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Imtiazy MN, Hunter K, Hudson JJ. In-reservoir transformation of dissolved organic matter as a function of hydrological flow. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 352:120099. [PMID: 38232598 DOI: 10.1016/j.jenvman.2024.120099] [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: 09/23/2023] [Revised: 12/21/2023] [Accepted: 01/08/2024] [Indexed: 01/19/2024]
Abstract
Reservoirs are vital to meet the ever-increasing demands for freshwater in a warming climate. Dissolved organic matter (DOM) represents an important pool of carbon and can be a major concern in drinking water sources. However, insights into DOM dynamics in temperate, semi-arid reservoirs remain limited. Therefore, we investigated the variations in DOM properties in Lake Diefenbaker, a large reservoir on the Canadian Prairies, by analyzing eight years of DOM concentrations and composition through linear mixed effect modeling. Contrary to expectations, reservoir dissolved organic carbon (DOC) concentration showed no correlation with inflow from the South Saskatchewan River (p = 0.12), while dissolved organic nitrogen (DON) increased with decreasing inflow (p = 0.002). DOM optical indices (SUVA254 and E4:E6 ratio) and DOC:DON ratio revealed a pronounced influence of inflow on reservoir DOM composition (p < 0.001), i.e., allochthonous characteristics increased with increasing flow, and autochthonous characteristics increased with declining flow. Travel time corrected comparison of approximately the same water parcel along the reservoir length revealed that increasing water residence time in downstream regions led to a significant transformation in DOM composition, favoring autochthonous characteristics (mean SUVA254 reduced by 0.52 L mg-C-1 m-1, and the E4:E6 and spectral slope ratio increased by 1.6 and 0.06, respectively). Autochthonous DOC inputs likely offset the allochthonous DOC losses, which resulted in a relatively stable DOC concentration throughout the reservoir (mean 3.7 mg L-1). Additionally, the effect of a large aquaculture operation on reservoir DOM properties was investigated, but no effect was detected. The results have significant implications for managing large river-reservoirs. Autochthonous DOM poses challenges to water processing, necessitating monitoring of DOM composition for reservoir drinking water quality. Insights on climate-induced changes in DOM properties will also assist with understanding changes to habitat conditions and contaminant transport.
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Affiliation(s)
- Md Noim Imtiazy
- Department of Biology, University of Saskatchewan, Collaborative Science Research Building, 112 Science Place, Saskatoon, SK S7N 5E2, Canada.
| | - Kristine Hunter
- Department of Biology, University of Saskatchewan, Collaborative Science Research Building, 112 Science Place, Saskatoon, SK S7N 5E2, Canada.
| | - Jeff J Hudson
- Department of Biology, University of Saskatchewan, Collaborative Science Research Building, 112 Science Place, Saskatoon, SK S7N 5E2, Canada.
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2
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Gatis N, Benaud P, Anderson K, Ashe J, Grand-Clement E, Luscombe DJ, Puttock A, Brazier RE. Peatland restoration increases water storage and attenuates downstream stormflow but does not guarantee an immediate reversal of long-term ecohydrological degradation. Sci Rep 2023; 13:15865. [PMID: 37739941 PMCID: PMC10516923 DOI: 10.1038/s41598-023-40285-4] [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: 05/29/2023] [Accepted: 08/08/2023] [Indexed: 09/24/2023] Open
Abstract
Peatland restoration is experiencing a global upsurge as a tool to protect and provide various ecosystem services. As the range of peatland types being restored diversifies, do previous findings present overly optimistic restoration expectations? In an eroding and restored upland peatland we assessed short-term (0-4 year) effects of restoration on ecohydrological functions. Restoration significantly reduced discharge from the site, transforming peat pans into pools. These retained surface water over half the time and were deeper during wet periods than before. In the surrounding haggs water tables stabilised, as drawdown during dry conditions reduced, increasing the saturated peat thickness. Despite these changes, there were no effects on photosynthesis, ecosystem respiration or dissolved organic carbon loads leaving the site. Soil respiration did not decrease as water tables rose, but methane emissions were higher from rewet pools. Restoration has had a dramatic effect on hydrology, however, consequent changes in other ecosystem functions were not measured in the 4 years after restoration. Whilst restoration is crucial in halting the expansion of degraded peatland areas, it is vital that practitioners and policymakers advocating for restoration are realistic about the expected outcomes and timescales over which these outcomes may manifest.
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Affiliation(s)
- Naomi Gatis
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, Devon, EX4 4RJ, UK.
- Centre for Resilience in Environment, Water and Waste, University of Exeter, North Park Road, Exeter, Devon, EX4 4TA, UK.
| | - Pia Benaud
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, Devon, EX4 4RJ, UK
- Centre for Resilience in Environment, Water and Waste, University of Exeter, North Park Road, Exeter, Devon, EX4 4TA, UK
| | - Karen Anderson
- Centre for Resilience in Environment, Water and Waste, University of Exeter, North Park Road, Exeter, Devon, EX4 4TA, UK
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, TR10 9FE, UK
| | - Josie Ashe
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, Devon, EX4 4RJ, UK
- Centre for Resilience in Environment, Water and Waste, University of Exeter, North Park Road, Exeter, Devon, EX4 4TA, UK
| | - Emilie Grand-Clement
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, Devon, EX4 4RJ, UK
- Centre for Resilience in Environment, Water and Waste, University of Exeter, North Park Road, Exeter, Devon, EX4 4TA, UK
| | - David J Luscombe
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, Devon, EX4 4RJ, UK
- Centre for Resilience in Environment, Water and Waste, University of Exeter, North Park Road, Exeter, Devon, EX4 4TA, UK
| | - Alan Puttock
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, Devon, EX4 4RJ, UK
- Centre for Resilience in Environment, Water and Waste, University of Exeter, North Park Road, Exeter, Devon, EX4 4TA, UK
| | - Richard E Brazier
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, Devon, EX4 4RJ, UK
- Centre for Resilience in Environment, Water and Waste, University of Exeter, North Park Road, Exeter, Devon, EX4 4TA, UK
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3
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Ritson JP, Kennedy-Blundell O, Croft J, Templeton MR, Hawkins CE, Clark JM, Evans MG, Brazier RE, Smith D, Graham NJD. High frequency UV-Vis sensors estimate error in riverine dissolved organic carbon load estimates from grab sampling. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 194:831. [PMID: 36163406 PMCID: PMC9512721 DOI: 10.1007/s10661-022-10515-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 09/16/2022] [Indexed: 06/16/2023]
Abstract
High frequency ultraviolet - visible (UV-VIS) sensors offer a way of improving dissolved organic carbon (DOC) load estimates in rivers as they can be calibrated to DOC concentration. This is an improvement on periodic grab sampling, or the use of pumped sampling systems which store samples in-field before collection. We hypothesised that the move to high frequency measurements would increase the load estimate based on grab sampling due to systemic under-sampling of high flows. To test our hypotheses, we calibrated two sensors in contrasting catchments (Exe and Bow Brook, UK) against weekly grab sampled DOC measurements and then created an hourly time series of DOC for the two sites. Taking this measurement as a 'true' value of DOC load, we simulated 1,000 grab sampling campaigns at weekly, fortnightly and monthly frequency to understand the likely distribution of load and error estimates. We also performed an analysis of daily grab samples collected using a pumped storage sampling system with weekly collection. Our results show that: a) grab sampling systemically underestimates DOC loads and gives positively skewed distributions of results, b) this under-estimation and positive skew decreases with increasing sampling frequency, c) commonly used estimates of error in the load value are also systemically lowered by the oversampling of low, stable flows due to their dependence on the variance in the flow-weighted mean concentration, and d) that pumped storage systems may lead to under-estimation of DOC and over estimation of specific ultra-violet absorbance (SUVA), a proxy for aromaticity, due to biodegradation during storage.
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Affiliation(s)
- J P Ritson
- School of Environment, Education and Development, The University of Manchester, Oxford Rd, Manchester, M13 9PL, UK.
| | - O Kennedy-Blundell
- School of Environment, Education and Development, The University of Manchester, Oxford Rd, Manchester, M13 9PL, UK
| | - J Croft
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington, London, SW7 2AZ, UK
| | - M R Templeton
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington, London, SW7 2AZ, UK
| | - C E Hawkins
- Department of Geography and Environmental Science, University of Reading, Whiteknights, PO box 227, Reading, RG6 6AB, UK
| | - J M Clark
- Department of Geography and Environmental Science, University of Reading, Whiteknights, PO box 227, Reading, RG6 6AB, UK
| | - M G Evans
- School of Environment, Education and Development, The University of Manchester, Oxford Rd, Manchester, M13 9PL, UK
| | - R E Brazier
- Centre for Resilience in Environment, Water and Waste, Geography, University of Exeter, Exeter, EX44RJ, UK
| | - D Smith
- South West Water, Peninsula House, Rydon Lane, Exeter, EX2 7HR, UK
| | - N J D Graham
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington, London, SW7 2AZ, UK
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Ferretto A, Brooker R, Matthews R, Smith P. Climate change and drinking water from Scottish peatlands: Where increasing DOC is an issue? JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 300:113688. [PMID: 34525430 DOI: 10.1016/j.jenvman.2021.113688] [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: 02/17/2021] [Revised: 08/31/2021] [Accepted: 09/03/2021] [Indexed: 06/13/2023]
Abstract
Increasing levels of dissolved organic carbon (DOC) have been detected in the last decades in water bodies of the Northern hemisphere, and climate change might fuel this rise. For drinking water reservoirs located in peatland catchments, already subjected to elevated amounts of DOC that needs to be removed, this might pose a further problem. Scotland is predicted to face warmer temperatures and a change in rainfall patterns, which will result in more frequent and severe summer droughts and in heavier winter precipitation. These conditions are not ideal for peatlands, which may undergo a drastic reduction in area. Using two bioclimatic envelope models (Blanket bog Tree model and Lindsay Modified model) that project blanket bog distribution in Scotland in the 2050s, we extracted the area of blanket bog that is at risk of loss. Assuming that part of the carbon stored in this area is likely to be lost, we calculated how much of it could be added to DOC in catchments that contain public drinking water reservoirs each year. This analysis is a first estimate of the risk for the provision of drinking water from peatlands in Scotland due to climate change. The aim is to identify the catchments that may face the highest consequences of future climates in terms of the concentration of DOC ([DOC]), where more sophisticated water treatments might be needed. Our results show a great variability among the catchments, with only a few being unaffected by this problem, whereas others could experience substantial seasonal increase in [DOC]. This highlights the necessity to frequently monitor DOC levels in the reservoirs located in catchments where the major problems could arise, and to take the necessary measures to reduce it. Given that peatland condition and vegetation cover play a fundamental role in influencing DOC losses, this study also offers an indication of where peatland restoration might be useful to counteract the projected DOC increase and bring the highest benefits in terms of safe drinking water provision.
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Affiliation(s)
- Anna Ferretto
- School of Biological Sciences, University of Aberdeen, 23 St Machar Drive, AB24 3UU, UK; The James Hutton Institute, Craigiebuckler, Aberdeen, AB15 8QH, UK.
| | - Rob Brooker
- The James Hutton Institute, Craigiebuckler, Aberdeen, AB15 8QH, UK
| | - Robin Matthews
- The James Hutton Institute, Craigiebuckler, Aberdeen, AB15 8QH, UK
| | - Pete Smith
- School of Biological Sciences, University of Aberdeen, 23 St Machar Drive, AB24 3UU, UK
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5
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Aggregate and Particle Size Distribution of the Soil Sediment Eroded on Steep Artificial Slopes. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11104427] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In this study, the particle size distribution (PSD) of the soil sediment from topsoil obtained from soil erosion experiments under different conditions was measured. Rainfall simulators were used for rain generation on the soil erosion plots with slopes 22°, 30°, 34° and length 4.25 m. The influence of the external factors (slope and initial state) on the particle and aggregate size distribution were evaluated by laser diffractometer (LD). The aggregate representation percentage in the eroded sediment was also investigated. It has been found that when the erosion processes are intensive (steep slope or long duration of the raining), the eroded sediment contains coarser particles and lower amounts of aggregates. Three methods for the soil particle analyses were tested: (i) conventional–sieving and hydrometer method; (ii) PARIO Soil Particle Analyzer combined with sieving; and (iii) laser diffraction (LD) using Mastersizer 3000. These methods were evaluated in terms of reproducibility of the results, time demands, and usability. It was verified that the LD has significant advantages compared to other two methods, especially the short measurement time for one sample (only 15 min per sample for LD) and the possibility to destroy soil aggregates using ultrasound which is much easier than using hexametaphosphate.
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Croghan D, Khamis K, Bradley C, Van Loon AF, Sadler J, Hannah DM. Combining in-situ fluorometry and distributed rainfall data provides new insights into natural organic matter transport dynamics in an urban river. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 755:142731. [PMID: 33097245 DOI: 10.1016/j.scitotenv.2020.142731] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/19/2020] [Accepted: 09/20/2020] [Indexed: 06/11/2023]
Abstract
Urbanization alters the quality and quantity of Dissolved Organic Matter (DOM) fluxes to rivers potentially leading to water quality problems and impaired ecosystem function. Traditional synoptic and point sampling approaches are generally inadequate for monitoring DOM source dynamics. To identify links between spatial heterogeneity in precipitation and DOM dynamics, we used a unique approach combining high spatial and temporal resolution precipitation datasets featuring point, catchment, and land-cover weighted precipitation to characterise catchment transport dynamics. These datasets were linked to fluorescence records from an urban stream (Bourn Brook, Birmingham, UK). Humic-like fluorescence (HLF: Ex. 365 nm, Em. 490 nm) and Tryptophan-like fluorescence (TLF: Ex. 285 nm, Em. 340 nm) were measured, (plus river flow and turbidity) at 5 min intervals for 10 weeks during Autumn 2017. The relationship between discharge (Q) and concentration (C) for TLF and HLF were strongly chemodynamic at low Q (<Q50) but TLF was chemostatic when Q exceeded this threshold. Figure of eight hysteresis was the most common response type for both HLF and TLF, indicating that DOM sources shift within and between events. Key drivers of DOM dynamics were identified using regression analysis and model outputs using point, catchment-averaged, and land-use weighted precipitation were compared. Antecedent rainfall was identified as the most important predictor (negative relationship) of TLF and HLF change suggesting DOM source exhaustion. Precipitation weighted by land cover showed that urbanization metrics were linked to increased TLF:HLF ratios and changes in hysteresis index. This study presents a novel approach of using land-cover weighted rainfall to enhance mechanistic understanding of DOM controls and sources. In contrast, catchment-average rainfall data have the potential to yield stronger understanding of TLF dynamics. This technique could be integrated with existing high resolution in-situ datasets to enhance our understanding of DOM dynamics in urban rivers.
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Affiliation(s)
- Danny Croghan
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom of Great Britain and Northern Ireland; Water Resources and Environmental Engineering, University of Oulu, Oulu, FI-90014, Finland.
| | - Kieran Khamis
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom of Great Britain and Northern Ireland
| | - Chris Bradley
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom of Great Britain and Northern Ireland
| | - Anne F Van Loon
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom of Great Britain and Northern Ireland; Institute for Environmental Studies, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, Netherlands
| | - Jon Sadler
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom of Great Britain and Northern Ireland
| | - David M Hannah
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom of Great Britain and Northern Ireland
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7
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Brazier RE, Puttock A, Graham HA, Auster RE, Davies KH, Brown CML. Beaver: Nature's ecosystem engineers. WIRES. WATER 2021; 8:e1494. [PMID: 33614026 PMCID: PMC7883483 DOI: 10.1002/wat2.1494] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 10/05/2020] [Accepted: 10/07/2020] [Indexed: 06/12/2023]
Abstract
Beavers have the ability to modify ecosystems profoundly to meet their ecological needs, with significant associated hydrological, geomorphological, ecological, and societal impacts. To bring together understanding of the role that beavers may play in the management of water resources, freshwater, and terrestrial ecosystems, this article reviews the state-of-the-art scientific understanding of the beaver as the quintessential ecosystem engineer. This review has a European focus but examines key research considering both Castor fiber-the Eurasian beaver and Castor canadensis-its North American counterpart. In recent decades species reintroductions across Europe, concurrent with natural expansion of refugia populations has led to the return of C. fiber to much of its European range with recent reviews estimating that the C. fiber population in Europe numbers over 1.5 million individuals. As such, there is an increasing need for understanding of the impacts of beaver in intensively populated and managed, contemporary European landscapes. This review summarizes how beaver impact: (a) ecosystem structure and geomorphology, (b) hydrology and water resources, (c) water quality, (d) freshwater ecology, and (e) humans and society. It concludes by examining future considerations that may need to be resolved as beavers further expand in the northern hemisphere with an emphasis upon the ecosystem services that they can provide and the associated management that will be necessary to maximize the benefits and minimize conflicts. This article is categorized under:Water and Life > Nature of Freshwater Ecosystems.
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Affiliation(s)
| | - Alan Puttock
- Department of GeographyUniversity of ExeterDevonUK
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8
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Gaffney PPJ, Hancock MH, Taggart MA, Andersen R. Restoration of afforested peatland: Immediate effects on aquatic carbon loss. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 742:140594. [PMID: 32640388 DOI: 10.1016/j.scitotenv.2020.140594] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 06/26/2020] [Accepted: 06/27/2020] [Indexed: 06/11/2023]
Abstract
Peatland restoration is undertaken to bring back key peatland ecosystem services, including carbon storage. In the case of drained, afforested blanket peatlands, restoration through drain blocking and tree removal may impact upon aquatic carbon concentrations and export, which needs to be accounted for when considering the carbon benefits of restoration. This study investigated concentrations and export of aquatic carbon from a drained, afforested blanket bog catchment, where 12% of the catchment underwent drain blocking and conifer removal (termed 'forest-to-bog' restoration), and from two control catchments: one in open bog and one that remained afforested. Using a before-after-control-impact (BACI) design, we found no significant increases in concentrations or export of aquatic carbon (DOC, POC or DIC) in the first year following forest-to-bog restoration (i.e. across the whole post-restoration period). However, increased DOC concentrations were observed in the first summer (2015) post-restoration, and seasonally increased DOC export was noted during storm events in the autumn of the same year. The lack of significant effects of forest-to-bog restoration on aquatic carbon export may be a consequence of the small proportion of the catchment (12%) undergoing management. In terms of management, the removal of more of the forestry residues (i.e., brash) may help to mitigate effects on aquatic carbon, by removing a potential DOC and POC source. Restoring small areas at a time (≤12%) should result in minimal aquatic carbon export issues, in contexts similar to the current study.
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Affiliation(s)
- Paul P J Gaffney
- Environmental Research Institute, North Highland College, University of the Highlands and Islands, Castle Street, Thurso KW14 7JD, UK.
| | - Mark H Hancock
- RSPB Centre for Conservation Science, Etive House, Beechwood Park, Inverness IV2 3BW, UK..
| | - Mark A Taggart
- Environmental Research Institute, North Highland College, University of the Highlands and Islands, Castle Street, Thurso KW14 7JD, UK.
| | - Roxane Andersen
- Environmental Research Institute, North Highland College, University of the Highlands and Islands, Castle Street, Thurso KW14 7JD, UK.
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Li D, Pan B, Zheng X, Jiang X, Zhao G, Han X. CDOM in the source regions of the Yangtze and Yellow Rivers, China: optical properties, possible sources, and their relationships with environmental variables. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:32856-32873. [PMID: 32524401 DOI: 10.1007/s11356-020-09385-w] [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: 08/23/2019] [Accepted: 05/19/2020] [Indexed: 06/11/2023]
Abstract
The source regions of the Yangtze and Yellow Rivers on the Qinghai-Tibet Plateau are extremely important water resources and ecological functional areas in China, and the ecological environment is fragile and sensitive to climate change. Chromophoric dissolved organic matter (CDOM) is an important component that plays a crucial role in the biogeochemical cycle in aquatic ecosystems. However, knowledge of the distribution characteristics of CDOM in this area is limited. In this study, the optical properties, possible sources of CDOM, and their relationships with environmental variables were investigated in the two regions. The results indicated that the CDOM absorption spectra of these two source regions had a high degree of consistency, and the absorption coefficient aCDOM(355) was small, with a mean of 2.07 ± 1.10 m-1. Two fluorescence components (C1 and C2) were identified and grouped into the humic-like component with parallel factor analysis (PARAFAC) of fluorescence excitation-emission matrices (EEMs), which exhibited highly similar (excitations/emission)max positions between each pair of components in the two regions. Comprehensive CDOM spectral absorption and fluorescence parameters suggested that CDOM was mainly derived from externally input humus, and the source region of the Yellow River showed stronger allochthonous sources. The dissolved organic carbon (DOC) gradients in the water affected the fluorescence intensity and indicated that the humic-like component was an important component of DOC. Water temperature (WT) and turbidity (Turb) positively affected the concentration of CDOM and the ability to absorb light in the aquatic ecosystems. Due to global warming, the rising temperature may lead to an increase in meltwater inflow in the source area and will also bring more external inputs through the runoff.
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Affiliation(s)
- Dianbao Li
- State Key Laboratory of Eco-hydraulic in Northwest Arid Region of China, Xi'an University of Technology, Xi'an, 710048, Shaanxi, China
| | - Baozhu Pan
- State Key Laboratory of Eco-hydraulic in Northwest Arid Region of China, Xi'an University of Technology, Xi'an, 710048, Shaanxi, China.
| | - Xing Zheng
- State Key Laboratory of Eco-hydraulic in Northwest Arid Region of China, Xi'an University of Technology, Xi'an, 710048, Shaanxi, China
| | - Xiaoming Jiang
- State Key Laboratory of Eco-hydraulic in Northwest Arid Region of China, Xi'an University of Technology, Xi'an, 710048, Shaanxi, China
| | - Gengnan Zhao
- State Key Laboratory of Eco-hydraulic in Northwest Arid Region of China, Xi'an University of Technology, Xi'an, 710048, Shaanxi, China
| | - Xu Han
- State Key Laboratory of Eco-hydraulic in Northwest Arid Region of China, Xi'an University of Technology, Xi'an, 710048, Shaanxi, China
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10
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Ritson JP, Croft JK, Clark JM, Brazier RE, Templeton MR, Smith D, Graham NJD. Sources of dissolved organic carbon (DOC) in a mixed land use catchment (Exe, UK). THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 666:165-175. [PMID: 30798227 DOI: 10.1016/j.scitotenv.2019.02.228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 02/12/2019] [Accepted: 02/15/2019] [Indexed: 06/09/2023]
Abstract
Many catchment management schemes in the UK have focussed on peatland restoration to improve ecosystem services such as carbon sequestration, water quality and biodiversity. The effect of these schemes on dissolved organic carbon (DOC) flux is critical in understanding peatland carbon budgets as well as the implications for drinking water treatment. In many catchments, however, peatland areas are not the only source of DOC, meaning that their significance at the full catchment scale is unclear. In this paper we have evaluated the importance of different land uses as sources of DOC by combining three datasets obtained from the Exe catchment, UK. The first dataset comprises a weekly monitoring record at three sites for six years, the second, a monthly monitoring record of 25 sites in the same catchment for one year, and the third, an assessment of DOC export from litter and soil carbon stocks. Our results suggest that DOC concentration significantly increased from the peaty headwaters to the mixed land-use areas (ANOVA F = 12.52, p < 0.001, df = 2), leading to higher flux estimates at the downstream sites. We present evidence for three possible explanations: firstly, that poor sampling of high flows may lead to underestimation of DOC flux, second, that there are significant sources of DOC besides the peatland headwaters, and finally, that biological- and photo-degradation decreases the influence of upstream DOC sources. Our results provide evidence both for the targeting of catchment management in peatland areas as well as the need to consider DOC from agricultural and forested areas of the catchment.
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Affiliation(s)
- J P Ritson
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington, London SW7 2AZ, UK.
| | - J K Croft
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington, London SW7 2AZ, UK
| | - J M Clark
- Department of Geography and Environmental Science, School of Archaeology, Geography and Environmental Science, The University of Reading, Whiteknights, PO Box 227, Reading RG6 6AB, UK
| | - R E Brazier
- Geography, College of Life and Environmental Sciences, University of Exeter, EX4 4RJ, UK
| | - M R Templeton
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington, London SW7 2AZ, UK
| | - D Smith
- South West Water Ltd., Peninsula House, Rydon Lane, Exeter, Devon EX2 7HR, UK
| | - N J D Graham
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington, London SW7 2AZ, UK
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11
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Puttock A, Graham HA, Cunliffe AM, Elliott M, Brazier RE. Eurasian beaver activity increases water storage, attenuates flow and mitigates diffuse pollution from intensively-managed grasslands. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 576:430-443. [PMID: 27792958 DOI: 10.1016/j.scitotenv.2016.10.122] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 10/03/2016] [Accepted: 10/17/2016] [Indexed: 06/06/2023]
Abstract
Beavers are the archetypal keystone species, which can profoundly alter ecosystem structure and function through their ecosystem engineering activity, most notably the building of dams. This can have a major impact upon water resource management, flow regimes and water quality. Previous research has predominantly focused on the activities of North American beaver (Castor canadensis) located in very different environments, to the intensive lowland agricultural landscapes of the United Kingdom and elsewhere in Europe. Two Eurasian beavers (Castor fiber) were introduced to a wooded site, situated on a first order tributary, draining from intensively managed grassland. The site was monitored to understand impacts upon water storage, flow regimes and water quality. Results indicated that beaver activity, primarily via the creation of 13 dams, has increased water storage within the site (holding ca. 1000m3 in beaver ponds) and beavers were likely to have had a significant flow attenuation impact, as determined from peak discharges (mean 30±19% reduction), total discharges (mean 34±9% reduction) and peak rainfall to peak discharge lag times (mean 29±21% increase) during storm events. Event monitoring of water entering and leaving the site showed lower concentrations of suspended sediment, nitrogen and phosphate leaving the site (e.g. for suspended sediment; average entering site: 112±72mgl-1, average leaving site: 39±37mgl-1). Combined with attenuated flows, this resulted in lower diffuse pollutant loads in water downstream. Conversely, dissolved organic carbon concentrations and loads downstream were higher. These observed changes are argued to be directly attributable to beaver activity at the site which has created a diverse wetland environment, reducing downstream hydrological connectivity. Results have important implications for beaver reintroduction programs which may provide nature based solutions to the catchment-scale water resource management issues that are faced in agricultural landscapes.
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Affiliation(s)
- Alan Puttock
- Geography, University of Exeter, Exeter, United Kindom.
| | - Hugh A Graham
- Geography, University of Exeter, Exeter, United Kindom
| | | | - Mark Elliott
- Devon Wildlife Trust, Cricklepit Mill, Exeter, United Kingdom
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Frank S, Tiemeyer B, Bechtold M, Lücke A, Bol R. Effect of past peat cultivation practices on present dynamics of dissolved organic carbon. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 574:1243-1253. [PMID: 27670597 DOI: 10.1016/j.scitotenv.2016.07.121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 07/07/2016] [Accepted: 07/09/2016] [Indexed: 05/21/2023]
Abstract
Peatlands are a major source of dissolved organic carbon (DOC) for aquatic ecosystems. Naturally high DOC concentrations in peatlands may be increased further by drainage. For agricultural purposes, peat has frequently been mixed with sand, but the effect of this measure on the release and cycling of DOC has rarely been investigated. This study examined the effects of (i) mixing peat with sand and (ii) water table depth (WTD) on DOC concentrations at three grassland sites on shallow organic soils. The soil solution was sampled bi-weekly for two years with suction plates at 15, 30 and 60cm depth. Selected samples were analysed for dissolved organic nitrogen (DON), δ13CDOM and δ15NDOM. Average DOC concentrations were surprisingly high, ranging from 161 to 192mgl-1. There was no significant impact of soil organic carbon (SOC) content or WTD on mean DOC concentrations. At all sites, DOC concentrations were highest at the boundary between the SOC-rich horizon and the mineral subsoil. In contrast to the mean concentrations, the temporal patterns of DOC concentrations, their drivers and the properties of dissolved organic matter (DOM) differed between peat-sand mixtures and peat. DOC concentrations responded to changes in environmental conditions, but only after a lag period of a few weeks. At the sites with a peat-sand mixture, temperature and therefore probably biological activity determined the DOC concentrations. At the peat site, the contribution of vegetation-derived DOM was higher. The highest concentrations occurred during long, cool periods of waterlogging, suggesting a stronger physicochemical-based DOC mobilisation. Overall, these results indicate that mixing peat with sand does not improve water quality and may result in DOC losses of around 200kg DOCha-1a-1.
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Affiliation(s)
- S Frank
- Thünen-Institute of Climate-Smart Agriculture, Bundesallee 50, 38116 Braunschweig, Germany
| | - B Tiemeyer
- Thünen-Institute of Climate-Smart Agriculture, Bundesallee 50, 38116 Braunschweig, Germany.
| | - M Bechtold
- Thünen-Institute of Climate-Smart Agriculture, Bundesallee 50, 38116 Braunschweig, Germany
| | - A Lücke
- Institute of Bio- and Geosciences, IBG-3: Agrosphere, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - R Bol
- Institute of Bio- and Geosciences, IBG-3: Agrosphere, Forschungszentrum Jülich, 52425, Jülich, Germany
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13
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Managing peatland vegetation for drinking water treatment. Sci Rep 2016; 6:36751. [PMID: 27857210 PMCID: PMC5114669 DOI: 10.1038/srep36751] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 10/13/2016] [Indexed: 11/15/2022] Open
Abstract
Peatland ecosystem services include drinking water provision, flood mitigation, habitat provision and carbon sequestration. Dissolved organic carbon (DOC) removal is a key treatment process for the supply of potable water downstream from peat-dominated catchments. A transition from peat-forming Sphagnum moss to vascular plants has been observed in peatlands degraded by (a) land management, (b) atmospheric deposition and (c) climate change. Here within we show that the presence of vascular plants with higher annual above-ground biomass production leads to a seasonal addition of labile plant material into the peatland ecosystem as litter recalcitrance is lower. The net effect will be a smaller litter carbon pool due to higher rates of decomposition, and a greater seasonal pattern of DOC flux. Conventional water treatment involving coagulation-flocculation-sedimentation may be impeded by vascular plant-derived DOC. It has been shown that vascular plant-derived DOC is more difficult to remove via these methods than DOC derived from Sphagnum, whilst also being less susceptible to microbial mineralisation before reaching the treatment works. These results provide evidence that practices aimed at re-establishing Sphagnum moss on degraded peatlands could reduce costs and improve efficacy at water treatment works, offering an alternative to ‘end-of-pipe’ solutions through management of ecosystem service provision.
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14
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Grace MA, Clifford E, Healy MG. Performance of novel media in stratified filters to remove organic carbon from lake water. WATER RESEARCH 2016; 104:371-380. [PMID: 27576156 DOI: 10.1016/j.watres.2016.08.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 08/08/2016] [Accepted: 08/12/2016] [Indexed: 06/06/2023]
Abstract
Disinfection by-products (DBPs) are an ever-increasing occurrence in water networks, particularly those which abstract water from peatland areas. Although much research has been carried out to discover novel methods to remove specific DBPs, the removal of natural organic matter (NOM) from source water may provide a more sustainable solution in many areas. This study focuses on the removal of NOM by novel filters, which could be retrospectively fitted to any conventional water treatment facility. The filters comprised stratified layers of a variety of media, including sand, Bayer residue, granular activated carbon (GAC), and pyritic fill. The filters were operated under two loading regimes, continuous and intermittent, at loading rates similar to recognised design standards. The most successful filter design comprised stratified layers of sand, GAC, and pyritic fill. Over the duration of a 240 day study, these filters obtained average dissolved organic carbon removal rates of 40%, and achieved average specific ultra-violet absorbance reductions from 2.9 to 2.4 L mg-1 m-1. The study demonstrates that these novel filters may be used to reduce NOM levels, thus reducing the potential for DBP formation. Such designs can incorporate the use of waste media, making the overall design more sustainable and robust.
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Affiliation(s)
- Maebh A Grace
- Civil Engineering, College of Engineering and Informatics, National University of Ireland, Galway, Ireland
| | - Eoghan Clifford
- Civil Engineering, College of Engineering and Informatics, National University of Ireland, Galway, Ireland.
| | - Mark G Healy
- Civil Engineering, College of Engineering and Informatics, National University of Ireland, Galway, Ireland
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15
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Grand-Clement E, Anderson K, Smith D, Angus M, Luscombe DJ, Gatis N, Bray LS, Brazier RE. New approaches to the restoration of shallow marginal peatlands. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2015; 161:417-430. [PMID: 26193762 DOI: 10.1016/j.jenvman.2015.06.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 05/29/2015] [Accepted: 06/09/2015] [Indexed: 06/04/2023]
Abstract
Globally, the historic and recent exploitation of peatlands through management practices such as agricultural reclamation, peat harvesting or forestry, have caused extensive damage to these ecosystems. Their value is now increasingly recognised, and restoration and rehabilitation programmes are underway to improve some of the ecosystem services provided by peatlands: blocking drainage ditches in deep peat has been shown to improve the storage of water, decrease carbon losses in the long-term, and improve biodiversity. However, whilst the restoration process has benefitted from experience and technical advice gained from restoration of deep peatlands, shallow peatlands have received less attention in the literature, despite being extensive in both uplands and lowlands. Using the experience gained from the restoration of the shallow peatlands of Exmoor National Park (UK), and two test catchments in particular, this paper provides technical guidance which can be applied to the restoration of other shallow peatlands worldwide. Experience showed that integrating knowledge of the historical environment at the planning stage of restoration was essential, as it enabled the effective mitigation of any threat to archaeological features and sites. The use of bales, commonly employed in other upland ecosystems, was found to be problematic. Instead, 'leaky dams' or wood and peat combination dams were used, which are both more efficient at reducing and diverting the flow, and longer lasting than bale dams. Finally, an average restoration cost (£306 ha(-1)) for Exmoor, below the median national value across the whole of the UK, demonstrates the cost-effectiveness of these techniques. However, local differences in peat depth and ditch characteristics (i.e. length, depth and width) between sites affect both the feasibility and the cost of restoration. Overall, the restoration of shallow peatlands is shown to be technically viable; this paper provides a template for such process over analogous landscapes.
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Affiliation(s)
- E Grand-Clement
- Geography, College of Life and Environmental Sciences, Amory Building, Rennes Drive, Exeter, Devon, EX4 4RJ, United Kingdom.
| | - K Anderson
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, TR10 9FE, United Kingdom.
| | - D Smith
- South West Water, Rydon Lane, Exeter, Devon, EX2 7HR, United Kingdom.
| | - M Angus
- South West Water, Rydon Lane, Exeter, Devon, EX2 7HR, United Kingdom.
| | - D J Luscombe
- Geography, College of Life and Environmental Sciences, Amory Building, Rennes Drive, Exeter, Devon, EX4 4RJ, United Kingdom.
| | - N Gatis
- Geography, College of Life and Environmental Sciences, Amory Building, Rennes Drive, Exeter, Devon, EX4 4RJ, United Kingdom.
| | - L S Bray
- Exmoor National Park Authority, Exmoor House, Dulverton, Somerset, TA22 9HL, United Kingdom.
| | - R E Brazier
- Geography, College of Life and Environmental Sciences, Amory Building, Rennes Drive, Exeter, Devon, EX4 4RJ, United Kingdom.
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16
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Ritson JP, Bell M, Graham NJD, Templeton MR, Brazier RE, Verhoef A, Freeman C, Clark JM. Simulated climate change impact on summer dissolved organic carbon release from peat and surface vegetation: implications for drinking water treatment. WATER RESEARCH 2014; 67:66-76. [PMID: 25262551 DOI: 10.1016/j.watres.2014.09.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 09/05/2014] [Accepted: 09/07/2014] [Indexed: 06/03/2023]
Abstract
Uncertainty regarding changes in dissolved organic carbon (DOC) quantity and quality has created interest in managing peatlands for their ecosystem services such as drinking water provision. The evidence base for such interventions is, however, sometimes contradictory. We performed a laboratory climate manipulation using a factorial design on two dominant peatland vegetation types (Calluna vulgaris and Sphagnum Spp.) and a peat soil collected from a drinking water catchment in Exmoor National Park, UK. Temperature and rainfall were set to represent baseline and future conditions under the UKCP09 2080s high emissions scenario for July and August. DOC leachate then underwent standard water treatment of coagulation/flocculation before chlorination. C. vulgaris leached more DOC than Sphagnum Spp. (7.17 versus 3.00 mg g(-1)) with higher specific ultraviolet (SUVA) values and a greater sensitivity to climate, leaching more DOC under simulated future conditions. The peat soil leached less DOC (0.37 mg g(-1)) than the vegetation and was less sensitive to climate. Differences in coagulation removal efficiency between the DOC sources appears to be driven by relative solubilisation of protein-like DOC, observed through the fluorescence peak C/T. Post-coagulation only differences between vegetation types were detected for the regulated disinfection by-products (DBPs), suggesting climate change influence at this scale can be removed via coagulation. Our results suggest current biodiversity restoration programmes to encourage Sphagnum Spp. will result in lower DOC concentrations and SUVA values, particularly with warmer and drier summers.
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Affiliation(s)
- Jonathan P Ritson
- Grantham Institute for Climate Change, Imperial College London, South Kensington, London SW7 2AZ, UK; Department of Civil and Environmental Engineering, Imperial College London, South Kensington, London SW7 2AZ, UK.
| | - Michael Bell
- Department of Geography and Environmental Science, School of Archaeology, Geography and Environmental Science, The University of Reading, Whiteknights, PO Box 227, Reading RG6 6AB, UK
| | - Nigel J D Graham
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington, London SW7 2AZ, UK
| | - Michael R Templeton
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington, London SW7 2AZ, UK
| | - Richard E Brazier
- Geography, College of Life and Environmental Sciences, University of Exeter, EX4 4RJ, UK
| | - Anne Verhoef
- Department of Geography and Environmental Science, School of Archaeology, Geography and Environmental Science, The University of Reading, Whiteknights, PO Box 227, Reading RG6 6AB, UK
| | - Chris Freeman
- Wolfson Carbon Capture Laboratory, School of Biological Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK
| | - Joanna M Clark
- Department of Geography and Environmental Science, School of Archaeology, Geography and Environmental Science, The University of Reading, Whiteknights, PO Box 227, Reading RG6 6AB, UK
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