沉水植物对富营养化水体的净化效果研究

通过建立小型围隔区,研究了沉水植物对富营养化水体中氮、磷等污染物的净化效果,以及对底泥中磷含量的影响.结果表明:(1)在放养沉水植物的围隔水体中各种营养盐浓度明显低于对照围隔;(2)沉水植物对磷的吸收能够有效地保持底泥中磷的含量,而在对照围隔中的底泥中磷元素含量却不断增加;(3)经50天后,水体中TN、NH4 -N、TP、PO43--P和CODMn平均去除率分别为36.3%、70.5%、54.6%、65.4%和43.1%.     

HISTORICAL TRENDS IN SEDIMENTATION RATES AND SEDIMENT PROVENANCE,FAIRFIELD LAKE,WESTERN NORTH CAROLINA1

Sedimentation rates and sediment provenance were examined for lacustrine sediments deposited in Fairfield Lake, western North Carolina, during the past 111 years. Stratigraphic, radionuclide, and cartographic data indicate that sedimentation rates have increased several fold during the past three decades in response to localized development. The magnitude of increased sedimentation was surprising given limited development within the basin: 0.12 to 0.68 buildings/ha in 2000 in those parts directly delivering sediment to the dated cores. Thus, the analysis illustrates the potential sensitivity of watersheds in the southern Appalachians to changes in land cover. An approach that combined geochemical fingerprinting with sediment mixing models was subsequently evaluated to determine its ability to accurately estimate the contribution of sediment from (1) major bedrock formations that underlie the watershed and (2) potential sources associated with four land cover categories. Sediment sources in both analyses proved difficult to geochemically fingerprint to greater than 90 percent accuracy using data on acid‐soluble metals and selected isotopes of lead (Pb). The relative contributions of sediment from delineated sources, estimated by the mixing models, generally corresponded with known temporal and spatial patterns of land cover. However, the models were plagued by two significant problems — the chemical alteration of sediments as they were transported through upland streams to depositional sites within the lake and the loss of elemental mass. Thus, future investigations using the fingerprinting approach in this area of intense weathering, and presumably others, will need to modify the existing methods to more accurately elucidate changes in sediment provenance related to development.     

长江口海域底栖生态环境质量评价——AMBI和M-AMBI法

AMBI(AZTI’s Marine Biotic Index)和M-AMBI(Multivariate-AMBI)指数可以有效地评价河口和近岸海域软底质海洋大型底栖动物群落对人为和自然扰动的响应.本研究根据2009年4月在长江口采集的大型底栖动物资料,首次在长江口海域同时运用栖息密度和生物量计算AMBI(BAMBI)和M-AMBI(M-BAMBI),对其进行底栖生态质量评价.结果表明,长江口底栖生态环境皆受到不同程度的干扰,其中受干扰最严重的区域集中在杭州湾、舟山及长江口门区附近海域,与该海域的陆源排污、富营养化以及大量的海岸工程建设等有密切的关系.单因素方差分析表明,运用栖息密度和生物量计算出的两个指数值,评价结果无明显的差异.与AMBI相比,M-AMBI与本研究生物群落结构参数以及环境因子的匹配度更高,能够更有效地评价长江口底栖生态环境质量.Pearson相关分析和一元线性回归分析表明,M-AMBI与底层水体的富营养化指数之间存在线性显著负相关关系,而与表层水体的呈非线性显著负相关;AMBI与富营养化指数之间却无显著相关关系,说明M-AMBI更适合指示长江口水域的富营养化压力.     

干湿循环对三峡支流消落带沉积物中可转化态氮及其形态分布的影响

水体富营养化的形成与沉积物中氮素的"源-汇"关系密切,本研究选取三峡典型支流澎溪河消落带上、中、下这3个水文断面,160 m和170 m两个水位高程,0~20、20~40、40~60、60~80、80~100 cm共5个深度的沉积物样品,通过研究其总可转化态氮(TF-N)与各形态可转化态氮含量及分布特征,旨在揭示周期性水位变化对消落带沉积物氮释放的影响.结果表明,澎溪河消落带沉积物总氮含量在313.02~3 255.53 mg·kg-1之间,空间分布上呈上站位(渠口)中站位(高阳)下站位(双江)的趋势;总可转化态氮含量范围为288.54~1 123.27mg·kg-1,均值为639.40 mg·kg-1,空间分布趋势与总氮一致;TF-N中各形态氮的大小顺序为:OSF-N(有机态和硫化物结合态)IMOF-N(铁锰结合态)CF-N(碳酸盐结合态)IEF-N(离子交换态).沉积物中TF-N主要以OSF-N(50.9%)和IMOF-N(33.3%)形态存在.OSF-N很难释放,不易参与氮循环.IMOF-N受水文条件影响显著,表现为在低水位高程和下采样站位沉积物中含量更低.淹水胁迫、水体富营养化等情况下氧含量较低,相对还原条件下有利于其向水体释放.而TF-N及其形态分布在垂直深度上无显著差异.可见,三峡库区特殊调蓄水制度加速了澎溪河下游、低水位高程消落带沉积物中IMOF-N向水体的释放.     

北方高盐景观水体氮磷时空分布特征及富营养化评价

为掌握北方高盐景观水体的水环境状况,选取天津市中新生态城3个景观水体(清净湖、蓟运河和蓟运河故道)为研究对象,于2013年12月—2014年11月对其进行定期取样监测,开展水体氮磷污染特征分析及富营养化评价。结果表明:1)蓟运河、清净湖和蓟运河故道的TDS均值分别为3.42,4.64,20.2 g/L,属于高盐景观水体;2)水体TN和TP浓度逐月变化显著,水质整体上冬春季优于夏秋季,其中蓟运河TP和TN的浓度最大,且波动较大;3)根据TN/TP比值判定,研究区水体除清净湖在短时间表现为氮限制外,水体大部分时间段内表现为磷限制,P为主要限制因子;4)富营养化评价表明:水体均处于富营养状态,且有蓟运河蓟运河故道清净湖;5)相关性结果表明:TDS与电导率、水温及EI呈显著正相关,相关系数分别为0.905、0.822和0.645,盐度也是影响富营养化的关键因素。     

富营养化淡水中黑色金属试样腐蚀加速的微生物学机制研究

目的探究黑色金属在污染淡水中后期腐蚀加速规律的生物学机制。方法采用高通量测序分析A3钢在富营养化水体和清洁水体中腐蚀产物内微生物的种群结构,并结合元素分析和XPS分析。结果获得了A3钢的腐蚀产物内微生物的门水平物种分布柱状图、OTU估计数统计表、OTU韦恩图、硫酸盐还原菌各属的相对丰度、微生物属水平热图等数据。结论在富营养化水体中,硫酸盐还原菌呈现更显著的水平,造成金属的硫化腐蚀更为严重,验证了黑色金属在富营养化污染淡水水体中后期腐蚀速率反转加速的现象。     

大庆市草原和湖泊生态保护建设研究

通过对大庆草甸草原和湖泊湿地发生发展自然生态过程的分析,以大庆生态环境的整体性特征为基础,提出草甸草原是大庆生态环境的基础,湖泊湿地是大庆生态环境的特色.以保护和恢复为主巩固草原生态基础地位,以生态重建为主突出湖泊湿地特色.对生态功能正常发挥的草原,以生态保护为主,对生态功能退化草原,以生态恢复为主.对油田生产区的草原,重视生态功能和景观效应.以生态重建为主突出湖泊湿地特色,通过地表水结构的调整增加生态系统的活力和生态服务功能.草甸草原和湖泊湿地的保护与利用要扬长补短、协同并进.     

杭州湾表层海水营养盐分布特征及富营养化状况研究

根据2015年3月和8月杭州湾的海水质量监测数据,分析了该海域的营养盐分布特征以及富营养化状况,结果表明:杭州湾表层海水无机氮变化范围为0.36~4.22 mg/L,活性磷酸盐的含量范围为0.014~1.51 mg/L,化学需氧量含量范围为0.56~3.18 mg/L.该海域无机氮和活性磷酸盐超标严重,表层海水已处于重度富营养化状态,调查站位EI均大于1.该海域表层海水无机氮、活性磷酸盐、化学需氧量和富营养化指数高值区均与陆源入海口、养殖区、排污口等人类活动影响较大的区域有关.     

三峡前置库汉丰湖试运行年水体水质现状及控制效果评估

三峡汉丰湖是世界范围较罕见的专为减弱消落带影响而修建的前置库,也是中国最大城市人工湖体,自汉丰湖试运行后,山水林田湖生态效益及建设宜居城市的社会效益显著.本文以三峡汉丰湖为研究对象,对汉丰湖试运行年支流来水及湖体断面进行水文、水质分层监测,包括水文参数(v、H等)、物理参数(T、pH、SD、DO、TSS等)、化学参数(高锰酸盐指数、Chl-a、TN、DN、NO_3~--N、NH_4~+-N、NO_2~--N、TP、DP、SRP等)共17个指标.监测结果表明:1 2月、10月等开始泄水蓄水时期水质较差,南河支流来水断面水质最差,调节坝出水断面最好;2汉丰湖水体总体呈轻度富营养化,主要污染指标为DN、TN、NO_3~--N、TP;3汉丰湖在试运行年对水体富营养化控制效果显著,Chl-a年平均消减率57.73%,高锰酸盐指数年平均消减率28.12%,SRP、TP、TN、TSS、NO_2~--N、DN、DP等年平均消减率20.15%~22.81%,NH_4~+-N、NO_3~--N等年平均消减率16.92%~18.74%,水体年平均富营养化指数降低15.74%.研究表明,1~3月、10~12月高水位湖泊形态试运行期间对各水质指标消减率高于5~8月河流形态时期,汉丰湖试运行良好,对水体富营养化控制效果显著,可消减三峡入库水体污染物浓度.     

Effects of physical and chemical characteristics of surface sediments in the formation of shallow lake algae-induced black bloom

Surface sediments are closely related to lake black blooms. The dissolved oxygen （DO） distribution and its penetration depth in surface sediments as well as the migration and transformation of redox sensitive elements such as Fe and S at the sediment-water interface are important factors that could influence the formation of the black bloom. In this study, dredged and undredged sediment cores with different surface properties were used to simulate black blooms in the laboratory. The Micro Profiling System was employed to explore features of the DO and ∑H2S distribution at the sediment-water interface. Physical and chemical characteristics in sediments and pore waters were also analyzed. The results showed that sediment dredging effectively suppressed the black blooms. In the undredged treatment, DO penetration depth was only 50 μm. Fe^2＋ concentrations, ∑H2S concentrations, and ∑H2S production rates were remarkably higher in surface sediments and pore waters compared to control and dredged treatments. Furthermore, depletion of DO and accumulation of Fe^2＋ and ∑H2S in surface sediments and pore waters provided favorable redox environments and necessary material sources for the blooms. The study results proved that physical and chemical characteristics in surface sediments are important factors in the formation of the black bloom, and could provide scientific guidance for emergency treatment and long-term pre-control of black blooms.