The Grand Calumet River flows through northwestern Indiana and was designated an EPA Area of Concern (AOC) in 1987. There are multiple legacy pollutants in the river including but not limited to heavy metals and PCBs. To investigate potential causes and patterns of eutrophication in the river, water samples were collected for 16S rRNA microbial and eukaryotic 18S rRNA amplicon sequencing during April - September 2021. This data release describes the resulting sequencing data.

The data being released were part of a project funded by the United States Environmental Protection Agency (USEPA). This study sought to identify the bacterial and planktonic communities (cyanobacteria, eukaryotic algae) potentially contributing to eutrophication within the Grand Calumet River Area of Concern (AOC) in northern Indiana along the southern shore of Lake Michigan. In 2021, triplicate water samples were collected from five locations during three events, 4/19/21 and 4/20/21, 7/7/21, and 9/15/21. Water samples were processed and planktonic communities were determined by a DNA-based technology (algal metabarcoding). Sampling locations: 1. Columbia Avenue, Hammond, IN 2. Lake George drainage ditch, Hammond, IN 3. Indiana Harbor Canal at Canal Street in East Chicago, IN 4. Airport Road in Gary, IN 5. Marquette Park Lagoon in Gary, IN

The data being released were part of a project funded by the United States Environmental Protection Agency (USEPA). This study sought to identify the planktonic communities (cyanobacteria, eukaryotic algae) potentially contributing to eutrophication within the Grand Calumet River Area of Concern (AOC) in northern Indiana along the southern shore of Lake Michigan. In 2021, triplicate water samples were collected from five locations during three events, 4/19/21 and 4/20/21, 7/7/21, and 9/15/21. Water samples were processed and planktonic communities were determined by a DNA-based technology (algal metabarcoding). Sampling locations: 1. Columbia Avenue, Hammond, IN 2. Lake George drainage ditch, Hammond, IN 3. Indiana Harbor Canal at Canal Street in East Chicago, IN 4. Airport Road in Gary, IN 5. Marquette Park Lagoon in Gary, IN

LMR watershed temporal DNA metabarcoding 2016 study. This dataset is associated with the following publication: Smucker, N., E. Pilgrim, H. Wu, C. Nietch, J. Darling, M. Molina, B. Johnson, and L. Yuan. Characterizing temporal variability in streams supports nutrient indicator development using diatom and bacterial DNA metabarcoding. SCIENCE OF THE TOTAL ENVIRONMENT. Elsevier BV, AMSTERDAM, NETHERLANDS, 831: 154960, (2022).

The Great Lakes Environmental Database (GLENDA) houses environmental data collected by EPA Great Lakes National Program Office (GLNPO) programs that sample water, aquatic life, sediments, and air to assess the health of the Great Lakes ecosystem. GLENDA is available to the public on the EPA Central Data Exchange (CDX). A CDX account is required, which anyone may create. GLENDA offers “Ready to Download Data Files” prepared by GLNPO or a “Query Data” interface that allows users to select from predefined parameters to create a customized query. Query results can be downloaded in .csv format. GLNPO programs providing data in GLENDA include the Great Lakes Water Quality Survey and Great Lakes Biology Monitoring Program (1983-present, biannual monitoring throughout the Great Lakes to assess water quality, chemical, nutrient, and physical parameters, and biota such as plankton and benthic invertebrates), the Great Lakes Fish Monitoring and Surveillance Program (1977-present, annual analysis of top predator fish composites to assess historic and emerging persistent, bioaccumulative, or toxic chemical contaminants), the Cooperative Science and Monitoring Initiative (2002-present, intensive water quality and biology sampling of one lake per year focusing on key challenges and data gaps), the Great Lakes Integrated Atmospheric Deposition Network (1990-present, monitoring Great Lakes air and precipitation for persistent toxic chemicals), the Lake Michigan Mass Balance Study (1993-1996, analyzed the atmosphere, tributaries, sediments, water column, and biota of Lake Michigan for nutrients, atrazine, PCBs, trans-nonachlor, and mercury modelling), and the Great Lakes Legacy Act (1996-present, evaluations of sediment contamination in Areas of Concern). GLENDA is updated frequently with new data.

Monitoring the community structure and metabolic activities of cyanobacterial blooms in Upper Klamath Lake, Oregon, is critical to lake management because these blooms degrade water quality and produce toxic microcystins that are harmful to humans, domestic animals, and wildlife. Genetic tools, such as DNA fingerprinting by terminal restriction fragment length polymorphism (T-RFLP) analysis, high-throughput DNA sequencing (HTS), and real-time, quantitative polymerase chain reaction (qPCR) provide more sensitive and rapid assessments of bloom ecology than traditional techniques. The objectives of this study were (1) to characterize the microbial community at one site in Upper Klamath Lake and determine changes in the cyanobacterial community through time using T-RFLP and HTS in comparison with traditional light microscopy; (2) to determine relative abundances and changes in abundance over time of toxigenic Microcystis using qPCR; and (3) to determine relative abundances and changes in abundance over time of Aphanizomenon, Microcystis, and total cyanobacteria using qPCR. T-RFLP analysis of total cyanobacteria showed a dominance of only one or two distinct genotypes in samples from 2013, but results of HTS in 2013 and 2014 showed more variations in the bloom cycle that fit with the previous understanding of bloom dynamics in Upper Klamath Lake and indicated that potentially toxigenic Microcystis was more prevalent in 2014 than in years prior. The qPCR-estimated copy numbers of all target genes were higher in 2014 than in 2013, when microcystin concentrations also were higher. Total Microcystis density was shown with qPCR to be a better predictor of late-season increases in microcystin concentrations than the relative proportions of potentially toxigenic cells. In addition, qPCR targeting Aphanizomenon at one site in Upper Klamath Lake indicated a moderate bloom of this species (corresponding to chlorophyll a concentrations between approximately 75 and 200 micrograms per liter) from mid-June to mid-August, 2014. After August 18, the Aphanizomenon bloom was overtaken by Microcystis late in the season as microcystin concentrations peaked. Overall, results of this study showed how DNA-based, genetic methods may provide rapid and sensitive diagnoses for the presence of toxigenic cyanobacteria and that they are useful for general monitoring or ecological studies and identification of cyanobacterial community members in complex aquatic habitats. These same methods can also be used to simultaneously address spatial (horizontal and vertical) and temporal variation under different conditions. Additionally, with some modifications, the same techniques can be applied to different sample types, including water, sediment, and tissue.