Nakai Ryosuke, Wakana Isamu, Niki Hironori
Microbial Physiology Laboratory, Department of Gene Function and Phenomics, National Institute of Genetics, 1111, Yata, Mishima, Shizuoka 411-8540 Japan.
Kushiro International Wetland Center, 7-5 Kuroganecho, Kushiro, Hokkaido 085-8505, Japan.
iScience. 2021 Jun 12;24(7):102720. doi: 10.1016/j.isci.2021.102720. eCollection 2021 Jul 23.
Marimo (lake ball) is an uncommon ball-like aggregation of the green alga, Although 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 , 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.
球藻（湖中之球）是一种罕见的绿藻球状聚集体。尽管它分布于北半球的淡水和微咸水中，但球藻群落仅在特定栖息地被发现。在此，我们报告了从日本阿寒湖采集的天然球藻的各种大小和聚集结构内部的细菌群落。我们观察到，仅在直径大于20厘米的大型辐射型球藻中存在由沉积物颗粒组成的多层结构，而在缠结型球藻中则没有。深层富含潜在的硫氧化细菌和硫酸盐还原细菌。多层结构中的微生物会形成包含附近沉积物的生物膜，这将在大型辐射型球藻中起到微生物“密封”的作用。这些发现为解读濒危球藻的生长提供了线索。
