Sediment texture and nutrient data from: Bacterial assembly in agricultural streams

Agriculture is the most dominant land use globally and is projected to increase in the future to support a growing human population but also threatens ecosystem structure and services. Bacteria mediate numerous biogeochemical pathways within ecosystems. Therefore, identifying linkages between stressors associated with agricultural land use and responses of bacterial diversity is an important step in understanding and improving resource management. Here, we use the Mississippi Alluvial Plain (MAP) ecoregion, a highly modified agroecosystem, as a case study to better understand agriculturally-associated drivers of stream bacterial diversity and assembly mechanisms. In the MAP, we found that planktonic bacterial communities were strongly influenced by salinity. Tolerant taxa increased with increasing ion concentrations, likely driving homogenous selection which accounted for ~90% of assembly processes. Sediment bacterial phylogenetic diversity increased with increasing agricultural land us..., Prior to analyses, sediments were dried, ground, and pre-sieved through a 2 mm sieve to remove any coarse material. We measured sediment P (Sed P) concentrations using a Melich-3 extraction method. Briefly, 1 g of dried sediment was digested using an extract composed of 0.2 M acetic acid, 0.25 M ammonium nitrate, 0.015 M ammonium fluoride, 0.013 M nitric acid, and 0.001 M ethylene diamine tetraacetic acid. Phosphorus content of extracted sediment samples was then determined using the standard ascorbic-ammonium molybdate method using a MULTISKAN SkyHigh microplate reader (Thermo Scientific). We determined percent carbon (C) and N of 1 g of dried sediment using a CN analyzer (Elementar). We determined sediment texture and particle size distribution using a digital hydrometer and the integral suspension pressure method (ISP+) (Pario, METER AG, Munich) following manufacture protocols (see Durner and Iden 2021 for theory). Briefly, dried sediments were shaken overnight in 5% Sodium Hexametap...,