Sinking Trichodesmium fixes nitrogen in the dark ocean.

ABSTRACT: The photosynthetic cyanobacterium Trichodesmium is widely distributed in the surface low latitude ocean where it contributes significantly to N₂ fixation and primary productivity. Previous studies found nifH genes and intact Trichodesmium colonies in the sunlight-deprived meso- and bathypelagic layers of the ocean (200-4000 m depth). Yet, the ability of Trichodesmium to fix N₂ in the dark ocean has not been explored. We performed ¹⁵N₂ incubations in sediment traps at 170, 270 and 1000 m at two locations in the South Pacific. Sinking Trichodesmium colonies fixed N₂ at similar rates than previously observed in the surface ocean (36-214 fmol N cell^-1 d^-1). This activity accounted for 40 ± 28% of the bulk N₂

SUBMITTER: Benavides M 

PROVIDER: S-EPMC9478103 | biostudies-literature | 2022 Oct

REPOSITORIES: biostudies-literature