Temporal distributions and environmental adaptations of two types of multicellular magnetotactic prokaryote in the sediments of Lake Yuehu, China.

Two morphotypes (spherical and ellipsoidal) of multicellular magnetotactic prokaryotes (MMPs) have been reported from the sediments of Lake Yuehu, China. Here, their temporal distributions and their relationships with biogeochemical parameters are studied. Samples were collected at approximately 2-week intervals from two sites (A and B) during the period September 2012 to December 2013. The abundance of MMPs was high in summer and autumn, but low in winter and spring. Furthermore, the peaks in the numbers of the two types of MMPs were sequential, with the highest concentration of the spherical MMPs occurring prior to that of the ellipsoidal MMPs. This may be related to different optimal growth temperatures for the two types. Although the two types of MMP coexisted at both sites, their numbers were different; at most times, spherical MMPs dominated at site A, whereas ellipsoidal MMPs dominated at site B. Geochemical analysis revealed that the environmental conditions at site A varied more than at site B. Compared with the widely distributed spherical MMPs, ellipsoidal MMPs seemed to prefer more stable habitats. This is the first report of the temporal distribution of ellipsoidal MMPs in sediments, suggesting that their environmental adaptations differ from those of spherical MMPs.