anoxie

CONT: [...] le déversement des eaux de la Durance a occasionné l'apparition d'un phénomène de manque d'oxygénation (anoxie) des eaux profondes du fait de la stratification de l'eau salée (au fond de l'étang) et de l'eau douce (en surface) [qui a causé] de graves dommages pour la flore et la faune de l'étang de Berre […]

CONT: Phosphorous is a fertilizer that induces plant growth and algae and was also found in many commercial detergents at the time. Plants began growing, dying and decomposing in Lake Erie, creating anoxia (severe deficiency of oxygen) at the bottom of the lake and leaving the water's surface putrid and mossy.
OBS: Anoxic conditions can develop in a lake bottom when oxygen is depleted by decomposition processes. This often happens in eutrophic lakes and can result in fish kills.