Coupling between Sediment and Water Column Populations of Ammonia Oxidizing Thaumarchaeota in the Duplin River near Sapelo Island, Georgia

Populations of nitrifying organisms in the water column at Marsh Landing display a midsummer peak in the abundance of ammonia oxidizing Archaea (AOA) at the site, coinciding with a peak in nitrite concentration. Marsh Landing is at the mouth of the Duplin River, a dead-end tidal channel that drains an extensive area of salt marsh. While the lower Duplin River at Marsh Landing exchanges tidally with Doboy Sound and thus South Atlantic Bight (SAB) coastal waters, water in its upper reaches has a residence time of weeks. The work reported here had two goals: 1) test the hypothesis that the surrounding salt marsh is the source of nitrifiers seen in water samples taken at Marsh Landing; and 2) compare the seasonal dynamics of nitrifiers in surficial sediments with those in the water column. We sampled 6 stations along the ~20 km length of the Duplin River. We collected surface water samples (~0.20 m) at low- to mid-tide, monthly from April-December 2014. Sediment samples (top 1 cm) were collected at the same time from unvegetated creek bank at 2 locations on the Duplin River and from 4 locations spanning the creek bank-to-upland gradient of the saltmarsh accessible from the Teal Boardwalk. The abundance of ammonia oxidizing Archaea, Marine Group 1 Archaea (Thaumarchaeota), ammonia oxidizing Betaproteobacteria (AOB), Bacteria and Nitrospina, a nitrite oxidizing bacterium, were determined by quantitative PCR (qPCR) of DNA extracted from the samples. This data set contains the abundance estimates from April to December 2014 for sediment and water column samples, with corresponding water quality measurements (temperature, salinity and nitrogenous nutrient concentrations).