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ORIGINAL RESEARCH article

Front. Environ. Sci.
Sec. Freshwater Science
Volume 12 - 2024 | doi: 10.3389/fenvs.2024.1468869
This article is part of the Research Topic Nitrate from field to stream: characterization and mitigation View all articles

Impacts of climate change and best management practices on nitrate loading to a eutrophic coastal lagoon

Provisionally accepted
Alexandra Oliver Alexandra Oliver Barret Kurylyk Barret Kurylyk Lindsay Johnston Lindsay Johnston Nicole Leroux Nicole Leroux Lauren Somers Lauren Somers Rob Jamieson Rob Jamieson *
  • Dalhousie University, Halifax, Canada

The final, formatted version of the article will be published soon.

    Anthropogenic climate change and associated increasing nutrient loading to coasts will worsen coastal eutrophication on a global scale. Basin Head is a coastal lagoon located in northeastern Prince Edward Island, Canada, with a federally protected ecosystem. Nitrate-nitrogen (NO3-N) is conveyed from agricultural fields in the watershed to the eutrophic lagoon via intertidal groundwater springs and groundwater-dominated tributaries. A field program focused on four main tributaries that discharge into the lagoon was conducted to measure year-round NO3-N loading. These measurements were used to calibrate a SWAT+ hydrologic model capable of simulating hydrologic and NO3-N loads to the lagoon. Several climate change scenarios incorporating different agricultural best management practices (BMPs) were simulated to better understand potential future NO3-N loading dynamics. Results indicate that all climate change scenarios produced increased annual NO3-N loading to the lagoon when comparing historical (1990-2020) to future, end of century time periods (2070-2100); however, only one climate scenario (MRI-ESM2-0 SSP5-8.5) resulted in a statistically significant (p-value < 0.05) increase. Enlarged buffer strips and delayed tillage BMP simulations produced small (0-8%) effects on loading, while changing the crop rotation from potato-barley-clover to potato-soybean-barley yielded a small reduction in NO3-N loading between the historical period and the end of the century (26-33%). Modeling revealed changes in seasonal loading dynamics under climate change where NO3-N loads remained more consistent throughout the year as opposed to current conditions where the dominant load is in the spring. An increase in baseflow contributions to streamflow was also noted under climate change, with the largest change occurring in the winter (e.g., up to a five-fold increase in February). These findings have direct implications for coastal management in groundwater-dominated agricultural watersheds in a changing climate.

    Keywords: Hydrologic model1, SWAT+2, climate change3, best management practice4, nitrate loading5 Hydrologic model1, nitrate loading5

    Received: 22 Jul 2024; Accepted: 15 Aug 2024.

    Copyright: © 2024 Oliver, Kurylyk, Johnston, Leroux, Somers and Jamieson. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Rob Jamieson, Dalhousie University, Halifax, Canada

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