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.     

Concentration‐Duration‐Frequency Curves for Stream Turbidity: Possibilities for Assessing Biological Impairment1

Abstract: Siltation and subsequent biological impairment is a national problem prompting state regulatory agencies to develop sediment total maximum daily loads (TMDL) for many streams. To support TMDL targets for reduced sediment yield in disturbed watersheds, a critical need exists for stream assessments to identify threshold concentrations of suspended sediment that impact aquatic biota. Because of the episodic nature of stream sediment transport, thresholds should not only be a function of sediment concentration, but also of duration and dose frequency. Water quality sondes can collect voluminous amounts of turbidity data, a surrogate for suspended sediment, at intervals that can be used to characterize concentration, duration, and frequency of elevated turbidity events. To characterize turbidity sonde data in an ecologically relevant manner, a methodology for concentration‐duration‐frequency (CDF) curves was developed using turbidity doses that relate to different levels of biological impairment. To illustrate this methodology, turbidity CDF curves were generated for two sites on Little Pigeon River in the Great Smoky Mountains National Park, Tennessee, using over 30,000 sonde data measurements per site for a one‐year period. Utilizing a Poisson arrival approach, turbidity spikes were analyzed stochastically by observing the frequency and duration of recorded events over a turbidity level that relates to a biological dose response. An exponential equation was used to fit duration and frequency of a specified turbidity level to generate concentric‐shaped CDF curves, where at specific turbidities longer durations occurred less frequently and conversely shorter durations occurred more frequently. The significance of the equation fit to the data was accomplished with a Kolmogorov‐Smirnov goodness‐of‐fit test. Our findings showed that the CDF curves derived by an exponential function performed reasonable well, with most curves significant at a 95% confidence level. These CDF curves were then used to demonstrate how they could be used to assess biological impairment, and identify future research needs for improved development of sediment TMDLs.     

Model Calculations of Total Maximum Daily Loads of Mercury for Drainage Lakes1

Abstract: The Watershed Analysis Risk Management Framework watershed model was enhanced to simulate the transport and fate of mercury and to calculate the fish mercury concentrations (FMC) attained by fish through the food web. The model was applied to Western Lake Superior Basin of Minnesota, which has many peat lands and lakes. Topographic, land use, and soil data were used to set up the model. Meteorology and precipitation chemistry data from nearby monitoring stations were compiled to drive the model. Simulated flow and mercury concentrations for several stream stations were comparable to available data. The model was used to perform mercury total maximum daily load calculations for two contrasting drainage lakes (Wild Rice Lake and Whiteface Reservoir). The model results for wet deposition, dry deposition, evasion, watershed yield, and soil sequestration of mercury were comparable with available actual data. The model predicted lake ice cover from November to April and weak stratification in summer, typical of shallow lakes in cold regions. The simulated sulfate decrease and methylmercury increase near the lake bottom in late summer are caused by sulfate reduction and mercury methylation that occur in the surficial sediment. Simulated FMC were within the range of observed values and the R² of correlation between the simulated and observed FMC was 0.77. Under the 1989‐2004 base condition, the average simulated FMC of four‐year‐old walleye was 0.31 μg/g for Whiteface Reservoir and 0.15 μg/g for Wild Rice Lake. The FMC criterion in Minnesota is 0.2 μg/g. Wild Rice Lake already meets this criterion without any load reduction. The model showed that a 65% reduction in atmospheric mercury deposition will not, by itself, allow Whiteface Reservoir to meet the criterion in 15 years. Additional best management practices will be needed to reduce 50% of the watershed input.     

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.     

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.     

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。     

基塘系统改良低洼盐碱地环境效应研究

鲁西北地区是黄淮海平原中低产田低洼盐碱地的主要分布区之一，在鲁西北的禹城市具有该类型洼地科方亩，应用基塘系统工程措施，使浅层地下水地表化，解决了洼地季节性积水、蒸发等形成的盐渍化问题，同时洼地池塘养鱼改碱治水，使原来偏微咸碱水质达到适合水产养殖高产稳产的水质条件，改变了洼地原有的自然状况，并且向良性转化。     

水库网箱养鱼富营养化生态修复模式研究——以青狮潭水库为例

为有效控制青狮潭水库富营养化的发展,确保库区及饮用水源保护区水质达标,结合库区水质现状及网箱养鱼对富营养化成因分析,本文提出青狮潭水库网箱养鱼富营养化生态修复模式。根据青狮潭水库水环境容量及水域的地理特点,对库区水域进行分类管理,划分网箱养鱼禁止区和控制区,并对出现富营养化的水域进行水生生态修复,为青狮潭水库水环境管理和决策提供科学依据。     

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