Effects of methyl bromide fumigation on anhydrobiotic micrometazoans

Anhydrobiotic organisms are well known for their resistance to extreme environmental conditions while in the inactive, ametabolic, state. This study confirms that this resistance also transfers to treatments with the fumigant methyl bromide. Live specimens of nematodes, rotifers, and tardigrades were found after 70 h of treatment with methyl bromide. Quantitative estimates of survival in the eutardigrade Richtersius coronifer revealed no difference between treated and untreated samples which had been kept dry for a short time. However, R. coronifer from samples collected 11 months before treatment had lower survival compared to samples collected shortly before the treatment. The fact that anhydrobiotic organisms escape treatments with biocides should be considered a serious problem, both for the food industry and from the perspective of human-mediated spread of organisms.