Journal article
Linking eutrophication to carbon dioxide and methane emissions from exposed mangrove soils along an urban gradient
The Science of the Total Environment, Vol.850, pp.1-15
01/12/2022
PMID: 35963403
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Abstract
Mangroves are one of the most important but threatened blue carbon ecosystems globally. Rapid urban growth has resulted in nutrient inputs and subsequent coastal eutrophication, associated with an enrichment in organic matter (OM) from algal and sewage sources and substantial changes in greenhouse gas (GHG) emissions. However, the effects of nitrogen (N) and phosphorus (P) enrichment on mangrove soil OM composition and GHG emissions, such as methane (CH4) and carbon dioxide (CO2), are still poorly understood. Here, we aim to evaluate the relationships between CO2 and CH4 efflux with OM composition in exposed soils from three mangrove areas along watersheds with different urbanization levels (Rio de Janeiro State, Brazil). To assess spatial (lower vs. upper intertidal zones) and seasonal (summer vs. winter) variability, we measured soil-air CO2 and CH4 fluxes at low spring tide, analyzing elementary (C, N, and P), isotopic (δ13C and δ15N), and the molecular (n-alkanes and sterols) composition of surface soil OM. A general trend of OM composition was found with increasing urban influence, with higher δ15N (proxy of anthropogenic N enrichment), less negative δ13C, more short-chain n-alkanes, lower C:N ratio (proxies of algal biomass), and higher epicoprostanol content (proxies of sewage-derived OM). The CO2 efflux from exposed soils increased greatly in median (25/75 % interquartile range) from 4.6 (2.9/8.3) to 24.0 (21.5/32.7) mmol m−2 h−1 from more pristine to more urbanized watersheds, independent of intertidal zone and seasonality. The CO2 fluxes at the most eutrophicated site were among the highest reported worldwide for mangrove soils. Conversely, CH4 emissions were relatively low (three orders of magnitude lower than CO2 fluxes), with high peaks in the lower intertidal zone during the rainy summer. Thus, our findings demonstrate the influence of coastal eutrophication on global warming potentials related to enhanced heterotrophic remineralization of blue carbon within mangrove soils.
Details
- Title
- Linking eutrophication to carbon dioxide and methane emissions from exposed mangrove soils along an urban gradient
- Creators
- Glenda C. Barroso - Universidade Federal FluminenseGwenaël Abril - Biologie des Organismes et Écosystèmes AquatiquesWilson Machado - Universidade Federal FluminenseRodrigo C. Abuchacra - Rio de Janeiro State UniversityRoberta B. Peixoto - Universidade Federal FluminenseMarcelo Bernardes - Universidade Federal FluminenseGabriela S. Marques - Universidade Federal FluminenseChristian J. Sanders - Southern Cross UniversityGabriela B. Oliveira - Universidade Federal FluminenseSilvio R. Oliveira Filho - Universidade Federal FluminenseLeonardo Amora-Nogueira - Universidade Federal FluminenseHumberto Marotta - Universidade Federal Fluminense
- Publication Details
- The Science of the Total Environment, Vol.850, pp.1-15
- Publisher
- Elsevier BV
- Grant note
- This work was supported by the Brazilian National Council for Scientific and Technological Development (CNPq no. 314995/2020-0 and 203366/2019-0), the Carlos Chagas Filho Foundation for Research Support of the State of Rio de Janeiro (FAPERJ no. E–26/203.304/2017, E-26/210.441/2021, E-26/211.329/2021, and E-26/201.118/2022), the Coordination for the Improvement of Higher Education Personnel (CAPES, Finance Code 001 and the internalization program PRINTCAPES/UFF FEEDBACKS no. 99997.310301/2018-00), the French CNRS-INSU LEFE program and the France-Brazil International Research Project VELITROP (Vulnerability of Tropical Littoral Ecosystem facing eutrophication) funded by the CNRS-INEE, France. HM was the recipient of CNPq Research Productivity and FAPERJ Rio de Janeiro State Scientist grants.
- Identifiers
- 991013045912202368
- Copyright
- © 2022 Elsevier B.V. All rights reserved.
- Academic Unit
- Faculty of Science and Engineering; Science; National Marine Science Centre
- Language
- English
- Resource Type
- Journal article