC主要受浮游植物光合作用、陆地径流等因素影响,不同季节主要环境因素具有一定差异。     

珠江三角洲表层水中多环芳烃的季节分布、来源和原位分配

分别于2011年4月(春季)和2011年9月(夏季)采集珠江广州河段及东江东莞河段表层水体样品,对该区域表层水体中优控多环芳烃(PAHs)的时空分布、固液分配及其来源进行了分析和讨论.结果表明,珠江广州河段及东江东莞河段表层水体中多环芳烃浓度春季高于夏季.藻类有机碳是该水环境有机碳的主要成分.溶解有机碳(DOC)、颗粒态有机碳(POC)以及叶绿素a(Chl a)含量是控制水体PAHs浓度的主要因素,说明水环境的富营养化程度可以通过增长的浮游生物量来影响多环芳烃的生物地球化学过程,继而影响其环境行为和归宿.多环芳烃在水/颗粒物间的有机碳归一化分配系数(log Koc)与辛醇/水分配系数(log Kow)间存在明显的线性关系,其斜率是夏季大于春季,可能与多环芳烃的非平衡吸附有关.多环芳烃同系物比值法和主成分分析(PCA)的结果表明,研究区域水体中PAHs主要来源于石化燃料、煤和生物质的混合燃烧,并且PAHs的来源未体现出明显的季节变化.通过本研究我们能够比较全面的了解该流域多环芳烃的时空分布状况,固液分配及其可能的来源,并且为珠江广州河段及东江东莞河段多环芳烃污染的控制和生态风险评价提供科学依据.     

闽江河口区文武砂水库水体溶存CH4浓度时空变化特征

甲烷（CH₄）是一种重要的温室气体,在全球气候变化中扮演着重要角色.水库作为大气库中CH₄的重要来源而备受关注.为探究亚热带河口区水库溶存CH₄浓度时空变化特征及其影响因素,于2018年11月（秋季）、2019年3月（春季）和6月（夏季）分别对文武砂水库表层水进行高精度多空间点位采样分析.结果表明,文武砂水库表层水体CH₄浓度在研究期间的变化范围为0.03～27.35μmol·L^-1,呈现春、夏季显著高于秋季的时间变化特征（p<0.01）;在空间变化上,外源输入强度大的库区水体溶存CH₄浓度显著较高,且呈现出由库区沿海区向中心区递减的趋势.相关分析结果显示,水库表层水体CH₄浓度与水温、DOC浓度呈显著正相关关系（p<0.05或p<0.01）,与水体盐度和溶解氧呈显著负相关关系（p<0.01）.本研究结果证实亚热带水库是一个重要的CH₄排放源,库区周边的废水排入等因素影响了CH_4...     

红枫水库和普定水库碳、磷、硅生源要素时空分布特征

选取了营养盐浓度和水体滞留时间存在明显差异的普定水库和红枫水库作为研究对象,通过对两个水库碳、磷、硅生源要素时空变化的分析,揭示了河流筑坝水库营养盐时空分布的主要影响因素.分析结果显示:普定水库表层水体溶解性无机碳(DIC)、总磷(TP)、溶解性总磷(DTP)和溶解性硅(DSi)大体上均表现出冬季较高、夏季较低的变化趋...     

北黄海大气氮氧化物的季节分布

根据2006年夏季2、007年冬春秋四个季节分别对北黄海进行的大面调查,分析研究了四季氮氧化物(NOx)的季节变化和浓度分布。结果显示,大气NOx浓度呈现明显的季节变化,表现为冬季>夏季>秋季>春季,冬季北黄海空气中NOx浓度的平均值分别是春季的4倍、夏季的2倍和秋季的2.1倍。NOx浓度在北黄海的不同区域特征呈现为近岸向远岸逐渐降低的趋势,说明陆源污染物对北黄海NOx分布有较大影响。     

南黄海浒苔绿潮暴发区氨基酸时空分布特征

根据南黄海绿潮发展过程将浒苔绿潮区分为35°N以南和35°N以北2个区域,并利用2018年南黄海海域春、夏季2个航次的调查数据研究分析了浒苔绿潮发生前后2个区域总溶解氨基酸（TDAA）、溶解游离氨基酸（DFAA）的分布特征及变化规律.结果表明,TDAA和DFAA的浓度均基本呈现近岸高远岸底的水平分布特点,35°N以南海域夏季相对于春季水体TDAA、DFAA的浓度整体呈现上升趋势,其中TDAA浓度升高程度明显,表、中层TDAA浓度分别升高了24.8%、60.6%,而35°N以北海域水体中TDAA的浓度却降低了8.7%,其中表层水体TDAA含量下降了30.1%.在DIN浓度较低的35°N以北海域,浒苔的吸收利用可能是造成该区域表层水体TDAA含量降低的重要原因.由此可见,35°N以北海域水体氨基酸等小分子有机氮对浒苔绿潮后期的维持发展起着重要的支持作用.     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes

In this study an effort has been made to use plant polyphenol oxidases; potato （Solanum tuberosum） and brinjal （Solanum melongena）, for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.     

Removal of heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

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Single and joint effects of pesticides and mercury on soil urease

The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase （up to 13%-21%） in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship （P〈0.05） between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose （ED50） values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.     

Isolation and preliminary characterization of a 3-chlorobenzoate degrading bacteria

A study was conducted to compare the diversity of 2-, 3-, and 4-chlorobenzoate degraders in two pristine soils and one contaminated sewage sludge. These samples contained strikingly different populations of mono-chlorobenzoate degraders. Although fewer cultures were isolated in the uncontaminated soils than contaminated one, the ability of microbial populations to mineralize chlorobenzoate was widespread. The 3- and 4-chlorobenzoate degraders were more diverse than the 2-chlorobenzoate degraders. One of the strains isolated from the sewage sludge was obtained. Based on its phenotype, chemotaxonomic properties and 16S rRNA gene, the organism S-7 was classified as Rhodococcus erythropolis. The strain can grow at temperature from 4 to 37℃. It can utilize several （halo）aromatic compounds. Moreover, strain S-7 can grow and use 3-chlorobenzoate as sole carbon source in a temperatures range of 10-30℃ with stoichiometric release of chloride ions. The psychrotolerant ability was significant for bioremediation in low temperature regions. Catechol and chlorocatechol 1,2-dioxygenase activities were present in cell free extracts of the strain, but no （chloro）catechol 2,3- dioxygenase activities was detected. Spectral conversion assays with extracts from R. erythropolis S-7 showed accumulation of a compound with a similar UV spectrum as chloro-cis,cis-muconate from 3-chlorobenzoate. On the basis of these results, we proposed that S-7 degraded 3-chlorobenzoate through the modified ortho-cleave pathway.     

Organochlorine pesticides in soils under different land usage in the Taihu Lake region, China

A field study was conducted in the Taihu Lake region, China in 2004 to reveal the organochlorine pesticide concentrations in soils after the ban of these substances in the year 1983. Thirteen organochlorine pesticides (OCPs) were analyzed in soils from paddy field, tree land and fallow land. Total organochlorine pesticide residues were higher in agricultural soils than in uncultivated fallow land soils. Among all the pesticides, ΣDDX (DDD, DDE and DDT) had the highest concentration for all the soil samples, ranging from 3.10 ng/g to 166.55 ng/g with a mean value of 57.04 ng/g and followed by ΣHCH, ranging from 0.73 ng/g to 60.97 ng/g with a mean value of 24.06 ng/g. Dieldrin, endrin, HCB and α-endosulfan were also found in soils with less than 15 ng/g. Ratios of p,p'-(DDD DDE)/DDT in soils under three land usages were: paddy field ＞ tree land ＞ fallow land, indicating that land usage inlfuenced the degradation of DDT in soils. Ratios of p,p'-(DDD DDE)/DDT ＞1, showing aged residues of DDTs in soils of the Taihu Lake region. The results were discussed with data from a former study that showed very low actual concentrations of HCH and DDT in soils in the Taihu Lake region, but according to the chemical half-lives and their concentrations in soils in 1980s, the concentration of DDT in soils seemed to be underestimated. In any case our data show that the ban on the use of HCH and DDT resulted in a tremendous reduction of these pesticide residues in soils, but there are still high amounts of pesticide residues in soils, which need more remediation processes.     

Sorption of 1-naphthol by plant cuticular fractions

The contribution of aliphatic-rich plant biopolymer to sorption of hydrophobic organic compounds is significantly important because of their preservation and accumulation in the soil environment,but sorption mechanism is still not fully understood.In this study, sorption of 1-naphthol by plant cuticular fractions was examined to better understand the contributions of respective fraction.Toward this end,cuticular materials were isolated from the fruits of tomato by chemical method.The tomato cuticle sheet consisted of waxes (6.5 wt%),cuticular monomer (69.5 wt%),and polysaccharide (24.0 wt%).Isotherms of l-naphthol to the cuticular fractions were nonlinear (N value (0.82-0.90)) at the whole tested concentration ranges.The KodKow ratios for bulk cuticle (TC1),dewaxed cuticle (TC2),cutin (TC4),and desugared cuticle (TC5) were larger than unity,suggested that tomato bulk cuticle and cutin are much powerful solption medium.Sorption capability of cutin (TC4) was 2.4 times higher than the nonsaponifiable fraction (TC3).The 1-naphthol interactions with tomato cuticular materials were governed by both hydrophobic-type interactions and polar (H-bonding) interactions. Removal of the wax and polysaccharide materials from the bulk tomato cuticle caused a significant increase in the sorption ability of the cuticular material.There was a linear negative trend between K_(oc) values and the amount of polysaccharides or fraction's polarities ((N O)/C);while a linear positive relationship between K_(oc) values and the content of cutin monomer (linear R~2=0.993) was observed for present in the cuticular fractions.Predominant sorbent of the hydrophobic organic compounds (HOCs) in the plant cuticular fraction was the cutin monomer,contributing to 91.7% of the total sorption of tomato bulk cuticle.     

Alterations of organ histopathology and metallolhionein mRNA expression in silver barb, Puntius gonionotus during subchronic cadmium exposure

Common silver barb,Puntius gonionotus,exposed to the nominal concentration of 0.06 mg/L Cd for 60 d,were assessed for histopathological alterations(gills,liver and kidney),metal accumulation,and metallothionein(MT)mRNA expression.Fish exhibited pathological symptoms such as hypertrophy and hyperplasia of primary and secondary gill lamellae,vacuolization in hepatocytes,and prominent tubular and glomerular damage in the kidney.In addition,kidney accumulated the highest content of cadmium,more than gills and liver.Expression of MT mRNA was increased in both liver and kidney of treated fish.Hepatic MT levels remained high after fish were removed to Cd-free water.In contrast,MT expression in kidney was peaked after 28 d of treatment and drastically dropped when fish were removed to Cd-free water.The high concentrations of Cd in hepatic tissues indicated an accumulation site or permanent damage on this tissue.     

Seed selections for crystallization of calcium phosphate for phosphorus recovery

Seed induces and promotes the crystallization of calcium phosphate, and acts as carrier of the recovered phosphorus （P）. In order to select suitable seed for P recovery from wastewater, three seeds including Apatite （AP）, Juraperle （JP） and phosphate-modified Juraperle （M-JP） were tested and compared. Batch and fixed-bed column experiments of seeded crystallization of calcium phosphate were undertaken by using synthetic wastewater with 10 mg/L P phosphate. It shows that AP has bad enduring property in the crystallization process, while JP has better performance for multiple uses, and M-JP is a hopeful seed for P recovery by crystallization of calcium phosphate.