Abstract
Microbial ammonia oxidation plays a central role in nitrogen cycling. Hitherto, four types of autotrophic ammonia-oxidizing microorganisms are identified, including aerobic ammonia-oxidizing archaea (AOA), aerobic partial-nitrification ammonia-oxidizing bacteria (parAOB), aerobic complete-nitrification AOB (comAOB), and anaerobic AOB (AnAOB). However, revelation and comparison of the active ammonia-oxidizing community in the marine sponges and their ambient environments is scarce. Here, transcribed ammonia oxidation phylomarker gene amoA of AOA, parAOB, and comAOB and hzsB of AnAOB were amplified to investigate the active ammonia-oxidizing populations in a representative marine sponge Cinachyrella australiensis, ambient seawater, and sediment niches. Ammonia-oxidizing population in C. australiensis consists of AOA, parAOB, and AnAOB, significantly different from that in seawaters comprising of AOA and in sediments containing AOA, parAOB, comAOB, and AnAOB. The quantitative assay demonstrates that AOA amoA transcripts are exclusively detectable or higher in abundance than parAOB amoA, comAOB amoA, or AnAOB hzsB transcripts by orders of magnitude in C. australiensis, seawater, and sediment niches. This transcript-based analysis clarifies the remarkable niche differentiation of putatively active ammonia-oxidizing microbiota in C. australiensis and the ambient environments. Such a work further contributes to the understanding of in situ active ecological functions of sponge microsymbionts in nitrogen cycling.
Transcriptional Activity of Aerobic and Anaerobic Ammonia-Oxidizing community in the Intertidal Sponge Cinachyrella Australiensis, Ambient Seawater, and Sediment
