Organic matter distribution in the icy environments of Taylor Valley, Antarctica

TitleOrganic matter distribution in the icy environments of Taylor Valley, Antarctica
Publication TypeJournal Article
Year of Publication2022
AuthorsGuo, B, Li, W, Santibáñez, P, Priscu, JC, Liu, Y, Liu, K
JournalScience of The Total Environment
Date Published06/2022
KeywordsAntarctica, bacteria, ice cores, katabatic wind, marine aerosol, organic matter

Glaciers can accumulate and release organic matter affecting the structure and function of associated terrestrial and aquatic ecosystems. We analyzed 18 ice cores collected from six locations in Taylor Valley (McMurdo Dry Valleys), Antarctica to determine the spatial abundance and quality of organic matter, and the spatial distribution of bacterial density and community structure from the terminus of the Taylor Glacier to the coast (McMurdo Sound). Our results showed that dissolved and particulate organic carbon concentrations in the ice core samples increased from the Taylor Glacier to McMurdo Sound, a pattern also shown by bacterial cell density. Fluorescence Excitation Emission Matrices Spectroscopy (EEMs) and multivariate parallel factor (PARAFAC) modeling identified one humic-like (C1) and one protein-like (C2) component in ice cores whose fluorescent intensities all increased from the Polar Plateau to the coast. The fluorescence index showed that the bioavailability of dissolved organic matter (DOM) also decreased from the Polar Plateau to the coast. Partial least squares path modeling analysis revealed that bacterial abundance was the main positive biotic factor influencing both the quantity and quality of organic matter. Marine aerosol influenced the spatial distribution of dissolved organic carbon (DOC) more than katabatic winds in the ice cores. Certain bacterial taxa showed significant correlations with DOC and particle organic carbon (POC) concentrations. Collectively, our results show the tight connectivity among organic matter spatial distribution, bacterial abundance and meteorology in the McMurdo Dry Valley ecosystem.