Aquatic Invertebrate Samples Research Articles

Macroinvertebrates and its impact in assessing water quality of riverine system: A case study of Mahanadi river, Cuttack, India

The aim of this study was to identify the diverse macroinvertebrates present in river Mahanadi, Cuttack in India and to evaluate the role of macroinvertebrates in assessing river water quality and pollution level. We conducted field study of the river at Cuttack (85°46’21.29” E 20°28’15.81” N & 85°49’45.23” E 20°30’50.00” N) during 2013-2014 and collected aquatic invertebrate samples from 12 stations on river basin. The samples were analysed to explore the various families of Macroinvertebrates communities present in river Mahanadi, to examine the status of water quality of the river using biological indicators, to determine whether there are relationships between water chemistry and presence of typical macroinvertebrates and to develop a Macroinvertebrates based index to bio-assessment of Mahanadi River. A total of 484 taxa were identified and about 244 taxa of bivalves and 184 taxa of gastropods were collected. Presence of high number of pollution tolerant taxa and pollution sensitive taxa (Ephemeroptera, Plecoptera, Tricoptera and Chironomidae) indicated increased risk of water pollution and calculated biotic score (8), biological monitoring working party (BMWP) score (52), average score per taxa (ASPT) score (4) and macroinvertebrate-based index (MBI) value indicated moderate pollution level in the river. We recorded pH, total hardness, dissolved oxygen (DO), biological oxygen demand (BOD), total nitrite, chloride and total phosphate of water and physico-chemical parameters supported the values of biological assessment of water quality. Studying macaroinvertebrates helped to gain knowledge about aquatic faunal biodiversity in river Mahanadi and to develop a method for diagnosis of the health of river ecosystem and for measuring water pollution level.

Assessing the ecological impact of banana farms on water quality using aquatic macroinvertebrate community composition

In Costa Rica, considerable effort goes to conservation and protection of biodiversity, while at the same time agricultural pesticide use is among the highest in the world. Several protected areas, some being wetlands or marine reserves, are situated downstream large-scale banana farms, with an average of 57 pesticide applications per year. The banana industry is increasingly aware of the need to reduce their negative environmental impact, but few ecological field studies have been made to evaluate the efficiency of proposed mitigation strategies. This study compared the composition of benthic macroinvertebrate communities up- and downstream effluent water from banana farms in order to assess whether benthic invertebrate community structure can be used to detect environmental impact of banana farming, and thereby usable to assess improvements in management practises. Aquatic invertebrate samples were collected at 13 sites, using kick-net sampling, both up- and downstream banana farms in fast flowing streams in the Caribbean zone of Costa Rica. In total, 2888 invertebrate specimens were collected, belonging to 15 orders and 48 families or taxa. The change in community composition was analysed using multivariate statistics. Additionally, a biodiversity index and the Biological Monitoring Working Party (BMWP) score system was applied along with a number of community composition descriptors. Multivariate analyses indicated that surface waters immediately up- and downstream large-scale banana farms have different macroinvertebrate community compositions with the most evident differences being higher dominance by a single taxa and a much higher total abundance, mostly of that same taxon. Assessment of macroinvertebrate community composition thus appears to be a viable approach to detect negative impact from chemical-intensive agriculture and could become an effective means to monitor the efficacy of changes/proposed improvements in farming practises in Costa Rica and similar systems.

Fall diel diet composition of American eel (Anguilla rostrata) in a tributary of the Hudson River, New York, USA

American eel (Anguilla rostrata), a once common species, is now in decline throughout much of its native range in North America. There is little information on the role of American eel in river food webs. A better understanding of the diet and ecological role of American eel will help in the conservation of this important species. During autumn 2009, eel and aquatic invertebrate samples were collected from Hannacroix Creek, a tributary of the Hudson River, in Albany and Greene counties, New York, USA. Eel diet was analyzed by the eel size and time period (day or night). A high proportion of eel stomachs were empty (73%). Eel diets varied among size classes and day and night feeding periods (p = 0.001). Diet overlap was significant between small and medium eels caught both during the day (α = 0.71) and at night (α = 0.84). Nocturnal diet and nocturnal invertebrate samples were similar (α = 0.65), indicating a preference for bottom feeding during the night. Mayfly nymphs were the major prey consumed in each period by all size classes. Among eels that fed, night-feeding eels had the greatest stomach weight (as a percent of total body weight). The swim-bladder parasite, Anguillicoloides crassus, was also observed in eels of all size classes with nearly 50% afflicted.

Comparison of Methods for Processing Sweep-Net Samples of Aquatic Invertebrates From Forested Wetlands

Abstract Aquatic invertebrate data are useful for assessing wetland community structure, function, and water quality. Although collecting samples of aquatic invertebrates is relatively efficient and economical, processing these samples can be time consumptive and costly. Accordingly, researchers have devised methods to increase processing efficiency and effectiveness. For example, supersaturated solutions of solutes in various aqueous media have been used to separate invertebrates from aquatic media and organic matter. However, no study has evaluated this method for extracting invertebrates from sweep-net samples from flooded bottomland hardwood forests. We compared invertebrate recovery rates from samples processed using 1) tap water (control), 2) a supersaturated solution of sugar and water, and 3) a supersaturated solution of salt and water. We also evaluated a subsampling procedure by comparing taxonomic Order-level richness and Shannon diversity between sub- and whole samples. Numbers and dry biomass of invertebrates recovered were similar among the three aforementioned treatments. Use of supersaturated solutions did not reduce processing time, because invertebrates and leaf litter both floated instead of separating. Thus, we recommend using only tap water in processing sweep-net samples of invertebrates from forested wetlands that contain abundant leaf litter. Overall, we recovered 72.2% (95% CI = 3.0%) of all detected invertebrates and 48.0% (95% CI = 7.5%) of invertebrate biomass. Invertebrates that weighed less than others (e.g., mosquito larvae; Diptera) were more efficiently recovered than were heavier taxa (e.g., snails; Pulmonata). Our subsampling method underestimated Order-level richness and diversity indexes by 12% and 19%, respectively. However, processing subsamples was nearly two times faster than processing whole samples. Our method of using a sieve to subsample invertebrates is appropriate when numerical abundances are desired, because most (70%) invertebrates were detected and recovered.

The effects of small fish presence on a species-poor community dominated by omnivores: Example of a size-based trophic cascade

Omnivory is important in determining species interactions and weakening possible trophic cascade effects. The present study is focused on determining if an indirect effect of fish presence (trophic cascade effect) can be observed regardless of a high abundance of omnivores. With this aim a field experiment was carried out in a Mediterranean salt marsh. The natural top predator of these systems is a small and endangered fish, the Iberian toothcarp (Aphanius iberus). We wanted to assess if the presence of this fish could trigger a trophic cascade in the aquatic community. Six mesocosms were installed in a salt marsh lagoon without A. iberus presence, for two months. Twenty adult females of A. iberus were added to three mesocosms (fish treatment), while the other three were used as control (without any A. iberus addition). Physical and chemical water characteristics, as well as aquatic invertebrate samples (from bacteria to amphipoda, the largest organisms detected beside fish) were collected at the begining and the end of the experiment. To assess the trophic position of organisms, stable isotope analyses were used (13C and 15N). Our results show that the presence of A. iberus produces a trophic cascade even though only two trophic levels were differentiated by the stable isotope analysis. Body size appears to be determinant, since trophic interactions observed within the food web were mainly body-size dependent. Moreover, an unexpected positive but weak effect of A. iberus on macrophyte biomass was observed, caused probably by the decrease of small phytoplankton abundance. This effect may suppose an advantage for A. iberus, since macrophytes provide refuge and a food supply for this small fish.

Evaluation of 3-trifluoromethyl-4-nitrophenol (TFM) residues following a lampricide treatment as a risk assessment to the endangered piping plover

To evaluate the risk to the federally endangered piping plover (Charadrius melodus) from exposure to 3-trifluoromethyl-4-nitrophenol (TFM) during a sea lamprey control treatment we collected and analyzed a series of water, sediment, and aquatic invertebrate samples for the presence of TFM before, during, and after treatment of the Little Two Hearted River, Luce County, Michigan in July 2008. Results of the analyses in water showed the treatment resulted in a maximum concentration of 1.14mg/L TFM. Residues of TFM in water were greatest 50m east of the mouth (0.73mg/L TFM) and had decreased below detection at most of the sampling sites one day after treatment. Residues of TFM in sediment were greatest 50m east of the mouth (105ng/g TFM) with lower levels observed west of the mouth (3-5ng/g TFM) the day of the treatment. Residues decreased rapidly and were below detection in most of the samples the day after treatment. Residues of TFM in caged mayflies were greatest one day after treatment (3,193ng/g wet weight), decreased substantially by 4days after treatment (74ng/g), but were still present 8days after treatment (80ng/g). Based on results from this study the overall TFM exposure to adult piping plovers (0.425mg/kg) was 85 times less than the estimated No Observable Effects Concentration (NOEC) of 36mg/kg and was 17 times less than the NOEC for plover chicks (2.13mg/kg) indicating the risk from sea lamprey control operations would likely be minimal.

American Dippers Indicate Contaminant Biotransport by Pacific Salmon

Migrating salmon can increase productivity in Pacific Northwestern streams and lakes through the deposition of nutrients from their decomposing carcasses after spawning. Several studies also report simultaneous biotransport of persistent organic pollutants that have contaminated lake food webs, although no similar effect has been shown conclusively in rivers. We tested the prediction that salmon enhance contaminants in river food webs using the American dipper (Cinclus mexicanus), an aquatic songbird and a recognized indicator of stream quality. Over 3 years, we analyzed 29 dipper eggs and aquatic invertebrate samples from 14 different rivers in 10 catchments in southern British Columbia, Canada to assess whether variations in autumn spawning density of Pacific salmon were reflected in dipper egg contamination or stable carbon and nitrogen isotopes. δ(13)C isotope signatures, but not δ(15)N, in aquatic invertebrates and dipper eggs increased among catchments in proportion to the average density of spawning salmon. Concentrations of brominated flame retardants (PBDEs), dichlorodiphenyltrichloroethane metabolites (DDTs), and chlordane compounds were related in part to the δ(13)C measure of salmon density, but mercury, chlorobenzenes, and polychlorinated biphenyls (PCBs) were explained better by dipper trophic level. We conclude that spawning Pacific salmon result in the increased availability of salmon fry as dipper prey and salmon are a significant source of PBDEs, DDTs, and chlordanes to river ecosystems. However, contrary to lake studies, postspawn concentrations of legacy PCBs in river birds, even in salmon-rich rivers, were not significantly higher than would be expected from atmospheric deposition alone. We recommend using δ(13)C isotopes to trace salmon-derived lipids which may persist over winter particularly in rivers, and are potentially a better reflection of lipophilic contaminant transfer.

A Method for Subsampling Terrestrial Invertebrate Samples in the Laboratory: Estimating Abundance and Taxa Richness

Significant progress has been made in developing subsampling techniques to process large samples of aquatic invertebrates. However, limited information is available regarding subsampling techniques for terrestrial invertebrate samples. Therefore a novel subsampling procedure was evaluated for processing samples of terrestrial invertebrates collected using two common field techniques: pitfall and pan traps. A three-phase sorting protocol was developed for estimating abundance and taxa richness of invertebrates. First, large invertebrates and plant material were removed from the sample using a sieve with a 4 mm mesh size. Second, the sample was poured into a specially designed, gridded sampling tray, and 16 cells, comprising 25% of the sampling tray, were randomly subsampled and processed. Third, the remainder of the sample was scanned for 4–7 min to record rare taxa missed in the second phase. To compare estimated abundance and taxa richness with the true values of these variables for the samples, the remainder of each sample was processed completely. The results were analyzed relative to three sample size categories: samples with less than 250 invertebrates (low abundance samples), samples with 250–500 invertebrates (moderate abundance samples), and samples with more than 500 invertebrates (high abundance samples). The number of invertebrates estimated after subsampling eight or more cells was highly precise for all sizes and types of samples. High accuracy for moderate and high abundance samples was achieved after even as few as six subsamples. However, estimates of the number of invertebrates for low abundance samples were less reliable. The subsampling technique also adequately estimated taxa richness; on average, subsampling detected 89% of taxa found in samples. Thus, the subsampling technique provided accurate data on both the abundance and taxa richness of terrestrial invertebrate samples. Importantly, subsampling greatly decreased the time required to process samples, cutting the time per sample by up to 80%. Based on these data, this subsampling technique is recommended to minimize the time and cost of processing moderate to large samples without compromising the integrity of the data and to maximize the information extracted from large terrestrial invertebrate samples. For samples with a relatively low number of invertebrates, complete counting is preferred.

A laboratory technique to speed processing of samples with large numbers of invertebrates

AbstractThe amount of time needed to process samples with large numbers of terrestrial invertebrates in the laboratory has been a long‐standing obstacle impeding progress in invertebrate conservation biology and applied ecology. Laboratory subsampling of samples with large numbers of invertebrates is one method that saves time and reduces processing cost. In this study, a laboratory vacuum processing technique, consisting of a vacuum pump, aspirator and voice recognition software, was compared with a subsampling technique, and a conventional whole sample counting method. Vacuum processing was the most efficient technique; on average, more than five times more insects were processed per minute compared with whole sample counting and subsampling techniques. Differences in efficiencies among techniques were affected by trap type and invertebrate abundance. The vacuum technique was most efficient when processing high abundance pitfall trap samples, and was less efficient in processing pan trap samples that had invertebrates entangled by algae and other materials. Caution should be exercised when using the technique on soft‐bodied or poorly preserved specimens; a subsampling technique may be more appropriate in these cases, especially if specimens must be identified to genus or species level at a later time. The efficiency of the vacuum technique is reduced relative to the amount of time it takes to locate invertebrates in a sample; therefore, the technique does not save substantial time when processing samples with large amounts of substrate or debris, such as is the case with some aquatic invertebrate samples. However, if flotation or another method that separates invertebrates from other materials is used first, then the vacuum method would be useful for these types of samples as well.

Aquatic Invertebrates Of the Grand Staircase–Escalante National Monument, Utah

We use multiple years of collections in rivers, perennial wetlands, and ephemeral tinajas to report on overall biodiversity of aquatic invertebrates in the Grand Staircase–Escalante National Monument, Utah. A total of 570 samples of aquatic invertebrates was collected at 166 locations. Over the study period, invertebrates were identified from 31 orders, 104 families, and 192 genera. Major habitat types (rivers, perennial wetlands, and ephemeral tinajas) supported unique and taxonomically rich assemblages of invertebrates; taxonomic richness was greatest in rivers. Among rivers, richness of genera of aquatic invertebrates was greatest in groundwater-fed streams and perennial, snowmelt-runoff, rivers and least in flood-prone rivers. Future studies should focus on identifying and collecting invertebrates from unique habitats, especially the numerous wetland-like habitats that occur across the Grand Staircase–Escalante National Monument, such as hanging gardens and alcove pools, as well as ephemeral streams.

Structure and Functional Organization of Benthic Invertebrates in a Regulated Stream

AbstractThis paper examines modifications of benthic structure and species/traits organization of macroinvertebrate communities affected by various hydro‐technical structures in the regulated mountain Trzemesnia stream (southern Poland). The samples of aquatic invertebrates were collected seasonally (6 times) at: (1) one control site with natural substrate and at (2) five sites altered by sills, weirs, and canals during 1999.The stream canals, covered by Cladophora glomerata, were clearly distinguished from the other sites by: highest fauna density (mean of 8.5 103 ind. m−2), lowest taxa richness (mean number of 4.7 taxa), and lowest diversity (H′ = 1.1). The benthic communities consisted mainly of collector‐gatherers with the highest contribution in the stream canals (range 87–96%). These results suggest that most types of stream regulations (i.e. stream bed formed by concrete bricks) negatively affect the functional organization of benthic invertebrates (collector‐gatherers, predators, and scrapers).

Measuring the intensity of disturbancein zooplankton communities of Mediterranean salt marshes using multivariate analysis

The possibility of using multivariate analysis for measuring disturbance intensity in fluctuating ecosystems is discussed. As an example, two variables derived from the results of correspondence analysis of aquatic invertebrate samples from the Aiguamolls de l’Emporda (NE Spain), Mediterranean salt marshes, are proposed as measures of the severity and intensity of disturbance. The behaviour of these variables allows us to discuss several topics of disturbance theory, such as the relationship between disturbance intensity and the distribution of planktonic biomass by size, stability and diversity. A better adjustment to a curve (r 2 = 0.743) is obtained when testing Connell’s intermediate disturbance hypothesis when evenness and severity are used to measure diversity and disturbance, respectively. This hypothesis may be expressed as follows: at intermediate severity, the maximum links between present species are found. These measurements are simple to obtain and may be useful tools for the management of Mediterranean ecosystems. Although they cannot be directly applied to other ecosystems, a relationship between multivariate results and measurements of disturbance might be observed in similar ecosystems if analogies between some multivariate results and the flux of external energy are investigated.

Acetic Acid Digestion of High-Carbonate Substrates: An Aid to Sorting Aquatic Invertebrate Samples

ABSTRACT Soaking high-carbonate sediment samples in 5% acetic acid reduces initial sample volumes; sorting times per unit of original volume and per organism also declined significantly compared with untreated samples. This procedure speeds the sorting of invertebrate samples, especially when similar specific gravities of organisms and substrates render useless the techniques of flotation and elutriation.

L'analyse hydrobiologique des cours d'eau au benelux

his paper describes the principles and the methods, generally used in the countries of Benelux (Belgium, The Netherlands and Luxemburg) to assess the biological quality of running waters. With these methods, it is possible in particular to measure a biotic index or a quality index only on the basis of samples of aquatic invertebrates. After a short historical review, the interrelationship between the typology of a watercourse and the organisms belonging to this typology is first exemplified. Then the use of different aquatic organisms as possible water quality “bio-indicators” is discussed. Finally, on the base of several years of studies, it is shown why the macro-invertebrate community is considered to be the most relevant group for this purpose. It appears in particular, that these integrate the water quality over a long period of time, which is considered a true advantage. The general ecological degradation occurring in case of organic as well as inorganic pollution seems well reflected by this methodology. The method with macro-invertebrates used in Belgium and Luxemburg is a variation of, and combines the advantages of two existing biological assessment methods worked out by Woodiwiss (1964) and by Tuffery and Verneaux (1968). The comparable method in The Netherlands is based on the work of Moller-Pillot (1971). Between the countries of the Benelux study is made of the comparability of these methods: valuable exercices in the river Sure near the frontier Belgium-Luxemburg have shown comparable results. The practical interest of the methods lies not only in the fact that they are complementary to the chemical and bacteriological analyses, but also that they give more information about the whole ecological situation of the watercourses especially for general policy and management purposes (water sanitation, recreation, fishing….).