{"id":{"repo_id":"oxford-brookes","oai_identifier":"tle:1cd98af7-cc95-4e6b-b970-fbab5a861de5:d6bd9758-527a-46cd-bfe2-c433766e8fca:1"},"canonical_url":"https://search.dev.ndltd.org/etd/oxford-brookes/tle:1cd98af7-cc95-4e6b-b970-fbab5a861de5:d6bd9758-527a-46cd-bfe2-c433766e8fca:1","repository":{"repo_id":"oxford-brookes","name":"Oxford Brookes University","base_url":"https://radar.brookes.ac.uk/radar/oai"},"display":{"title":"AGRICULTURAL SMALL WATER BODIES: CARBON SOURCE OR CARBON SINK?","abstract":"The terrestrial landmass is thought to be a major greenhouse gas sink (GHG), and while freshwaters were thought to be neutral entities, they may in fact be potent producers and emitters of CO2 and CH4. Little is known about their contribution to the global carbon budget, especially in agricultural landscapes. This research aimed to determine the rate of organic carbon accumulation in agricultural ponds in relation to nutrients, and to estimate CO2 and CH4 production processes in, and emission routes from, ponds in relation to physico-chemical conditions. Sampling sites were three catchments in Leicestershire in a characteristic agricultural environment. Year 1 fieldwork (April―June 2013) covered 98 of an original 180 sampling sites, and encompassed a mixture of water bodies. Sites were accessed in stages according to specified access routes, and samples were analysed the same day. Year 2 fieldwork (August―September 2014) focused on ponds, those from year 1 and new established ponds. Analysis was done with a quadrupole mass spectrometer. The data obtained from the air-flux time series samples, plotted as scatter graphs, showed a very varied scatter with, at times, negative sloping trendlines, resulting in very low r2 values in all but one graph. It is thought that a lack of measurement precision, analysing the air-flux samples, is the main cause of unreliable data. The inconclusive data was initially thought to derive from a poor sampling regime, but was ultimately linked to the analytical method and instruments. Investigations suggested that an inter-technique comparison of the analyser would help to determine the validity of the data. Although data analysis could not be completed, descriptive analyse of the processes undertaken are provided. Water samples, from ponds, streams, and ditches were collected for analysis of dissolved CO2 and CH4 in the three catchments (Eye, Stonton, and Barkby). Data analysis revealed significant differences between catchments in both, CO2 and CH4 concentrations amongst the three catchments. To establish sediment organic and inorganic carbon content of ponds, sediment traps were installed, and the retrieved samples analysed using the loss on ignition method. The regression analysis showed that about 33% of CO2 emission is dependent on organic carbon. Organic carbon and inorganic carbon were not significantly correlated with CH4 emissions. Data obtained from water samples analysed for dissolved CO2 and CH4, and the slope values of the air-flux samples were compared to the 2013 baseline data collected by Freshwater Habitats Trust using correlation half-matrix. The analysis showed correlation at P=0.050 r=0.381 between CO2 and nitrogen, between CH4 dissolved in water and suspended solids, and between CO2 slope air-flux and zinc. At P=0.10 r=0.487 correlation was between CO2 water and CO2 slope air-flux, between CH4 slope air-flux and turbidity, and between CH4 air-flux and zinc. Since an essential part of the data was deemed unfit for data analysis recommendations are given for ensuring reliability before commencing sampling, and for improving the methodology.","abstract_html":"The terrestrial landmass is thought to be a major greenhouse gas sink (GHG), and while freshwaters were thought to be neutral entities, they may in fact be potent producers and emitters of CO2 and CH4. Little is known about their contribution to the global carbon budget, especially in agricultural landscapes. This research aimed to determine the rate of organic carbon accumulation in agricultural ponds in relation to nutrients, and to estimate CO2 and CH4 production processes in, and emission routes from, ponds in relation to physico-chemical conditions. Sampling sites were three catchments in Leicestershire in a characteristic agricultural environment. Year 1 fieldwork (April―June 2013) covered 98 of an original 180 sampling sites, and encompassed a mixture of water bodies. Sites were accessed in stages according to specified access routes, and samples were analysed the same day. Year 2 fieldwork (August―September 2014) focused on ponds, those from year 1 and new established ponds. Analysis was done with a quadrupole mass spectrometer. The data obtained from the air-flux time series samples, plotted as scatter graphs, showed a very varied scatter with, at times, negative sloping trendlines, resulting in very low r2 values in all but one graph. It is thought that a lack of measurement precision, analysing the air-flux samples, is the main cause of unreliable data. The inconclusive data was initially thought to derive from a poor sampling regime, but was ultimately linked to the analytical method and instruments. Investigations suggested that an inter-technique comparison of the analyser would help to determine the validity of the data. Although data analysis could not be completed, descriptive analyse of the processes undertaken are provided. Water samples, from ponds, streams, and ditches were collected for analysis of dissolved CO2 and CH4 in the three catchments (Eye, Stonton, and Barkby). Data analysis revealed significant differences between catchments in both, CO2 and CH4 concentrations amongst the three catchments. To establish sediment organic and inorganic carbon content of ponds, sediment traps were installed, and the retrieved samples analysed using the loss on ignition method. The regression analysis showed that about 33% of CO2 emission is dependent on organic carbon. Organic carbon and inorganic carbon were not significantly correlated with CH4 emissions. Data obtained from water samples analysed for dissolved CO2 and CH4, and the slope values of the air-flux samples were compared to the 2013 baseline data collected by Freshwater Habitats Trust using correlation half-matrix. The analysis showed correlation at P=0.050 r=0.381 between CO2 and nitrogen, between CH4 dissolved in water and suspended solids, and between CO2 slope air-flux and zinc. At P=0.10 r=0.487 correlation was between CO2 water and CO2 slope air-flux, between CH4 slope air-flux and turbidity, and between CH4 air-flux and zinc. Since an essential part of the data was deemed unfit for data analysis recommendations are given for ensuring reliability before commencing sampling, and for improving the methodology.","abstract_has_math":false,"creators":["Zweifel, Barbara"],"institution":"Oxford Brookes University","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2018,"date_issued":"2018","date_published":"2018","updated_at":"2026-07-24T03:43:24Z","subjects":[],"languages":["en"],"rights":["All rights reserved"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://doi.org/10.24384/4nvs-4s88","outbound_label":"DOI","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Zweifel, Barbara"]},{"key":"dc:creator","label":"Author","values":["Zweifel, Barbara"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2018"]},{"key":"dc:publisher","label":"Institution","values":["Oxford Brookes University"]},{"key":"dc:type","label":"Dc Type","values":["thesis"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["All rights reserved"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://doi.org/10.24384/4nvs-4s88","https://radar.brookes.ac.uk/radar/file/1cd98af7-cc95-4e6b-b970-fbab5a861de5/1/fulltext.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The terrestrial landmass is thought to be a major greenhouse gas sink (GHG), and while freshwaters were thought to be neutral entities, they may in fact be potent producers and emitters of CO2 and CH4. Little is known about their contribution to the global carbon budget, especially in agricultural landscapes. This research aimed to determine the rate of organic carbon accumulation in agricultural ponds in relation to nutrients, and to estimate CO2 and CH4 production processes in, and emission routes from, ponds in relation to physico-chemical conditions. Sampling sites were three catchments in Leicestershire in a characteristic agricultural environment. Year 1 fieldwork (April―June 2013) covered 98 of an original 180 sampling sites, and encompassed a mixture of water bodies. Sites were accessed in stages according to specified access routes, and samples were analysed the same day. Year 2 fieldwork (August―September 2014) focused on ponds, those from year 1 and new established ponds. Analysis was done with a quadrupole mass spectrometer. The data obtained from the air-flux time series samples, plotted as scatter graphs, showed a very varied scatter with, at times, negative sloping trendlines, resulting in very low r2 values in all but one graph. It is thought that a lack of measurement precision, analysing the air-flux samples, is the main cause of unreliable data. The inconclusive data was initially thought to derive from a poor sampling regime, but was ultimately linked to the analytical method and instruments. Investigations suggested that an inter-technique comparison of the analyser would help to determine the validity of the data. Although data analysis could not be completed, descriptive analyse of the processes undertaken are provided. Water samples, from ponds, streams, and ditches were collected for analysis of dissolved CO2 and CH4 in the three catchments (Eye, Stonton, and Barkby). Data analysis revealed significant differences between catchments in both, CO2 and CH4 concentrations amongst the three catchments. To establish sediment organic and inorganic carbon content of ponds, sediment traps were installed, and the retrieved samples analysed using the loss on ignition method. The regression analysis showed that about 33% of CO2 emission is dependent on organic carbon. Organic carbon and inorganic carbon were not significantly correlated with CH4 emissions. Data obtained from water samples analysed for dissolved CO2 and CH4, and the slope values of the air-flux samples were compared to the 2013 baseline data collected by Freshwater Habitats Trust using correlation half-matrix. The analysis showed correlation at P=0.050 r=0.381 between CO2 and nitrogen, between CH4 dissolved in water and suspended solids, and between CO2 slope air-flux and zinc. At P=0.10 r=0.487 correlation was between CO2 water and CO2 slope air-flux, between CH4 slope air-flux and turbidity, and between CH4 air-flux and zinc. Since an essential part of the data was deemed unfit for data analysis recommendations are given for ensuring reliability before commencing sampling, and for improving the methodology."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["AGRICULTURAL SMALL WATER BODIES: CARBON SOURCE OR CARBON SINK?"]}]}],"canonical_facts":{"dc:contributor":["Zweifel, Barbara"],"dc:creator":["Zweifel, Barbara"],"dc:date":["2018"],"dc:description":["The terrestrial landmass is thought to be a major greenhouse gas sink (GHG), and while freshwaters were thought to be neutral entities, they may in fact be potent producers and emitters of CO2 and CH4. Little is known about their contribution to the global carbon budget, especially in agricultural landscapes. This research aimed to determine the rate of organic carbon accumulation in agricultural ponds in relation to nutrients, and to estimate CO2 and CH4 production processes in, and emission routes from, ponds in relation to physico-chemical conditions. Sampling sites were three catchments in Leicestershire in a characteristic agricultural environment. Year 1 fieldwork (April―June 2013) covered 98 of an original 180 sampling sites, and encompassed a mixture of water bodies. Sites were accessed in stages according to specified access routes, and samples were analysed the same day. Year 2 fieldwork (August―September 2014) focused on ponds, those from year 1 and new established ponds. Analysis was done with a quadrupole mass spectrometer. The data obtained from the air-flux time series samples, plotted as scatter graphs, showed a very varied scatter with, at times, negative sloping trendlines, resulting in very low r2 values in all but one graph. It is thought that a lack of measurement precision, analysing the air-flux samples, is the main cause of unreliable data. The inconclusive data was initially thought to derive from a poor sampling regime, but was ultimately linked to the analytical method and instruments. Investigations suggested that an inter-technique comparison of the analyser would help to determine the validity of the data. Although data analysis could not be completed, descriptive analyse of the processes undertaken are provided. Water samples, from ponds, streams, and ditches were collected for analysis of dissolved CO2 and CH4 in the three catchments (Eye, Stonton, and Barkby). Data analysis revealed significant differences between catchments in both, CO2 and CH4 concentrations amongst the three catchments. To establish sediment organic and inorganic carbon content of ponds, sediment traps were installed, and the retrieved samples analysed using the loss on ignition method. The regression analysis showed that about 33% of CO2 emission is dependent on organic carbon. Organic carbon and inorganic carbon were not significantly correlated with CH4 emissions. Data obtained from water samples analysed for dissolved CO2 and CH4, and the slope values of the air-flux samples were compared to the 2013 baseline data collected by Freshwater Habitats Trust using correlation half-matrix. The analysis showed correlation at P=0.050 r=0.381 between CO2 and nitrogen, between CH4 dissolved in water and suspended solids, and between CO2 slope air-flux and zinc. At P=0.10 r=0.487 correlation was between CO2 water and CO2 slope air-flux, between CH4 slope air-flux and turbidity, and between CH4 air-flux and zinc. Since an essential part of the data was deemed unfit for data analysis recommendations are given for ensuring reliability before commencing sampling, and for improving the methodology."],"dc:format":["application/pdf"],"dc:identifier":["https://doi.org/10.24384/4nvs-4s88","https://radar.brookes.ac.uk/radar/file/1cd98af7-cc95-4e6b-b970-fbab5a861de5/1/fulltext.pdf"],"dc:language":["en"],"dc:publisher":["Oxford Brookes University"],"dc:rights":["All rights reserved"],"dc:title":["AGRICULTURAL SMALL WATER BODIES: CARBON SOURCE OR CARBON SINK?"],"dc:type":["thesis"]},"updated_at":"2026-07-24T03:43:24Z"}