Crocosphaera as a Major Consumer of Fixed Nitrogen
Document Type
Article
Date of Original Version
8-1-2022
Abstract
Crocosphaera watsonii (hereafter referred to as Crocosphaera) is a key nitrogen (N) fixer in the ocean, but its ability to consume combined-N sources is still unclear. Using in situ microcosm incubations with an ecological model, we show that Crocosphaera has high competitive capability both under low and moderately high combined-N concentrations. In field incubations, Crocosphaera accounted for the highest consumption of ammonium and nitrate, followed by picoeukaryotes. The model analysis shows that cells have a high ammonium uptake rate (;7 mol N [mol N]21 d21 at the maximum), which allows them to compete against picoeukaryotes and nondiazotrophic cyanobacteria when combined N is sufficiently available. Even when combined N is depleted, their capability of nitrogen fixation allows higher growth rates compared to potential competitors. These results suggest the high fitness of Crocosphaera in combined-N limiting, oligotrophic oceans heightening its potential significance in its ecosystem and in biogeochemical cycling.
Publication Title, e.g., Journal
Microbiology Spectrum
Volume
10
Issue
4
Citation/Publisher Attribution
Masuda, Takako, Keisuke Inomura, Taketoshi Kodama, Takuhei Shiozaki, Satoshi Kitajima, Gabrielle Armin, Takato Matsui, Koji Suzuki, Shigenobu Takeda, Mitsuhide Sato, Ondřej Prášil, and Ken Furuya. "Crocosphaera as a Major Consumer of Fixed Nitrogen." Microbiology Spectrum 10, 4 (2022). doi: 10.1128/spectrum.02177-21.