Processes and microorganisms driving nitrous oxide production in the Benguela Upwelling System

作者：Gabriela Dangl, Claudia Frey, Christiane Hassenrück, Bita Sabbaghzadeh, Janine Wäge, Moritz F. Lehmann, Heide N. Schulz‐Vogt, Jenny Fabian, M. Ley, Gregor Rehder, Klaus Jürgens · 发表于：Limnology and Oceanography · 年份：2025 · DOI：10.1002/lno.12811 · 被引用次数：8 · 研究领域：Microbial Community Ecology and Physiology、Methane Hydrates and Related Phenomena、Marine Bivalve and Aquaculture Studies

Abstract Upwelling systems and their associated oxygen deficient zones (ODZs) are hotspots of nitrous oxide (N 2 O) production in the ocean. The Benguela Upwelling System (BUS) is a highly productive region and an important, yet variable source of N 2 O to the atmosphere. This study examined underlying processes and microbial key players governing N 2 O production in the BUS during the austral winter. 15 N‐tracer incubation experiments were conducted to track N 2 O production from NH 4 + oxidation and denitrification. N 2 O production and consumption mechanisms over a longer temporal scale were determined through natural‐abundance isotope analyses. Metagenomics and 16S rRNA gene amplicon sequencing were used to identify potential key prokaryotes driving N 2 O production. Our results showed that, compared with permanent ODZs, the BUS is characterized by a higher oxidative and a lower reductive N 2 O production, both of which exhibit substantial spatial variability. N 2 O production peaked in low‐oxygen (O 2 ) waters, with nearly equal contributions of oxidative and reductive processes, suggesting their co‐occurrence across an O 2 concentration range broader than previously thought. However, the observed N 2 O isotope signatures implied a legacy of recent and extensive N 2 O reduction to N 2 . Metagenomic and 16S rRNA gene data identified denitrifiers belonging to Thioglobaceae and the archaeal ammonia‐oxidizers Nitrosopumilaceae among the potential key drivers of N 2 O product...