Integrating microbiome responses across warming experiments in coastal marshes

Coastal marshes are critical carbon sinks in the global carbon system, yet rising temperatures may alter microbial processes that regulate carbon and nutrient cycling. In a recent ex-situ warming experiment conducted in the Climate Change Marsh Mesocosm Facility (CCMMF) at the University of Hamburg, Germany, we could show that warming can alter soil microbial communities, and that responses vary with environmental context, such as plant community diversity and ecosystem age. We also found that warming favored microbial taxa with traits supporting plant growth and nutrient cycling. Here, we expanded our analysis and included microbial 16S rRNA gene sequencing data sets from two in-situ coastal marsh warming experiments: MERIT (“Marsh Ecosystem Response to Increased Temperatures”) in northern Germany and SMARTX (“Salt Marsh Accretion Response to Temperature eXperiment”) in a brackish marsh on Chesapeake Bay, USA. By this, we combined three genetic microbial data sets of coastal marshes characterized by different soil type, ecosystem age, vegetation type, tidal regime, and soil carbon and nitrogen stocks.We will show how warming-induced shifts in microbial community relate to ecological parameters across sites building on the hypothesis that microbial responses to warming vary strongly with vegetation composition and ecosystem age. With this meta study, we will be able to identify key factors controlling microbial responses to experimentally increased temperatures to better understand how climate change reshapes microbial composition and thereby carbon dynamics in coastal wetlands.