An assessment of the microbial contribution to aquatic dissolved organic nitrogen using amino acid enantiomeric ratios

Authors

Vera Jones, Department of Earth and Ocean Sciences, University of LiverpoolFollow
Matthew J. Collins, North East Amino Acid Racemization (NEAAR), Departments of Biology and Archaeology, University of York
Kirsten E.H. Penkman, North East Amino Acid Racemization (NEAAR), Departments of Biology and Archaeology, University of York
Rudolf Jaffe´, Southeast Environmental Research Center, Department of Chemistry and Biochemistry, Florida International University,Follow
George A. Wolfe, Department of Earth and Ocean Sciences, University of Liverpool

Abstract

There is increasing evidence that certain microbially-derived compounds may account for part of the aquatic dissolved organic nitrogen (DON) pool. Enantiomeric ratios of amino acids were used to assess the microbial input to the DON pool in the Florida Everglades, USA. Elevated levels of d-alanine, d-aspartic acid, d-glutamic acid and d-serine indicated the presence of peptidoglycan in the samples. The estimated peptidoglycan contribution to amino acid nitrogen ranged from 2.8 ± 0.1% to 6.4 ± 0.9%, increasing with salinity from freshwater to coastal waters. The distribution of individual d-amino acids in the samples suggests additional inputs to DON, possibly from archaea or from abiotic racemization of l-amino acids.

Comments

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

Jones, V., M.J. Collins, K.E.H. Penkman, R. Jaffe, G.A. Wolff. 2005. An assessment of the microbial contribution to aquatic dissolved organic nitrogen using amino acid enantiomeric ratios. Organic Geochemistry 36(7): 1099-1107.