Fig. 3.

In situ nitrogenase activity of microbial mats and streamers

A, Ethylene production after the in situ incubation of microbial mats and streamers. One to 17 were different vials containing microbial mats collected at the Wall Site (WS), and 18 to 20 were streamers collected at the Stream Site (SS). One to three and 18 to 20, four to 11, and 12 to 17 were collected on July 22, August 4, and November 8, 2016, respectively. B, A plot of ethylene production shown in A (1–17) versus methane production.