Evolution of microbial dynamics with the introduction of real seawater portions in a low-strength feeding anammox process

Abstract

The salinity effect on anammox bacteria has been widely reported; however, rare studies describe the microbial dynamics of anammox-based process response to the introduction of real seawater at mainstream conditions. In this study, an anammox process at mainstream conditions without pre-enriching anammox bacteria was shifted to the feeds of a synthetic wastewater with a portion of seawater mixture. It achieved over 0.180 kg-N/(m 3 day) of nitrogen removal rate with an additional seawater proportion of 20% in the influent. The bacterial biodiversity was significantly increased with the increase of seawater proportions. High relative abundance of anammox bacteria (34.24-39.92%) related to Ca. Brocadia was enriched and acclimated to the saline environment. However, the introduction of seawater caused the enrichment of nitrite-oxidizing Ca. Nitrospira, which was responsible for the deterioration of nitrogen removal efficiency. Possible adaptation metabolisms in anammox bacteria and other nitrogen transforming bacteria are discussed. These results highlight the importance of microbial diversity for anammox process under the saline environments of 20% and 40% seawater composition.

Melon/cowpea intercropping pattern influenced the N and C soil cycling and the abundance of soil rare bacterial taxa

“…Bacteria have been linked to C acquisition strategies and their interactions can contribute to soil stabilization through the biopolymers they exuded (Chenu, 1989;Deng et al, 2015) which act as binding agents in which bacteria are causal factors in enhancing soil aggregation (Lehmann et al, 2017). It highlighted the changes in those members contributing to the "rare biosphere" (Pascoal et al, 2021) increasing the sensitivity of detecting effects on microbiomes as having been observed by other studies (Jiao and Lu, 2020a;Ji et al, 2020), where they suggested that abundant taxa play a dominant role in the stability and maintenance of agro-soils whereas rare taxa have a high influence under environmental disturbances (Jiao and Lu, 2020b). In our study, the increase in bacterial diversity (Supplementary Table S1, Figure 2) was due principally to the increase of rare bacterial diversity (oligotrophic and synergistic bacteria) instead of the most abundant (copiotrophics and competitive) bacteria, as was observed by Liu et al (2022).…”