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Simonetti I, Lubello C, Cappietti L. On the use of hydrodynamic modelling and random forest classifiers for the prediction of hypoxia in coastal lagoons. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 951:175424. [PMID: 39142405 DOI: 10.1016/j.scitotenv.2024.175424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2024] [Revised: 07/19/2024] [Accepted: 08/07/2024] [Indexed: 08/16/2024]
Abstract
Hypoxia is one of the fundamental threats to water quality globally, particularly for partially enclosed basins with limited water renewal, such as coastal lagoons. This work proposes the combined use of a machine learning technique, field observations, and data derived from a hydrodynamic and heat exchange numerical model to predict, and forecast up to 10 days in advance, the occurrence of hypoxia in a eutrophic coastal lagoon. The random forest machine learning algorithm is used, training and validating a set of models to classify dissolved oxygen levels in the lagoon. The Orbetello lagoon, in the central Mediterranean Sea (Italy), has provided a test case for assessing the reliability of the proposed methodology. Results proved that the methodology is effective in providing a reliable short-term evaluation of DO levels, with a high resolution in both time and space throughout an entire lagoon. An overall classification accuracy of up to 91 % was found in the models, with a score for identifying the occurrence of severe hypoxia - i.e. hourly DO levels lower than 2 mg/l - of 86 %. The use of predictors extracted from a numerical hydrodynamic model allows us to overcome the intrinsic limitation of machine learning modelling approaches which rely on input data from relatively few, local field measurements, i.e. the inability to capture the spatial heterogeneity of DO distributions, unless several measuring points are available. The methodological approach is proposed for application to similar eutrophic environments.
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Affiliation(s)
- Irene Simonetti
- Dept. of Civil and Environmental Engineering, University of Florence, Italy.
| | - Claudio Lubello
- Dept. of Civil and Environmental Engineering, University of Florence, Italy
| | - Lorenzo Cappietti
- Dept. of Civil and Environmental Engineering, University of Florence, Italy
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2
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Elnabwy MT, Alshahri AH, El-Gamal AA. An integrated deep learning approach for modeling dissolved oxygen concentration at coastal inlets based on hydro-climatic parameters. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 367:122018. [PMID: 39111007 DOI: 10.1016/j.jenvman.2024.122018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Revised: 07/15/2024] [Accepted: 07/26/2024] [Indexed: 08/15/2024]
Abstract
Climate change has a significant impact on dissolved oxygen (DO) concentrations, particularly in coastal inlets where numerous human activities occur. Due to the various water quality (WQ), hydrological, and climatic parameters that influence this phenomenon, predicting and modeling DO variation is a challenging process. Accordingly, this study introduces an innovative Deep Learning Neural Network (DLNN) methodology to model and predict DO concentrations for the Egyptian Rashid coastal inlet, leveraging field-recorded WQ and hydroclimatic datasets. Initially, statistical and exploratory data analyses are performed to provide a thorough understanding of the relationship between DO fluctuations and associated WQ and hydroclimatic stressors. As an initial step towards developing an effective DO predictive model, conventional Machine Learning (ML) approaches such as Gaussian Process Regression (GPR), Support Vector Regression (SVR), and Decision Tree Regressor (DTR) are employed. Subsequently, a DLNN approach is utilized to validate the prediction capabilities of the investigated conventional ML approaches. Finally, a sensitivity analysis is conducted to evaluate the impact of WQ and hydroclimatic parameters on predicted DO. The outcomes demonstrate that DLNN significantly improves DO prediction accuracy by 4% compared to the best-performing ML approach, achieving a Correlation Coefficient of 0.95 with a root mean square error (RMSE) of 0.42 mg/l. Solar radiation (SR), pH, water levels (WL), and atmospheric pressure (P) emerge as the most significant hydroclimatic parameters influencing DO fluctuations. Ultimately, the developed models could serve as effective indicators for coastal authorities to monitor DO changes resulting from accelerated climate change along the Egyptian coast.
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Affiliation(s)
- Mohamed T Elnabwy
- Coastal Research Institute (CORI), National Water Research Center, Alexandria 21415, Egypt; Civil Engineering Department., Faculty of Engineering, Damietta University., New Damietta 34517, Egypt.
| | - Abdullah H Alshahri
- Department of Civil Engineering, College of Engineering, Taif University, P.O. Box 11099, Taif City 21974, Saudi Arabia.
| | - Ayman A El-Gamal
- Department of Marine Geology, Coastal Research Institute (CoRI), National Water Research Center, Alexandria 21415 Egypt.
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3
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Koloti LE, Nkuna R, Matambo TS. Impact of current anthropogenic activities on Blesbokspruit wetland microbiome and functions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 915:170010. [PMID: 38219994 DOI: 10.1016/j.scitotenv.2024.170010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 01/03/2024] [Accepted: 01/06/2024] [Indexed: 01/16/2024]
Abstract
Till present, natural wetlands have been continuously subjected to intensive pollution stress in recent years, mainly because of the rapidly growing industrialization and urbanization that are associated with a myriad of anthropogenic activities and land use practices. These man-made sources of pollution change the chemical properties of the natural wetlands, which in turn alter their microbial ecological biodiversity and functions. For the first time, the impact of the current anthropogenic activities and land use practices on the Blesbokspruit wetland chemical status and their consequential effect on the microbial structure and functions were investigated. Sites of high pollution intensity were identified using geographic information systems mapping (GISMapping) and the wetland microbiome and functional profile were studied through the use of high throughput shotgun metagenomics sequencing analysis. The predominant phyla that stemmed along the Blesbokspruit wetland were found to be Proteobacteria which was more dominant in water (93 %) than in the sediments (89 %), followed by firmicutes which was more abundant in sediments (9 %) than in water (6 %), and Bacteroidetes were relatively low in abundance within both the sediments (2 %) and the overlying water (1 %). The genera Klebsiella (70.4 %-28.2 %), Citrobacter (52.0 %-30.6 %), Escherichia (51.0 %-8.4 %), and Lynsinibacillus (9.3 %-1.5 %) were observed in most water and sediment samples. Within the six polluted sites, Site 2 was found to be the most highly polluted site in the Blesbokspruit wetland with very high COD (900 mg/L), TOC (11.60 mg/L), NO3- (39.74 mg/L), NO2- (12.64 mg/L), PO43 (4.14 mg/L), Fl- (143.88 mg/L), Cl- (145.95 mg/L) concentrations recorded in the water and high levels of TOC (0.37 mg/L), TC (6.92 %), TN (1.82 %), TS (0.53 %) in sediments. The microbial community structure and functions were found to be strongly influenced by the high organic content from the intense agricultural activities and sewage spillages and heavy metals from the mining activities nearby.
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Affiliation(s)
- Lebohang E Koloti
- Institute for the Development of Energy for African Sustainability (IDEAS), University of South Africa, Christiaan De Wet/Pioneer, P.O. Box X6, FL 1710, South Africa
| | - Rosina Nkuna
- Institute for the Development of Energy for African Sustainability (IDEAS), University of South Africa, Christiaan De Wet/Pioneer, P.O. Box X6, FL 1710, South Africa
| | - Tonderayi S Matambo
- Institute for the Development of Energy for African Sustainability (IDEAS), University of South Africa, Christiaan De Wet/Pioneer, P.O. Box X6, FL 1710, South Africa; Centre of Competence in Environmental Biotechnology, College of Agriculture and Environmental Sciences, University of South Africa, Christiaan De Wet/Pioneer, P.O. Box X6, FL 1710, South Africa.
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Cormier JM, Coffin MRS, Pater CC, Knysh KM, Gilmour RF, Guyondet T, Courtenay SC, van den Heuvel MR. Internal nutrients dominate load and drive hypoxia in a eutrophic estuary. ENVIRONMENTAL MONITORING AND ASSESSMENT 2023; 195:1211. [PMID: 37707663 DOI: 10.1007/s10661-023-11621-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 07/19/2023] [Indexed: 09/15/2023]
Abstract
The hypothesis that local hypoxia and chlorophyll concentration are spatially tethered to local, sediment-driven nutrient release was examined in a small, nutrient-impacted estuary in the Southern Gulf of St. Lawrence, Canada. Sediment reactor core samples were taken at 10 locations between 0.25 and 100% of the estuary area in spring and fall (2019) and used to estimate nitrogen and phosphate flux. Sediment organic matter, carbonate, percent nitrogen, percent carbon, δ13C, and δ15N were measured from the reactor core stations. Oxygen was recorded continually using oxygen loggers while chlorophyll and salinity were measured bi-weekly. A hydrodynamic model was used to determine water renewal time at each station. The most severe eutrophication effects were in the upper one-fifth of the estuary. There were strong local relationships between sediment biogeochemistry, hypoxia, and chlorophyll metrics but not with water renewal time. Internal nutrient loading represented 65% and 69% of total N loading, and 98% and 89% of total P loading to the estuary in June and September, respectively. Sediment nitrogen flux was highly predictable from a range of local sediment variables that reflect either nutrient content, or organic carbon enrichment in general. Percent nitrogen and percent carbon were highly correlated but sediment P flux was poorly predicted from sediment parameters examined. The highest correlations were with percent nitrogen and percent carbon. These results indicate that incorporating internal nutrient loading into nutrient monitoring programs is a critical next step to improve predictive capacity for eutrophication endpoints and to mitigate nutrient effects.
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Affiliation(s)
- Jerrica M Cormier
- Canadian Rivers Institute, Department of Biology, University of Prince Edward Island, Charlottetown, PE, Canada.
| | | | - Christina C Pater
- Canadian Rivers Institute, Department of Biology, University of Prince Edward Island, Charlottetown, PE, Canada
| | - Kyle M Knysh
- Canadian Rivers Institute, Department of Biology, University of Prince Edward Island, Charlottetown, PE, Canada
| | - Robert F Gilmour
- Faculty of Sustainable Design Engineering, University of Prince Edward Island, Charlottetown, PE, Canada
| | - Thomas Guyondet
- Fisheries and Oceans Canada, Gulf Fisheries Center, Moncton, NB, Canada
| | - Simon C Courtenay
- Canadian Rivers Institute, School of Environment, Resources and Sustainability, University of Waterloo, Waterloo, ON, Canada
| | - Michael R van den Heuvel
- Canadian Rivers Institute, Department of Biology, University of Prince Edward Island, Charlottetown, PE, Canada
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Ma JL, Xu DP, Tao YF, Zheng T, Xu P, Qiang J. Integrated transcriptome and miRNA sequencing analyses reveal that hypoxia stress induces immune and metabolic disorders in gill of genetically improved farmed tilapia (GIFT, Oreochromis niloticus). FISH & SHELLFISH IMMUNOLOGY 2023; 139:108909. [PMID: 37353064 DOI: 10.1016/j.fsi.2023.108909] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 06/12/2023] [Accepted: 06/20/2023] [Indexed: 06/25/2023]
Abstract
The survival and growth of fish are significantly impacted by a hypoxic environment (low dissolved oxygen). In this study, we compared tissue structure, physiological changes, and mRNA/miRNA transcriptome, in gills of genetically improved farmed tilapia (GIFT, Oreochromis niloticus) between the hypoxic group (DO: 0.55 mg/L, HG) and the control group (DO: 5 mg/L, CG). The results showed that the gill filaments in the hypoxic group showed curling, engorgement, and apoptotic cells increased, and that exposure for 96 h resulted in a reduction in the antioxidant capacity. We constructed and sequenced miRNA and mRNA libraries from gill tissues of GIFT at 96 h of hypoxia stress. Between the HG and CG, a total of 14 differentially expressed (DE) miRNAs and 1557 DE genes were obtained. GO and KEGG enrichment showed that DE genes were mainly enriched in immune and metabolic pathways such as natural killer cell mediated cytotoxicity, steroid biosynthesis, primary immunodeficiency, and synthesis and degradation of ketone bodies. Based on the results of mRNA sequencing and screening for miRNA-mRNA pairs, we selected and verified six DE miRNAs and their probable target genes. The sequencing results were consistent with the qRT-PCR validation results. The result showed that under hypoxia stress, the innate immune response was up-regulated, and the adaptive immune response was down-regulated in the gill of GIFT. The synthesis of cholesterol in gill cells is reduced, which is conducive to the absorption of solvent oxygen. These findings offer fresh information about the processes of fish adaptation to hypoxic stress.
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Affiliation(s)
- Jun-Lei Ma
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, China
| | - Dong-Po Xu
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, China; Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, China.
| | - Yi-Fan Tao
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, China
| | - Tao Zheng
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, China
| | - Pao Xu
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, China; Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, China
| | - Jun Qiang
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, China; Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, China.
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6
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Zhang F, Fu H, Lou H, Sun X, Zhang D, Sun P, Wang X, Li Y, Lu J, Bao M. Assessment of eutrophication from Xiaoqing River estuary to Laizhou Bay: Further warning of ecosystem degradation in typically polluted estuary. MARINE POLLUTION BULLETIN 2023; 193:115209. [PMID: 37364339 DOI: 10.1016/j.marpolbul.2023.115209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/17/2023] [Accepted: 06/20/2023] [Indexed: 06/28/2023]
Abstract
The coast of Laizhou Bay is plagued by a number of environmental issues, such as eutrophication, which are likely to worsen over the next few decades as a result of trends toward industrialization and urbanization. High nutrient levels in the Xiaoqing River are believed to be the main cause of Laizhou Bay becoming eutrophicated. Therefore, we conducted two cruises from the Xiaoqing River estuary to Laizhou Bay in August 2022 and December 2022, respectively, in the wet and dry periods to assess the potential impact of status of eutrophication due to human activities. The results showed that the concentration of DIN was higher than the quality standard for water (fi > 1) in both the wet season (August 2022) and the dry season (December 2022). DIN has major environmental impacts in Laizhou Bay. The eutrophication level index and organic pollution index have obvious spatial and temporal characteristics. In terms of time, the dry season is higher than the wet season. In space, Xiaoqing estuary is higher than Laizhou Bay. In the two surveys, DIN and DIP concentrations were significantly positively correlated, indicating that N and P pollution in the region had a common source and destination, and the spatial distribution was also similar. In addition, the current environmental conditions in the region are not ideal, reaching moderate and severe eutrophication levels, which proves that the ecosystem has the risk of aggravating degradation. As the Xiaoqing River is about to resume full navigation, human-related nutrient input (especially DIN) will continue to increase, and it is expected that the eutrophication risk in this area will increase in the next few years due to the increase in nutrient load.
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Affiliation(s)
- Feifei Zhang
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Institute for Advanced, Ocean Study, Ocean University of China, Qingdao 266100, China; College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China
| | - Hongrui Fu
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Institute for Advanced, Ocean Study, Ocean University of China, Qingdao 266100, China; College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China
| | - Huawei Lou
- Shouguang Marine Fishery Development Center, Weifang 262700, China
| | - Xiaojun Sun
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Institute for Advanced, Ocean Study, Ocean University of China, Qingdao 266100, China; College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China
| | - Dong Zhang
- Shouguang Marine Fishery Development Center, Weifang 262700, China.
| | - Peiyan Sun
- Key Laboratory of Ecological Warning, Protection & Restoration for Bohai Sea, Ministry of Natural Resources, Qingdao 266100, China
| | - Xinping Wang
- Key Laboratory of Ecological Warning, Protection & Restoration for Bohai Sea, Ministry of Natural Resources, Qingdao 266100, China
| | - Yiming Li
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Institute for Advanced, Ocean Study, Ocean University of China, Qingdao 266100, China; College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China
| | - Jinren Lu
- College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China
| | - Mutai Bao
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Institute for Advanced, Ocean Study, Ocean University of China, Qingdao 266100, China; College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China.
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7
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Biswas JK, Pramanik S, Kumar M. Fish parasites as proxy bioindicators of degraded water quality of River Saraswati, India. ENVIRONMENTAL MONITORING AND ASSESSMENT 2023; 195:818. [PMID: 37286743 DOI: 10.1007/s10661-023-11411-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 05/18/2023] [Indexed: 06/09/2023]
Abstract
The nature and intensity of water pollution determine the effects on aquatic biota and aquatic ecosystem health. The present study aimed at assessing the impact of the degraded physicochemical regime of river Saraswati, a polluted river having a historical legacy, on the parasitic infection and the role of fish parasite as a bioindicator of water quality. Two Water Quality Indices (WQIs) were adopted as useful tools for assessing the overall water quality status of polluted river based on 10 physicochemical parameters. Total 394 fish (Channa punctata) were examined. Ectoparasite Trichodina sp., Gyrodactylus sp., and endoparasites Eustrongylides sp. were collected from the host fish. Prevalence, mean intensity and abundance for each sampling period were calculated for the determination of parasitic load. The parasitic load of Trichodina sp. and Gyrodactylus sp. was significantly (p < 0.001) higher in winter, whereas the parasitic load of Eustrongylides sp. showed no significant (p > 0.05) seasonal fluctuation. The parasitic load of ectoparasites was negatively correlated with temperature, free carbon dioxide, biochemical oxygen demand, and WAWQI but positively correlated with electrical conductivity and CCMEWQI. Fish health was found to be adversely affected by degrading water qualities and parasitic infection. A 'vicious cycle' develops as a result of the interplay among deteriorating water quality, withering fish immunological defence, and amplifying parasitic infection. Since parasitic load was strongly conditioned by the combined influence of a suite of water quality parameters the fish parasites can be used as a powerful indicator of deteriorating water quality.
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Affiliation(s)
- Jayanta Kumar Biswas
- Department of Ecological Studies and International Centre for Ecological Engineering, University of Kalyani, Kalyani, West Bengal, 741235, Nadia, India.
| | - Sasanka Pramanik
- Department of Zoology, Sreegopal Banerjee College, Bagati, Mogra, West Bengal, 712148, Hooghly, India
| | - Manish Kumar
- Sustainability Cluster, University of Petroleum and Energy Studies, Dehradun, 248007, Uttarakhand, India
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Berthold M, Schumann R, Reiff V, Wulff R, Schubert H. Mesopredator‐mediated trophic cascade can break persistent phytoplankton blooms in coastal waters. OIKOS 2023. [DOI: 10.1111/oik.09469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Maximilian Berthold
- Biological Station Zingst, Univ. of Rostock Zingst Germany
- Phytoplankton Ecophysiology, Mount Allison Univ. Sackville Canada
| | - Rhena Schumann
- Biological Station Zingst, Univ. of Rostock Zingst Germany
| | - Volker Reiff
- Biological Station Zingst, Univ. of Rostock Zingst Germany
| | - Rita Wulff
- Biological Station Zingst, Univ. of Rostock Zingst Germany
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Nitrogen Treatment by a Dry Detention Basin with Stormwater Wetland Characteristics. HYDROLOGY 2022. [DOI: 10.3390/hydrology9050085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Dry detention basins (DB) are commonly used to reduce the rate of runoff in urban areas and may provide open space for recreation between storms. However, most are not effective at nitrogen removal in comparison to other measures, such as constructed wetlands. The study goal was to assess the nitrogen treatment efficiency of a DB that exhibited some wetland characteristics, including saturated soil near the inlet and wetland vegetation that covered 40% of the surface area. Influent and effluent samples were collected during multiple stages of eight storm events for nitrogen concentration analyses. High-frequency water stage, pH, dissolved oxygen (DO), and temperature loggers were deployed at the inlet and outlet prior to anticipated rain. As stormwater passed through the DB, the event mean concentrations (EMCs) and masses of TN declined by 20.7% and 52.3%, respectively, while the DO and pH dropped by 62% and 20.5%, respectively. Load reductions of TN exceeding 93% were observed during two small storms with rain depths of less than 0.16 cm and when the outflow volumes were reduced by greater than 82%. Temperature was significantly correlated (p < 0.001; r = 0.964) with volume reductions (via infiltration and evapotranspiration), and, thus, the treatment was better during warmer periods. The DB was effective at removing inorganic nitrogen, likely via nitrification, denitrification, and immobilization, but frequently exported higher EMCs of organic nitrogen. Overall, the DB exceeded the 10% TN removal expectation for dry basins. The findings from this study suggest that the TN treatment efficiency of DBs may be improved by incorporating wetland characteristics.
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Coffin M, Knysh KM, Roloson SD, Pater CC, Theriaul E, Cormier JM, Courtenay SC, van den Heuvel MR. Influence of nutrient enrichment on temporal and spatial dynamics of dissolved oxygen within northern temperate estuaries. ENVIRONMENTAL MONITORING AND ASSESSMENT 2021; 193:804. [PMID: 34779929 PMCID: PMC8593059 DOI: 10.1007/s10661-021-09589-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 11/05/2021] [Indexed: 06/13/2023]
Abstract
In temperate estuaries of the southern Gulf of St. Lawrence, intermittent seasonal anoxia coupled with phytoplankton blooms is a regular occurrence in watersheds dominated by agricultural land use. To examine the spatial relationship between dissolved oxygen and phytoplankton throughout the estuary to assist in designing monitoring programs, oxygen depth profiles and chlorophyll measurements were taken bi-weekly from May to December in 18 estuaries. In five of those estuaries, dissolved oxygen data loggers were set to measure oxygen at hourly intervals and at multiple locations within the estuary the subsequent year. The primary hypothesis was that dissolved oxygen in the upper estuary (first 10% of estuary area) is predictive of dissolved oxygen mid-estuary (50% of estuary area). The second hypothesis was that hypoxia/superoxia in the estuary is influenced by temperature and tidal flushing. Oxygen depth profiles conducted in the first year of study provided preliminary support that dissolved oxygen in the upper estuary was related to dissolved oxygen throughout the estuary. However, dissolved oxygen from loggers deployed at 10% and 50% of estuary area did not show as strong a correlation as expected (less than half the variance explained). The strength of the correlation declined towards the end of summer. Spatial decoupling of oxygen within the estuary suggested influence of local conditions. Chlorophyll concentration seemed also to be dependent on local conditions as it appeared to be coupled with the presence of sustained anoxia in the upper estuary with blooms typically occurring within 7 to 14 days of anoxia. The practical implication for oxygen monitoring is that one location within the most severely impacted part of the estuary is not sufficient to fully evaluate the severity of eutrophication effects.
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Affiliation(s)
- Mrs Coffin
- Fisheries and Oceans Canada, Gulf Fisheries Centre, 343 University Ave, Moncton, NB, E1C 5K4, Canada.
| | - K M Knysh
- Department of Biology, Canadian Rivers Institute, University of Prince Edward Island, Charlottetown, Canada
| | - S D Roloson
- Fisheries and Oceans Canada, Gulf Fisheries Centre, 343 University Ave, Moncton, NB, E1C 5K4, Canada
| | - C C Pater
- Department of Biology, Canadian Rivers Institute, University of Prince Edward Island, Charlottetown, Canada
| | - E Theriaul
- Department of Biology, Canadian Rivers Institute, University of Prince Edward Island, Charlottetown, Canada
| | - J M Cormier
- Department of Biology, Canadian Rivers Institute, University of Prince Edward Island, Charlottetown, Canada
| | - S C Courtenay
- Canadian Water Network, School of Environment, Resources and Sustainability, Canadian Rivers Institute, University of Waterloo, Waterloo, Canada
| | - M R van den Heuvel
- Department of Biology, Canadian Rivers Institute, University of Prince Edward Island, Charlottetown, Canada
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11
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Mohan NS, M K VS, Joseph S. An appraisal of nutrient status and productivity with emphasis on phytoplankton assemblage in Karamana River, Kerala, India. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2021; 84:2885-2902. [PMID: 34850701 DOI: 10.2166/wst.2021.260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Nutrient pollution of rivers is one of the prime threats facing the aquatic systems. In the present study, water samples (n = 20) were collected from the Karamana river (KR) during the pre-monsoon (PMN) and monsoon (MN) seasons of 2019 to analyze the seasonal variations. The water samples were analyzed for various physico-chemical parameters and to understand the nutrient status of the river. Furthermore, gross primary productivity (GPP), net primary productivity (NPP) and phytoplankton analysis were carried out to assess relationship among productivity variables and phytoplanktons. The study revealed that water quality is better during MN than PMN due to dilution. Among the two seasons, PMN showed relatively higher values for most of parameters like pH, EC, TDS, TA, Cl, NH4-N, NO3-N, NO2-N, Chl-a, GPP and NPP. The correlation among GPP, NPP, nutrients and other water quality parameters were done using SPSS. Phytoplankton of 23 genera belonging to three classes, namely Chlorophyceae (40%), Bacillariophyceae (40%) and Cyanophyceae (20%) have been identified in KR. The various phytoplankton diversity indices and statistical analyses were estimated and their relevance discussed in this paper. The nutrient enrichment in the downstream regions was affected the phytoplanktonic structure and diversity of the river.
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Affiliation(s)
- Nivedi S Mohan
- Department of Environmental Sciences, University of Kerala, Kariavattom campus, Thiruvananthapuram, Kerala 695581, India E-mail:
| | - Vishnu Sagar M K
- Department of Environmental Sciences, University of Kerala, Kariavattom campus, Thiruvananthapuram, Kerala 695581, India E-mail:
| | - Sabu Joseph
- Department of Environmental Sciences, University of Kerala, Kariavattom campus, Thiruvananthapuram, Kerala 695581, India E-mail:
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12
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Derolez V, Malet N, Fiandrino A, Lagarde F, Richard M, Ouisse V, Bec B, Aliaume C. Fifty years of ecological changes: Regime shifts and drivers in a coastal Mediterranean lagoon during oligotrophication. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 732:139292. [PMID: 32438187 DOI: 10.1016/j.scitotenv.2020.139292] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/06/2020] [Accepted: 05/06/2020] [Indexed: 06/11/2023]
Abstract
Thau lagoon is a large Mediterranean coastal lagoons and it supports traditional shellfish farming activities. It has been subject to eutrophication leading to major anoxic events associated with massive mortalities of shellfish stocks. Since the 1970s, improvements have been made to wastewater treatment systems, which have gradually led to oligotrophication of the lagoon. The aim of our study was to determine how the decrease in nutrient inputs resulted in major ecological changes in Thau lagoon, by analysing five decades of time-series (1970-2018) of observations on pelagic and benthic autotrophic communities. We were able to identify two periods during the oligotrophication process. Period 1 (1970-1992) was considered a eutrophic period, characterised by the shift from seagrass dominance to dominance of red macroalgae. Period 2 (1993-2018), characterised by improved eutrophication status, was further divided into three: a transition phase (1993-2003) during which the water column continued to recover but the benthic community lagged behind in recovery and in partial resilience; a regime shift (2003-2006), after which the water column became oligotrophic and seagrass began to recover (2007-2018). Considering anoxia crises as indicators of ecosystem resilience and resistance, we used a generalised linear model to analyse meteorological and environmental data with the aim of identifying the triggers of summer anoxia over the study period. Among the meteorological variables studied, air temperature had the strongest positive effect, followed by the period and wind intensity (both negative effects) and by rainfall in July (positive effect). The risk of triggering anoxia was lower in period 2, evidence for the increasing resistance of the ecosystem to climatic stress throughout the oligotrophication process. At the ecosystem scale and in the long term perspective, the ecological gains related to oligotrophication are especially important in the context of climate change, with more frequent and severe heat waves predicted.
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Affiliation(s)
| | | | | | - Franck Lagarde
- MARBEC, Univ Montpellier, CNRS, IRD, Ifremer, Sète, France
| | - Marion Richard
- MARBEC, Univ Montpellier, CNRS, IRD, Ifremer, Sète, France
| | - Vincent Ouisse
- MARBEC, Univ Montpellier, CNRS, IRD, Ifremer, Sète, France
| | - Béatrice Bec
- MARBEC, Univ Montpellier, CNRS, IRD, Ifremer, Montpellier, France
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Lavaud R, Guyondet T, Filgueira R, Tremblay R, Comeau LA. Modelling bivalve culture - Eutrophication interactions in shallow coastal ecosystems. MARINE POLLUTION BULLETIN 2020; 157:111282. [PMID: 32658665 DOI: 10.1016/j.marpolbul.2020.111282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 05/14/2020] [Accepted: 05/16/2020] [Indexed: 06/11/2023]
Abstract
Assessing the carrying capacity of ecosystems is crucial to the selection of suitable and sustainable locations for aquaculture farms. In Malpeque Bay (PEI, Canada), the potential expansion of mussel farms has driven a series of numerical modelling studies. We coupled sub-models for sea lettuce, wild and cultured oysters and wild softshell clams to an existing ecosystem model to better understand nutrient dynamics and the carrying capacity of Malpeque Bay. Simulations suggested that competition for nutrients between phytoplankton and sea lettuce and filtration by cultured bivalves predominantly mitigate eutrophication effects. The addition of sea lettuce reduced mussel growth by 2% on average and up to 9% near eutrophic estuaries favouring macroalgae growth. Projected new mussel farms reduced current mussel growth by 2% also, suggesting that the carrying capacity of the bay may not be reached yet. Both current and projected aquaculture activities seemed to have limited effects on natural bivalve growth.
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Affiliation(s)
- Romain Lavaud
- Fisheries and Oceans Canada, Gulf Fisheries Center, Moncton, NB, Canada; Marine Affairs Program, Dalhousie University, Halifax, NS, Canada; Institut des Sciences de la Mer, Université du Québec à Rimouski, Rimouski, QC, Canada.
| | - Thomas Guyondet
- Fisheries and Oceans Canada, Gulf Fisheries Center, Moncton, NB, Canada
| | - Ramón Filgueira
- Marine Affairs Program, Dalhousie University, Halifax, NS, Canada
| | - Réjean Tremblay
- Institut des Sciences de la Mer, Université du Québec à Rimouski, Rimouski, QC, Canada
| | - Luc A Comeau
- Fisheries and Oceans Canada, Gulf Fisheries Center, Moncton, NB, Canada
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Lavaud R, Filgueira R, Nadeau A, Steeves L, Guyondet T. A Dynamic Energy Budget model for the macroalga Ulva lactuca. Ecol Modell 2020. [DOI: 10.1016/j.ecolmodel.2019.108922] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Comparison of Acoustic to Optical Backscatter Continuous Measurements of Suspended Sediment Concentrations and Their Characterization in an Agriculturally Impacted River. WATER 2019. [DOI: 10.3390/w11050981] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The increased soil loss in an agricultural watershed raises challengers for river water quality and a reliable automated monitoring for suspended sediment concentrations (SSC) is crucial to evaluate sediment budgets variation in systems. The aims of this study were (1) to test if an acoustic doppler current profiler (ADCP) would give similar results to turbidity probe measurements as a high frequency monitoring tool for suspended sediment; and (2) to analyze the relationship between sediment drivers and SSC in a typical agricultural drainage basin. The acoustic and optical backscatter sensors were used to collect SSC data during the ice-free seasons of four consecutive years in the Dunk River (PEI, Canada). The slopes of the relationships between the two SSC indirect measurements were not significantly different than 1. Correlations between SSC and hydro-meteorological variables showed that the high SSC values were more associated with the streamflow and water velocity than precipitation. This study highlighted the great potential of ADCP for the continuous monitoring of suspended sediment in an agricultural watershed. For summer periods the prevalence of clockwise hysteresis (74.1% of measured rainstorm events with SSC > 25 mg L−1) appeared related to rainstorm behaviors.
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Coffin MR, Courtenay SC, Knysh KM, Pater CC, van den Heuvel MR. Impacts of hypoxia on estuarine macroinvertebrate assemblages across a regional nutrient gradient. Facets (Ott) 2018. [DOI: 10.1139/facets-2017-0044] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In this study, we examined the effects of dissolved oxygen, via metrics based on hourly measurements, and other environmental variables on invertebrate assemblages in estuaries spanning a gradient of nutrient loading and geography in the southern Gulf of St. Lawrence, Canada. Upper areas (15–25 practical salinity units (PSU)) of 13 estuaries that were dominated by either seagrass ( Zostera marina Linnaeus, 1753) or macroalgae ( Ulva spp. Linnaeus, 1753) were sampled from June to September 2013. Macroinvertebrate assemblages from Z. marina were found to be distinct from Ulva assemblages for both epifauna and infauna. Small snails dominated each vegetation type, specifically cerithids in Z. marina and hydrobids in Ulva. Although Z. marina had higher species richness, approximately 70% of species were common to both habitats. Faunal communities differed among estuaries with large, within-estuary, temporal variance only observed at Ulva sites impacted by hypoxia and particularly at sites with long water residence time. Indeed, abundances varied by several orders of magnitude in Ulva ranging from zero to thousands of macroinvertebrates. There was a strong negative correlation between hypoxic or anoxic water, 48 h prior to sampling, with relative abundances of amphipods, and a positive correlation with the relative abundances of snails. As one of the first studies to use high-frequency oxygen monitoring, this study revealed probable impacts and the transient nature of hypoxia in eutrophication.
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Affiliation(s)
- Michael R.S. Coffin
- Canadian Rivers Institute, Department of Biology, University of Prince Edward Island, Charlottetown, PE C1A 4P3, Canada
| | - Simon C. Courtenay
- Canadian Rivers Institute, Department of Biology, University of Prince Edward Island, Charlottetown, PE C1A 4P3, Canada
- Canadian Rivers Institute, Canadian Water Network, School of Environment, Resources and Sustainability, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Kyle M. Knysh
- Canadian Rivers Institute, Department of Biology, University of Prince Edward Island, Charlottetown, PE C1A 4P3, Canada
| | - Christina C. Pater
- Canadian Rivers Institute, Department of Biology, University of Prince Edward Island, Charlottetown, PE C1A 4P3, Canada
| | - Michael R. van den Heuvel
- Canadian Rivers Institute, Department of Biology, University of Prince Edward Island, Charlottetown, PE C1A 4P3, Canada
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