于桥水库网箱养鱼对水质影响分析

本文通过采样监测分析了网箱养鱼对水质的影响。分析结果表明,网箱养鱼明显增加了水库水体中藻类密度ＣＯＤ、ＴＰ、ＴＮ的含量,并引起水温上升,溶解氧减少,促进水库富营养化进程,是水质恶化的重要之一。同时,残余饵料和粪便的沉积,增加了底质中的有机质ＴＰ和ＴＮ,造成水库水体的二次污染。     

海洋酸化对藻类生态学效应及作用机制的研究进展

目前全球海洋酸化(ocean acidification, OA)问题正在以前所未有的速度快速恶化,使海洋生物以及海洋生态环境面临着巨大的威胁。藻类作为海洋中最主要的初级生产者,贡献了约95%的初级生产力,是物质循环和能量流动的重要环节。海洋酸化能够改变藻类的初级生产力,从而影响海洋食物网中物质和能量从初级到次级生产者及更高营养级的传递,引发食物链效应,进而对整个海洋生态系统带来不可逆转的影响,因此评估海洋酸化对藻类的影响具有重要的生态学研究意义。本文总结了近年来海洋酸化对藻类的光合作用、碳固定、生长、钙化、繁殖等生理生化过程以及对代谢组分和显微结构的影响,归纳了海洋酸化对藻类的分子调控机制,同时围绕海洋酸化与环境因子以及海洋污染物对藻类的复合胁迫展开综述,并基于当前海洋酸化对藻类影响研究中存在的不足做出展望,以期为人们解决海洋酸化问题提供思路和方法。     

台风强降雨输入水源水库的泥沙沉降模拟分析

台风强降雨作用能够引起湖泊水体中悬浮泥沙含量升高、水体营养盐浓度改变、透明度降低,使得藻类生长受到影响。目前关于水体中悬浮泥沙静态沉降的研究主要集中在正常条件下,而有关极端气候台风强降雨后泥沙自然沉降过程对水质的影响研究还相对较少。因此,进行台风强降雨输入水源水库的泥沙静态沉降实验研究,对于分析识别极端气候条件对水源水库水质和富营养化的影响具有重要意义。该研究于2015年10月强台风"彩虹"登陆粤西期间,采集台风强降雨后高州水库含悬浮泥沙的原水,通过实验模拟台风强降雨期间水库含沙原水自然沉降过程中水环境因子的变化情况,分析台风强降雨输入的泥沙沉降对高州水库水质的影响。结果表明,泥沙沉降过程中水体水质变化明显,随沉淀时间延长,水体溶解氧、pH、泥沙含量、浊度、氮磷浓度、叶绿素a、综合营养状态指数(Trophic Level Index,TLI)降低,透明度增大,氮磷比呈先增加后降低趋势;水体叶绿素a浓度与浊度、泥沙含量、总磷、pH和溶解氧呈显著正相关(P0.001),且与浊度的相关系数最高(r=0.941,P0.001),与透明度呈显著负相关(P0.001),与总氮、电导率、CODMn的相关性未达到显著水平(P0.01);台风后约9d时间,水体pH、电导率、溶解氧、透明度、浊度和泥沙含量可以恢复至正常水平;台风强降雨输入高州水库的泥沙沉降作用降低了水体磷营养盐和叶绿素a浓度,使得综合营养状态指数TLI由中营养水平的41.6降低至贫营养水平的23.4,减缓了高州水库富营养化进程。     

青海尕海盐湖初级生产力特点

１９９７ 年夏季对青海尕海盐湖的生态系统进行了初步研究． 初级生产力研究结果表明：（１） 水域毛初级产氧量平均值为３ ．２７３ｇ ｍ －２ｄ－１ ,其中底栖藻类占７０．９９％ ,底栖藻类单位面积毛初级生产力是浮游植物的２．４５倍．（２） 水域初级生产力构成格局为：由沿岸到湖心区,随着水深的逐步增大,底栖藻类初级生产力逐步减少,浮游植物初级生产力逐渐占主导地位． 前者所占的比例在０．５５ ｍ 水深时为９７．７２ ％ ,在大于１３．０ ｍ 水深后即降至０．０ ％ ．（３）与国际有关文献相比,尕海盐湖初级生产力较低     

秸秆还田配施氮肥对砂姜黑土有机质组分与碳库管理指数的影响

在安徽蒙城砂姜黑土上进行4 a的秸秆还田定位试验,研究砂姜黑土耕层土壤有机质组分和碳库管理指数的变化特征,分析不同有机质组分、作物产量以及碳库管理指数之间的相关性。结果表明,秸秆还田显著提高了砂姜黑土耕层土壤总有机质、活性有机质含量和碳库管理指数(P0.05),秸秆还田配施360~720 kg·hm-2氮肥较秸秆还田但不施肥土壤总有机质、活性有机质含量和碳库管理指数分别提高10.1%~15.8%、20.4%~32.5%和41.7%~74.6%。秸秆还田且配施540 kg·hm-2氮肥处理土壤活性有机质含量增幅最高,且主要提高了惰活性有机质组分含量。玉米产量与土壤总有机质、活性有机质含量和碳库管理指数均表现为显著相关(P0.01)。秸秆还田配施氮肥促进了土壤有机质质量水平,尤其是与540 kg·hm-2氮肥配施对土壤有机质含量的提高效果显著。     

惠州白盆珠水库沉积物营养元素时空变化特征及源解析

为了探究自然过程和人类活动对水库水环境演变过程的影响,采集广东惠州白盆珠水库表层沉积物和沉积柱样品,测定表层沉积物总氮(TN)、总磷(TP)和总有机碳(TOC)含量,将水库划分为入库区、中部区和近坝区,分析表层沉积物的营养元素空间分布特征;利用放射性核素(~(210)Pb)和稳定初始放射性通量(CIC)模式为长度为27 cm的沉积柱建立年代序列,测定沉积柱TN、TP、TOC含量,碳稳定同位素(δ~(13)C)值和粒径垂向分布特征,分析营养元素时间分布特征及来源。结果表明:表层沉积物TN、TP和TOC含量分别在水库3个区域间无显著性差异(P0.05),营养物质污染程度低;沉积柱沉积历史约53年,平均沉积速率为0.5 cm·a~(-1);沉积柱TN、TP和TOC含量垂向分布特征可分为3个阶段:1983年之前含量均保持相对稳定,1984—2004年受人类活动影响而逐渐增加,2005—2018年呈先减小后逐渐增加趋势;沉积柱的总有机碳与总氮比值(C/N)和δ~(13)C指示沉积物中的有机质为陆源和内源的混合来源,由于白盆珠水库具有供水功能,以及流域内水土流失控制措施,陆源有机质占比与珠江三角洲其他水库相比较低,约占50%。     

金盆水库表层沉积物中营养盐分布特征与污染评价

为探究西安黑河金盆水库表层沉积物中营养盐的分布特征及其污染状况,本研究测定了表层沉积物中总氮(TN)、总磷(TP)和有机质(OM)的含量,并与其它湖库进行比较,分析了TN、TP和OM的相关性,并探究了表层沉积物中营养元素的来源及其污染状况.结果表明,TN平均含量为1132 mg·kg~(-1),TP平均含量为1131 mg·kg~(-1),OM平均含量为7.02%,三者空间变化趋势基本一致,从上游至库区,含量先减小后增加.与其它湖库相比,金盆水库表层沉积物中TN含量相对较小,TP和OM含量均处于中等水平.TOC/TN值表明,水库表层沉积物中OM均来源于高等陆生植物.TOC与TN、TP均存在显著的相关性,且与TN相关性更高,表明金盆水库表层沉积物有机质的矿化过程与氮、磷,尤其是氮的物质来源和沉积变化过程关系更为密切.根据沉积物质量评价指南,TN、TP和TOC含量均达到最低级别,说明金盆水库已受到一定程度的污染.     

不同类型外加碳源对制药污泥堆肥过程中青霉素降解的影响

以制药污泥为研究对象,采用葡萄糖、蔗糖、玉米秸秆粉及其混合物作为外加碳源,研究不同类型的外加碳源对堆肥系统一次发酵周期内温度、有机质等理化参数变化及青霉素的降解情况的影响.结果表明,堆体中有机质含量与外加碳源的量呈正比,堆体中有机质的质量分数随堆肥时间不断下降且趋于稳定.温度是青霉素降解的主要影响因素.外加碳源增加了堆体溶解性有机质质量分数,生物可利用碳源的增加促进了堆肥过程中微生物的转化作用,并有助于提高堆肥过程温度.在堆肥周期内外加碳源可以提高青霉素的降解速率(15 d内对照组青霉素降解率为94.44%,其他组均大于95%),且外加蔗糖与玉米秸秆粉的混合碳源处理组青霉素降解速率最快(15 d内降解率可达到99.08%).堆肥过程中升温阶段(中温阶段和高温阶段)青霉素含量与温度呈负相关(P0.01),与溶解性有机碳呈正相关(P0.01).15 d内所有处理组青霉素降解率均可以达到90%以上.     

胶州湾棘皮动物的数量变化及与环境因子的关系

利用1998～2002年19个季度月胶州湾10个站的海洋调查资料，对底栖棘皮动物的数量变化及与环境因子的关系进行了初步研究．胶州湾棘皮动物平均总生物量11．82g／m^3，平均总栖息密度5．63个／m^3．分布区主要在1、3、4、7号站，底质沉积类型为粉砂-粘土、有机质含量较高的区域．棘皮动物的分布除与底质有关外，其数量变化与温度、初级生产力关系较明显，二者升高，其生物量、密度也较明显升高．图5表3参9     

100年来东湖富营养化发生的沉积学记录

在210Pb计年的基础上,运用水生生物遗存、色素、有机碳同位素和磁化率分析了东湖钻孔沉积物中的生物与环境信息,重建了东湖100多年来湖泊营养与环境演化历史.研究发现东湖100多年来在人类活动不断增强的背景下,指示重金属污染的磁化率和指示湖泊富营养化的色素指标如蓝藻叶黄素(Myx)、颤藻黄素(Osc)快速上升,相应的水生生物如介形虫、腹足类、水生高等植物等表现明显的组合和变化阶段,同时有机碳同位素偏正与湖泊生产力升高和藻类繁盛有关.沉积记录表明东湖生态系统近代发生了深刻变化,湖泊营养演化自早至晚呈现四阶段性:贫营养阶段(1900-1966AD)色素水平低、拥有较丰富的水生高等植物和腹足类;中营养阶段(1966-1983AD)色素含量增高、水生高等植物和腹足类减少;富营养化阶段(1983-1989AD)色素含量快速增高、水生高等植物消失;超富营养化阶段(1989AD－至今)色素含量稳定居高、某些耐污染的介形类较繁盛.结果对于认识湖泊生态环境演化与人类活动的关系、以及如何治理湖泊环境具有现实的意义.     

粤西三座重要供水水库沉积物营养盐负荷与重金属污染特征

为揭示粤西3座供水水库（高州水库、鹤地水库、大水桥水库）沉积物营养盐负荷及重金属污染特征,于2008年6月在各水库大坝前湖泊区采集柱状沉积物,运用SMT法、碱性过硫酸钾消解法、烧失法和ICP-MS法分别测定其柱状沉积物中氮磷营养盐、有机质和7种重金属（Cu、Pb、Zn、Cd、Ni、Cr与Hg）的含量,并采用潜在生态风险指数法对表层重金属污染的潜在生态风险进行评价,同时通过相关性分析重金属的可能来源。结果表明：3座水库沉积物总氮质量分数为1.13~3.37 mg·g-1,有机质为11.83~20.37 mg·g-1,其表层总氮、有机质的质量分数大小顺序为高州水库〉大水桥水库〉鹤地水库,总磷的质量浓度在0.22~0.77 mg·g-1之间,其表层总磷质量分数大小顺序为高州水库〉鹤地水库〉大水桥水库,在垂直剖面上,总氮、总磷与有机质的质量分数在16 cm至表层沉积物垂直断面显著高于其他断面,表明近些年来水库内源营养盐负荷逐渐加重。重金属质量分数平均值均高于广东省土壤环境背景值,总体呈现随深度增加而降低的趋势,但3座水库间重金属质量分数差异较大,其中鹤地和高州水库的Zn和Pb污染相对严重（质量分数分别为Zn：353.15、693.35 mg·kg-1;Pb：74.51、127.91 mg·kg-1）,大水桥水库的Cr和Ni污染相对严重（质量分数分别为Cr：238.69 mg·kg-1;Ni：251.06 mg·kg-1）。潜在生态风险评价表明,3座水库Cd和Hg具有高的生态危害,应引起重视,其他重金属则处于轻微的生态危害等级。同时沉积物高有机质的质量浓度经矿化分解可能加剧水体重金属生态危害。根据相关性分析和其他相关资料可知,粤西农业区大量化肥农药面源污染汇入造成水库初级生产力提高并最终沉降可能是沉积物营养盐、有机质与重金属的主要来源。     

Detritus-Bacteria-Meiofauna interactions in a seagrass bed (Posidonia oceanica) of the NW Mediterranean

The biochemical composition of the sediment organic matter, and bacterial and meiofaunal dynamics, were monitored over an annual cycle in aPosidonia oceanica bed of the NW Mediterranean to test the response of the meiofauna assemblage to fluctuations in food availability. Primary production cycles of the seagrass and its epiphytes were responsible for relatively high (compared to other Mediterranean systems) standing stocks of organic carbon in sediments (from 1.98 to 6.16 mg Cg^–1 sediment dry weight). The biopolymeric fraction of the organic matter (measured as lipids, carbohydrates, and proteins) accounted for only a small fraction (18%) of the total sedimentary organic carbon. About 25% of the biopolymeric fraction was of microphytobenthic origin. Sedimentary organic carbon was mostly refractory (56 to 84%) and probably largely not utilizable for benthic consumers. The biopolymeric fraction of the organic matter was characterized by high carbohydrate concentrations (from 0.27 to 5.31 mg g^–1 sediment dry weight in the top 2 cm) and a very low protein content (from 0.07 to 0.80 mg g^–1 sediment dry weight), which may be a limiting factor for heterotrophic metabolism in seagrass sediments. RNA and DNA concentrations of the Sediments varied significantly during the year. High RNA and DNA values occurred during the microphytobenthic bloom and in correspondence with peaks of bacterial abundance. Bacteria accounted for a small fraction of the total organic carbon (0.65%) and of the biopolymeric organic carbon (4.64%), whilst microphytobenthos accounted for 3.79% of total organic carbon and for 25.08% of the biopolymeric carbon. Bacterial abundance (from 0.8 to 5.8 × 10⁸ g^–1 sediment dry weight) responded significantly to seasonal changes of organic matter content and composition and was significantly correlated with carbohydrate concentrations. Bacteria might be, in the seagrass system, an important N storage for higher trophic levels as il accounted for 25% of the easily soluble protein. pool and contributed significantly to the total DNA pool (on average 12%). Total meiofaunal density ranged from 236 to 1858 ind. 10 cm^–2 and was significantly related, with a time lag, to changes in bacterial standing stocks indicating that microbes might represent an important resource. Bacterial abundance and biomass were also significantly related to nematode abundance. These results indicate that bacteria may play a key role in the benthic trophic     

Biochemical composition and early diagenesis of organic matter in coastal sediments of the NW Adriatic Sea influenced by riverine inputs

River inputs influence trophodynamic and biogeochemical processes of adjacent continental shelves. In order to provide new insights on the influence of continental inputs on the benthic trophic state and early diagenesis of sediment organic matter we collected surface sediments in the NW Adriatic Sea at three stations located at increasing distance from the Po River. Sediment samples were collected in four periods characterized by different river outflows and analysed for chloropigment content (chlorophyll-a and phaeopygments), protein, carbohydrate and lipid concentrations, prokaryote abundance and aminopeptidase activity. Sediments of the NW Adriatic Sea displayed high organic loads, tightly coupled with the outflow dynamics of the Po River. A major flooding event was responsible of an enhanced accumulation of organic material on the sea bottom. The resulting increased nutrient load in the sediment impaired organic matter degradation processes. The results of the present study suggest that the enhanced trophic state of marine coastal sediments subjected to riverine inputs are related not only to the increased nutrient inputs, but that they may be amplified by impaired degradation processes.     

Mesoscale variability of organic matter composition in nw adriatic sediments

We investigated the spatial variability of sediment organic matter content and composition in three areas (A, B and C) of the Northwestern Adriatic Sea, subjected to a putative gradient of trophic state ( i.e. , increasing distance from the Po river outflow) in order to determine the appropriate sample size and replication. The analysis of the mesoscale variability was carried out comparing variability on the scale of meters ( i.e. among different deployments) with the variability observed on a scale of several kilometres ( i.e. among different sampling areas). Sediment samples, collected on April 1999, October 1999, April and October 2000, were analysed for chloropigment content (chlorophyll-a and phaeopygments) and protein, carbohydrate and lipid concentrations. Chloropigment, protein, carbohydrate and lipid concentrations were high, indicating that this system shares trophic conditions typical of highly productive environments. All organic matter components displayed a distribution independent from the increasing distance from the Po river outflow and a clear spatial variability, characterised by significant differences among different areas, but not among deployments. Carbohydrates were the biochemical compound displaying the highest spatial variability among the three areas. Chloropigment, protein, carbohydrate and lipid concentrations displayed also significant temporal changes. When spatial and temporal variability were compared, chlorophyll-a, phaeopigment and protein concentrations displayed a higher temporal than spatial variability. Conversely, for carbohydrates and lipids spatial and temporal variability was of the same order of magnitude. Organic matter composition displayed limited changes among areas, but a strong temporal variability. The results from the Adriatic sea suggest that analyses from sediments collected from a single deployment are sufficient for assessing organic matter concentration and composition over areas of several hundreds of square meters. However, for estimating organic matter composition over larger spatial scales ( i.e. miles) the identification of different sampling areas is needed.     

Methane Production in River and Lake Sediments in Taiwan

To investigate the relationship between methane production in the sediments and pollution of the river and lake, biochemical oxygen demand (BOD) and chemical oxygen demand (COD) of the water sample, organic matter content and methane production of the sediment were measured. Experimental results indicated that BOD, COD and organic matter contents were low in Bei-tan Lake, the I-lan River and reservoirs; and methane production of these sediments ranged from 0.24 to 1.06 mg L- 1. However, BOD, COD and organic matter contents were high in the Hsin-dan River, Keelung River, drainage river of Taoyuan County, park pond and fishery pond. Methane production of these sediments was between 11.75 and 54.54 mg L-1. Sediments of drain river and fishery pond had high methane production, at 25.41 to 54.54 mg methane L. Methane production of sediments had a good correlation with BOD, COD and organic matter contents. Methane production was proportional to the increment in incubation temperature from 12 to 40C.     

MESOSCALE VARIABILITY OF ORGANIC MATTER COMPOSITION IN NW ADRIATIC SEDIMENTS

We investigated the spatial variability of sediment organic matter content and composition in three areas (A, B and C) of the Northwestern Adriatic Sea, subjected to a putative gradient of trophic state ( i.e. , increasing distance from the Po river outflow) in order to determine the appropriate sample size and replication. The analysis of the mesoscale variability was carried out comparing variability on the scale of meters ( i.e. among different deployments) with the variability observed on a scale of several kilometres ( i.e. among different sampling areas). Sediment samples, collected on April 1999, October 1999, April and October 2000, were analysed for chloropigment content (chlorophyll-a and phaeopygments) and protein, carbohydrate and lipid concentrations. Chloropigment, protein, carbohydrate and lipid concentrations were high, indicating that this system shares trophic conditions typical of highly productive environments. All organic matter components displayed a distribution independent from the increasing distance from the Po river outflow and a clear spatial variability, characterised by significant differences among different areas, but not among deployments. Carbohydrates were the biochemical compound displaying the highest spatial variability among the three areas. Chloropigment, protein, carbohydrate and lipid concentrations displayed also significant temporal changes. When spatial and temporal variability were compared, chlorophyll-a, phaeopigment and protein concentrations displayed a higher temporal than spatial variability. Conversely, for carbohydrates and lipids spatial and temporal variability was of the same order of magnitude. Organic matter composition displayed limited changes among areas, but a strong temporal variability. The results from the Adriatic sea suggest that analyses from sediments collected from a single deployment are sufficient for assessing organic matter concentration and composition over areas of several hundreds of square meters. However, for estimating organic matter composition over larger spatial scales ( i.e. miles) the identification of different sampling areas is needed.     

Productivity of bacteria and microalgae and the effect of grazing by holothurians in sediments on a coral reef flat

Bacterial productivity in sandy sediments on reef flats at Lizard Island, Great Barrier Reef was determined from the rate of incorporation of tritiated thymidine into DNA. The study was conducted during January 1982 and July 1983. A small diurnal increase occurred in sediments having a dense population of microalgae. Bacterial production was 120 to 370 mg C m^-2 d^-1 in summer on reef flats, which was equivalent to 30–40% of primary production by benthic microalgae. In winter, rates of primary production by benthic microalgae and secondary production by bacteria were about one-half to one-fifth of those in summer. There was much variation in production, due to patchiness in the distribution of benthic microbes, especially microalgae. Doubling times for the bacteria in surface sediment were 1 to 2 d in summer and 4 to 16 d in winter on the reef flats. These high productivity values for bacteria indicated that a net input of organic matter to the sediment was needed to support the growth of bacteria. Sediment bacteria thus have a very important role in transforming organic matter on the reef flats. Grazing by Holothuria atra depressed both primary production and bacterial production. It was estimated that these holothurians ate about 10 to 40% of bacterial carbon produced each day in summer, and thus have an important role in the carbon cycle. Harpacticoid copepods were numerically important components of the benthic meiofaunal community and probably had a significant impact on bacterial density as grazers.     

A detailed analysis of carbohydrates in marine particulate matter

Detailed profiles of organic carbon, organic nitrogen, carbohydrate and proteinous amino acid have been determined in particulate matter from various depths at a station in Sagami Nada off eastern Honshu, Japan. The profiles suggest that carbohydrate is decayed from particulate matter more rapidly than proteinous amino acid in the euphotic zone, while the latter is removed to a higher extent than the former in deep waters,which results in the increase of the C/N values of particulate matter in the depths. All of the particulate matter gave D-galactose, D-glucose, D-mannose, D-xylose and D-glucuronic acid upon acid hydrolysis. Vertical change of the monosaccharide composition of this particulate matter indicates that only D-glucose and its polymers are preferentially removed from it during its descent. Carbohydrates from the particulate matter of 20 m depth were fractionated into water-soluble and insoluble carbohydrates. Detailed analysis of these fractions indicates that 1,3-glucan and its related low molecular weight carbohydrates from the water-soluble fraction decay between 50 and 300 m depth, to leave waterinsoluble carbohydrates, immune to biological attack during the course of further sinking. On the basis of these facts, the effects of the biochemical nature of these carbohydrates on the vertical change of the particulate carbohydrate distribution are discussed.     

Microbial activity and accumulation of organic matter in the burrow of the mud shrimp, <Emphasis Type="Italic">Upogebia major</Emphasis> (Crustacea: Thalassinidea)

Microbial activity and accumulation of organic matter in the burrow of the thalassinidean mud shrimp, Upogebia major, were studied on a tidal flat along the northern coast of Tokyo Bay, Japan. The burrow of U. major is Y-shaped with an upper U-shaped part plus a lower I-shaped part. Its lower part can extend to a depth of 2 m. In the present study, we compare electron transport system activity (ETSA), bacterial abundance and organic matter content [total organic carbon (TOC), total nitrogen (TN) and chlorophyll a (chl. a)] of the burrow wall sediment with the tidal flat surface and non-burrow sediments. We also compared the U- and I-shaped part in terms of these parameters. ETSA in the burrow wall was higher than at the tidal flat surface in the warmer season, and was always higher than at surrounding non-burrow sediments. Bacterial abundance in the burrow wall was higher than at the tidal flat surface and surrounding sediment. TOC and TN contents in the burrow wall were two to three times higher than those at the tidal flat surface and non-burrow sediments, regardless of season. However, there was no significant difference in chl. a content between burrow wall and tidal flat surface. These results suggest that organic enrichment of the burrow wall is a result of organic matter particles such as phytodebris accumulation along the burrow wall. For all parameters of the burrow walls, no statistical differences were found between the two parts. Present results indicate that U. major actively transports the water containing suspended organic particles not only through the U-part but also into the deeper I-part. These indicate that burrow of the mud shrimp provides a dynamic environment for microbial community in tidal flat sediment.