Publication Date

Spring 5-26-2021

Degree Type

Master's Project

Degree Name

Master of Science in Bioinformatics (MSBI)

Department

Computer Science

First Advisor

Philip Heller

Keywords

Marine bacteria, 16S rRNA gene amplicons, bacterial community composition, microbial oceanography, Western Antarctic Peninsula, Palmer LTER

Abstract

The Western Antarctic Peninsula has experienced dramatic warming due to climate change over the last 50 years and the consequences to the marine microbial community are not fully clear. The marine bacterial community are fundamental contributors to biogeochemical cycling of nutrients and minerals in the ocean. Molecular data of bacteria from the surface waters of the Western Antarctic Peninsula are lacking and most existing studies do not capture the annual variation of bacterial community dynamics. In this study, 15 different 16S rRNA gene amplicon samples covering 3 austral summers were processed and analyzed to investigate the marine bacterial community composition and its changes over the summer season. Between the 3 summer seasons, a similar pattern of dominance in relative community composition by the classes of Alphaproteobacteria, Gammaproteobacteria, and Bacteroidetes was observed. Alphaproteobacteria were mainly composed of the order Rhodobacterales and increased in relative abundance as the summer progressed. Gammaproteobacteria were represented by a wide array of taxa at the order level. The class Bacteroidetes had the highest relative abundance in the early summer and decreased as the season progressed. Bacteroidetes were primarily represented by the order Flavobacteriales and genus Polaribacter. A high degree of interannual variability was observed for some taxa, like the order Sphingobacteriales, which exhibited a high relative abundance in only 1 season. Richness and evenness diversity measures were found to be at the lowest during phytoplankton blooms, and these diversity measures were observed to increase by the end of the summer. Code written for data processing and analysis are available at: https://github.com/codey-phoun/palmer_station_16S

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