Mangrove forest degradation indicated by mangrove-derived organic matter in the Qinzhou Bay,Guangxi,China,and its response to the Asian monsoon during the Holocene climatic optimum

The response of mangrove ecosystems to the Asian monsoon in the future global warming can be understood by reconstructing the development of mangrove forests during the Holocene climatic optimum（HCO）, using proxies preserved in coastal sediments. The total organic matter in sediments of a segmented core, with calibrated age ranges between 5.6 and 7.7 cal. ka BP and corresponding to the HCO, from the Qinzhou Bay in Guangxi, China, is quantitatively partitioned into three end-members according to their sources： mangrove-derived, terrigenous,and marine phytoplanktonic, using a three-end-member model depicted by organic carbon isotope（δ13Corg） and the molar ratio of total organic carbon to total nitrogen（C/N）. The percentage of mangrove-derived organic matter（MOM） contribution is used as a proxy for mangrove development. Three visible drops in MOM contribution occurred at ca. 7.3, ca. 6.9, and ca. 6.2 cal. ka BP, respectively, are recognized against a relatively stable and higher MOM contribution level, indicating that three distinct mangrove forest degradations occurred in the Qinzhou Bay during the HCO. The three mangrove forest degradations approximately correspond to the time of the strengthened/weakened Asian winter/summer monsoon. This indicates that even during a period favorable for the mangrove development, such as the HCO, climatic extremes, such as cold and dry events driven by the strengthened/weakened Asian winter/summer monsoon, can trigger the degradation of mangrove forests.

Combination of chlorine and magnetic ion exchange resin for drinking water treatment of algae

The effectiveness of a magnetic ion exchange resin （MIEX） for the treatment of Hongze Lake water in China was evaluated, The kinetics of natural organic matter （NOM） removal at various MIEX doses and contact time, multiple-loading experiments, impacts of MIEX prior to coagulation on coagulant demands and the effectiveness of combination of MIEX, pre-chlorination and coagulation were investigated. Kinetic experimental results show that more than 80% UV254 and 67% dissolved organic carbon （DOC） from raw water can be removed by the use of MIEX alone. 94% sulfate, 69% nitrate and 98% bromide removals are obtained after the first use of MIEX in multiple-loading experiments. It is suggested that MIEX can be loaded up to 1 250 bed volume （BV, volume ratio of tested water to resin） or more without saturation when regarding organics removal as a target. MIEX can remove organics to a greater extend than coagulation and lower the coagulant demand when combining with coagulation. Chlorination experimental results show that MIEX can remove 57% chlorine demand and 77% trihalomethane formation potential （THMFP） for raw water. Pre-chlorination followed by MIEX and coagulation can give additional organic and THMFP removals. The results suggest that MIEX provides a new method to solve thc problem algae reproduction.

Organic Material and Trace Elements of Bituminous Rocks in the Ozank(?)y Field,Ankara,Turkey

Bituminous rocks in the Ozankoey （Ankara） field are different from those of the Paleocene- Eocene Mengen and Giineytepe （Bolu） regions in metal enrichment levels. Organic carbon （Corg） content of organic material-rich rocks in the Ozankoey （Ankara） field is 3.66-40.72% wt averaging 14.34%. The dominant organic materials are algae/amorphous accompanied by minor amount of herbaceous material （The dominant kerogen type is Type-I with a limited amount of Type-Ⅱ kerogen.）. The bituminous rocks in the Ozankoey field are enriched in heavy metals such as Ni, Mn, As and Cr. In comparison with the average enrichment values of dements, Ni, Mn, As and Cr in bituminous shales of the Ozankoey field are as about 4.38, 14.93, 10.90 and 5.58 times as average values. The average concentrations of these heavy metals are also as high as 215× 10^-6, 828 × 10^-6, 58.54 × 10^-6, and 148 × 10^-6 respectively. In addition, sorption properties of day and organic materials are also important for metal enrichments in the bituminous shales.

The Dietary Importance of Kelp-Derived Detritus to Pelagic and Benthic Consumers along the West Coast of Vancouver Island, Canada

Stable isotope analysis was used to determine the relative dietary importance of kelp-derived detritus to plankton and benthic organisms along a gradient of kelp abundance driven by recovering sea otter populations along the west coast of Vancouver Island (WCVI), Canada. The study used region-specific kelp isotope values (δ13C and δ15N) and season-specific phytoplankton isotope values to model dietary contributions of kelp-derived detritus (KDD). In general, KDD contributions were moderate to high in most plankton size fractions during the summer and decreased during the winter, particularly in the kelp sparse region. Hypothesized regional and spatial (distance from the coast) differences in kelp detritus contributions to zooplankton were not evident. Modeled estimates of the KDD contribution to benthic invertebrates were high (>40%) and independent of the organism size, among regions and between seasons, with the exception of Astraea gibberosa in the kelp abundant region. Local oceanography, natural kelp isotope signature variation, and significant overlap between kelps’ and blooming phytoplankton isotope values led to a large uncertainty in the assessed KDD contributions in benthic organisms. These results highlighted the importance of the KDD as a widespread and stable year-round food source in coastal kelp populated regions.

藻源有机质对近海沉积物微生物群落结构影响

为研究赤潮产生的藻源有机质(AOM)对近海沉积物中微生物群落结构的影响,利用宏基因组学分析探究AOM对沉积物细菌和真菌结构的影响.结果表明,AOM降低了细菌和真菌的α多样性,并改变了细菌和真菌群落的β多样性.此外,AOM能够改变细菌和真菌的组成,微生物相对丰度在不同处理中呈现显著的时间异质性.AOM的存在能够改变细菌和真菌的种间关系,增强参与AOM分解代谢微生物之间的联系,并最终导致细菌和真菌共生模式的改变.

Organic matter produced by algae and cyanobacteria: Quantitative and qualitative characterization

This work aims at characterizing organic matter produced by an alga Euglena gracil~ and a cyanobacteria Microcystis aeruginosa and assessing the evolution of its characteristics during growth. A culture medium was optimized. The species growth phases were monitored using both visible spectrophotometry and flow cytometry cell counting. Organic matter fractionation according to hydrophobicity and specific UV absorbance （SUVA） index were used to specifically characterize the produced algal organic matter （AOM）. The AOM characteristics were both growth phase and species dependent. However, a similar evolution was observed. The hydrophilic fraction （HPI） was the major fraction whatever the growth phases and was almost the only one produced during lag and exponential phases. It represented around 75% of AOM during exponential phase and then decreased when the stationary phase appeared. It represented 46% and 60% of the AOM during late decline phase for the cyanobacteria and the alga respectively. The hydrophobic （HPO） and transphilic （TPH） fractions started to appear from the beginning of the stationary phase with more hydrophobic compounds coming from intracellular organic material of dying cells. HPO and TPH percentages still increased during the decline phase probably because of two additional processes： photo-dissolution and leaching of particulate organic matter from cells fragments. A comparison of AOM during late decline phase and natural organic matter （NOM） from Glane River （France） underlined that AOM was more fiydrophilic and presented a lower SUVA for each fractions than NOM. However, the difference between NOM and AOM hydrophobicity narrowed during decline phase.

Experimental study of gold distribution in the algae-organic matter-fluid system

THE previous simulating experiments show that many algae can greatly accumulate goldfrom solution under some conditions. Some other experiments further indicate that organ-ic matter and crude oil can also play an important role in gold geochemistry processes such asleaching, migration, reduction and precipitation. However, these biometallogeneses are

岩溶水库藻源性有机质来源对表层沉积物有机碳矿化过程的影响

岩溶水生环境富含HCO-3,有利于内源藻类发生生物碳泵作用,形成大量藻源有机质沉积到库底。丰富的藻源性有机质在沉积物中发生矿化作用,影响有机质埋藏过程,影响岩溶水生环境碳循环过程和碳汇潜力。为探究藻源性有机质对矿化作用的影响和岩溶水生环境碳循环稳定性的影响,以岩溶地下水补给型水库(广西大龙洞水库)为研究对象,初步分析从上游到下游不同区域藻源有机质对表层沉积物有机质矿化过程的影响。结果表明:大龙洞水库有机质主要来源为内源藻类(20.9%~65%)和外源土壤(11.8%~53.4%)且具有一定的空间差异,水库上游以土壤来源为主,下游以藻类来源为主。大龙洞水库表层沉积物矿化过程在空间上呈现上游潜在矿化量高于下游潜在矿化量,产生差异的主要因素是在岩溶高溶解无机碳水环境中,藻源性有机碳对微生物矿化过程具有抑制性,降低矿化强度。在生物碳泵作用和无机碳保护下,以藻源性来源为主的岩溶水库表层沉积物有机碳潜在埋藏总量略高于岩溶区土壤的潜在埋藏总量,表明岩溶水库沉积物有着稳定的有机成分积累。

Evidence on the causes of the rising levels of COD_(Mn) along the middle route of the South-to-North Diversion Project in China:The role of algal dissolved organic matter

As the biggest inter-basin water transfer scheme in the world,the South-to-North Water Diversion Project(SNWD) was designed to alleviate the water crisis in North China.The main channel of the middle route of the SNWD is of great concern in terms of the drinking water quality.In this study,we tested the hypothesis that the dissolved organic matter(DOM) derived from the planktonic algae causes the rising levels of COD_(Mn) along the middle route by monitoring data on water quality(2015-2019,monthly resolution).The results showed that algal density in the main channel increased along the channel and was significantly correlated with COD_(Mn)(p <0.01).Five fluorescent components of DOM,including tyrosine-like(14.85%),tryptophan-like(22.48%),microbial byproduct-like(26.34%),fulvic acid-like(11.41%),and humic acid-like(24.92%) components,were detected.The level of tyrosine-like components increased along the channel and was significantly correlated with algal density(p<0.01),indicating that algae significantly changed the level of DOM in the channel.Algal decomposition and metabolism were found to be the main mechanisms that drive the changes in COD_(Mn).Therefore,controlling algal density would be an important measure to prevent further increase in CODMn and for the guarantee of excellent water quality.

藻源性有机质对高原深水湖泊沉积物矿化作用的激发效应

湖泊营养水平提升,浮游植物快速增殖,大量藻类碎屑沉降到沉积物表面。藻屑作为新生不稳定有机质,对湖泊沉积物有机质(SOM)产生激发效应,影响湖泊沉积物碳循环过程。本文以深水湖泊抚仙湖南湖心沉积物为研究对象,采用优势种水华束丝藻(Aphanizomenon flos-aquae),进行不同浓度藻屑添加(×1倍组、×5倍组和×10倍组)的培养实验。应用碳同位素在线监测仪,探究藻屑添加对于SOM矿化作用的激发效应并预测可能产生的环境效应。结果表明:(1)添加的藻屑对上覆水和间隙水发光性溶解性有机质(CDOM)组成和性质产生影响,前期CDOM中类蛋白组分含量显著增加,但后期CDOM腐殖化程度升高。同时,藻屑的添加使二氧化碳(CO_(2))释放量增大,蛋白酶活性和转化酶活性增强;(2)3个不同浓度的藻屑添加组均检测到不同程度激发效应,其中×1倍组和×5倍组对SOM矿化过程前期体现为正激发效应,最大值分别达到(12.18±0.65)和(26.60±9.14)μg/(mL ws),后期两个组别都转为负激发效应;×10倍组则在整个实验过程中均表现为负激发效应;(3)藻屑的添加使得间隙水易于富集亚铁离子(Fe^(2+))和硫离子(S^(2-));且沉积物反硝化作用受到抑制,易于富集硝酸根(NO_(3)^(-));同时沉积物碱性磷酸酶活性升高,促进活性磷释放,藻屑的添加增大了抚仙湖沉积物产生黑色物质和水体富营养化的风险。因此系统研究新生有机质输入对抚仙湖SOM的生物地球化学过程的影响将为保护抚仙湖提供理论依据。

福林酚比色法测定海藻多酚的反应条件优化

为明确福林酚比色法测定海藻多酚含量的反应条件,本研究采用单因素试验和正交试验相结合的方法,优化了福林酚用量、碳酸钠用量、反应时间、反应温度等福林酚法测海藻多酚含量的检测条件;并进一步分析了外源物质(有机物质、无机离子)对测定结果的影响。结果表明,应用福林酚比色法测定海藻多酚的最佳反应条件为:12%福林酚5 ml、3%碳酸钠4 ml、反应温度37℃、反应时间30 min、最佳吸收波长730 nm;该方法的加标回收率为96.70%-103.67%,相对标准差2.68%。优化的福林酚法测得7种藻类的多酚含量为120.0~273.0 mg/L,其测定结果与国家标准茶多酚检测法的检测结果一致。外源添加1%或5%的Cu^(2+)、Ni^(2+)、Mn^(2+)、Cl^(-)、I^(-)、蛋白质、可溶性淀粉测定结果增加2.31%-149.79%;添加5%的Zn^(2+)、CO_(3)^(2-)、NO_(3)^(-)、PO_(4)^(3-)测定结果显著降低,而山梨酸钾、葡萄糖、D-山梨醇对福林酚比色法检测海藻多酚含量无明显影响。本研究建立的海藻多酚检测法的稳定性、重现性以及加标回收率的相对标准差均低于3%,符合检测要求。

渔业养殖区藻源溶解性有机质性质特征对汞甲基化影响

溶解性有机质(dissolved organic matter,DOM)是水生生态系统中的重要成分,能够显著影响汞的甲基化等形态变化过程.以近岸渔业养殖区藻源DOM为研究对象,运用傅里叶变换红外光谱和三维荧光光谱技术,对其结构特征进行表征;并选取总有机碳浓度TOC_(DOM)=10 mg·L^(-1)(DOM_(10))和TOC_(DOM)=50 mg·L^(-1)(DOM_(50))两种水平藻源DOM提取液,分析其在不同汞浓度条件下对汞甲基化过程的影响.结果表明,藻源DOM主要由类蛋白和类腐殖质组分组成,其中前者含量较高,疏水及芳香组分含量较低;红外光谱显示藻源DOM中含有—OH、—CH3、—CH2、芳香性C=C等官能团.甲基化实验表明,在溶液中DOM含量相对较少时(DOM:Hg浓度比≤15625),DOM表现出抑制汞甲基化的趋势,而当溶液中DOM含量逐渐升高(DOM:Hg浓度比>15625),DOM可以显著促进水体中汞向甲基汞的转化.藻源DOM既能作为碳氮来源提高微生物活性,为汞的甲基化提供甲基供体,又可以与溶液中Hg^(2+)发生络合,从而影响汞甲基化过程.在汞溶液浓度相对较低时,DOM对汞甲基化过程的影响主要表现为提供大量的甲基供体,同时作为微生物利用的底物,促进无机汞向甲基汞的转化,甲基汞转化率最高可达0.257%;但在高汞浓度条件下,DOM对汞的络合作用降低了无机汞的微生物可利用性,水体中甲基汞下降,表现出抑制作用.

水华鱼腥藻源有机物混凝去除特性研究

混凝工艺对水中的藻类去除规律的研究有助于对混凝工艺的理解和应用。文章利用引黄河水库水与水华鱼腥培养液混合配制了模拟高藻水,研究不同条件下其消毒副产物的生成特性,探讨藻源有机物及其消毒副产物混凝去除规律。结果表明:模拟高藻水的有机物主要包括微生物代谢产物、腐殖酸、酪氨酸和色氨酸;不同成分模拟高藻水均会生成三卤甲烷和N,N-二甲基亚硝胺(N-Nitrosodimethylamine,NDMA),且含胞内有机物的模拟水样有更高的三卤甲烷和NDMA生成潜能;混凝对模拟高藻水有机物的去除效果一般;而对不同类型消毒副产物前体物去除能力不同,对三卤甲烷前体物去除率最高,为60.9%,NDMA前体物最高去除率只有28.1%;混凝对含稳定期藻源有机物的水样去除效果最好,对含藻类指数期与稳定期的水样去除机理以电中和吸附为主,衰亡期以网捕和卷扫为主。

预氧化耦合超滤工艺净化处理含藻水研究进展

湖库等水源地藻类暴发问题依然突出,严重威胁着居民的饮水安全。超滤可以有效截留藻细胞,但在含藻水净化时仍面临着溶解性有机物去除率低、膜污染等瓶颈。为提升净化效率,氧化预处理耦合超滤工艺在含藻水处理领域受到了越来越多的关注。基于此,文章系统地分析了超滤工艺净化含藻水的效能,综述了氯、臭氧、紫外、过硫酸盐和高锰酸盐耦合超滤工艺净化含藻水的研究进展,对氧化预处理耦合超滤工艺净化含藻水的应用前景进行了总结和展望。

Thermal-induced polycondensation of soluble organic matter in coal of lower maturation stage

A brief discussion is given to the thermal-induced polycondensation of soluble organic matter (SOM) in coal during lower maturation stage, based on laboratory simulation on hydrocarbon generation from coal and on correlation with natural maturation of coal. An essential relationship between the retrogressive variation of SOM and thermal-induced polycondensation during the lower maturation stage has been established.

磁性离子交换树脂对原水中有机物去除效能的研究

采用磁性离子交换树脂(MIEX)预处理原水中有机物的中试试验结果表明,MIEX技术可有效地去除原水中的有机物,对UV254,DOC和CODMn的去除率分别稳定在82%、66%和50%,MIEX预处理可以有效强化混凝沉淀对有机物、藻细胞和浊度的去除.与常规工艺相比,在混凝剂聚合氯化铝投加量降低56%时,该工艺对UV254和CODMn的去除率分别为90%和71%,对藻细胞数和浊度的去除率分别为99%和95%.对溶解性有机物分级和分子量分布的测定表明,MIEX预处理主要去除混凝沉淀无法有效去除的小分子区间的亲水性和疏水性有机物,可以有效控制消毒副产物的产生,MIEX预处理与混凝沉淀联用工艺出水的三卤甲烷生成势(THMFP)和卤乙酸生成势(HAAFP)比原水降低了88%和87%.

藻类及其胞外分泌物对净水工艺的影响

以原水中常见蓝绿藻及其胞外分泌物的基本性质为基础,概述了目前净水工艺除藻的一般方法和原理,以及藻类及其胞外分泌物对净水工艺的影响,指出应特别关注胞外分泌物在净水处理中对消毒副产物的贡献及去除方法,采用组合工艺优化处理效果。

藻类对土壤肥力的影响

通过完全蔽光和正常光照两个对照实验组,研究了光照、植物和藻类3个因子对土壤有机质、有效磷、微生物的影响.由极差分析知,混合藻对有效磷的变化和微生物数量的提高起主导作用.作者认为在80d内,混合藻类是藻类数量和有机质变化的主要原因;80d后,光照起主要的作用.在各处理组中,混合藻和光照的作用都强于植物的作用.土壤藻类对土壤肥力有明显的影响,与高等植物共同作用,对土壤肥力的提高效果明显.

基于高光谱特征的土壤有机质含量估测研究

在室内条件下,利用ASD2500高光谱仪测定了潮土和水稻土自然风干土壤样品的光谱。通过系统分析两种不同类型土壤的高光谱特征差异及其有机质含量的敏感波段区位,建立了土壤有机质含量的光谱估测模型。结果表明,具有相同有机质含量的两种类型土壤整体光谱变化趋势无明显差别,但反射率表现出明显差异,一阶导数变换能较好地显现谱图中的肩峰。潮土和水稻土有机质的敏感波段集中在相同区域,原始反射率在685 nm处相关性最高,而一阶导数光谱在554 nm处相关性最高。通过对整体样本的多元逐步回归分析,筛选出两种土壤有机质相同的敏感波段为800 nm、1 398 nm和546 nm。进一步以一阶导数为自变量,基于1 400nm和554 nm两个波段构建了土壤有机质差值指数SOMDI及估测模型,即Y=4.19 12.85×(R_FD554 R_FD1 400)。利用独立的样本对建立的光谱模型进行了检验,预测决定系数均达0.79以上。上述结果表明,利用高光谱技术可实现土壤有机质的快速监测与诊断。

利用土壤微藻改良贫瘠土壤的研究

将自然条件下肥沃土壤中的微藻接种到贫瘠土壤中 ,分别在黑暗和光照条件下进行培养 ,结果显示 :黑暗条件下的微藻在 30d内进入休眠状态或死亡 ;在光照条件下 ,微藻的数量在第 30d以后迅速增殖 ,随着藻类的生长 ,土壤pH值也发生了一定变化 ,且藻类数量的变化与土壤有机质和土壤有效磷的变化呈极显著相关 ,说明土壤微藻能改善贫瘠土壤的微生态环境和提高土壤肥力 。