Quantification of nitrogen-fixing microorganisms (targeting nifH gene) in Cladophora algae by quantitative polymerase chain reaction (qPCR)

Data were collected to determine the abundance of nitrogen-fixing microorganisms in Cladophora algae growing on rocks, breakwall structures, or submerged dreissenid mussel beds around southern Lake Michigan. Cladophora samples (N=33) were collected between June and September 2015 from three urban areas: (a) Jeorse Park, East Chicago, Indiana, (b) Calumet Beach, Chicago, Illinois, and (c) North Beach, Racine, Wisconsin, and a National Park site, Portage Lakefront, Indiana Dunes National Park, Indiana. Corresponding lake water samples (N=33) were collected approximately 15-20 feet away from submerged algal mats. Genomic DNA was extracted from water and processed algal samples. The abundance of nitrogen-fixing microorganisms in water and algal samples was determined by a SYBR-Green quantitative polymerase chain reaction (qPCR) assay by targeting the nifH gene. The coordinate file includes information regarding sampling locations and their corresponding latitudes and longitudes. The data files include DNA quality and yield from water and algal samples, and abundance of nitrogen-fixing microorganisms in water and algal samples as determined by the SYBR-Green qPCR assay.