Environmental Dynamics of Dissolved Black Carbon in Wetlands

Authors

Yan Ding, Department of Chemistry and Biochemistry, Marine Sciences Program and Southeast Environmental Research Center, Florida International UniversityFollow
Kaelin M. Cawley, Southeast Environmental Research Center, Florida International University; Department of Civil, Environmental, and Architectural Engineering, The Institute for Arctic and Alpine Research (INSTAAR), University of Colorado at BoulderFollow
Catia Nunes da Cunha, Depto. Botânica e Ecologia, Núcleo de Estudos Ecológicos do Pantanal, Universidade Federal de Mato Grosso
Rudolf Jaffe´, Southeast Environmental Research Center, Department of Chemistry and Biochemistry, Florida International University,Follow

Abstract

Wetlands are ecosystems commonly characterized by elevated levels of dissolved organic carbon (DOC), and although they cover a surface area less than 2 % worldwide, they are an important carbon source representing an estimated 15 % of global annual DOC flux to the oceans. Because of their unique hydrological characteristics, fire can be an important ecological driver in pulsed wetland systems. Consequently, wetlands may be important sources not only of DOC but also of products derived from biomass burning, such as dissolved black carbon (DBC). However, the biogeochemistry of DBC in wetlands has not been studied in detail. The objective of this study is to determine the environmental dynamics of DBC in different fire-impacted wetlands. An intensive, 2-year spatial and temporal dynamics study of DBC in a coastal wetland, the Everglades (Florida) system, as well as one-time sampling surveys for the other two inland wetlands, Okavango Delta (Botswana) and the Pantanal (Brazil), were reported. Our data reveal that DBC dynamics are strongly coupled with the DOC dynamics regardless of location, season or recent fire history. The statistically significant linear regression between DOC and DBC was applied to estimate DBC fluxes to the coastal zone through two main riverine DOC export routes in the Everglades ecosystem. The presence of significant amounts of DBC in these three fire-impacted ecosystems suggests that sub-tropical wetlands could represent an important continental-ocean carrier of combustion products from biomass burning. The discrimination of DBC molecular structure (i.e. aromaticity) between coastal and terrestrial samples, and between samples collected in wet and dry season, suggests that spatially-significant variation in DBC source strength and/or degree of degradation may also influence DBC dynamics.

Comments

The final publication is available at Springer via http://dx.doi.org/ 10.1007/s10533-014-9964-3

This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Recommended Citation

Ding, Y., K. Cawley, C.N. da Cunha, R. Jaffe. 2014 (In Press). Environmental dynamics of dissolved black carbon in wetlands. Biogeochemistry DOI: 10.1007/s10533-014-9964-3