The Eastern Nebraska Salt Marsh Microbiome Is Well Adapted to an Alkaline and Extreme Saline Environment

• Main Authors: Sierra R. Athen, Shivangi Dubey, John A. Kyndt
• Format: Article
• Language: English
• Published: MDPI AG 2021-05-01
• Series: Life
• Subjects: salt marsh; microbiome; <i>Rubribacterium</i>; <i>Prosthecochloris</i>; <i>Marichromatium</i>; <i>Sulfurimonas</i>
• Online Access: https://www.mdpi.com/2075-1729/11/5/446

The Eastern Nebraska Salt Marshes contain a unique, alkaline, and saline wetland area that is a remnant of prehistoric oceans that once covered this area. The microbial composition of these salt marshes, identified by metagenomic sequencing, appears to be different from well-studied coastal salt marshes as it contains bacterial genera that have only been found in cold-adapted, alkaline, saline environments. For example, <i>Rubribacterium</i> was only isolated before from an Eastern Siberian soda lake, but appears to be one of the most abundant bacteria present at the time of sampling of the Eastern Nebraska Salt Marshes. Further enrichment, followed by genome sequencing and metagenomic binning, revealed the presence of several halophilic, alkalophilic bacteria that play important roles in sulfur and carbon cycling, as well as in nitrogen fixation within this ecosystem. Photosynthetic sulfur bacteria, belonging to <i>Prosthecochloris</i> and <i>Marichromatium</i>, and chemotrophic sulfur bacteria of the genera <i>Sulfurimonas</i>, <i>Arcobacter</i>, and <i>Thiomicrospira</i> produce valuable oxidized sulfur compounds for algal and plant growth, while alkaliphilic, sulfur-reducing bacteria belonging to <i>Sulfurospirillum</i> help balance the sulfur cycle. This metagenome-based study provides a baseline to understand the complex, but balanced, syntrophic microbial interactions that occur in this unique inland salt marsh environment.