scholarly journals Relationship between salt use in fish farms and drift of macroinvertebrates in a freshwater stream

2020 ◽  
Vol 12 ◽  
pp. 205-213
Author(s):  
F Encina-Montoya ◽  
L Boyero ◽  
AM Tonin ◽  
M Fernanda Aguayo ◽  
C Esse ◽  
...  
Keyword(s):  
Fungal Infections ◽  
Fish Farm ◽  
Ecosystem Functions ◽  
Benthic Macroinvertebrate ◽  
Macroinvertebrate Communities ◽  
Fish Farms ◽  
Freshwater Biodiversity ◽  
Freshwater Stream ◽  
Stream Macroinvertebrate ◽  
And Control

In Chile, salt (NaCl) use per salmon fish farm ranges between 20-30 t yr-1 and is used to prevent and control fungal infections. An increase in salinity in freshwater can have adverse effects on freshwater biodiversity and ecosystem functions and services. We studied the effects of fish-farm effluents on benthic macroinvertebrate communities in a northern Patagonian stream (Chile). Benthic samples were collected at 3 sites near a land-based salmon aquaculture facility (one located 100 m upstream from the fish-farm outlet for effluent, 2 sites located 200 and 400 m downstream from the effluent source). We found changes in benthic macroinvertebrate communities downstream from the effluent, with higher abundances of tolerant taxa and lower abundances of sensitive taxa, which was related to nutrient and salt concentration in the water. We also studied the effects of salinity on macroinvertebrate drift in a mesocosm experiment conducted in recirculating channels, measuring the drift of 2 salt-sensitive macroinvertebrates (Andesiops peruvianus and Smicridea annulicornis), collected from an unpolluted northern Patagonian stream, after exposure to a range of salinity concentration pulses similar to those from fish farms. Our results demonstrate that (1) fish-farm effluent can alter stream macroinvertebrate community composition and dynamics, and (2) such effects are at least partly driven by high salt concentrations in effluent waters.

Impacts and solutions associated with glacier-driven river toxicity in the Cordillera Blanca, Peru

2021 ◽  
Author(s):  
Moya Macdonald ◽  
Jemma Wadham ◽  
Fiorella La Matta Romero ◽  
Jon Hawkings ◽  
Bram Willems ◽  
...  
Keyword(s):  
Water Quality ◽  
Water Supply ◽  
Green Infrastructure ◽  
Low Ph ◽  
Glacier Retreat ◽  
Metal Species ◽  
Benthic Macroinvertebrate ◽  
Macroinvertebrate Communities ◽  
Freshwater Biodiversity ◽  
Cordillera Blanca

<p>Approximately 70% of the world’s tropical glaciers are found in Peru, with 40% of these in the Cordillera Blanca (CB). Here, glaciers are an important source of meltwater to downstream people (~0.25 million) and ecosystems, supporting 40% of streamflow in the dry season. However, the CB has experienced high levels of glacier retreat and mass loss in recent decades, which has influenced the quantity and quality of water supply. During this time, some meltwater-fed rivers have become ‘toxic’, characterised by low pH and high metal concentrations. This toxicity has been linked to exposure of sulphide- and metal-rich rock types as glaciers retreat, and has implications for clean water supply (SDG 6), subsistence farming (contributing to SDG1 and 2), and freshwater biodiversity (SDG 15). Here, we present a comprehensive spatial analysis of water quality in the CB to understand the key drivers of worsening water quality and to predict which catchments may be vulnerable in the future. We sampled 18 glacierised catchments in the CB for geochemical and biological parameters during the dry and wet seasons. River pH ranged from 2.5 to 8.3, with two catchments highly acidic (~pH 2.5-3.8). The concentrations of several riverine metal species (including manganese, nickel, copper and a suite of rare-earth elements) were strongly negatively correlated with pH in the catchments. Additionally, most of the 40 metals analysed in rivers with low pH were present in a truly dissolved phase (>90% of 0.45 µm filtered concentrations were <0.02 µm), indicating high potential bioavailability and biotoxicity. Indeed, shifts in community composition of benthic macroinvertebrates indicated a replacement of sensitive benthic macroinvertebrate taxa (Limnephilidae, Hyaleliidae) in pristine rivers by more tolerant taxa (Chironomidae) in acidic rivers. We suggest that metal leaching and altitude may be important factors influencing diversity, richness and abundance of benthic macroinvertebrate communities. Here, we synthesize data on water quality and glacier retreat, offer predictions of future river toxicity and introduce a novel citizen-science, green-infrastructure initiative being developed to combat water quality degradation in the region.</p>

scholarly journals Recovery of Subtidal Benthic Macroinvertebrate Communities Following Natural and Experimental Disturbances

2021 ◽  
Author(s):  
◽  
Kerstin Kroger
Keyword(s):  
Community Composition ◽  
Complete Recovery ◽  
Hydrodynamic Regime ◽  
Benthic Macroinvertebrate ◽  
Macroinvertebrate Communities ◽  
Community Recovery ◽  
Recovery Processes ◽  
Plankton Bloom ◽  
And Control ◽  
First Time

<p>The recovery processes of subtidal benthic macroinvertebrate communities following large-scale natural and meso-scale experimental disturbances were studied in Wellington Harbour, New Zealand, a temperate semi-enclosed embayment. This is the first time that long-term effects (>1 year post-disturbance) of a naturally occurring toxic plankton bloom have been investigated in the Southern hemisphere. For 2 years macroinvertebrate communities were studied at three sites of differing hydrodynamic regime. Samples were taken with a Van Veen grab and washed through a 500 [mu]m mesh. Community recovery following the bloom was site-specific. Multivariate analyses revealed that at two sites community recovery was not completed >3 years post-bloom, whereas at the third site the community composition oscillated from year to year, but did not show any signs of a sequential recovery process. The hydrodynamic regime was identified as a major factor influencing the observed recovery processes. Communities exposed to an active hydrodynamic regime were less affected by the bloom and recovered faster, as they were naturally in a perpetual state of recovery as indicated by a dominance of r-selected species. The community at the hydrodynamically less active site was more affected by the bloom. Complete recovery to the pre-disturbance climax community dominated by K-selected species was estimated to take 4-5 years, if not interrupted by other disturbances. For the first time a defaunation experiment was conducted in a hydrodynamically active site to mimic the effects of a plankton bloom on the benthic macroinvertebrate community. Three sediment plots of 25 m2 were covered by plastic tarpaulins, thereby creating a benthic die-off caused by oxygen depletion. This method of defaunation had not been used in the subtidal before. Community recovery was studied for 1 year and compared with community composition in undisturbed control plots. Macroinvertebrate samples were taken by diver-operated cores and washed through a 500 [mu]m mesh. Recovery was slow until after 70 days when abundance and number of species increased synchronously in disturbed and control plots. Multivariate analyses showed that community composition fluctuated strongly in the first 100 days. After 1 year, although disturbed and control communities were converging, differences in community composition were still significant. Time for complete recovery was estimated to be approximately 2 years. Predictions of current succession models were generally fulfilled in both studies. Recovered communities were similar in their composition to either pre-disturbance or surrounding communities. The major deviation from model predictions was that no abundance peak of opportunistic species occurred in either study. Timing of the disturbance, in both studies past the major macroinvertebrate recruitment peak, and the hydrodynamic regime were identified as major factors influencing recovery processes of the communities studied. Such deviation from model predictions indicates that the general models cannot take into account the multiplicity and complexity of factors influencing recovery processes. Thus, their applicability in predicting recovery times and endpoints for specific disturbances at specific locations is limited. Location-specific models might be a useful alternative. Recommendations are made to combine uni- and multivariate techniques to assess recovery processes due to their different sensibilities to changes in community composition.</p>

Salmon carcasses as a marine-derived resource for benthic macroinvertebrates in a developing postglacial stream, Alaska

2008 ◽  
Vol 65 (7) ◽  
pp. 1342-1351 ◽  
Author(s):  
Kieran A. Monaghan ◽  
Alexander M. Milner
Keyword(s):  
Community Structure ◽  
Benthic Macroinvertebrates ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Separate Experiment ◽  
Macroinvertebrate Communities ◽  
Southeast Alaska ◽  
Stream Macroinvertebrate ◽  
Experimental Approaches ◽  
And Control

Streams formed in Glacier Bay, southeast Alaska, following glacial recession rapidly support populations of spawning salmon. Using both observational and experimental approaches, we examined the importance of pink salmon ( Oncorhynchus gorbuscha ) carcasses for benthic macroinvertebrate communities, approximately 10 years after salmon first colonized Wolf Point Creek, a first-order, lake-fed stream. Macroinvertebrate abundance on carcasses naturally accumulating in the stream channel was low, dominated by chironomids ( Eukiefferiella spp.). Macroinvertebrate drift was significantly lower from artificial experimental channels containing salmon flesh (P < 0.001) compared with channels without. However, the density and community structure of macroinvertebrates colonizing rock baskets in channels was not significantly different between treatments. In a separate experiment, colonization of substrate trays with salmon and control (inert) fillets were associated with differences in community structure; simuliids dominated control fillets, and chironomids dominated fish fillets, while underlying stone substrate was colonized by a more diverse community including Ephemeroptera, Plecoptera, and Trichoptera taxa (EPT). Excluding simuliids, abundance was significantly higher on fish compared with control fillets (P < 0.001). These data suggest that scales and mucus prevent the direct consumption of flesh from whole carcasses, highlighting the role predators–scavengers in facilitating flesh consumption by benthic macroinvertebrates.

scholarly journals Recovery of Subtidal Benthic Macroinvertebrate Communities Following Natural and Experimental Disturbances

2021 ◽  
Author(s):  
◽  
Kerstin Kroger
Keyword(s):  
Community Composition ◽  
Complete Recovery ◽  
Hydrodynamic Regime ◽  
Benthic Macroinvertebrate ◽  
Macroinvertebrate Communities ◽  
Community Recovery ◽  
Recovery Processes ◽  
Plankton Bloom ◽  
And Control ◽  
First Time

<p>The recovery processes of subtidal benthic macroinvertebrate communities following large-scale natural and meso-scale experimental disturbances were studied in Wellington Harbour, New Zealand, a temperate semi-enclosed embayment. This is the first time that long-term effects (>1 year post-disturbance) of a naturally occurring toxic plankton bloom have been investigated in the Southern hemisphere. For 2 years macroinvertebrate communities were studied at three sites of differing hydrodynamic regime. Samples were taken with a Van Veen grab and washed through a 500 [mu]m mesh. Community recovery following the bloom was site-specific. Multivariate analyses revealed that at two sites community recovery was not completed >3 years post-bloom, whereas at the third site the community composition oscillated from year to year, but did not show any signs of a sequential recovery process. The hydrodynamic regime was identified as a major factor influencing the observed recovery processes. Communities exposed to an active hydrodynamic regime were less affected by the bloom and recovered faster, as they were naturally in a perpetual state of recovery as indicated by a dominance of r-selected species. The community at the hydrodynamically less active site was more affected by the bloom. Complete recovery to the pre-disturbance climax community dominated by K-selected species was estimated to take 4-5 years, if not interrupted by other disturbances. For the first time a defaunation experiment was conducted in a hydrodynamically active site to mimic the effects of a plankton bloom on the benthic macroinvertebrate community. Three sediment plots of 25 m2 were covered by plastic tarpaulins, thereby creating a benthic die-off caused by oxygen depletion. This method of defaunation had not been used in the subtidal before. Community recovery was studied for 1 year and compared with community composition in undisturbed control plots. Macroinvertebrate samples were taken by diver-operated cores and washed through a 500 [mu]m mesh. Recovery was slow until after 70 days when abundance and number of species increased synchronously in disturbed and control plots. Multivariate analyses showed that community composition fluctuated strongly in the first 100 days. After 1 year, although disturbed and control communities were converging, differences in community composition were still significant. Time for complete recovery was estimated to be approximately 2 years. Predictions of current succession models were generally fulfilled in both studies. Recovered communities were similar in their composition to either pre-disturbance or surrounding communities. The major deviation from model predictions was that no abundance peak of opportunistic species occurred in either study. Timing of the disturbance, in both studies past the major macroinvertebrate recruitment peak, and the hydrodynamic regime were identified as major factors influencing recovery processes of the communities studied. Such deviation from model predictions indicates that the general models cannot take into account the multiplicity and complexity of factors influencing recovery processes. Thus, their applicability in predicting recovery times and endpoints for specific disturbances at specific locations is limited. Location-specific models might be a useful alternative. Recommendations are made to combine uni- and multivariate techniques to assess recovery processes due to their different sensibilities to changes in community composition.</p>

The Influence of Benthic Biota on Copper Speciation and Distribution in Freshwater-Sediment Systems

1981 ◽  
Vol 16 (1) ◽  
pp. 45-58 ◽  
Author(s):  
G. Krantzberg ◽  
P.M. Stokes
Keyword(s):  
Freshwater Sediment ◽  
Benthic Macroinvertebrate ◽  
Macroinvertebrate Communities ◽  
Copper Species ◽  
Copper Speciation ◽  
Physico Chemical ◽  
Macro Benthos

Abstract An investigation was made of the effects exerted by benthic macroinvertebrate communities on copper speciation in sediments from a lake which is becoming acidified. In laboratory microcosms, benthic macroinvertebrate communities stimulated the flux of copper from sediment to water. The presence of the macro-benthos resulted in a redistribution of physico-chemical copper species within the sediment with a transfer from more strongly complexed forms (HC1 extractable) to adsorbed and cation exchangeable forms (MgCl2 extractable). The role of bio-turbation in copper transformations is discussed.

A Unique Case of Cutaneous Cunninghamella infection in an Immunocompromised Patient (Preprint)

2020 ◽  
Author(s):  
Mauricio Portillo ◽  
Shyam Allamaneni ◽  
Richard Goodman
Keyword(s):  
Fungal Infections ◽  
Immunocompromised Patient ◽  
Lymphocytic Leukemia ◽  
Peripherally Inserted Central Catheter ◽  
Central Catheter ◽  
Unique Case ◽  
Systemic Complications ◽  
Prompt Treatment ◽  
Mode Of Transmission ◽  
And Control

UNSTRUCTURED Cunninghamella species are an extremely rare cause of fungal infections. The usual mode of transmission is through inhalation however rare cases of cutaneous spread have been reported. The objective of this clinical case report is to highlight the uniqueness of which the patient acquired the infection, the progression, and control of it. A 57-year-old male with chronic lymphocytic leukemia was found to have an abscess next to his peripherally inserted central catheter (PICC) line. The abscess culture grew back Cunninghamella and was debrided and treated with a novel antifungal. The fungal infection was controlled and the total timeframe took 28 days. Rapid recognition and prompt treatment demonstrate the prevention of rapidly progressive angioinvasian and further systemic complications. This case also proves that a novel antifungal may be appropriate in controlling the spread of Cunninghamella species.

scholarly journals Effects of multiple stressors associated with agriculture on stream macroinvertebrate communities in a tropical catchment

PLoS ONE ◽  
2019 ◽  
Vol 14 (8) ◽  
pp. e0220528 ◽  
Author(s):  
Aydeé Cornejo ◽  
Alan M. Tonin ◽  
Brenda Checa ◽  
Ana Raquel Tuñon ◽  
Diana Pérez ◽  
...  
Keyword(s):  
Multiple Stressors ◽  
Macroinvertebrate Communities ◽  
Stream Macroinvertebrate

scholarly journals Development of a Hydropower Turbine Using Seawater from a Fish Farm

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 266
Author(s):  
Md Rakibuzzaman ◽  
Sang-Ho Suh ◽  
Hyoung-Ho Kim ◽  
Youngtae Ryu ◽  
Kyung Yup Kim
Keyword(s):  
Power Plants ◽  
Guide Vane ◽  
Cross Flow ◽  
Synchronous Generator ◽  
Fish Farm ◽  
Hydropower Plant ◽  
Fish Farms ◽  
Data Simulation ◽  
Small Hydropower ◽  
Hydropower Plants

Discharge water from fish farms is a clean, renewable, and abundant energy source that has been used to obtain renewable energy via small hydropower plants. Small hydropower plants may be installed at offshore fish farms where suitable water is obtained throughout the year. It is necessary to meet the challenges of developing small hydropower systems, including sustainability and turbine efficiency. The main objective of this study was to investigate the possibility of constructing a small hydropower plant and develop 100 kW class propeller-type turbines in a fish farm with a permanent magnet synchronous generator (PMSG). The turbine was optimized using a computer simulation, and an experiment was conducted to obtain performance data. Simulation results were then validated with experimental results. Results revealed that streamlining the designed shape of the guide vane reduced the flow separation and improved the efficiency of the turbine. Optimizing the shape of the runner vane decreased the flow rate, reducing the water power and increasing the efficiency by about 5.57%. Also, results revealed that tubular or cross-flow turbines could be suitable for use in fish farm power plants, and the generator used should be waterproofed to avoid exposure to seawater.

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