Disentangling the responses of dissolved organic carbon and nitrogen concentrations to overlapping drivers in a northeastern United States forested watershed
The concurrent reduction in acid deposition and increase in precipitation impact stream solute dynamics in complex ways that make predictions of future water quality difficult. To understand how changes in acid deposition and precipitation have influenced dissolved organic carbon (DOC) and nitrogen...
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| Format: | Article |
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Frontiers Media S.A.
2023-03-01
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| Series: | Frontiers in Water |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/frwa.2023.1065300/full |
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| author | Manya Ruckhaus Erin C. Seybold Kristen L. Underwood Bryn Stewart Dustin W. Kincaid James B. Shanley Li Li Julia N. Perdrial |
| author_facet | Manya Ruckhaus Erin C. Seybold Kristen L. Underwood Bryn Stewart Dustin W. Kincaid James B. Shanley Li Li Julia N. Perdrial |
| author_sort | Manya Ruckhaus |
| collection | DOAJ |
| description | The concurrent reduction in acid deposition and increase in precipitation impact stream solute dynamics in complex ways that make predictions of future water quality difficult. To understand how changes in acid deposition and precipitation have influenced dissolved organic carbon (DOC) and nitrogen (N) loading to streams, we investigated trends from 1991 to 2018 in stream concentrations (DOC, ~3,800 measurements), dissolved organic nitrogen (DON, ~1,160 measurements), and dissolved inorganic N (DIN, ~2,130 measurements) in a forested watershed in Vermont, USA. Our analysis included concentration-discharge (C-Q) relationships and Seasonal Mann-Kendall tests on long-term, flow-adjusted concentrations. To understand whether hydrologic flushing and changes in acid deposition influenced long-term patterns by liberating DOC and dissolved N from watershed soils, we measured their concentrations in the leachate of 108 topsoil cores of 5 cm diameter that we flushed with solutions simulating high and low acid deposition during four different seasons. Our results indicate that DOC and DON often co-varied in both the long-term stream dataset and the soil core experiment. Additionally, leachate from winter soil cores produced especially high concentrations of all three solutes. This seasonal signal was consistent with C-Q relation showing that organic materials (e.g., DOC and DON), which accumulate during winter, are flushed into streams during spring snowmelt. Acid deposition had opposite effects on DOC and DON compared to DIN in the soil core experiment. Low acid deposition solutions, which mimic present day precipitation, produced the highest DOC and DON leachate concentrations. Conversely, high acid deposition solutions generally produced the highest DIN leachate concentrations. These results are consistent with the increasing trend in stream DOC concentrations and generally decreasing trend in stream DIN we observed in the long-term data. These results suggest that the impact of acid deposition on the liberation of soil carbon (C) and N differed for DOC and DON vs. DIN, and these impacts were reflected in long-term stream chemistry patterns. As watersheds continue to recover from acid deposition, stream C:N ratios will likely continue to increase, with important consequences for stream metabolism and biogeochemical processes. |
| first_indexed | 2024-04-10T04:07:30Z |
| format | Article |
| id | doaj.art-a710422c6ab9468cb6f516079fdbd0da |
| institution | Directory Open Access Journal |
| issn | 2624-9375 |
| language | English |
| last_indexed | 2024-04-10T04:07:30Z |
| publishDate | 2023-03-01 |
| publisher | Frontiers Media S.A. |
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| series | Frontiers in Water |
| spelling | doaj.art-a710422c6ab9468cb6f516079fdbd0da2023-03-13T04:44:39ZengFrontiers Media S.A.Frontiers in Water2624-93752023-03-01510.3389/frwa.2023.10653001065300Disentangling the responses of dissolved organic carbon and nitrogen concentrations to overlapping drivers in a northeastern United States forested watershedManya Ruckhaus0Erin C. Seybold1Kristen L. Underwood2Bryn Stewart3Dustin W. Kincaid4James B. Shanley5Li Li6Julia N. Perdrial7Department of Geography and Geosciences, University of Vermont, Burlington, VT, United StatesKansas Geological Survey, University of Kansas, Lawrence, KS, United StatesDepartment of Civil and Environmental Engineering, University of Vermont, Burlington, VT, United StatesDepartment of Civil and Environmental Engineering, Penn State University, University Park, PA, United StatesDepartment of Civil and Environmental Engineering, University of Vermont, Burlington, VT, United StatesU.S. Geological Survey, Montpelier, VT, United StatesDepartment of Civil and Environmental Engineering, Penn State University, University Park, PA, United StatesDepartment of Geography and Geosciences, University of Vermont, Burlington, VT, United StatesThe concurrent reduction in acid deposition and increase in precipitation impact stream solute dynamics in complex ways that make predictions of future water quality difficult. To understand how changes in acid deposition and precipitation have influenced dissolved organic carbon (DOC) and nitrogen (N) loading to streams, we investigated trends from 1991 to 2018 in stream concentrations (DOC, ~3,800 measurements), dissolved organic nitrogen (DON, ~1,160 measurements), and dissolved inorganic N (DIN, ~2,130 measurements) in a forested watershed in Vermont, USA. Our analysis included concentration-discharge (C-Q) relationships and Seasonal Mann-Kendall tests on long-term, flow-adjusted concentrations. To understand whether hydrologic flushing and changes in acid deposition influenced long-term patterns by liberating DOC and dissolved N from watershed soils, we measured their concentrations in the leachate of 108 topsoil cores of 5 cm diameter that we flushed with solutions simulating high and low acid deposition during four different seasons. Our results indicate that DOC and DON often co-varied in both the long-term stream dataset and the soil core experiment. Additionally, leachate from winter soil cores produced especially high concentrations of all three solutes. This seasonal signal was consistent with C-Q relation showing that organic materials (e.g., DOC and DON), which accumulate during winter, are flushed into streams during spring snowmelt. Acid deposition had opposite effects on DOC and DON compared to DIN in the soil core experiment. Low acid deposition solutions, which mimic present day precipitation, produced the highest DOC and DON leachate concentrations. Conversely, high acid deposition solutions generally produced the highest DIN leachate concentrations. These results are consistent with the increasing trend in stream DOC concentrations and generally decreasing trend in stream DIN we observed in the long-term data. These results suggest that the impact of acid deposition on the liberation of soil carbon (C) and N differed for DOC and DON vs. DIN, and these impacts were reflected in long-term stream chemistry patterns. As watersheds continue to recover from acid deposition, stream C:N ratios will likely continue to increase, with important consequences for stream metabolism and biogeochemical processes.https://www.frontiersin.org/articles/10.3389/frwa.2023.1065300/fullcarbonnitrogenstoichiometryoverlapping driverslong-term dataexperiments |
| spellingShingle | Manya Ruckhaus Erin C. Seybold Kristen L. Underwood Bryn Stewart Dustin W. Kincaid James B. Shanley Li Li Julia N. Perdrial Disentangling the responses of dissolved organic carbon and nitrogen concentrations to overlapping drivers in a northeastern United States forested watershed Frontiers in Water carbon nitrogen stoichiometry overlapping drivers long-term data experiments |
| title | Disentangling the responses of dissolved organic carbon and nitrogen concentrations to overlapping drivers in a northeastern United States forested watershed |
| title_full | Disentangling the responses of dissolved organic carbon and nitrogen concentrations to overlapping drivers in a northeastern United States forested watershed |
| title_fullStr | Disentangling the responses of dissolved organic carbon and nitrogen concentrations to overlapping drivers in a northeastern United States forested watershed |
| title_full_unstemmed | Disentangling the responses of dissolved organic carbon and nitrogen concentrations to overlapping drivers in a northeastern United States forested watershed |
| title_short | Disentangling the responses of dissolved organic carbon and nitrogen concentrations to overlapping drivers in a northeastern United States forested watershed |
| title_sort | disentangling the responses of dissolved organic carbon and nitrogen concentrations to overlapping drivers in a northeastern united states forested watershed |
| topic | carbon nitrogen stoichiometry overlapping drivers long-term data experiments |
| url | https://www.frontiersin.org/articles/10.3389/frwa.2023.1065300/full |
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