Yukon-Kuskokwim Delta, Alaska unburned and burned aquatic data, 2022

The Yukon-Kuskokwim Delta (YKD) in southwestern Alaska in the discontinuous permafrost region is undergoing rapid change as a result of climate warming and disturbance. This area is made up upland peat plateau tundra interspersed with patchwork steams, fens, ponds, and lakes. In 2015, a tundra wildfire burned more than 541.54 square kilometers (km2) in the YKD. In 2022, a research team conducted terrestrial and aquatic studies to determine wildfire and permafrost thaw effects on carbon and nutrient cycling and vegetation change. This aquatic data set includes surface water collected from unburned and burned (2015 wildfire) small ponds, fens, and streams. The water samples were analyzed for dissolved organic carbon (DOC), total dissolved nitrogen (TDN), deuterium and oxygen-18 (O-18) isotopes, and chromophoric dissolved organic matter (CDOM). CDOM indices calculated include a250, A254, a350, a375, the log transformed spectral slope in the 275-295 nanometer (nm) region, slope ratio, and specific ultraviolet absorbance (SUVA). Field measurements at the location where each sample was collected include temperature, pressure, pH, conductivity, dissolved oxygen (DO), oxidation reduction potential (ORP), and dissolved carbon dioxide (CO2) and methane (CH4) fluxes. At two of the ponds (one unburned and one burned) where samples were collected, a dissolved CO2 probe (eosense eosGP) and temperature/light sensor was deployed 1 meter below the surface to collect half hourly carbon dioxide (CO2) concentrations, temperature, and photosynthetically active radiation (PAR).