Organic Matter Supply Triggers Rapid Microbial-Driven Changes in Carbon and Nitrogen Cycling in Subterranean Estuary Sediments: A continuous investigation using flow-through reactors

To investigate carbon transformations and the coupling between carbon and nitrate reactivity in subterranean estuaries, laboratory flow-through reactor experiments were conducted with permeable sandy sediments from Sanggou Bay, China. These included a control and five experimental treatments with different dissolved carbon sources (~500 μM final concentration), including fucoidan, chitosan, oligosaccharide, Phragmites australis extracts, and Laminaria japonica extracts. After 48 h incubation, ca. 80 μM nitrate (NO3-) was added in all treatments to further identify carbon-nitrogen coupling in STEs. Our study involved continuous monitoring of water and sediment samples across all phases of cultivation.