Internal microbial zonation during the massive growth of marimo, a lake ball of Aegagropila linnaei in Lake Akan

• Published in: iScience Vol. 24; no. 7; p. 102720
• Main Authors: Nakai, Ryosuke, Wakana, Isamu, Niki, Hironori
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 23.07.2021; Elsevier
• Subjects: Algology; Ecology; Microbiome; Omics; Ecology; Algology; Omics; Microbiome
• ISSN: 2589-0042; 2589-0042
• DOI: 10.1016/j.isci.2021.102720

Marimo (lake ball) is an uncommon ball-like aggregation of the green alga, Aegagropila linnaei. Although A. linnaei is distributed in fresh and brackish waters in the northern hemisphere, marimo colonies are found only in particular habitats. Here, we report the bacterial communities inside various sizes and aggregating structures of natural marimo collected from Lake Akan, Japan. We observed multi-layers composed of sediment particles only in the sizable radial-type marimo with >20 cm diameter and not in the tangled-type marimo. The deeper layers were enriched by Nitrospira, potential sulfur-oxidizing bacteria, and sulfate-reducing bacteria. Microorganisms of the multi-layers would form biofilms incorporating nearby sediment, which would function as microbial “seals” within large radial-type marimo. These findings provide clues to deciphering the growth of endangered marimo. [Display omitted] •The radial type of marimo (lake ball) can grow to over 20 cm in diameter•The sizable radial-type marimo develops the internal multi-layers and hollow structure•The layers provide different diverse microbiomes and structural strength•The internal multi-layers support the massive growth of the radial-type marimo Ecology; Microbiome; Algology; Omics