Excessive phosphorus loading contributes to future vulnerability of mangrove ecosystems by reducing net ecosystem exchange of carbon

Coastal Futures
By: , and 

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Abstract

J.N. “Ding” Darling National Wildlife Refuge (DDNWR) is located on Sanibel Island along the southwestern coast of Florida, USA. There, eutrophication attributed to agricultural discharge along the Caloosahatchee River has affected the area’s aquatic habitat. In anticipation of additional nutrient loading, we experimentally fertilized mangrove forests with nitrogen (+N; NH4) and phosphorus (+P; P2O5) for 3 years, and monitored soil and pneumatophore CO2 fluxes and tree sap flow from two mangrove species. Furthermore, we modeled individual tree and stand water use, from which we developed carbon (C) budgets for +N and + P vs. control simulations based on a novel application of water use efficiency conversion. Many of the measured response variables provided hints of subtle changes in response to +P rather than +N, which were enhanced when scaled. From this, we found that additional P loading is expected to reduce both gross and net primary productivity as well as CO2 uptake via net ecosystem exchange of C, likely pressing the system beyond metabolic capacity and leading to a 48–62% decrease in projected lateral C export. Greater eutrophication will likely compound vulnerabilities to sea-level rise submergence, especially where P concentrations are high and already reducing soil surface elevations.

Suggested Citation

Krauss, K.W., Conrad, J.R., Duberstein, J.A., Ward, E.J., Drexler, J.Z., Buffington, K.J., Benscoter, B.W., Miller, H.J., Faron, N.T., Merino, S., From, A., Peneva-Reed, E., Zhu, Z., Thorne, K., and Feller, I.C., 2026, Excessive phosphorus loading contributes to future vulnerability of mangrove ecosystems by reducing net ecosystem exchange of carbon: Coastal Futures, v. 4, e6, 16 p., https://doi.org/10.1017/cft.2026.10025.

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Publication type Article
Publication Subtype Journal Article
Title Excessive phosphorus loading contributes to future vulnerability of mangrove ecosystems by reducing net ecosystem exchange of carbon
Series title Coastal Futures
DOI 10.1017/cft.2026.10025
Volume 4
Publication Date April 01, 2026
Year Published 2026
Language English
Publisher Cambridge University Press
Contributing office(s) California Water Science Center, Western Ecological Research Center, Wetland and Aquatic Research Center
Description e6, 16 p.
Country United States
State Florida
Other Geospatial J.N. “Ding” Darling National Wildlife Refuge
Additional publication details