1. Cadmium effects on net N2O production by the deep-sea isolate Shewanella loihica PV-4.
- Author
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Pizarro, Leonor, Magalhães, Catarina, Almeida, C Marisa R, Carvalho, Maria de Fátima, and Semedo, Miguel
- Subjects
SHEWANELLA ,OCEAN mining ,NITRITE reductase ,ANOXIC zones ,GENE expression ,MICROBIAL communities ,CADMIUM - Abstract
Deep-sea mining may lead to the release of high concentrations of metals into the surrounding seabed, which can disturb important ecosystem functions provided by microbial communities. Among these, the production of N
2 O and its reduction to N2 is of great relevance since N2 O is an important greenhouse gas. Metal impacts on net N2 O production by deep-sea bacteria are, however, currently unexplored. Here, we evaluated the effects of cadmium (Cd) on net N2 O production by a deep-sea isolate, Shewanella loihica PV-4. We performed a series of Cd exposure incubations in oxic conditions and determined N2 O fluxes during induced anoxic conditions, as well as the relative expression of the nitrite reductase gene (nirK), preceding N2 O production, and N2 O reductase gene (nosZ), responsible for N2 O reduction. Net N2 O production by S. loihica PV-4 exposed to Cd was strongly inhibited when compared to the control treatment (no metal). Both nirK and nosZ gene expression were inhibited in reactors with Cd, but nirK inhibition was stronger, supporting the lower net N2 O production observed with Cd. The Cd inhibition of net N2 O production observed in this study poses the question whether other deep-sea bacteria would undergo the same effects. Future studies should address this question as well as its applicability to complex communities and other physicochemical conditions, which remain to be evaluated. [ABSTRACT FROM AUTHOR]- Published
- 2023
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