Title

Compositions and isotopic differences of iso- and anteiso-alkanes in black mangroves (Avicennia germinans) across a salinity gradient in a subtropical estuary

Authors

Ding He, Southeast Environmental Research Center and Department of Chemistry and Biochemistry, Florida International UniversityFollow
Bernd R. T. Simoneit, Oregon State UniversityFollow
Blanca Jara, Department of Chemistry and Biochemistry and Southeast Environmental Research Center, Florida International UniversityFollow
Rudolf Jaffé, Southeast Environmental Research Center and Department of Chemistry and Biochemistry, Florida International University,Follow

Abstract

A series of iso- and anteiso-monomethylalkanes (MMAs) with carbon numbers from C₂₃ to C₃₅ and C₁₄ to C₃₄ respectively were detected in Avicennia germinans. These compounds were present in varying amounts up to 54.1, 1.0 and 3.4 µg g^–1 dry weight in the leaves, bark and the crustose lichens attached to the bark of A. germinans respectively. These MMAs were not detected in the leaf waxes of Rhizophora mangle and Laguncularia racemosa, but were detected in significantly lower abundances (2–6 % of that in A. germinans leaf wax) in the bark and lichen of R. mangle. Significant odd-carbon number distributions and even-carbon number distributions were observed for long chain (C ≥ 25) iso- (maximising at C₃₁) and anteiso-MMAs (maximising at C₃₂) respectively in A. germinans leaf wax. However, no obvious carbon number preferences were detected for bark and lichen. The long chain (LC) iso- and anteiso-MMAs in A. germinans leaf waxes were found to be enriched in ¹³C by 0.3–4.3 and 0.7–4.2 per mille (‰) compared to the n-alkanes with the same carbon numbers respectively across the salinity gradient of 19.7–32.0 practical salinity units (psu). In comparison, the LC iso- and anteiso-MMAs were found to be more depleted in D by 6.1–55.1 and 7.3–57.0 ‰ compared to the n-alkanes with same carbon numbers respectively. The results imply that A. germinans could be another important source of iso- and anteiso-alkanes in sediments and soils, and that these compounds could potentially be used as biomarkers for this species in mixed mangrove environments.

Comments

http://dx.doi.org/10.1071/EN15128

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 #DEB-1237517, #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

He, Ding; Simoneit, Bernd R. T.; Jara, Blanca; and Jaffé, Rudolf, "Compositions and isotopic differences of iso- and anteiso-alkanes in black mangroves (Avicennia germinans) across a salinity gradient in a subtropical estuary" (2015). FCE LTER Journal Articles. 449.
https://digitalcommons.fiu.edu/fce_lter_journal_articles/449