Pub Date : 2024-11-19DOI: 10.1016/j.watres.2024.122814
Md Noim Imtiazy, Andrew M. Paterson, Scott N. Higgins, Huaxia Yao, Daniel Houle, Jeff J. Hudson
The increase in dissolved organic carbon (DOC) concentrations in freshwater systems has received considerable attention due to its implications for drinking water treatment and numerous limnological processes. While past studies have documented the influence of recovery from acidification and climate change on long-term DOC trends, the emerging importance of these explanatory factors remains less understood. In addition, few studies have followed up on recent trends in sites that have undergone increases in DOC. Using a dataset from 1980 to 2020, we investigated interannual variations in DOC and dissolved organic nitrogen (DON) in 49 lakes across four eastern Canadian regions with a history of increases in DOC. We identified recent shifts in DOC patterns using LOESS smoothing and piecewise regression. We observed a stabilizing pattern or even a decrease (p < 0.001) in high acidification regions (Dorset and Nova Scotia), where increases in DOC were previously documented. At the low acid deposition region, IISD-Experimental Lakes Area, an increasing pattern in DOC stabilized in the early 2000s; however, DOC appears to be increasing again in recent years (p = 0.03). Our analysis identified precipitation and SO4 deposition as the primary explanatory variables for DOC patterns (explaining 56–71% of variance). However, because acid deposition has declined substantially, climate and local watershed factors are becoming increasingly influential, leading to the emergence of new DOC patterns. Long-term changes in DOC and DON were not always synchronous, as these were often correlated with different factors (e.g., DON with ammonium deposition). This resulted in observable shifts in DOC:DON ratios, indicative of changes in dissolved organic matter (DOM) composition. We underscore the importance of ongoing monitoring in diverse regions because of the changing nature of environmental variables and new emerging trends.
{"title":"Has lake brownification ceased? Stabilization, re-browning, and other factors associated with dissolved organic matter trends in eastern Canadian lakes","authors":"Md Noim Imtiazy, Andrew M. Paterson, Scott N. Higgins, Huaxia Yao, Daniel Houle, Jeff J. Hudson","doi":"10.1016/j.watres.2024.122814","DOIUrl":"https://doi.org/10.1016/j.watres.2024.122814","url":null,"abstract":"The increase in dissolved organic carbon (DOC) concentrations in freshwater systems has received considerable attention due to its implications for drinking water treatment and numerous limnological processes. While past studies have documented the influence of recovery from acidification and climate change on long-term DOC trends, the emerging importance of these explanatory factors remains less understood. In addition, few studies have followed up on recent trends in sites that have undergone increases in DOC. Using a dataset from 1980 to 2020, we investigated interannual variations in DOC and dissolved organic nitrogen (DON) in 49 lakes across four eastern Canadian regions with a history of increases in DOC. We identified recent shifts in DOC patterns using LOESS smoothing and piecewise regression. We observed a stabilizing pattern or even a decrease (p < 0.001) in high acidification regions (Dorset and Nova Scotia), where increases in DOC were previously documented. At the low acid deposition region, IISD-Experimental Lakes Area, an increasing pattern in DOC stabilized in the early 2000s; however, DOC appears to be increasing again in recent years (p = 0.03). Our analysis identified precipitation and SO<sub>4</sub> deposition as the primary explanatory variables for DOC patterns (explaining 56–71% of variance). However, because acid deposition has declined substantially, climate and local watershed factors are becoming increasingly influential, leading to the emergence of new DOC patterns. Long-term changes in DOC and DON were not always synchronous, as these were often correlated with different factors (e.g., DON with ammonium deposition). This resulted in observable shifts in DOC:DON ratios, indicative of changes in dissolved organic matter (DOM) composition. We underscore the importance of ongoing monitoring in diverse regions because of the changing nature of environmental variables and new emerging trends.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"22 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aquaculture systems are of increasing concern as an important source of atmospheric methane (CH4) and nitrous oxide (N2O). However, the role of animals in regulating CH4 and N2O emissions from aquaculture systems remains unclear. Here, we established mesocosm trials to investigate impacts of bioturbation of different aquaculture species (i.e., clam, shrimp, and crab) on CH4 and N2O fluxes in a mariculture pond. Across the initial, middle, and final culturing stages, mean CH4 flux in mesocosm without animals was 4.81 ± 0.09 µg CH4 m‒2 h‒1, while the existence of clam, shrimp, and crab significantly increased CH4 flux by 35.3%, 80.6%, and 138%, respectively. Bioturbation significantly decreased dissolved oxygen (DO) concentration by 5.19‒44.8% but increased porewater CH4 concentration by 14.1‒59.9%, indicating that lowered DO caused by animal respiration promoted CH4 production in sediment. Moreover, bioturbation of animals significantly increased ebullitive CH4 fluxes by 41.0‒216%, contributing 57.4‒77.2% of the increased CH4 emission in mesocosms with animals. However, shrimp and crab significantly reduced N2O flux by 30.3% and 42.5%, respectively, primarily due to lowered DO conditions suppressing nitrification and limiting NO3‒ supply for denitrification. By contrast, clam significantly increased N2O emission by 181% because its filter-feeding behavior excreted more NH4+ and NO3‒ into overlying water and thereby facilitating N2O production. The N2O concentration in overlying water was 1.72‒2.83-fold of that in porewater, and the calculated diffusive N2O flux was 1.80‒37.5% greater than chamber-measured N2O efflux. This implied that N2O might be primarily produced in overlying water rather than sediments, and the produced N2O can either evade as water-air fluxes or diffuse downwards into sediments to be consumed. Overall, our study advocates that aquaculture-related climate mitigation strategies should place more attention on the divergent impacts of animal bioturbation on CH4 and N2O emissions.
{"title":"Divergent impacts of animal bioturbation on methane and nitrous oxide emissions from mariculture ponds","authors":"Yanhong Dong, Junji Yuan, Junjie Li, Deyan Liu, Xian Wu, Huijie Zheng, Hui Wang, Huiqin Wang, Weixin Ding","doi":"10.1016/j.watres.2024.122822","DOIUrl":"https://doi.org/10.1016/j.watres.2024.122822","url":null,"abstract":"Aquaculture systems are of increasing concern as an important source of atmospheric methane (CH<sub>4</sub>) and nitrous oxide (N<sub>2</sub>O). However, the role of animals in regulating CH<sub>4</sub> and N<sub>2</sub>O emissions from aquaculture systems remains unclear. Here, we established mesocosm trials to investigate impacts of bioturbation of different aquaculture species (i.e., clam, shrimp, and crab) on CH<sub>4</sub> and N<sub>2</sub>O fluxes in a mariculture pond. Across the initial, middle, and final culturing stages, mean CH<sub>4</sub> flux in mesocosm without animals was 4.81 ± 0.09 µg CH<sub>4</sub> m<sup>‒2</sup> h<sup>‒1</sup>, while the existence of clam, shrimp, and crab significantly increased CH<sub>4</sub> flux by 35.3%, 80.6%, and 138%, respectively. Bioturbation significantly decreased dissolved oxygen (DO) concentration by 5.19‒44.8% but increased porewater CH<sub>4</sub> concentration by 14.1‒59.9%, indicating that lowered DO caused by animal respiration promoted CH<sub>4</sub> production in sediment. Moreover, bioturbation of animals significantly increased ebullitive CH<sub>4</sub> fluxes by 41.0‒216%, contributing 57.4‒77.2% of the increased CH<sub>4</sub> emission in mesocosms with animals. However, shrimp and crab significantly reduced N<sub>2</sub>O flux by 30.3% and 42.5%, respectively, primarily due to lowered DO conditions suppressing nitrification and limiting NO<sub>3</sub><sup>‒</sup> supply for denitrification. By contrast, clam significantly increased N<sub>2</sub>O emission by 181% because its filter-feeding behavior excreted more NH<sub>4</sub><sup>+</sup> and NO<sub>3</sub><sup>‒</sup> into overlying water and thereby facilitating N<sub>2</sub>O production. The N<sub>2</sub>O concentration in overlying water was 1.72‒2.83-fold of that in porewater, and the calculated diffusive N<sub>2</sub>O flux was 1.80‒37.5% greater than chamber-measured N<sub>2</sub>O efflux. This implied that N<sub>2</sub>O might be primarily produced in overlying water rather than sediments, and the produced N<sub>2</sub>O can either evade as water-air fluxes or diffuse downwards into sediments to be consumed. Overall, our study advocates that aquaculture-related climate mitigation strategies should place more attention on the divergent impacts of animal bioturbation on CH<sub>4</sub> and N<sub>2</sub>O emissions.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"19 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sludge treatment is of great significance for environmental protection and sustainable development. Existing treatment technologies fall short in terms of carbon emissions, process efficiency, and resource recovery. This study focuses on alkaline hydrothermal treatment, proposing a short-cycle, low-energy, high-value management process for sludge valorization. Here, we investigate the impact of treatment duration, temperature, and solid content on the synthesis of high-value products and their effects on both solid and liquid phases. Based on the comprehensive results, 2 h, 160°C, and 14% solid content can be regarded as the optimized treatment condition. The resulting products, including phytohormones, humic substances, and essential nutrients (C, N, P and K), exhibit substantial potential for high-value agricultural utilization. In the unconcentrated solution, a single phytohormone can reach a concentration of 104 μg/L. Heavy metal content is well below standard limits, simultaneously achieving biological stability, and the volume can be reduced to 60%. This process is 42.12 times more energy-efficient than conventional anaerobic digestion. This novel approach promotes waste resource recycling and sustainable urban management.
{"title":"Sewage Sludge Valorization via Phytohormones Production: Parameter Regulation and Process Evaluation","authors":"Shuxian Chen, Yu Hua, Qi Song, Xin Yuan, Junwei Yang, Yue Zhang, Xiaohu Dai","doi":"10.1016/j.watres.2024.122813","DOIUrl":"https://doi.org/10.1016/j.watres.2024.122813","url":null,"abstract":"Sludge treatment is of great significance for environmental protection and sustainable development. Existing treatment technologies fall short in terms of carbon emissions, process efficiency, and resource recovery. This study focuses on alkaline hydrothermal treatment, proposing a short-cycle, low-energy, high-value management process for sludge valorization. Here, we investigate the impact of treatment duration, temperature, and solid content on the synthesis of high-value products and their effects on both solid and liquid phases. Based on the comprehensive results, 2 h, 160°C, and 14% solid content can be regarded as the optimized treatment condition. The resulting products, including phytohormones, humic substances, and essential nutrients (C, N, P and K), exhibit substantial potential for high-value agricultural utilization. In the unconcentrated solution, a single phytohormone can reach a concentration of 10<sup>4</sup> μg/L. Heavy metal content is well below standard limits, simultaneously achieving biological stability, and the volume can be reduced to 60%. This process is 42.12 times more energy-efficient than conventional anaerobic digestion. This novel approach promotes waste resource recycling and sustainable urban management.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"128 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sulfur-based autotrophic denitrification (SADN) offers new pathway for nitrite supply. However, sequential transformation of nitrogen and sulfur forms, and the functional microorganisms driving nitrite accumulation in SADN with different reduced inorganic sulfur compounds (RISCs), remain unclear. Desirable nitrite accumulation was achieved using elemental sulfur (S0-group), sulfide (S2--group) and thiosulfate (S2O32--group) as electron donors. Under equivalent electron supply conditions, S2O32--group exhibited a superior nitrate conversion rate (NCR) of 0.285 kg N/(m³·d) compared to S2--group (0.103 kg N/(m³·d)). Lower NCR in S2--group was attributed to sulfide strongly inhibiting energy metabolism process of TCA cycle, resulting in reduced reaction rates. Moreover, the NCR of S0-group (0.035 kg N/(m³·d)) was poor due to the chemical inertness of S0. Specific microbial communities were selectively enriched in phylum level, with Proteobacteria increasing to an astonished 96.27-98.49%. Comprehensive analyses of functional genus, genes, and metabolic pathways revealed significant variability in the active functional genus, with even the same genus showed significant metabolic differences in response to different RISCs. In S0-group, Thiomonas (10.0%) and Acidithiobacillus (5.1%) were the primary contributor to nitrite accumulation. Thiobacillus was the most abundant sulfur-oxidizing bacteria in S2--group (43.84%) and S2O32--group (18.92%). In S2--group, it contributed to nitrite accumulation, while in S2O32--group, it acted as a complete denitrifier (NO3--N→N2). Notably, heterotrophic denitrifying bacteria, Comamonas (12.52%), were crucial for nitrite accumulation in S2O32--group, predominating NarG while lacking NirK/S. Overall, this work advances our understanding of SADN systems with different RISCs, offering insights for optimizing nitrogen and sulfur removal.
{"title":"Metagenomic insights into nitrite accumulation in sulfur-based denitrification systems utilizing different electron donors: functional microbial communities and metabolic mechanisms","authors":"Jiahui Wang, Fangzhai Zhang, Zhaozhi Wang, Haoran Liang, Ziyi Du, Yujing Zhang, Hongying Lu, Yongzhen Peng","doi":"10.1016/j.watres.2024.122805","DOIUrl":"https://doi.org/10.1016/j.watres.2024.122805","url":null,"abstract":"Sulfur-based autotrophic denitrification (SADN) offers new pathway for nitrite supply. However, sequential transformation of nitrogen and sulfur forms, and the functional microorganisms driving nitrite accumulation in SADN with different reduced inorganic sulfur compounds (RISCs), remain unclear. Desirable nitrite accumulation was achieved using elemental sulfur (S<sup>0</sup>-group), sulfide (S<sup>2-</sup>-group) and thiosulfate (S<sub>2</sub>O<sub>3</sub><sup>2-</sup>-group) as electron donors. Under equivalent electron supply conditions, S<sub>2</sub>O<sub>3</sub><sup>2-</sup>-group exhibited a superior nitrate conversion rate (NCR) of 0.285 kg N/(m³·d) compared to S<sup>2-</sup>-group (0.103 kg N/(m³·d)). Lower NCR in S<sup>2-</sup>-group was attributed to sulfide strongly inhibiting energy metabolism process of TCA cycle, resulting in reduced reaction rates. Moreover, the NCR of S<sup>0</sup>-group (0.035 kg N/(m³·d)) was poor due to the chemical inertness of S<sup>0</sup>. Specific microbial communities were selectively enriched in phylum level, with <em>Proteobacteria</em> increasing to an astonished 96.27-98.49%. Comprehensive analyses of functional genus, genes, and metabolic pathways revealed significant variability in the active functional genus, with even the same genus showed significant metabolic differences in response to different RISCs. In S<sup>0</sup>-group, <em>Thiomonas</em> (10.0%) and <em>Acidithiobacillus</em> (5.1%) were the primary contributor to nitrite accumulation. <em>Thiobacillus</em> was the most abundant sulfur-oxidizing bacteria in S<sup>2-</sup>-group (43.84%) and S<sub>2</sub>O<sub>3</sub><sup>2-</sup>-group (18.92%). In S<sup>2-</sup>-group, it contributed to nitrite accumulation, while in S<sub>2</sub>O<sub>3</sub><sup>2-</sup>-group, it acted as a complete denitrifier (NO<sub>3</sub><sup>-</sup>-N→N<sub>2</sub>). Notably, heterotrophic denitrifying bacteria, <em>Comamonas</em> (12.52%), were crucial for nitrite accumulation in S<sub>2</sub>O<sub>3</sub><sup>2-</sup>-group, predominating <em>NarG</em> while lacking <em>NirK/S</em>. Overall, this work advances our understanding of SADN systems with different RISCs, offering insights for optimizing nitrogen and sulfur removal.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"1 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-19DOI: 10.1016/j.watres.2024.122803
Sidesse S.Y. Saapi, Harinaivo A. Andrianisa, Malicki Zorom, Lawani A. Mounirou, Swaib Semiyaga, Noel Tindouré
Discharging untreated or partially treated greywater spreads diseases to humans and depletes dissolved oxygen in water, endangering aquatic life. Current greywater treatment methods often require high capital investment, large floor space, and significant energy, whereas vermifiltration is an ecologically safe, cost-effective technology that efficiently reduces high levels of organic matter in wastewater. The present study focuses on the modeling and optimization of COD removal of a vermifiltration system, using Response Surface Methodology. The vermifilter consists of sawdust, sand, and gravel as filter media, and Eudrilus Eugenia as worm species. Experiences were conducted at room temperatures (26 - 31°C). Key factors considered as influencing COD removal were hydraulic loading rate (HLR), initial COD, and earthworm density (EWD). All three factors significantly impacted COD removal, with notable cross effects. The model predicted a maximum COD removal of 91.51% for influent with 1087 mg/L COD, 178 earthworms, and 133 L/m²/day HLR, achieving a residual COD value of 92.29 mg/L, that meet the requirements for the WHO discharge guidelines. However, due to high variability of household greywater quality in the area, the system has been full-scale designed for the value of 2500 mg/L which corresponds according to the model, to 123L/m²/day HLR. The life cycle cost (LCC) of the treated water is therefore 0.083USdollars /m3. Earthworm's growth was satisfactory (17 - 52.5%) in most filters. Finally, results suggest that the model can be used to design field-scale vermifiltration systems with minimal variation.
{"title":"Optimization of a Vermifiltration process for the treatment of high strength domestic greywater in hot climate area: A Response Surface Methodology approach","authors":"Sidesse S.Y. Saapi, Harinaivo A. Andrianisa, Malicki Zorom, Lawani A. Mounirou, Swaib Semiyaga, Noel Tindouré","doi":"10.1016/j.watres.2024.122803","DOIUrl":"https://doi.org/10.1016/j.watres.2024.122803","url":null,"abstract":"Discharging untreated or partially treated greywater spreads diseases to humans and depletes dissolved oxygen in water, endangering aquatic life. Current greywater treatment methods often require high capital investment, large floor space, and significant energy, whereas vermifiltration is an ecologically safe, cost-effective technology that efficiently reduces high levels of organic matter in wastewater. The present study focuses on the modeling and optimization of COD removal of a vermifiltration system, using Response Surface Methodology. The vermifilter consists of sawdust, sand, and gravel as filter media, and <em>Eudrilus Eugenia</em> as worm species. Experiences were conducted at room temperatures (26 - 31°C). Key factors considered as influencing COD removal were hydraulic loading rate (HLR), initial COD, and earthworm density (EWD). All three factors significantly impacted COD removal, with notable cross effects. The model predicted a maximum COD removal of 91.51% for influent with 1087 mg/L COD, 178 earthworms, and 133 L/m²/day HLR, achieving a residual COD value of 92.29 mg/L, that meet the requirements for the WHO discharge guidelines. However, due to high variability of household greywater quality in the area, the system has been full-scale designed for the value of 2500 mg/L which corresponds according to the model, to 123L/m²/day HLR. The life cycle cost (LCC) of the treated water is therefore 0.083USdollars /m<sup>3</sup>. Earthworm's growth was satisfactory (17 - 52.5%) in most filters. Finally, results suggest that the model can be used to design field-scale vermifiltration systems with minimal variation.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"18 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142671106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-18DOI: 10.1016/j.watres.2024.122812
Kevin J. Lyons, Vadim Yapiyev, Kaisa Lehosmaa, Anna-Kaisa Ronkanen, Pekka M. Rossi, Katharina Kujala
Intruding surface water can impact the physicochemical and microbiological quality of groundwater. Understanding these impacts is important because groundwater provides much of the world's potable water, and reduced quality is a potential public health risk. In this study, we monitored six shallow groundwater wells and three surface water bodies in the North Ostrobothnia region of Finland twice monthly for 12 months (October 2021–October 2022) via (i) on-site and off-site measurements of physicochemical water quality parameters, (ii) determination of stable water isotope compositions, and (iii) analysis of microbial communities (via amplicon sequencing of the V3–V4 16S rRNA gene sub-regions). Water from one well showed clear overall physicochemical and isotopic similarity with a nearby pond, as well as temporal fluctuations in water temperature and isotopes that mirrored those of the pond. Isotope mixing analyses suggested that about 80–95% of the well water comes from the pond. Such large-scale intrusion might be expected to reduce prokaryotic diversity and composition in the aquifer, either by strong influx of surface water taxa or changes to aquifer physicochemistry. Compared to the pond, however, prokaryotic communities from the well showed significantly higher alpha diversity and a composition more similar to a nearby well unaffected by intrusion. The finding that physicochemical and isotopic similarity between well water and intruding surface water is not synonymous with similarity in prokaryotic diversity and community composition makes clear the need for a multi-method approach when studying the impact of surface water intrusion on shallow wells.
{"title":"Physicochemical and isotopic similarity between well water and intruding surface water is not synonymous with similarity in prokaryotic diversity and community composition","authors":"Kevin J. Lyons, Vadim Yapiyev, Kaisa Lehosmaa, Anna-Kaisa Ronkanen, Pekka M. Rossi, Katharina Kujala","doi":"10.1016/j.watres.2024.122812","DOIUrl":"https://doi.org/10.1016/j.watres.2024.122812","url":null,"abstract":"Intruding surface water can impact the physicochemical and microbiological quality of groundwater. Understanding these impacts is important because groundwater provides much of the world's potable water, and reduced quality is a potential public health risk. In this study, we monitored six shallow groundwater wells and three surface water bodies in the North Ostrobothnia region of Finland twice monthly for 12 months (October 2021–October 2022) via (i) on-site and off-site measurements of physicochemical water quality parameters, (ii) determination of stable water isotope compositions, and (iii) analysis of microbial communities (via amplicon sequencing of the V3–V4 16S rRNA gene sub-regions). Water from one well showed clear overall physicochemical and isotopic similarity with a nearby pond, as well as temporal fluctuations in water temperature and isotopes that mirrored those of the pond. Isotope mixing analyses suggested that about 80–95% of the well water comes from the pond. Such large-scale intrusion might be expected to reduce prokaryotic diversity and composition in the aquifer, either by strong influx of surface water taxa or changes to aquifer physicochemistry. Compared to the pond, however, prokaryotic communities from the well showed significantly higher alpha diversity and a composition more similar to a nearby well unaffected by intrusion. The finding that physicochemical and isotopic similarity between well water and intruding surface water is not synonymous with similarity in prokaryotic diversity and community composition makes clear the need for a multi-method approach when studying the impact of surface water intrusion on shallow wells.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"23 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-17DOI: 10.1016/j.watres.2024.122801
Chang Qian, Qianqian Wang, Benjamin S. Gilfedder, Sven Frei, Jieyu Yu, Giri R. Kattel, Zhi-Guo Yu
The pronounced topographical differences, giving rise to numerous water bodies, also endow these formations with substantial hydraulic gradients, leading to pronounced groundwater discharge within their low-lying, natural reservoir settings. However, the dynamics of groundwater discharge in reservoirs and their impact on greenhouse gas (GHG) production and emission under different conditions remain unclear. This study focuses on a reservoir in southeastern China, where we conducted seasonal field observations alongside microcosm incubation experiments to elucidate the relationship between greenhouse gas emissions and groundwater discharge. Based on the radon (222Rn) mass balance model, groundwater discharge rates were estimated to be 2.14 ± 0.49 cm d−1 in autumn, 4.04 ± 2.09 cm d−1 in winter, 2.55 ± 1.32 cm d−1 in spring, and 2.61 ± 1.93 cm d−1 in summer. Groundwater discharge contributes on average to 31.23% of CH4, 35.65% of CO2, and 11.26% of N2O emissions across all seasons in the reservoir. Groundwater primarily influences GHG emissions by directly inputting carbon and nitrogen, as well as by altering aquatic chemical conditions and the environment of dissolved organic matter (DOM), exerting significant effects particularly during spring and autumn seasons. Especially, in winter, higher groundwater discharge rates influence microbial activity and environmental conditions in the water body, including the C/N ratio, which somewhat reduces its enhancement of greenhouse gas emissions. This study provides an in-depth exploration of greenhouse gas emissions from reservoirs and examines the impact of groundwater on these emissions, aiming to reduce uncertainties in understanding greenhouse gas emission mechanisms and carbon and nitrogen cycling.
明显的地形差异带来了众多水体，也赋予了这些地层巨大的水力梯度，导致其低洼的天然水库环境中地下水排放明显。然而，水库地下水排放的动态及其在不同条件下对温室气体（GHG）产生和排放的影响仍不清楚。本研究以中国东南部的一座水库为研究对象，在进行季节性实地观测的同时，还进行了微生态培养实验，以阐明温室气体排放与地下水排放之间的关系。根据氡（222Rn）质量平衡模型，估计秋季地下水排放量为 2.14 ± 0.49 cm d-1，冬季为 4.04 ± 2.09 cm d-1，春季为 2.55 ± 1.32 cm d-1，夏季为 2.61 ± 1.93 cm d-1。在水库的各个季节，地下水排放量平均占 CH4 排放量的 31.23%、CO2 排放量的 35.65%、N2O 排放量的 11.26%。地下水主要通过直接输入碳和氮以及改变水生化学条件和溶解有机物（DOM）环境来影响温室气体排放，尤其在春秋两季影响显著。特别是在冬季，较高的地下水排放率会影响水体中的微生物活动和环境条件，包括碳氮比，这在一定程度上降低了其对温室气体排放的促进作用。本研究深入探讨了水库的温室气体排放，并研究了地下水对这些排放的影响，旨在减少对温室气体排放机制和碳氮循环的不确定性认识。
{"title":"Seasonal Dynamics of Groundwater Discharge: Unveiling the Complex Control Over Reservoir Greenhouse Gas Emissions","authors":"Chang Qian, Qianqian Wang, Benjamin S. Gilfedder, Sven Frei, Jieyu Yu, Giri R. Kattel, Zhi-Guo Yu","doi":"10.1016/j.watres.2024.122801","DOIUrl":"https://doi.org/10.1016/j.watres.2024.122801","url":null,"abstract":"The pronounced topographical differences, giving rise to numerous water bodies, also endow these formations with substantial hydraulic gradients, leading to pronounced groundwater discharge within their low-lying, natural reservoir settings. However, the dynamics of groundwater discharge in reservoirs and their impact on greenhouse gas (GHG) production and emission under different conditions remain unclear. This study focuses on a reservoir in southeastern China, where we conducted seasonal field observations alongside microcosm incubation experiments to elucidate the relationship between greenhouse gas emissions and groundwater discharge. Based on the radon (<sup>222</sup>Rn) mass balance model, groundwater discharge rates were estimated to be 2.14 ± 0.49 cm d<sup>−1</sup> in autumn, 4.04 ± 2.09 cm d<sup>−1</sup> in winter, 2.55 ± 1.32 cm d<sup>−1</sup> in spring, and 2.61 ± 1.93 cm d<sup>−1</sup> in summer. Groundwater discharge contributes on average to 31.23% of CH<sub>4</sub>, 35.65% of CO<sub>2</sub>, and 11.26% of N<sub>2</sub>O emissions across all seasons in the reservoir. Groundwater primarily influences GHG emissions by directly inputting carbon and nitrogen, as well as by altering aquatic chemical conditions and the environment of dissolved organic matter (DOM), exerting significant effects particularly during spring and autumn seasons. Especially, in winter, higher groundwater discharge rates influence microbial activity and environmental conditions in the water body, including the C/N ratio, which somewhat reduces its enhancement of greenhouse gas emissions. This study provides an in-depth exploration of greenhouse gas emissions from reservoirs and examines the impact of groundwater on these emissions, aiming to reduce uncertainties in understanding greenhouse gas emission mechanisms and carbon and nitrogen cycling.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"76 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cyanobacterial blooms pose a significant environmental threat in freshwater ecosystems. These cyanobacteria exhibit resilience to cold and dark conditions during winter and flourish as temperature rise in warmer seasons. However, there is a limited understanding of the dynamic growth recovery process and regulatory signaling mechanisms in cyanobacteria after overwintering. In this study, we employed Microcystis aeruginosa (M. aeruginosa) as a model to simulate its growth recovery when subjected to increasing temperature after overwintering under low temperature (4 °C) and dark conditions. We investigated changes in cell growth, microcystin levels, and signaling pathways throughout this recovery phase. Our results indicated that compared to the non-overwintering treatment (T1), the overwintered treatment (T2) experienced a 55.6% decrease in algae density and a significant reduction in microcystin-LR (MC-LR) levels within the 15-20 °C temperature range (p < 0.05). Overwintering suppressed photosynthetic efficiency during the recovery phase of M. aeruginosa, activated the antioxidant system, and impaired cellular ultrastructure, making algal cells more vulnerable to death. At the transcriptional level, overwintering down-regulated pathways such as photosynthesis, ribosome, the Calvin cycle, and oxidative phosphorylation, hindering the growth and metabolic capacity of M. aeruginosa. In conclusion, this study highlights the inhibitory impacts of overwintering on growth and metabolism of cyanobacteria during the recovery process. It provides insights into the mechanistic foundations of seasonal cyanobacterial blooms and the crucial role of signaling regulation in these processes.
{"title":"From Winter Dormancy to Spring Bloom: Regulatory Mechanisms in Microcystis aeruginosa Post-Overwintering Recovery","authors":"Chenjun Fu, Xinyi Wang, Jing Yu, Hu Cui, Shengnan Hou, Hui Zhu","doi":"10.1016/j.watres.2024.122807","DOIUrl":"https://doi.org/10.1016/j.watres.2024.122807","url":null,"abstract":"Cyanobacterial blooms pose a significant environmental threat in freshwater ecosystems. These cyanobacteria exhibit resilience to cold and dark conditions during winter and flourish as temperature rise in warmer seasons. However, there is a limited understanding of the dynamic growth recovery process and regulatory signaling mechanisms in cyanobacteria after overwintering. In this study, we employed <em>Microcystis aeruginosa</em> (<em>M. aeruginosa</em>) as a model to simulate its growth recovery when subjected to increasing temperature after overwintering under low temperature (4 °C) and dark conditions. We investigated changes in cell growth, microcystin levels, and signaling pathways throughout this recovery phase. Our results indicated that compared to the non-overwintering treatment (T1), the overwintered treatment (T2) experienced a 55.6% decrease in algae density and a significant reduction in microcystin-LR (MC-LR) levels within the 15-20 °C temperature range (<em>p</em> < 0.05). Overwintering suppressed photosynthetic efficiency during the recovery phase of <em>M. aeruginosa</em>, activated the antioxidant system, and impaired cellular ultrastructure, making algal cells more vulnerable to death. At the transcriptional level, overwintering down-regulated pathways such as photosynthesis, ribosome, the Calvin cycle, and oxidative phosphorylation, hindering the growth and metabolic capacity of <em>M. aeruginosa</em>. In conclusion, this study highlights the inhibitory impacts of overwintering on growth and metabolism of cyanobacteria during the recovery process. It provides insights into the mechanistic foundations of seasonal cyanobacterial blooms and the crucial role of signaling regulation in these processes.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"37 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142645838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-17DOI: 10.1016/j.watres.2024.122808
Yang Gao, Jiajia Li, Shuoyue Wang, Junjie Jia, Fan Wu, Guirui Yu
Inland water ecosystems are unique, whereby water level changes can lead to variance in greenhouse gas (GHG) emissions. The GHG circulation intensity of inland waterbodies is high, so different water depths affect the temperature sensitivity of greenhouse gases, and have different cooling effects on CO2 storage and warming effects on CH4 emissions, being a typical GHG conversion channel. This study systematically reveals geographical GHG emission patterns from inland waterbodies and GHG impact mechanisms from regional waterbodies. Special emphasis is also paid to compounded environmental impact changes on GHG emissions under water level regulations. Additionally, we explore how increases in primary productivity can convert aquatic ecosystems from CO2 sources to CO2 sinks. However, GHG formation and emissions under ecological reservoir water level fluctuations in flood-ebb zones, intertidal tidal zones, wetlands, and lacustrine systems remain uncertain compared with those under natural hydrological conditions. Therefore, mechanisms that control GHG exchange and production processes under water level changes must first be determined, especially regarding post flood hydrological-based drying effects on GHG flux at the water-air interface. Finally, we recommend instituting environmental management and water-level control measures to reduce GHG emissions, which are favorable for minimizing GHG flux while protecting ecosystem functions and biodiversity.
{"title":"Global inland water greenhouse gas (GHG) geographical patterns and escape mechanisms under different water level","authors":"Yang Gao, Jiajia Li, Shuoyue Wang, Junjie Jia, Fan Wu, Guirui Yu","doi":"10.1016/j.watres.2024.122808","DOIUrl":"https://doi.org/10.1016/j.watres.2024.122808","url":null,"abstract":"Inland water ecosystems are unique, whereby water level changes can lead to variance in greenhouse gas (GHG) emissions. The GHG circulation intensity of inland waterbodies is high, so different water depths affect the temperature sensitivity of greenhouse gases, and have different cooling effects on CO<sub>2</sub> storage and warming effects on CH<sub>4</sub> emissions, being a typical GHG conversion channel. This study systematically reveals geographical GHG emission patterns from inland waterbodies and GHG impact mechanisms from regional waterbodies. Special emphasis is also paid to compounded environmental impact changes on GHG emissions under water level regulations. Additionally, we explore how increases in primary productivity can convert aquatic ecosystems from CO<sub>2</sub> sources to CO<sub>2</sub> sinks. However, GHG formation and emissions under ecological reservoir water level fluctuations in flood-ebb zones, intertidal tidal zones, wetlands, and lacustrine systems remain uncertain compared with those under natural hydrological conditions. Therefore, mechanisms that control GHG exchange and production processes under water level changes must first be determined, especially regarding post flood hydrological-based drying effects on GHG flux at the water-air interface. Finally, we recommend instituting environmental management and water-level control measures to reduce GHG emissions, which are favorable for minimizing GHG flux while protecting ecosystem functions and biodiversity.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"46 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fe3O4 is a recognized addictive to enhance low solid anaerobic digestion (AD), while for high solid AD challenged by acidity inhibition, its feasibility and mechanism remain unclear. In this study, the positive effect of Fe3O4 on high solid AD of food waste by regulating microbial physiology and energy conservation to enhance mutualistic propionate methanation was documented. The methane yield was increased by 36.7% with Fe3O4, which because Fe3O4 alleviated propionate stress on methane generation, along with improved propionate degradation and methanogenic metabolism. Fe3O4 facilitated the production of extracellular polymeric substances and the formation of tightly bio-aggregates, fostering an enriched microbial population (e.g., Smithella and Methanosaeta) to resist propionate stress. Also, Fe3O4 up-regulated the genes in stress defense system, cytomembrane biosynthesis/function, metal irons transporter, cell division and enzyme synthesis, verifying its superiority on cellular physiology. In addition, energy-conservation strategies related to intracellular and extracellular electron transfer were enhanced by Fe3O4. Specifically, the enzyme expressions involved in reversed electron transfer and electron bifurcation coupled with direct interspecies electron transfer (DIET) were upregulated by at least 2.2 times with Fe3O4, providing sufficient energy to drive thermodynamic adverse methanogenesis from propionate-stressed condition. Consequently, the reinforced enzyme expression in the dismutation and DIET pathway make it to be the predominant drivers for enhanced methanogenic propionate metabolism. This study fills the knowledge gaps of Fe3O4-induced microbial physiological and energetic strategies to resist environmental stress, and has remarkable practical implicated for restoring inhibited bioactivities.
{"title":"Deciphering the function of Fe3O4 in alleviating propionate inhibition during high-solids anaerobic digestion: insights of physiological response and energy conservation","authors":"Yu Su, Leiyu Feng, Xu Duan, Haojin Peng, Yinlan Zhao, Yinguang Chen","doi":"10.1016/j.watres.2024.122811","DOIUrl":"https://doi.org/10.1016/j.watres.2024.122811","url":null,"abstract":"Fe<sub>3</sub>O<sub>4</sub> is a recognized addictive to enhance low solid anaerobic digestion (AD), while for high solid AD challenged by acidity inhibition, its feasibility and mechanism remain unclear. In this study, the positive effect of Fe<sub>3</sub>O<sub>4</sub> on high solid AD of food waste by regulating microbial physiology and energy conservation to enhance mutualistic propionate methanation was documented. The methane yield was increased by 36.7% with Fe<sub>3</sub>O<sub>4</sub>, which because Fe<sub>3</sub>O<sub>4</sub> alleviated propionate stress on methane generation, along with improved propionate degradation and methanogenic metabolism. Fe<sub>3</sub>O<sub>4</sub> facilitated the production of extracellular polymeric substances and the formation of tightly bio-aggregates, fostering an enriched microbial population (e.g., <em>Smithella</em> and <em>Methanosaeta</em>) to resist propionate stress. Also, Fe<sub>3</sub>O<sub>4</sub> up-regulated the genes in stress defense system, cytomembrane biosynthesis/function, metal irons transporter, cell division and enzyme synthesis, verifying its superiority on cellular physiology. In addition, energy-conservation strategies related to intracellular and extracellular electron transfer were enhanced by Fe<sub>3</sub>O<sub>4</sub>. Specifically, the enzyme expressions involved in reversed electron transfer and electron bifurcation coupled with direct interspecies electron transfer (DIET) were upregulated by at least 2.2 times with Fe<sub>3</sub>O<sub>4</sub>, providing sufficient energy to drive thermodynamic adverse methanogenesis from propionate-stressed condition. Consequently, the reinforced enzyme expression in the dismutation and DIET pathway make it to be the predominant drivers for enhanced methanogenic propionate metabolism. This study fills the knowledge gaps of Fe<sub>3</sub>O<sub>4</sub>-induced microbial physiological and energetic strategies to resist environmental stress, and has remarkable practical implicated for restoring inhibited bioactivities.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"12 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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