Wikipedia
Nodularia
Nodularia is a genus of filamentous nitrogen-fixing cyanobacteria, or blue-green algae. They occur mainly in brackish or salinic waters, such as the hypersaline Makgadikgadi Pans, the Peel-Harvey Estuary in Western Australia or the Baltic Sea. Nodularia cells occasionally form heavy algal blooms. Some strains produce a cyanotoxin called nodularin R, which is harmful to humans.
The type species for the genus is Nodularia spumigena Mertens ex Bornet & Flahault, 1886.