Spatiotemporal and temperature-dependent disconnect between ammonia oxidation and dark DIC fixation in deep oligotrophic Lake Constance.

ABSTRACT: Deep oligotrophic lakes hold over 80% of global lake water. In their hypolimnion, ammonia oxidation (the first step of nitrification) and non-photosynthetic fixation of dissolved inorganic carbon (DIC) are key processes, presumably linked by large populations of ammonia-oxidizing archaea (AOA). We used stable isotope-based activity measurements to follow both processes below the thermocline and in the central hypolimnion in deep oligotrophic Lake Constance. Throughout seasons, they varied substantially below the thermocline peaking at 139.0 NH₄ ⁺ nmol l^-1 d^-1 oxidized and 14.6 nmol DIC l^-1 d^-1 fixed. At the center of the hypolimnion, they were rather stable averaging 7.5 nmol NH₄ ⁺ l^-1 d

SUBMITTER: Bosviel J 

PROVIDER: S-EPMC12642877 | biostudies-literature | 2025 Jan

REPOSITORIES: biostudies-literature