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Animal carcasses introduce large amounts of nitrates and ammonium into the soil ecosystem. Some of this ammonium is transformed from nitrite through the nrfA-type microbial community. However, it is unclear how nrfA-type microorganisms respond to the decomposition of corpses. This study applied high-throughput sequencing to characterize the ecological succession of nrfA-type microbial communities in grassland soil. Our results showed that Cyclobacterium and Trueperella were the predominant genera for nrfA-type communities in soil with a decomposing corpse (experimental group), while Cyclobacterium and Archangium were dominant in soil without a corpse (control group). The alpha diversity indexes and the resistance and resilience indexes of the microbial communities initially increased and then decreased during decomposition. Compared with the control group, nrfA-encoding community structure in the experimental group gradually became divergent with succession and temporal turnover accelerated. Network analysis revealed that the microbial communities of the experimental group had more complex interactions than those of the control groups. Moreover, the bacterial community assembly in the experimental group was governed by stochastic processes, and the communities of the experimental group had a weaker dispersal capacity than those of the control group. Our results reveal the succession patterns of the nrfA-type microbial communities during degradation of wild animal corpses, which can offer references for demonstrating the ecological mechanism underlying the changes in the nrfA-type microbial community during carcass decay. Key points: • Corpse decay accelerates the temporal turnover of the nrfA-type community in soil. • Corpse decay changes the ecological succession of the nrfA-type community in soil. • Corpse decay leads to a complex co-occurrence pattern of the nrfA-type community in soil. [ABSTRACT FROM AUTHOR]

Corpse decomposition is a key process of the biogeochemical cycle in natural ecosystems, in which denitrification takes part. Denitrification is the process of nitrogen transformation which converts nitrate into nitrogenous gas. Nevertheless, the response and succession patterns of the denitrification communities during cadaver decomposition are largely unknown. To address this gap, we investigated the succession of the narG -encoding denitrifying communities during the decomposition process of wild animals (plateau pika) corpses using high-throughput Miseq sequencing. Our results showed that soil TP significantly accumulated in response to long-term cadaveric decomposition and could not be restored to control levels. But the abundance of many genera (e.g., Thiohalorhabdus , Acidovorax , Caballeronia) exhibited quadratic curvilinear recovery patterns during the cadaver decomposition. The alpha diversity also showed strong resilience and resistance to the cadaver decomposition. However, corpse decay led to the structural separation of the denitrifying communities with succession and increased the temporal turnover rate of the narG -type denitrifiers. The migration of the narG denitrification community was gradually limited during the cadaver decomposition. Moreover, the networks of the cadaver groups were more connected and complex than those of the control groups. Incubation time, cadaver decomposition, total carbon, and ammonium nitrogen were the most important factors driving the narG denitrification communities. These results suggest that denitrifying communities have a strong response to the decomposition of wild animal carcasses in soil habitats. This experiment provides a new view of the effect of wild animal corpse decomposition on the succession of denitrifying communities. [Display omitted] • The narG -type denitrifiers show divergent succession during corpse decomposition. • Carcass decomposition increased the temporal turnover rate of narG denitrifiers. • Corpse decomposition limited the migration of the narG denitrification communities. • Incubation time and corpse decay affected the narG denitrifiers mostly. [ABSTRACT FROM AUTHOR]

As a common natural phenomenon, corpse decomposition may lead to serious environmental pollution such as nitrogen pollution. However, less is known about antibiotic resistance genes (ARGs), an emerging contaminant, during corpse degradation. Here, ARGs and microbiome in three soil types (black, red and yellow soil) have been investigated between experimental and control groups based on next-generation sequencing and high-throughput quantitative PCR techniques. We found that the absolute abundance of total ARGs and mobile genetic elements (MGEs) in the experimental groups were respectively enriched 536.96 and 240.60 times in different soil types, and the number of ARGs in experimental groups was 7–25 more than that in control groups. For experimental groups, the distribution of ARGs was distinct in different soil types, but sulfonamide resistance genes were always enriched. Corpse decomposition was a primary determinant for ARGs profiles. Microbiome, NH 4 + concentrates and pH also significantly affected ARGs profiles. Nevertheless, soil types had few effects on ARGs. For soil microbiome, some genera were elevated in experimental groups such as the Ignatzschineria and Myroides. The alpha diversity is decreased in experimental groups and microbial community structures are different between treatments. Additionally, the Escherichia and Neisseria were potential pathogens elevated in experimental groups. Network analysis indicated that most of ARGs like sulfonamide and multidrug resistance genes presented strong positively correlations with NH 4 + concentrates and pH, and some genera like Ignatzschineria and Dysgonomonas were positively correlated with several ARGs such as aminoglycoside and sulfonamide resistance genes. Our study reveals a law of ARGs' enrichment markedly during corpse decomposing in different soil types, and these ARGs contaminant maintaining in environment may pose a potential threat to environmental safety and human health. [Display omitted] • Corpse decomposition changes soil environment. • Corpse decomposition causes the accumulation of ARGs in all soil types. • Soil types have few impact on ARGs. • Treatment, microbiome, NH 4 + concentrates and pH are primary determinants. • ARGs are correlated with integrons, NH 4 +, pH and microbes during corpse decay. [ABSTRACT FROM AUTHOR]

Animal carcass decay produces many poisonous metabolites and chemical pollutants, which pose potential ecological risks to the aquatic environment and human health. However, the effects of animal cadaver decomposition on high-risk antibiotic resistance genes (ARGs) and potential pathogens in different water types are still unknown. In this study, fifteen freshwater economic fish (Carassius auratus) corpses were put into three types of water (i.e., pond water, tap water, and domestic sewage) for a 100-day decomposition. Next generation sequencing and HT-qPCR were used to illustrate how corpse decomposition affected microbial communities and ARG profiles. Our results revealed that fish corpse degradation caused similar resistomes and microbiome in different water types. MLSB (Macrolide-Lincosamide-Streptogramin B), β-lactamase, sulfonamide, tetracycline resistance genes and transposase genes in the experimental groups were increased. Among them, tetracycline resistance genes were enriched by 224 to 136,218-fold during the process of corpse degradation. Furthermore, high-risk ARGs (ermB , floR and dfrA1), which resist to MLSB, multidrug and sulfonamide respectively, were significantly enriched in the cadaver groups and had co-occurrence patterns with opportunistic pathogens, such as Bacteroidetes , which was more than 37 times in carcass groups than that in control groups. The study is able to draw a general conclusion that cadaver decomposition of freshwater economic fish deteriorates the aquatic environment by affecting high-risk ARGs and pathogenic microorganisms regardless of water types, which poses potential threats to human health. Therefore, timely management and treatment of animal carcasses is of great significance to the protection of water environment. [Display omitted] • Fish corpse degradation caused similar resistomes and microbiome in different water types. • Fish cadaver decomposition led to enrichment of opportunistic pathogens and high-risk ARGs. • Corpse decay, microbiomes, MGEs and environment factors primarily affect ARG profiles. • Timely management and treatment of animal carcasses is of great significance to the protection of water environment. [ABSTRACT FROM AUTHOR]

Serious concerns have been raised regarding resistomes caused by corpse decomposition in the aquatic environment, which has posed threats to the water environment and human health. However, antibiotic resistance genes (ARGs) in large-volume tap water and their temporal stability during corpse decay are poorly explored. Here, high-throughput quantitative polymerase chain reaction (HT-qPCR) and amplicon sequencing were applied to profile ARGs and bacterial communities in experimental and control groups containing 50 L of tap water at 7th, 15th and 100th day during corpse decomposition. Our results suggested that most of the ARGs in experimental group had higher abundance compared with the control group independent of time. Some ARGs' absolute abundance like tetracycline and beta-lactamase was even enriched by 259 – 413,640-folds during corpse decay. Twelve opportunistic pathogens, especially Burkholderia , Legionella and Halomonas , remarkably increased as decomposition proceeded. Furthermore, network analysis showed that opportunistic pathogens were significantly associated with ARGs. Our results emphasize that corpse decay increases the abundance and diversity of ARGs in large-volume drinking water independent of time while exhibiting temporal persistence of ARGs, thereby uncovering the harmful effects of animal cadavers. Our study also provides valuable suggestions for the risk assessment and management of source water caused by corpse decay. [Display omitted] ∙ Corpse decay increases the abundance of ARGs in large-volume drinking water ∙ Most of the ARGs remains relative stable abundance over decomposition time. ∙ Twelve opportunistic pathogens were significantly associated with ARGs. ∙ Treatment, dissolve oxygen (DO) and pH were important factors influencing ARGs' spread. [ABSTRACT FROM AUTHOR]