What’s for dinner? How about detritus?

Latitude: -063 46.154  Longitude: -057 49.085

The question “what’s for dinner?” happens to be one of the least favorite question for my wife and I to answer.  As we are both scientists, we would prefer to talk about the electrons that come from our food but planning out meals and getting groceries are a much less exciting.   Thankfully, my research focus on this cruise is more about electrons and metabolism as it will look at what the microbial community in the sediments are having for “dinner.” 
 
My work in Antarctica started with a  collaboration between Andrew Mahon and Ken Halanych a few years ago.  Together, we pushed two papers that examined the bacteria, archaea, and meiofaunal diversity of Antarctic benthic sediments from the Ross Sea all the way to the northern tip of the Antarctic Peninsula.  Both studies shared a finding:  the diversity within these sediment communities were heavily influenced by the quantity and quality of organic matter.   The microbial community data implicated both heterotrophs and lithotrophs in these sediments.  This is also currently being invested, as our group is actively analyzing metagenomic data to investigate lithotrophic metabolism.  The samples from the Ross, Amundsen, and Bellingshausen Sea have a diverse array of lithotrophic metabolism as the metagenomic data contains genes that would support hydrogen, nitrogen (both ammonium and nitrite) and sulfur oxidation. 
 
The goal for this work is to examine the detritus degrading community in sediments from the north side of the Antarctic Pennisula and the Weddell Sea.  Our past work documented more organic matter at sites in the Antarctic Peninsula, with possible sources being phytoplankton.  This cruise will allow us to collect new samples from areas we expect to have relatively high and low concentrations of organic matter.  These will then be investigated with metagenomics and extracellular enzyme assay to determine the genetics that are driving organic matter degradation in these benthic sediments. 

Dr. Deric Learman
Professor
Central Michigan University