Phylogenetic and Physiological Characterization of Amino Acid Nitrogen Stable Isotopes in Phytoplankton

The nitrogen isotope ratios (δ15N) of individual amino acid (AA) have been increasingly used as tracers in contemporary and paleo marine biogeochemistry and trophic ecology. The observed distinctive δ15N signatures among different AAs, in particular phenylalanine (Phe) and glutamic acid (Glu), known as the canonical “source” and “trophic” AAs have been used to retrieve N isotope baseline of food webs and estimate the numbers of trophic transfers in various sample matrices like biota, particles, coral skeletons, and sediments. Although these applications heavily depend on the δ15N -AA produced by phytoplankton, the potential variations of δ15N -AA fabricated by different phylogenetic species remain poorly understood. Here, we aim to help to bridge this gap in knowledge by analyzing the Phe and Glu δ15N values as well as the concentration of AAs within different, well known phytoplankton species, cultured under the same nutrient conditions and in different growth phases and examine its potential effect on trophic position. 

Presentation Preference: Oral

Primary Presenter: Jesus Baca, Texas A&M University - Corpus Christi (bacaje12@gmail.com)

Authors:

Jesus Baca, Texas A&M University - Corpus Christi  (jbaca2@islander.tamucc.edu)

Nayani Vidyarathna, University of Maryland Center for Environmental Science  (nvidyarathna@umces.edu)

KhDola Wahid, University of Massachusetts Dartmouth  (kwahid1@umassd.edu)

Patricia Glibert, University of Maryland Center for Environmental Science  (glibert@umces.edu)

Mark Altabet, University of Massachusetts Dartmouth  (maltabet@umassd.edu)

Charlotte Lee, Texas A&M University - Corpus Christi  (wlee4@islander.tamucc.edu)

Lin Zhang, Texas A&M University - Corpus Christi  (lin.zhang@tamucc.edu)