Have decades of abiotic studies in sediments been misinterpreted?

N. Layglon (1) , Benjamin Misson (1) , Stéphane Mounier (1) , Véronique Lenoble (1) , Dario Omanović (2) , Cédric Garnier (1)

1 MIO - Institut méditerranéen d'océanologie
2 Rudjer Boskovic Institute [Zagreb]

Sterilization techniques are largely employed to distinguish biotic and abiotic processes in biogeochemical studies as they inhibit microbial activity. Since one century, chemical sterilizers, supposed to preserve original environmental samples, have taken precedence over physical sterilization techniques considered too destructive. Sodium azide (NaN3) is nowadays the most commonly used inorganic chemical sterilizer. It is sufficiently purified to study trace metals, as well. Nevertheless, its (in)activity in physico-chemical processes was never ascertained. Through the investigation of sediment resuspension in seawater, the present work unequivocally demonstrated that NaN3 can impact carbon and trace metals' transfers by altering the redox balance and pH. Unlike decades of blind practice, NaN3 should be used with great care to track abiotic processes from organic matter rich and reductive matrices.

Mots clés: Metals; Organic matter; Impact; Mixing; Sediment; Sodium Azide

Domaines: Sciences de l'environnement; Géochimie

N. Layglon, Benjamin Misson, Stéphane Mounier, Véronique Lenoble, Dario Omanović, et al.. Have decades of abiotic studies in sediments been misinterpreted?. Science of the Total Environment, 2020, 707, pp.135949. ⟨10.1016/j.scitotenv.2019.135949⟩. ⟨hal-02409414⟩