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Cao X, Li SA, Huang H, Ma H. Wildfire Impacts on Molecular Changes of Dissolved Organic Matter during Its Passage through Soil. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024. [PMID: 38904350 DOI: 10.1021/acs.est.3c11056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Abstract
The frequency and intensity of global wildfires are escalating, leading to an increase in derived pyrogenic dissolved organic matter (pyDOM), which potentially influences the riverine carbon reservoir and poses risks to drinking water safety. However, changes in pyDOM properties as it traverses through soil to water bodies are highly understudied due to the challenges of simulating such processes under laboratory conditions. In this study, we extracted soil DOM along hillslope gradients and soil depths in both burned and unburned catchments post wildfire. Using high-resolution mass spectrometry and a substrate-explicit model, we observed significant increases in the relative abundance of condensed aromatics (ConAC) and tannins in wildfire-affected soil DOM. Wildfire-affected soil DOM also displayed a broader spectrum of molecular and thermodynamic properties, indicative of its diverse composition and reactivity. Furthermore, as the fire-induced weakening of topsoil microbial reprocessing abilities hindered the transformation of plant-derived DOM, the relative abundance of lignin-like compounds increased with soil depth in the fire regions. Meanwhile, the distribution of shared molecular formulas along the hillslope gradient (from shoulder to toeslope) exhibited analogous patterns in both burned and unburned catchments. Although there was an increased prevalence of ConAC and tannin in the burned catchments, the relative abundance of these fractions diminished along the hillslope in all three catchments. Based on the substrate-explicit model, the biodegradability exhibited by wildfire-affected DOM fractions offers the possibility of its conversion along hillslopes. Our findings reveal the spatial distribution of DOM properties after a wildfire, facilitating accurate evaluation of dissolved organic carbon composition involved in the watershed-scale carbon cycle.
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Affiliation(s)
- Xinghong Cao
- College of Environment and Ecology, Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Sheng-Ao Li
- College of Environment and Ecology, Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Hai Huang
- College of Environment and Ecology, Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Hua Ma
- College of Environment and Ecology, Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
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Song F, Li T, Hur J, Chow ATS, Leung KMY, Wu F. Wildfire-Derived Pyrogenic Organic Matter Posing Overlooked Emerging Risks to Aquatic Ecosystems. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024. [PMID: 38869366 DOI: 10.1021/acs.est.4c05412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2024]
Affiliation(s)
- Fanhao Song
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Tingting Li
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Jin Hur
- Department of Environment and Energy, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul 05006, South Korea
| | - Alex Tat-Shing Chow
- Earth and Environmental Sciences Programme, Faculty of Science, The Chinese University of Hong Kong, Hong Kong 999077, China
| | - Kenneth Mei Yee Leung
- State Key Laboratory of Marine Pollution, School of Energy and Environment, and Department of Chemistry, City University of Hong Kong, Kowloon, Hong Kong 999077, China
| | - Fengchang Wu
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
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Spiegel CJ, Mladenov N, Wall CB, Hollman K, Tran CH, Symons CC, Shurin JB. Life after a fiery death: Fire and plant biomass loading affect dissolved organic matter in experimental ponds. GLOBAL CHANGE BIOLOGY 2024; 30:e17061. [PMID: 38273537 DOI: 10.1111/gcb.17061] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 10/19/2023] [Accepted: 11/02/2023] [Indexed: 01/27/2024]
Abstract
Drier and hotter conditions linked with anthropogenic climate change can increase wildfire frequency and severity, influencing terrestrial and aquatic carbon cycles at broad spatial and temporal scales. The impacts of wildfire are complex and dependent on several factors that may increase terrestrial deposition and the influx of dissolved organic matter (DOM) from plants into nearby aquatic systems, resulting in the darkening of water color. We tested the effects of plant biomass quantity and its interaction with fire (burned vs. unburned plant biomass) on dissolved organic carbon (DOC) concentration and degradation (biological vs. photochemical) and DOM composition in 400 L freshwater ponds using a gradient experimental design. DOC concentration increased nonlinearly with plant biomass loading in both treatments, with overall higher concentrations (>56 mg/L) in the unburned treatment shortly after plant addition. We also observed nonlinear trends in fluorescence and UV-visible absorbance spectroscopic indices as a function of fire treatment and plant biomass, such as greater humification and specific UV absorbance at 254 nm (a proxy for aromatic DOM) over time. DOM humification occurred gradually over time with less humification in the burned treatment compared to the unburned treatment. Both burned and unburned biomass released noncolored, low molecular weight carbon compounds that were rapidly consumed by microbes. DOC decomposition exhibited a unimodal relationship with plant biomass, with microbes contributing more to DOC loss than photodegradation at intermediate biomass levels (100-300 g). Our findings demonstrate that the quantity of plant biomass leads to nonlinear responses in the dynamics and composition of DOM in experimental ponds that are altered by fire, indicating how disturbances interactively affect DOM processing and its role in aquatic environments.
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Affiliation(s)
- Cody J Spiegel
- Department of Ecology, Behavior and Evolution, School of Biological Sciences, University of California, San Diego, California, USA
| | - Natalie Mladenov
- Department of Civil, Construction and Environmental Engineering, San Diego State University, San Diego, California, USA
| | - Christopher B Wall
- Department of Ecology, Behavior and Evolution, School of Biological Sciences, University of California, San Diego, California, USA
| | - Kelly Hollman
- Department of Civil, Construction and Environmental Engineering, San Diego State University, San Diego, California, USA
| | - Cindy H Tran
- Department of Ecology, Behavior and Evolution, School of Biological Sciences, University of California, San Diego, California, USA
| | - Celia C Symons
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California, USA
| | - Jonathan B Shurin
- Department of Ecology, Behavior and Evolution, School of Biological Sciences, University of California, San Diego, California, USA
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Zito P, Bekins BA, Martinović-Weigelt D, Harsha ML, Humpal KE, Trost J, Cozzarelli I, Mazzoleni LR, Schum SK, Podgorski DC. Photochemical mobilization of dissolved hydrocarbon oxidation products from petroleum contaminated soil into a shallow aquifer activate human nuclear receptors. JOURNAL OF HAZARDOUS MATERIALS 2023; 459:132312. [PMID: 37604033 DOI: 10.1016/j.jhazmat.2023.132312] [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: 04/21/2023] [Revised: 07/29/2023] [Accepted: 08/14/2023] [Indexed: 08/23/2023]
Abstract
Elevated non-volatile dissolved organic carbon (NVDOC) concentrations in groundwater (GW) monitoring wells under oil-contaminated hydrophobic soils originating from a pipeline rupture at the National Crude Oil Spill & Natural Attenuation Research Site near Bemidji, MN are documented. We hypothesized the elevated NVDOC is comprised of water-soluble photooxidation products transported from the surface to the aquifer. We use field and laboratory samples in combination with complementary analytical methods to test this hypothesis and determine the biological response to these products. Observations from optical spectroscopy and ultrahigh-resolution mass spectrometry reveal a significant correlation between the chemical composition of NVDOC leached from photochemically weathered soils and GW monitoring wells with high NVDOC concentrations measured in the aquifer beneath the contaminated soil. Conversely, the chemical composition from the uncontaminated soil photoleachate matches the NVDOC observed in the uncontaminated wells. Contaminated GW and photodissolution leachates from contaminated soil activated biological targets indicative of xenobiotic metabolism and exhibited potential for adverse effects. Newly formed hydrocarbon oxidation products (HOPs) from fresh oil could be distinguished from those downgradient. This study illustrates another pathway for dissolved HOPs to infiltrate GW and potentially affect human health and the environment.
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Affiliation(s)
- Phoebe Zito
- Department of Chemistry, Chemical Analysis Mass Spectrometry Facility, University of New Orleans, New Orleans, LA 70148, USA.
| | | | | | - Maxwell L Harsha
- Department of Chemistry, Chemical Analysis Mass Spectrometry Facility, University of New Orleans, New Orleans, LA 70148, USA
| | - Katherine E Humpal
- Department of Chemistry, Chemical Analysis Mass Spectrometry Facility, University of New Orleans, New Orleans, LA 70148, USA
| | - Jared Trost
- US Geological Survey, Mounds View, MN 55112, USA
| | - Isabelle Cozzarelli
- US Geological Survey, Geology, Energy & Minerals Science Center, Reston, VA 20191, USA
| | - Lynn R Mazzoleni
- Department of Chemistry, Chemical Advanced Resolution Methods Laboratory, Michigan Technological University, 1400, Townsend Dr., Houghton, MI 49931, USA
| | - Simeon K Schum
- Department of Chemistry, Chemical Advanced Resolution Methods Laboratory, Michigan Technological University, 1400, Townsend Dr., Houghton, MI 49931, USA
| | - David C Podgorski
- Department of Chemistry, Chemical Analysis Mass Spectrometry Facility, University of New Orleans, New Orleans, LA 70148, USA; Pontchartrain Institute for Environmental Sciences, Shea Penland Coastal Education Research Facility, University of New Orleans, New Orleans, LA 70148 USA
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An S, Mao Z, Chen M, Huang X, Shi L, Xing P, Kong L, Zhou Y, Du Y, Zhang Y. Sunlight irradiation promotes both the chemodiversity of terrestrial DOM and the biodiversity of bacterial community in a subalpine lake. ENVIRONMENTAL RESEARCH 2023; 227:115823. [PMID: 37004851 DOI: 10.1016/j.envres.2023.115823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 03/28/2023] [Accepted: 03/30/2023] [Indexed: 05/08/2023]
Abstract
Alpine lake habitats are evolving into subalpine lakes under the scenario of climate change, where the vegetation are promoted due to increasing temperature and precipitation. The abundant terrestrial dissolved organic matter (TDOM) leached from watershed soil into subalpine lakes would undergo strong photochemical reaction due to the high altitude, with the potential to alter DOM composition and affect the bacterial communities. To reveal the transformation of TDOM by both photochemical and microbial processes in a typical subalpine lake, Lake Tiancai (located 200 m below the tree line) was chosen. TDOM was extracted from the surrounding soil of Lake Tiancai and then subjected to the photo/micro-processing for 107 days. The transformation of TDOM was analyzed by Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and fluorescence spectroscopy, and the shift of bacterial communities was analyzed using 16s rRNA gene sequencing technology. Dissolved organic carbon and light-absorbing components (a350) decay accounted for approximately 40% and 80% of the original, respectively, in the sunlight process, but both less than 20% in the microbial process for 107 days. The photochemical process promoted the chemodiversity as there were ∼7000 molecules after sunlight irradiation, compared to ∼3000 molecules in the original TDOM. Light promoted the production of highly unsaturated molecules and aliphatics, which were significantly associated with Bacteroidota, suggesting that light may influence bacterial communities by regulating the DOM molecules. Carboxylic-rich alicyclic molecules were generated in both photochemical and biological processes, suggesting TDOM was converted to a stable pool over time. Our finding on the transformation of terrestrial DOM and the alternation of bacterial community under the simultaneously photochemical and microbial processes will help to reveal the response of the carbon cycle and lake system structure to climate change for high-altitude lakes.
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Affiliation(s)
- ShiLin An
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - ZhenDu Mao
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Meilian Chen
- Department of Geosciences & Natural Resources, Western Carolina University, Cullowhee, NC 28723, United States
| | - XiuLin Huang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China; School of Environmental and Chemical Engineering, Chongqing Three Gorges University, Chongqing, 404020, China
| | - LiMei Shi
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Peng Xing
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - LingYang Kong
- Yunnan Key Laboratory of Plateau Geographical Processes and Environmental Changes, Yunnan Normal University, Kunming, 650500, China
| | - YongQiang Zhou
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - YingXun Du
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - YunLin Zhang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China
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Yue Y, Xu L, Li G, Gao X, Ma H. Characterization of Dissolved Organic Matter Released from Aged Biochar: A Comparative Study of Two Feedstocks and Multiple Aging Approaches. Molecules 2023; 28:molecules28114558. [PMID: 37299032 DOI: 10.3390/molecules28114558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/26/2023] [Accepted: 05/31/2023] [Indexed: 06/12/2023] Open
Abstract
Dissolved organic matter (DOM) plays important roles in environmental ecosystems. While many studies have explored the characteristics of aged biochar, limited information is available about the properties of DOM derived from aged biochar. In this study, biochar obtained from maize stalk and soybean straw were aged using farmland or vegetable-soil solution, as well as soil solution containing hydrogen peroxide (H2O2). Chemical composition of the extracted DOM from the aged biochar was analyzed via excitation-emission matrix coupled with fluorescence regional integration (FRI) and parallel factor analysis (PARAFAC). Obtained results showed that biochar aged with H2O2-enriched soil solution had higher water-soluble organic carbon, ranging from 147.26-734.13% higher than the controls. FRI analysis revealed fulvic and humic-like organics as the key components, with a considerable increase of 57.48-235.96% in the humic-like component, especially in soybean-straw-aged biochar. PARAFAC identified four humic-like substance components. Concurrently, the aromaticity and humification of the aged-biochar-derived DOM increased, while the molecular weight decreased. These findings suggest that DOM derived from aged biochar, with a high content of humic-like organics, might impact the mobility and toxicity of pollutants in soil.
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Affiliation(s)
- Yan Yue
- Engineering & Technology Center of Electrochemistry, School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China
| | - Leqi Xu
- Yantai Research Institute, China Agricultural University, Yantai 264670, China
- College of Land Science and Technology, China Agricultural University, Beijing 100193, China
| | - Guitong Li
- Yantai Research Institute, China Agricultural University, Yantai 264670, China
- College of Land Science and Technology, China Agricultural University, Beijing 100193, China
| | - Xiang Gao
- Engineering & Technology Center of Electrochemistry, School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China
| | - Hongfang Ma
- School of Environmental Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China
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Lowman HE, Moingt M, Zimmerman AR, Dugan JE, Melack JM. Distribution of terrestrial organic material in intertidal and nearshore marine sediment due to debris flow response efforts. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 843:156886. [PMID: 35753466 DOI: 10.1016/j.scitotenv.2022.156886] [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: 04/08/2022] [Revised: 06/16/2022] [Accepted: 06/18/2022] [Indexed: 06/15/2023]
Abstract
We examined the distribution and processing of terrestrial organic material, derived from the disposal of material from a massive debris flow event following a major wildfire in a coastal California (USA) catchment in intertidal and nearshore subtidal marine sediments. Organic matter biomarkers, pyrogenic carbon and lignin phenols, were used to trace the distribution of terrestrial debris material in marine environments. In intertidal sediments located <1 km east of the debris deposition site, pyrogenic carbon values did not significantly change and lambda values, a lignin measure, decreased over time, indicating little lateral transport of the disposed material. In subtidal sediment, pyrogenic carbon and lambda values were greatest in 20 m water depths indicating transport and deposition of this material nearshore. An additional lignin measure indicative of degradation suggested terrestrial organic material degradation in subtidal sediment decreased with distance from shore. Terrestrial biomarkers demonstrated that the disposed material was not detected in the top 20 cm of intertidal sediment but was retained in subtidal sediment offshore of the disposal site. Results suggest coastal management should incorporate consideration of the effects of debris disposal activities on nearshore benthic communities and biogeochemical cycling.
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Affiliation(s)
- H E Lowman
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106, USA.
| | - M Moingt
- GEOTOP, Institut des Sciences de l'Environnement, Université du Québec à Montréal, Montréal, QC H3C 3P8, Canada
| | - A R Zimmerman
- Department of Geological Sciences, University of Florida, Gainesville, FL 32611, USA
| | - J E Dugan
- Marine Science Institute, University of California, Santa Barbara, CA 93106, USA
| | - J M Melack
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106, USA
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Barros TL, Bracewell SA, Mayer-Pinto M, Dafforn KA, Simpson SL, Farrell M, Johnston EL. Wildfires cause rapid changes to estuarine benthic habitat. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 308:119571. [PMID: 35661807 DOI: 10.1016/j.envpol.2022.119571] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 05/19/2022] [Accepted: 06/01/2022] [Indexed: 06/15/2023]
Abstract
Estuaries are one of the most valuable biomes on earth. Although humans are highly dependent on these ecosystems, anthropogenic activities have impacted estuaries worldwide, altering their ecological functions and ability to provide a variety of important ecosystem services. Many anthropogenic stressors combine to affect the soft sedimentary habitats that dominate estuarine ecosystems. Now, due to climate change, estuaries and other marine areas might be increasingly exposed to the emerging threat of megafires. Here, by sampling estuaries before and after a megafire, we describe impacts of wildfires on estuarine benthic habitats and justify why megafires are a new and concerning threat to coastal ecosystems. We (1) show that wildfires change the fundamental characteristics of estuarine benthic habitat, (2) identify the factors (burnt intensity and proximity to water's edge) that influence the consequences of fires on estuaries, and (3) identify relevant indicators of wildfire impact: metals, nutrients, and pyrogenic carbon. We then discuss how fires can impact estuaries globally, regardless of local variability and differences in catchment. In the first empirical assessment of the impact of wildfires on estuarine condition, our results highlight indicators that may assist waterway managers to empirically detect wildfire impacts in estuaries and identify catchment factors that should be included in fire risk assessments for estuaries. Overall, this study highlights the importance of considering fire threats in current and future estuarine and coastal management.
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Affiliation(s)
- Thayanne L Barros
- Centre for Marine Science and Innovation, Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Bedegal Country, NSW, 2052, Australia.
| | - Sally A Bracewell
- Centre for Marine Science and Innovation, Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Bedegal Country, NSW, 2052, Australia
| | - Mariana Mayer-Pinto
- Centre for Marine Science and Innovation, Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Bedegal Country, NSW, 2052, Australia
| | - Katherine A Dafforn
- School of Natural Sciences, Macquarie University, North Ryde, Wallamattagal Country, NSW, 2109, Australia
| | - Stuart L Simpson
- CSIRO Land and Water, Tharawal Country, Centre for Environmental Contaminants Research, NSW, 2234, Australia
| | - Mark Farrell
- CSIRO Agriculture & Food, Kaurna Country, Locked Bag 2, Glen Osmond, South Australia, 5064, Australia
| | - Emma L Johnston
- Centre for Marine Science and Innovation, Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Bedegal Country, NSW, 2052, Australia
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Physiological and transcriptomic responses of Chlorella sorokiniana to ciprofloxacin reveal molecular mechanisms for antibiotic removal. iScience 2022; 25:104638. [PMID: 35800754 PMCID: PMC9254343 DOI: 10.1016/j.isci.2022.104638] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 04/09/2022] [Accepted: 06/14/2022] [Indexed: 11/25/2022] Open
Abstract
Microalgae-based technology is an effective and environmentally friendly method for antibiotics-contaminated wastewater treatment. To assess the tolerance and removal ability of Chlorella sorokiniana to ciprofloxacin (CIP), this study comprehensively revealed the responses of C. sorokiniana to CIP exposure and its degradation processes through physiological and transcriptomic analyses. Although the photosynthetic system was inhibited, the growth of C. sorokiniana was not negatively affected by CIP. Dissolved organic matter was analyzed and indicated that humic-like substances were released to alleviate the stress of CIP. In addition, the maximum removal of CIP was 83.3% under 20 mg L−1 CIP exposure. HPLC-MS/MS and RNA-Seq analyses suggested that CIP could be bioaccumulated and biodegraded by C. sorokiniana through the reactions of hydroxylation, demethylation, ring cleavage, oxidation, dehydrogenation, and decarboxylation with the help of intracellular oxidoreductases, especially cytochrome P450. Collectively, this research shows that C. sorokiniana have a great potential for removing CIP from wastewater. Freshwater microalgae Chlorella sorokiniana was exposed to ciprofloxacin Microalgae released humic-like substances to alleviate the damage The maximum removal of ciprofloxacin was 83.3% under 20 mg L−1 CIP exposure Ciprofloxacin could be biodegraded with the help of intracellular oxidoreductases
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