Environmental implications of salinity and flooding induced changes in porewater nitrogen and phosphorous dynamics

ABSTRACT

This study aimed to investigate the effects of fresh water and seawater flooding on phosphorous (P) and nitrogen (N) dynamics in two calcareous soils (Biscayne and Krome) of South Florida using a 28-day greenhouse flooding experiment. Porewater samples were collected at three depths over four periods (1, 7, 14, and 28 days) of flooding and analyzed for selected water quality parameters. Results showed that seawater-flooded Biscayne soil had a 4.4 fold higher porewater soluble reactive phosphorus (SRP) concentration  than freshwater. Additionally, porewater SRP concentration and total phosphorus (TP) in Biscayne soil increased with prolonged flooding duration and column depth. Furthermore, both freshwater and seawater flooding increased porewater NH₄⁺ - N concentration; however, the increase was more pronounced in seawater flooded samples. NH₄⁺ - N concentration also increased with flooding duration. Overall, the study highlights the risks of nutrient leaching from seawater flooded coastal soils that could contribute to the deterioration of surface and groundwater quality.

KEYWORDS:

• Climate change
• sea level rise
• coastal agriculture
• water quality
• nutrients

Acknowledgments

This publication is based on research funded by the United States Department of Agriculture’s National Institute of Food and Agriculture under award number 2020-67019-31163 . Any opinions, results, conclusions, or recommendations contained in this publication are solely those of the authors and do not necessarily reflect the views of the USDA. The authors would like to express their gratitude to Christian Bartell and Syed Shaham for their help with the experiment and data collection . We would also like to thank Dr. Edzard van Santen for his help with statistical analysis.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

Haimanote K. Bayabil: Conceptualization and Research design. Haimanote K. Bayabil and Niguss Solomon Hailegnaw: Methodology. Niguss Solomon Hailegnaw: Writing- Original draft preparation. Haimanote K. Bayabil and Yuncong C. Li: Revision. Haimanote K. Bayabil: Supervision.

Additional information

Funding

This work was supported by the National Institute of Food and Agriculture [2020-67019-31163].