Use Of Periphyton Research Articles

Bioaccumulation of arsenic in fish (Labeo rohita) in presence of periphyton: ameliorative effect on oxidative stress, physiological condition, immune response and risk assessment.

The present study explores the use of periphyton to ameliorate toxic properties of arsenic (As) to Labeo rohita and also assesses the human food safety aspects. Fish were introduced to arsenite [As(III)] contaminated water (0.3 and 3mg/L) along with periphyton. Biochemical, physiological and immunological parameters, including gene expression, were assessed after 30days of exposure. Periphyton incorporation significantly improved (p < 0.05) the adverse effects of As on respiration, NH3 excretion and brain AChE activity by reducing oxidative stress and As bioaccumulation. The presence of periphyton in As(III) exposed fish (3mg/L) increased the immune response (Immunoglobulin M and Complement C3) in the serum and the regulation of the respective immune genes in the anterior kidney was found to be similar to the control. A speciation study using LC-ICP-MS confirmed the high accumulation of As by periphyton (5.0-31.9μg/g) as arsenate [As (V)], resulting in a lower amount of As in fish muscle. The calculated human health risk indices, Target Hazard Quotient (THQ) and Target Cancer risk (TCR) indicate that fish grown in periphyton-treated water may lower the human health risks associated with As. The study signifies the importance of periphyton-based aquaculture systems in As contaminated regions for safe fish production with enhanced yield.

Factors regulating lake periphyton biomass and nutrient limitation status across a large trophic gradient

Abstract Because of the historical focus of limnology on pelagic processes, the factors controlling lake periphyton growth and nutrient limitation are understudied compared to the phytoplankton. We deployed nutrient‐diffusing substrata at 28 sites spanning a wide trophic status gradient in Lakes Superior and Michigan to assess periphyton biomass accrual on control substrata and the response of periphyton to single and combined phosphorus (P) and nitrogen (N) additions. Periphyton growth was unimodally related to a composite metric of site trophic status, with highest biomass at mesotrophic sites and lower growth at oligotrophic and highly eutrophic sites. Contrary to expectations, P limitation was rare. Instead, several lines of evidence pointed to primary N or N + P co‐limitation of periphyton. Limitation extent was negatively related to site trophic status, with stronger nutrient limitation at oligotrophic sites. Our results support the hypothesis that phytoplankton and periphyton biomass respond differently to nutrient enrichment and suggest that different nutrients may limit pelagic and benthic primary production, even in the same system. Our findings also support the use of periphyton as an early warning indicator of nutrient pollution and help explain why large, oligotrophic lakes may be especially susceptible to localised benthic algal blooms.

Improving the sustainability of tilapia cage farming in Brazil: An emergy approach

The accelerated and disorderly expansion of aquaculture can lead to economic, social, and environmental problems. In this sense, it is necessary to prioritize the adoption of practices that aim for sustainable production. The aims of the present study were to identify the contributions from nature and economy in the system of tilapia cage farming. In addition, emergy accounting was utilized to evaluate whether the use of periphyton as a complementary food and the reduction of storage density improve the sustainability of this production system. Three different production managements were evaluated and compared: using traditional stocking density adopted by farmers (80 kg/m3) with 100% of the daily recommended feed and without substrates for periphyton (TRAD); traditional stocking density (80 kg/m3) with 50% of the daily recommended feed and with substrates for periphyton (TDS); lower density (40 kg/m3) with 50% of the daily recommended feed and with substrates for periphyton (LDS). We calculated using emergy accounting the transformity (Tr), renewability (%R), emergy yield ratio (EYR), emergy investment ratio (EIR), emergy loading ratio (ELR), emergy exchange ratio (EER), and emergy sustainability index (ESI) of the distinct production managements. The results showed that tilapia cage farming is highly dependent on resources from economy, and feed is mainly responsible for this. Thus, the decrease in stocking density and feed rate, combined with the use of periphyton, improved all emergy indices evaluated. This occurred because there was a decrease in the use of resources from economy and increase in the use of renewable natural resources. The study shows through the emergy accounting that the use of periphyton to feed cultured fish combined with a reduction in artificial feed use and a decrease in the stocking density should be encouraged to promote the sustainability on tilapia cage farming.

Functional and Compositional Responses of Periphyton Mats to Simulated Saltwater Intrusion in the Southern Everglades

Periphyton plays key ecological roles in karstic, freshwater wetlands and is extremely sensitive to environmental change making it a powerful tool to detect saltwater intrusion into these vulnerable and valuable ecosystems. We conducted field mesocosm experiments in the Florida Everglades, USA to test the effects of saltwater intrusion on periphyton metabolism, nutrient content, and diatom species composition, and how these responses differ between mats from a freshwater versus a brackish marsh. Pulsed saltwater intrusion was simulated by dosing treatment chambers monthly with a brine solution for 15 months; control chambers were simultaneously dosed with site water. Periphyton from the freshwater marsh responded to a 1-ppt increase in surface water salinity with reduced productivity and decreased concentrations of total carbon, nitrogen, and phosphorus. These functional responses were accompanied by significant shifts in periphytic diatom assemblages. Periphyton mats at the brackish marsh were more functionally resilient to the saltwater treatment (~ 2 ppt above ambient), but nonetheless experienced significant shifts in diatom composition. These findings suggest that freshwater periphyton is negatively affected by small, short-term increases in salinity and that periphytic diatom assemblages, particularly at the brackish marsh, are a better metric of salinity increases compared with periphyton functional metrics due to functional redundancy. This research provides new and valuable information regarding periphyton dynamics in response to changing water sources in the southern Everglades that will allow us to extend the use of periphyton, and their diatom assemblages, as tools for environmental assessments related to saltwater intrusion.

The potential of periphyton-based cage culture of Nile tilapia in a Brazilian reservoir

In land-based pond cultures, periphyton is considered to be a complementary food source for cultured fish. In cage aquaculture, studies on the use of periphyton are scarce and do not support the viability of periphyton-based cage culture. The aim of this study was to evaluate the potential of periphyton-based cage culture of Nile tilapia in a hydroelectric reservoir in Brazil at three stocking densities and two feeding regimes. Sex-reversed male Nile tilapia Oreochromis niloticus (46.56±2.53g) were placed in 21 cages (6m3 – 2×2×1.5m each) with or without bamboo substrates for periphyton growth. A completely randomized design with three replicates per treatment was used to test the effect of substrate inclusion in the three stocking densities (80, 60, 40kg of fish/m3) associated with two feeding regimes (100% and 50% of daily ration). Three cages without bamboo substrates were included in the experimental design as control group (CTRL) (80kg/m3 and 100% of daily ration). The study demonstrates the efficiency of using substrates for Nile tilapia in cages in the reservoir. The presence of bamboo substrates improved the weight gain of fish but reduced the carrying capacity of the cage at the highest density. The concentration of dissolved oxygen in the cages was improved by the presence of substrate between 50 and 140days of the trial and reduced after 155days of culture. The inclusion of bamboo substrates inside the cages allows producing up to 52kg/m3 of Nile tilapia using 32% less diet in a period almost 20% shorter than in the CTRL group. If farmers prefer to produce 80kg/m3, they can use 30% less diet but the production period would be 20% longer. Statement of relevanceThis study has high relevance to the general field of commercial aquaculture because the experiment was carried out at a commercial fish farm, under real environmental conditions and management. Presented results are promising because show that bamboo substrates in cages improve the efficiency of the system up to 52kg/m3. This production model may be an efficient alternative for family farmers.

Role of periphyton in ecological assessment of lakes

Assessment of ecological integrity is the basis for sustainable management of the ecosystem services lakes provide. Periphyton is used in stream assessment, but lake assessment is based mostly on water-column variables. We addressed the use of periphyton to assess lakes, how factors influence responses of periphyton metrics, and whether periphyton provides unique information for determining biological condition and identifying risks. Much effort directed at using periphyton for assessment has focused on linear relationships between taxonomic metrics and single stressors. These relationships can be good proxies for water chemistry, but do not always represent biological conditions. Community diversity is difficult to relate to stressors because low values may result from natural conditions (grazing, disturbance). Quantile regression, River Invertebrate Prediction and Classification System (RIVPACS)-type models, and taxonomic distinctiveness may provide more precise indicators. Periphyton biomass and productivity are linked closely to trophic status but are rarely used in assessment. Responses of these variables over a trophic gradient are often nonlinear, and surrogate metrics that use quantile regression or weighted-averaging calibration/regression based on community composition may overcome this problem for assessment. Measures, such as alkaline phosphatase activity, number of N-fixing taxa, and periphyton nutrient stoichiometry can be used to assess littoral-zone ecosystem function and to help establish causative effects of stressors. The value added by periphyton-based assessment is that it provides higher-level understanding of the ecological status of the littoral zone. Assessment must be rooted in a strong understanding of the science and must provide guidance and cost-effective options for lake managers. We outline a hierarchy for periphyton assessment methods that assess risk at different levels of effort and precision.

Imbalanced C/N - controlled, periphyton-based system has hampered tilapia growth in stagnant experimental tanks

The simultaneous use of periphyton and controlled C/N ratio of water may improve water quality and fish growth. The current assay investigated the interaction between periphyton and C/N ratio of water in rearing tanks with Nile tilapia juveniles. The study was carried out in 20 outdoor stagnant 250- L tanks. A wooden structure for periphyton development was submerged in five of the tanks. A completely randomized 2 x 2 factorial mode design was employed to evaluate the following factors: (1) substrate for periphyton and (2) the C/N ratio of water. Dry molasses were applied weekly in the tanks to raise C/N ratio of water to 20:1. The addition of molasses to the culture water significantly lowered DO2 and pH levels of water, and raised nitrite concentration. Fish stocked in the control tanks (no periphyton, no C/N ratio balance) attained a final body weight significantly higher than those observed for other treatments after 6 weeks of culture. In spite of the correction of C/N ratio of water to 20: 1, low DO2 concentrations avoided the suitable development of bioflocs.

Periphyton and its Role in Formation of Water Quality after Biological Treatment in Aerotanks

Paper deals with results of study of periphyton, formed in the secondary settling tanks of the municipal waste water treatment plant (Minsk, Belarus.) It was shown that by structural organization it is similar to periphyton of the natural waters. At the same time it was characterized by exceeding of destruction over production and high content of heavy metals and nutritive elements (nitrogen and phosphorus). Use of periphyton for the after-purification of the sewage water after biological treatment in aerotanks can significantly decrease content of the pollutants, first of all heavy metals and nutritive elements (nitrogen and phosphorus).

Heavy metal dynamics in the periphyton in small rivers of Kola Peninsula

The results of studies of heavy metal accumulation by periphyton algae in 12 rivers of Kola Peninsula are presented. The potentiality of the use of periphyton in heavy metal monitoring in water bodies is discussed.

Monitoring periphyton in lakes experiencing shoreline development

Early detection of degradation is crucial in previously pristine lakes experiencing residential development along their shores. Despite suggestions that the littoral zone responds to anthropogenic disturbance before open water, the use of periphyton for monitoring lake trophic status has been hindered by the heterogeneous distribution of this community. We examined the response of periphyton growing on different natural substrata — rocks, wood, sediments, and macrophytes — as well as on introduced plastic strips along a gradient of residential development in the Laurentian lakes (Quebec). We measured periphyton biomass as chlorophyll a and as thickness estimated with a ruler with the goal to evaluate the best method to monitor the incipient degradation of these lakes. Our findings suggest that rocks are the best substratum to sample because they are ubiquitous, and epilithic algae show a stronger response to shoreline residential development than algae on other substrata. Measurement of epilithon thickness appears a fast and reliable tool for estimating epilithon biomass. If measurements of chlorophyll a require several field and laboratory manipulations that are not readily available for voluntary lake monitoring by residents, measurement of periphyton thickness on rocks may allow examining spatial and temporal changes in a large number of lakes.

Benthic algae as bioindicators of agricultural pollution in the streams and rivers of southern Québec (Canada)

The objective of this study was to evaluate the effect of agricultural pollution on periphyton in streams and rivers of southern Québec. We sampled benthic algae incubated from mid-July to mid-August on artificial substrates at 29 sites and analysed the variations in community structure and total community biomass. Diatom community structure as well as total benthic algae community were analysed. Water samples were taken to provide background chemical information, and land use data were also obtained. Preliminary tests showed that colonisation of the artificial substrates (unglazed ceramic tiles) resulted in biomass levels (Chlorophyll a and ash-free dry weight) and species composition that were not statistically different from those on natural rock substrates. The canonical correspondence analyses showed that pH, conductivity and suspended solids were the most significant environmental variables accounting for variations among sites and diatom community structure. No additional resolving power was obtained by including cyanobacteria, green algae and flagellates. This total community analysis substantially increased variance and sample processing time while reducing the relationship with environmental variables. These results indicate that an analysis based exclusively on diatoms provided the optimal approach. Traditional nutrient measurements (phosphorus and nitrogen) did not explain a significant part of the variance in the species composition among sites. The ordination analyses clearly separated agriculturally-impacted streams from reference sites, but no significant grouping was observed related to the intensity and type of agriculture, indicating the greater importance of local farming practices. The use of periphyton as a bioindicator provides an integrated measurement of water quality as experienced by the aquatic biota, and therefore offers a useful addition to physico-chemical water quality monitoring strategies.

Biomonitoring of organic pollution using periphyton, South Branch, Canterbury, New Zealand

Abstract The use of periphyton to monitor the effects of organic pollution in shallow, swift New Zealand rivers was tested using a slaughterhouse effluent discharge to the South Branch, Canterbury. Eight 1 ‐week long artificial substrate accrual periods were used. A range of taxonomic and biomass determinands were analysed for during the first 2 periods. However, only chlorophyll a, ash‐free dry weight (AFDW) and their derivative the Autotrophic Index (AI), were used for subsequent monitoring as they provided the most efficient means of discriminating the effluent impacts. Intensive chemical monitoring during these first 2 sampling periods identified a highly concentrated organic waste with high daily variability (x total Kjeldahl nitrogen = 5.04 and 1.90 mg 1‐1, %CV = 74 and 79). Effluent volumes were slowly reduced over a 4‐month period. This resulted in reductions in the AI (maximum of 4377 down to 191) of downstream communities and demonstrated the benefit of effluent diversion. The community also responded to low‐level organic contamination at the control site as shown by the AI. There was a highly significant correlation (r=0.926) between biochemical oxygen demand and the AI. There were no significant differences in the AI between control and impact sites for 2 sampling periods after the effluent had been diverted from the river. It is concluded that periphyton have the potential to provide good data on the biological effects of organic discharges to shallow, swift New Zealand rivers to complement water quality monitoring data.

The use of periphyton from Lake Zürich to estimate the Algal Growth Potential in River Limmat water

Mit Hilfe von Ufersteinenaufwuchs aus dem Zurichsee ermittelten wir das Algenwachstumspotential von Limmatwasser verschiedener Probenahmestellen (Abb. 1). Unter Algenwachstumspotential, verstehen wir die Differenz der Biomasse, gemessen bei Beginn und Ende von Verschen in Erlenmeyer-Gefassen. Dabei sollte der Einfluss des Abwassers der Klaranlage Werdholzli der Stadt Zurich erfasst werden, deren Ausbau in nachster Zeit erfolgen wird. Die ermittelten Resultate ermoglichen einen Vergleich mit dem Limmatwasser nach Inbetriebnahme der vergrosserten Anlage.

The use of periphyton as a monitor of trace metals in two contaminated Indiana lakes.

The use of periphyton as a monitor of trace metals in two contaminated Indiana lakes.