Positive Priming Effects Induced by Allochthonous and Autochthonous Organic Matter Input in the Lake Sediments With Different Salinity

Ecological consequences of the increased input of allochthonous and autochthonous organic matter (OM) remains unknown in saline lakes. Here, we reported microbial mineralization of algal and grass OM (represented by autochthonous and allochthonous OM, respectively) in lake sediments with different salinity (1, 40, and 120 g L-1). The addition of algal and grass OM significantly increased the CO2 production rates in the studied sediments. Algal and grass OM input can induce positive priming effect (PE). PE intensity induced by grass OM input was significantly higher than that by algal OM input. PE intensity induced by algal and grass OM input decreased with increasing salinity. Bacterial taxa affiliated with Actinomycetia, Alphaproteobacteria, Bacilli, Bacteroidia, Clostridia, and Gammaproteobacteria played important roles in driving PE generation in the studied sediments. Our finding suggested that the PEs induced by allochthonous and autochthonous OM should be considered in saline lakes that are intensively influenced by climate change.

Automated summary

The microbial mineralization of algal and grass organic matter in lake sediments with different salinity levels was investigated. The addition of algal and grass organic matter significantly increased CO2 production rates in the sediments. The intensity of positive priming effect induced by grass organic matter was higher than that induced by algal organic matter. The intensity of positive priming effect induced by both algal and grass organic matter decreased with increasing salinity.