Fungal Colonization on Body Surfaces of Dead South American Sea Lions on Sandy Beaches, and an Evaluation of Risk of Contamination to Humans at Southern Brazil

Abstract

At the interface between public health and marine ecology, there is a knowledge gap concerning the extent to which the carbon that enters sandy sediments when large biomass marine mammals decompose changes the sediment, bringing risks to human health. This study aimed to: 1) identify the fungal microbiota present in decomposing carcasses of South American sea lions (Otaria flavescens) found on beaches on the coast of southern Brazil, and 2) verify the extent to which the fungal microbiota are dispersed in the sandy sediment around the carcasses, presenting risks to human health. Samples of the corporal surface of 10 carcasses of O. flavescens deposited on beaches along the southern coast of Brazil, in a moderate decomposition state, as well as of the sand around the carcasses, were collected for analysis. Fungal microbiota was identified to genus level based on their macro-and micro-morphological characteristics.From carcasses were identified: Trichoderma, Aspergillus, Penicilium, Cladosporium and Fusarium. Aspergillus and Cladosporium were the most frequently taxa in the sand around the carcasses and in the control samples. Furthermore, their distribution around the carcasses was not compatible with the findings of fungi from the respective parts of the body, suggesting that these microorganisms were of a marine origin, and that their presence in the sand is not exclusively associated with the presence of the carcasses. The presence of Aspergillus in the carcass and sandy sediment reaffirms its regional distribution and the human risk due to dispersion of the spores from carcasses caused by wind.