Linking Excess Nutrients,Light, and Fine Bedded Sediments to Impacts on Faunal Assemblages in Headwater Agricultural Streams1

Griffith, Michael B., F. Bernard Daniel, Matthew A. Morrison, Michael E. Troyer, James M. Lazorchak, and Joseph P. Schubauer‐Berigan, 2009. Linking Excess Nutrients, Light, and Fine Bedded Sediments to Impacts on Faunal Assemblages in Headwater Agricultural Streams. Journal of the American Water Resources Association (JAWRA) 45(6):1475‐1492. Abstract: Biological impairments in streams are typically defined by regulatory agencies in terms of altered invertebrate or fish assemblages. While nutrients, canopy cover, and sediment fines contribute to these impairments, these stressors are often defined, at least in part, by their impacts on periphyton. Path analysis can extend these assessments to impacts on invertebrates and fish by characterizing the direct and indirect relationships among variables along defined model pathways. With data from headwater tributaries in the Little Miami River, Ohio, we tested models of the impacts of nutrients [total nitrogen (TN), total phosphorus (TP), and the nitrogen to phosphorus (N/P) ratio], the percentage of (%) open canopy, and the % sand and fines on three periphyton metrics [periphytic ash‐free dry mass (AFDM), the percent abundance of cyanobacteria (% cyanobacteria), and the percent abundance of Chlorophyta (% Chlorophyta)] and, in turn, on selected invertebrate or fish metrics. Our objective was to develop and evaluate a statistical model that assesses the direct and indirect impacts of excess nutrients on macroinvertebrate and fish in these streams and demonstrate how this approach might be applicable elsewhere. The results suggest indirect pathways for the influences of nutrients, canopy cover, and fine bedded sediments on invertebrates or fish that are mediated by their influences on periphyton. This is in addition to any direct impacts of these stressors on the invertebrate and fish metrics. In most models, all three periphyton metrics increased with % open canopy. Periphytic AFDM increased with TN, while % cyanobacteria decreased. The % cyanobacteria also decreased with % sand and fines, but % Chlorophyta increased. The metrics, percent abundance of (%) three most dominant (macroinvertebrate) taxa, % Trichoptera, and % herbivorous fish all increased with periphytic AFDM, while % climbers, % swimmers, and %Lepomis cyanellus Rafinesque decreased. Lepomis cyanellus is an indicator species, because it is generally common in these streams and relatively tolerant to various common environmental stressors. The % three most dominant macroinvertebrate taxa increased while % Hydropsychidae (Trichoptera) and %L. cyanellus decreased with % cyanobacteria. The % Trichoptera and %L. cyanellus increased with % Chlorophyta. Some macroinvertebrate metrics, such as the % burrowers and number of burrower taxa, did not have any statistically significant relationships with the periphyton metrics but did exhibit a direct pathway with % sand and fines. These analyses illustrate how path analysis can be used to estimate the relationships among the variables in a conceptual model, modify the model, assess the relative importance of different paths, and explore responses resulting from stressors with interacting and indirect impacts.     

Chemical and biochemical tools to assess pollution exposure in cultured fish

There is little information regarding pollutant levels in farmed fish, and the risks associated to consumption. This study was designed to assess levels of exposure to metals, organochlorinated compounds, polycyclic aromatic hydrocarbons (PAHs) and alkylphenols (APEs) in farmed sea bass Dicentrarchus labrax from five aquacultures located in Southern Europe. Additionally, several biochemical responses (metallothionein, 7-ethoxyresorufin O-deethylase, vitellogenin) were determined as complementary tools. The obtained data indicate that pollutants exposure in farmed fish is similar to the levels reported in wild specimens from the area. Nonetheless, some biochemical responses were observed in the studied organisms, viz. metallothionein induction in Cu exposed organisms, and 7-ethoxyresorufin O-deethylase (EROD) and vitellogenin induction in PAHs and APEs exposed ones. The study further supports the usefulness of the biomarker approach as a first screening method to discriminate between basal and high levels of exposure in cultured fish.     

丹江口水库对汉江中下游影响的生态学分析

基于黄家港水文站1954～2000年的日径流量资料,以1967年为节点,将47年水文序列划分为节点前的“近自然状态河流”和节点后的“人工干扰状态河流”两种水文情势。采用Richter提出的变动范围法,基于包含32个水文参数的水文改变指标体系,定量评估了黄家港水文站1967年前后水文情势的变化。根据分析,把1967年之前的各个水文参数的第1至第3四分位数间的数值范围设为管理目标。进一步分析了丹江口水库的修建对汉江中下游生态水文的影响。结果表明,1967年以后,丹江口水库的修建对汉江中下游水文情势的影响较为显著：极大地改变了径流的年内分配,使流量过程均化,使极值流量出现日期提前、历时缩短等等。在此基础上,结合汉江中下游河道生态系统的特点,以鱼类为指示生物,初步探讨了上述水文情势的变化对汉江中下游鱼类的生长、繁殖和越冬等带来的影响,并对如何降低不利影响提出了相应的改进措施.     

东苕溪鱼类生物完整性评价河流健康体系的构建与应用

以东苕溪流域为研究区域,建立基于鱼类生物完整性指数(IBI)的河流健康评价指标体系.采样点来自2个不同的生态区,共建立了2套不同的IBI评价指标体系和标准.上游支流样点均来自浙闽山地常绿阔叶林生态区,从而建立了东苕溪上游支流的IBI指标体系:即鱼类总物种数(M1)、平鳍鳅科鱼类物种数百分比(M5)、中国土著鱼类物种数百分比(M6)、Shannon-Wiener多样性指数(M7)、无脊椎动物食性鱼类个体百分比(M13)、植食性鱼类个体百分比(M14)、敏感性鱼类个体百分比(M1)7个参数指标.中下游样点均来自长江三角洲城镇及城郊农业生态区,建立了东苕溪中下游区域的IBI指标体系:即鱼类总物种数(M1)、虾虎鱼科鱼类物种数百分比(M4)、中国土著鱼类物种数百分比(M6)、Shannon-Wiener多样性指数(M7)、上层鱼类物种数百分比(M8)、中上层鱼类物种数百分比(M9)、植食性鱼类个体百分比(M14)、借助贝类产卵鱼类物种数百分比(M21)、鱼类总个体数(M22)、畸形、患病鱼类个体数百分比(M23)等10个参数指标.河流健康状态划分为5个健康等级:即“健康”、“一般”、“较差”、“极差”和“无鱼”.应用IBI指标体系评价东苕溪流域的45个观测点的河流健康状况,结果显示东苕溪流域绝大多数河段的健康状况处于“一般”和“较差”水平.2011年,东苕溪中下游河段的健康状态较2010年有所改善,然而上游支流的健康状态较2010年有所下降.     

长江流域鲤鱼和鲟鱼的模型建立与剂量率估算研究

针对长江流域两种典型淡水鱼类-鲤鱼和鲟鱼,通过实验对两种鱼类各部分的浓集性质进行了研究,并建立了相关的的简化解剖学模型(区分了不同组织和器官部分)和外照射环境模型;用蒙特卡罗方法模拟源器官和环境水体对靶器官的能量沉积,采用某厂址水体数据以及实验得到的鱼类不同部位的浓集系数,估算了上述两种鱼类在该环境中所受到的内外照射剂量率,并与ERICA方法进行了比较分析.     

电厂冷却系统对梭幼鱼和对虾仔虾卷载效应的初步探讨

根据青岛电厂运行观测和模拟实验，分析了卷载效应中机械损伤和高温冲击对梭幼鱼和对虾仔虾的危害。研究表明，电厂冷却系统内流速≥２．０ｍ／ｓ，滤网孔径８ｍｍ时，对体长７－１７ｍｍ和２０－３４ｍｍ仔虾的致死率分别为２８．３％－５５．３％和２８．６％－６６．９％；对体长２０－４０ｍｍ梭幼鱼的致死率为６３．４％－７８．８％。卷载致死率与生物的密度、体长及形态特征有关。模拟实验结果为：０．９－１．０５ｍ／ｓ的流     

高岭土吸附态铜对鲤鱼鱼鳃的生物有效性

为了验证高岭土颗粒吸附态铜对鲤鱼鳃部的生物有效性并从形态的角度对其可能的机理进行说明,本研究在保持水相溶解态铜浓度不变、高岭土颗粒吸附态铜浓度递增的条件下进行了暴露实验,并利用MINTEQA2化学平衡计算软件分析了鱼鳃微环境中铜的形态分布特征.暴露实验的结果表明鲤鱼鳃样的铜吸收率随颗粒态铜浓度的递增而增加; 形态分析的结果表明颗粒吸附态铜在鱼鳃微环境中会发生一定程度的离解,从而转化为可被鱼鳃直接吸收的形态.     

大鹏澳网箱养殖区春季细菌的时空分布特征

2008年4月对大亚湾大鹏澳网箱养殖区环境中异养细菌与弧菌的空间分布及其与环境因子的关系进行了研究.结果表明,水体异养细菌水平分布特征为:养殖区>非养殖区,水平差异极显著(t检验,P=0.005);沉积物异养细菌:养殖区为非养殖区的12倍;水体异养细菌垂直分布特征为:表层海水>底层海水,垂直差异显著(t检验,P=0.0...     

影响浑太河流域鱼类群落结构的不同尺度环境因子分析

于2012年5月对浑太河流域65个采样点的鱼类进行调查采样.共采集到鱼类40种,分属9目14个科33属.其中鳅科鱼类占13.21%,鲤科占65.83%,构成了浑太河鱼类群落的主要部分.不同河流鱼类群落也有所不同,浑太河流域鱼类可分为2种分布类型,即上游林地为主的区域及支流源头区和中下游平原区.太子河葠窝水库上游和浑河大伙房水库上游区域的优势种类为北方条鳅(Nemachilus nudus)、北方花鳅(Cobitis granoei)和洛氏鱥(Phoxinus lagowskii),浑河和太子河平原区的优势种类为鲫(Carassius ayratus)和餐条(Hemiculter leucisculus).采用典范对应分析(CCA)方法定量分析流域、河段和微生境尺度环境因子对鱼类空间分布的影响.结果表明,浑太河流域鱼类空间分布主要受到流域和河段这2种尺度上环境因子的影响.在流域尺度上,林地、城镇建设用地、海拔对鱼类空间分布表现出显著影响,在河段尺度上,溶解氧、总氮、pH和栖息地质量对鱼类空间分布表现出显著影响.而微生境尺度上的底质类型则未对鱼类空间分布产生显著影响.流域尺度环境因子对鱼类群落结构变异的解释率为7.66%,河段尺度环境因子对鱼类群落结构变异的解释率为10.57%.河段尺度环境因子对鱼类群落结构的影响更为显著.     

石墨炉原子吸收分光光度法测定鱼肉中铍和铊

探讨了鱼肉中铍、铊的测定方法。样品用硝酸-硫酸消解,溴水氧化,聚氨酯泡塑吸附富集消解液中铊,消解液中铍不被吸附,石墨炉原子吸收分光光度法测定铍和铊,结果满意。