The microbial shift during the decomposition of Cambarellus diminutus in lake-water and – sediment under different environmental conditions

During the decomposition of crustaceans, a precipitation of calcite or aragonite crystal clusters precipitate composed out of calcite or aragonite were detected in several taphonomic experiments, up toresulting in the transformation mineralisation of organic tissue (e.g. muscles, digestive gland) into calcite or apatite . This mineralisation process, which might lead to the fossilisation of soft tissue and especially Tthe influence role of bacterial activity in these decay and mineralisation processes is something like an unknown “black box”is not well defined. This study Here, controlled taphonomic experiments were performed to is the first experimental approach that analyses the shifts in bacterial community composition in correlation to the different stages of decay and preservation, using 16S-rRNA amplicon analysisand the decay or preservation patterns in controlled taphonomic experiments with 16S-rRNA amplicon analysis. Precipitated minerals were analysed by µ-CT observation, SEM and Raman spectroscopy. Three dominating genera; , Aeromonas, Clostridium and Acetobacteroides, could bewere identified as the main drivers in the decomposition of crayfish in our freshwater experiments. Proteocatella sphenisci as the only known representative species of the genus Proteocatella, seems to play an important role in mineral precipitation. Using µ-CT measurements and scanning electron microscopy, crystal clusters were detected after three to four days and were identified as calcite by Raman spectroscopy. The presence of the genus Proteocatella was correlated with a stronger mineral precipitation.Precipitated minerals were analysed by µ-CT observation, SEM and Raman spectroscopy.

在甲壳类动物分解过程中，多项埋藏学（taphonomic）实验均检测到由方解石（calcite）或文石（aragonite）构成的晶体簇沉淀，该过程可将肌肉、消化腺等有机组织转化矿化为方解石或磷灰石（apatite）。这类矿化过程可能引发软组织的化石作用，而细菌活动在上述腐烂与矿化过程中所扮演的角色，至今仍是一个尚未被清晰界定的未知“黑箱”。本研究开展受控埋藏学实验，作为首个结合16S核糖体RNA扩增子分析（16S-rRNA amplicon analysis），探究细菌群落组成随腐烂、保存各阶段变化的研究，同时分析受控埋藏学实验中的腐烂与保存模式。沉淀矿物通过显微CT（µ-CT）观察、扫描电子显微镜（SEM）与拉曼光谱（Raman spectroscopy）进行分析。在淡水螯虾（crayfish）分解实验中，气单胞菌属（Aeromonas）、梭菌属（Clostridium）与乙酸杆菌属（Acetobacteroides）这三个优势菌属被确定为分解过程的主要驱动因子。普罗特卡特菌属（Proteocatella）目前仅知的代表物种斯氏普罗特卡特菌（Proteocatella sphenisci），似乎在矿物沉淀过程中发挥着重要作用。通过显微CT测量与扫描电子显微镜观察，研究团队在实验开展3至4天后检测到晶体簇，并通过拉曼光谱鉴定其为方解石。普罗特卡特菌属的存在与更强的矿物沉淀呈显著相关。沉淀矿物通过显微CT观察、扫描电子显微镜与拉曼光谱进行分析。