Size fractionation of dissolved organic nitrogen in peatland fluvial systemsCitation formats
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Size fractionation of dissolved organic nitrogen in peatland fluvial systems. / Edokpa, Donald; Evans, Martin G; Boult, Stephen; Rothwell, James J.
In: Environmental Science and Technology, 2018.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Size fractionation of dissolved organic nitrogen in peatland fluvial systems
AU - Edokpa, Donald
AU - Evans, Martin G
AU - Boult, Stephen
AU - Rothwell, James J
PY - 2018
Y1 - 2018
N2 - Understanding the nature and fate of nitrogen (N) in freshwater systems is crucial for assessing the risk of eutrophication. However, there is a paucity of information on the characterisation of fluvial N in upland peat-dominated environments. Here, we employ a combination of field sampling and tangential flow ultrafiltration (TFU) to investigate the concentrations and fluxes of low molecular weight (LMW) and high molecular weight (HMW) dissolved organic N (DON) in a peatland stream-reservoir system in the south Pennines (UK). Our TFU results show that ~ 26% of DON concentration is LMW DON and represents an estimated fluvial flux of 3.07±22 kg N ha-1 during the study period. Our mass balance results reveal that the reservoir retains 71% of LMW DON input, which accounts for ~ 25% retention of bioavailable (Dissolved inorganic N + LMW DON) N. Our study suggests that current understanding of inorganic N as the sole source of bioavailable N with eutrophic significance in upland freshwaters requires a reappraisal. Evaluation of ecosystem response to increased loading of N needs to include a consideration of LMW DON.
AB - Understanding the nature and fate of nitrogen (N) in freshwater systems is crucial for assessing the risk of eutrophication. However, there is a paucity of information on the characterisation of fluvial N in upland peat-dominated environments. Here, we employ a combination of field sampling and tangential flow ultrafiltration (TFU) to investigate the concentrations and fluxes of low molecular weight (LMW) and high molecular weight (HMW) dissolved organic N (DON) in a peatland stream-reservoir system in the south Pennines (UK). Our TFU results show that ~ 26% of DON concentration is LMW DON and represents an estimated fluvial flux of 3.07±22 kg N ha-1 during the study period. Our mass balance results reveal that the reservoir retains 71% of LMW DON input, which accounts for ~ 25% retention of bioavailable (Dissolved inorganic N + LMW DON) N. Our study suggests that current understanding of inorganic N as the sole source of bioavailable N with eutrophic significance in upland freshwaters requires a reappraisal. Evaluation of ecosystem response to increased loading of N needs to include a consideration of LMW DON.
U2 - 10.1021/acs.est.8b01417
DO - 10.1021/acs.est.8b01417
M3 - Article
JO - Environmental Science & Technology
JF - Environmental Science & Technology
SN - 0013-936X
ER -