Temporal dynamics of the diazotrophic community during corpse decomposition

Corpse decomposition is a complicated and dynamic process accompanied by multiple chemical and biochemical reactions, and it is prevalent in aquatic and terrestrial environments (Lauber et al. 2014 ; Mcalpine 2016 ). Microorganism plays an indispensable role in this natural process as decomposers in ecosystems. In terrestrial ecosystems, the decomposition process of animal carcasses with the participation of microorganisms is divided into six steps: fresh, bloated, active decay, advanced decay, dry, and remains (Zeariya et al. 2015 ). In turn, corpse decomposition affects the microbial community in soil adjacent to the carcass (i.e., gravesoil) by eliciting changes in soil substrate conditions, and this phenomenon can be explained well by the “cadaver decomposition island” (CDI) (Carter et al. 2007 ). On the one hand, the water and mineral ions in CDIs will change the moisture and salinity of surrounding soil, and the effects of these two factors on microorganisms have been reported previously (Dissanayake et al. 2022 ; Vallejos et al. 2022 ). On the other hand, unlike plant litters providing major carbon source for soil (Schneider et al. 2012 ), animal carcasses are rich in nutrients such as protein and lipids; they can not only provide carbon source for soil but also undoubtedly input abundant nitrogen into soil habitats, allowing for the obligatory selection of microorganisms capable of degrading carbon and nitrogen-related organic matter, which influences the microbial profiles in the soil to a large extent (Metcalf et al. 2016 ). Numerous studies have reported that carbon and nitrogen input could change the structure and diversity of soil microbial communities (Jia et al. 2022 ; Rong et al. 2022 ). CDI is regarded as an intense and ephemeral nutrient pulse in soil, and its contributions to underground organisms cannot be overlooked (Olakanye et al. 2014 ). Particularly, current knowledge about the influences of corpse decomposition on microbial communities with specific ecosystem functions (such as biological nitrogen fixation) still requires further exploration.