Molecular Diversity of Natural Dissolved Organic Matter Demonstrates Possible Linkage Between Carbon and Sulfur Cycling in Yellowstone National Park (WY) Hot Springs
Abstract
Microbial communities are influenced by a variety of parameters such as pH, temperature, and ion concentrations. In the extreme conditions found in hot springs, a shift in microbial communities from chemolithotrophic to phototrophic occurs as temperature decreases. Consequently, elemental cycling likely undergoes changes in these dynamic ecosystems, and the dissolved organic carbon (DOC) content can change dramatically over a small spatial area. Despite the information already available on DOC content, pH, geochemistry, and microbial communities, a detailed understanding of the dissolved organic matter (DOM) associated with different communities (chemolithotrophic and phototrophic) in such a dynamic environment has not been established. Furthermore, many environments exhibit linkages between carbon and sulfur cycling, mainly through biological processes. Herein we report results from an extreme environment in which carbon and sulfur cycling are mostly likely linked through abiotic processes. For the first time the complex natural organic matter (NOM) of Yellowstone hot springs was characterized using ultrahigh resolution mass spectrometry, high field NMR and excitation emission fluorescence. Nine hot springs were sampled for organic geochemical analysis in Fall 2009 and 2010; four more hot springs were added in 2010. The nine hot springs were sampled for inorganic geochemical analysis in Spring 2010 and Fall 2010, along with the new hot springs. Results show an extremely diverse organic matrix that can be related to the geochemistry of different classes of hot springs to varying extents. Some of the characterized organic matter has never been recorded in natural environments and gives hints about the interaction between the carbon and sulfur cycle. In hot springs containing hydrogen sulfide we observed an almost 1:1 match of carbon, hydrogen and oxygen (CmHnOo) formulas when compared with formulas also containing one single sulfur atom (CmHnOoS1). Hydrogen sulfide is suggested to be the main player in this abiotic sulfurization mechanism. The number of formulas assigned to nitrogen-containing compounds was low, similar to NOM described in other aquatic environments and indicating a different mechanism for incorporation of nitrogen into hot spring NOM. We use the organic geochemistry as an additional tool to classify hot springs and to evaluate linkages between NOM and biogeochemically important elements in Yellowstone National Park and beyond.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.B51I0512H
- Keywords:
-
- 0414 BIOGEOSCIENCES / Biogeochemical cycles;
- processes;
- and modeling;
- 0450 BIOGEOSCIENCES / Hydrothermal systems;
- 0456 BIOGEOSCIENCES / Life in extreme environments