Sediment phosphorus composition across lakes of the Canadian prairie region

The Prairie region of Canada is a key agricultural region of the nation, but one with important stressors impacting water quality and security. Within the prairies, rates of internal phosphorus (P) loading and trophic status of lakes are known to be high, and cyanobacterial blooms are common, owing in part to nutrient-rich soils, human activities in the watersheds, and often shallower lakes. However, there is important variation in the region in trophic status, internal loading, and sediment geochemistry. We characterized the variation in lake sediment composition, water chemistry, lake and watershed attributes expected to affect sediment P cycling within the prairie region (the southern portion of the provinces of Manitoba, Saskatchewan, and Alberta; Boreal Plains and Prairies Ecozones). We aim to help understand what drives variation in sediment P speciation, and porewater SRP. Multiple attributes expected to affect P cycling varied substantively between the two ecozones (e.g., lake t..., Field sampling was conducted during the summer of 2017, 2018, and 2019 (Huot et al., 2019), using a single sample approach intended as a snapshot of summer variability. In sum, we present data from 60 lakes for sediment P sequential fractionation, 58 lakes for select dissolved ions, 32 lakes for sediment porewater soluble reactive P (SRP), and 29 lakes for select sediment trace metals (Fig. 1). Porewater and trace metal analyses were restricted based on sampling time and cost (due to lab access limitations during the pandemic). These samples were selected using a stratified random sampling approach applied by LakePulse (Huot et al. 2019), with select samples missing due to shipping or lab issues. Water column sampling Water samples were collected at an ‘index site’ (usually in the deepest part of the lake). We collected the surface water samples within the euphotic zone (estimated with a Secchi disk) with a 2-metre-long integrated tube sampler (Huot et al., 2019; Canadian Lake Pulse Net..., # Sediment phosphorus composition across lakes of the Canadian prairie region Dataset DOI: [10.5061/dryad.5mkkwh7kt](https://doi.org/10.5061/dryad.5mkkwh7kt) ## Description of the data and file structure Data were collected as part of the NSERC Lake Pulse Network, a National lake assessment. Hundreds of lakes were sampled across the majority of Canadian ecozones, and about 100 variables were measured for each lake. The data shared here represent only the lakes from the prairie region. We also included the geospatial data (downloaded from public sources). ### Files and variables #### File: Manuscript_Data.csv **Description:** Missing values are indicated by blank cells. Units of variables are within parenthesis. The \"epi\" and \"hypo\" prefixes indicate samples from the epilimnium and hypolimnium respectively). The geospatial variables (e.g., agriculture, forestry, mines, chernozemic, luvisolic, glacial sediments) are presented as area (Km2) and the percentage area (%) occupied in th..., ,