METABOLITE EXCRETION RATES OF FOUR MIGRATORY ZOOPLANKTON

Zooplankton transform and transport nutrients across vertical zones of the ocean food web. Consuming particulate organic matter from a variety of trophic levels, they repackage carbon into biomass and sinking fecal matter. Although less studied than their particulate contributions, zooplankton directly release dissolved organic waste compounds. The identities and quantities of these waste products are poorly characterized, preventing an adequate analysis of their role in microbial ecology. Building on previous work, we measured excreted zooplankton metabolites from four taxonomic orders (calanoid copepod, amphipod, euphausiid, and pteropod), using a novel benzoyl chloride derivitization method for metabolite quantification via liquid chromatography–mass spectrometry. We were able to quantify the production of 42 distinct metabolites, with the sensitivity to take measurements from a single organism. We found that this set of targeted compounds compose up to 18% of the total excreted nitrogen. Our findings demonstrate that not only do excreta from multiple zooplankton taxa consistently contain specific organic nutrients, but that the rates can be measured and applied to extant zooplankton abundance data to estimate source terms for individual ecologically important chemicals. This quantification provides insight into the magnitude of the injection of labile fuel into microbial food webs from these higher tropic levels and highlights substrate availability for specific microbial metabolic pathways that bear further investigation.

Presentation Preference: Poster

Primary Presenter: Amy Maas, BIOS/ASU (amaas4@asu.edu)

Authors:

Noah Germolus, University of Hawai'i at Manoa  (germolus@hawaii.edu)

Amy Maas, BIOS/ASU  (amaas4@asu.edu)

Melissa Kido Soule, WHOI  (msoule@whoi.edu)

Elizabeth Kujawinski, WHOI  (ekujawinski@whoi.edu)