Bacteria rather than fungi mediate the chemodiversity of dissolved organic matter in a mudflat intertidal zone

Sediment samples were collected from a mudflat intertidal zone (120.75 °E, 36.46 °N) located in Qingdao, China. A nested sector sampling scheme was designed to investigate the DOM chemodiversity and its associations with biotic and abiotic factors. Specifically, the circular center of the sector (quarter circle) was located on the mudflat between the highest and lowest tide levels, and the radii of the nested sectors were 5m, 10m, 20m, 50m, 100m and 200m. A total of 13 sediment samples were collected after the tide had retreated when the sediment was exposed to the air. For each sample, five surface sediment cores (~15 cm depth) were collected, homogenized and immediately placed in ice boxes before transporting to the laboratory. The chemical composition of DOM was determined by SPE-ESI for 13 samples.