AME 86:1-19 (2021) - DOI: https://doi.org/10.3354/ame01954
Nitrogen cycling in coastal sediment microbial communities with seasonally variable benthic nutrient fluxes
Alexis J. Marshall1,2,5,*, Andrew Longmore3, Lori Phillips2,6, Caixian Tang1, Helen L. Hayden2, Karla B. Heidelberg4, Pauline Mele1,2
ABSTRACT: Benthic microbial communities contribute to nitrogen (N) cycling in coastal ecosystems through taxon-specific processes such as anammox, nitrification and N-fixation and community attributed pathways such as denitrification. By measuring the total (DNA-based) and active (RNA-based) surface sediment microbial community composition and the abundance and activity profiles of key N-cycling genes in a semi-enclosed embayment—Port Phillip Bay (PPB), Australia—we show that although the total relative abundance of N-cycling taxa is comparatively lower close to estuary inputs (Hobsons Bay [HB]), the capacity for this community to perform diverse Ncycling processes is comparatively higher than in sediments isolated from inputs (Central PPB [CPPB]). In HB, seasonal structuring of the sediment microbial community occurred between spring and summer, co-occurring with decreases in the activity profiles of anammox bacteria and organic carbon content. No changes were detected in the activity profiles of nitrifiers or the community-based pathway denitrification. Although no seasonal structuring of the sediment microbial community occurred in CPPB, the activity profiles of key N-cycling genes displayed comparatively higher within-site variability. These results show that despite N-cycling taxa representing a smaller fraction of the total community composition in estuary impacted sediments (HB) these microbial communities consistently engage in N-cycling processes and that seasonal instability in the composition of this community is not reflective of changes in its capacity to cycle N through coupled nitrification-denitrification but potentially via changes within the anammox community.
KEY WORDS: 16S rDNA · Coastal sediment · Nitrogen cycling · Seasonal variability · Spatial microbial variation · Temporal microbial variation
Full text in pdf format  Supplementary material | Cite this article as: Marshall AJ, Longmore A, Phillips L, Tang C, Hayden HL, Heidelberg KB, Mele P
(2021) Nitrogen cycling in coastal sediment microbial communities with seasonally variable benthic nutrient fluxes. Aquat Microb Ecol 86:1-19. https://doi.org/10.3354/ame01954
Export citation Share: Facebook - - linkedIn |
| Next article |