Algae are commonly found in Indiana lakes and streams without concern, however, the concentrated presence of blue-green algae can be linked to some health effects.
 

USGS Photo

USGS Photo

IDEM fact sheet for Blue-Green Algae
IUPUI fact sheet for Blue-Green Algae
 

• Two Indianapolis-area reservoirs (Geist and Eagle Creek) were essentially closed for swimming and recreational usage in late summer 2007 due to high blue-green algae concentrations and the detection of an algal toxin in Geist Reservoir?
   
• Blue-green algae occur throughout area lakes, reservoirs, and streams and have for many years.  There are numerous different species present but recent years have seen both an increase in the dominance of some species and the appearance of other species?
   
• Some blue-green algae are capable of producing toxins that have potentially serious human and animal health effects; but, not all blue-green algae produce toxins?
   
• In recent years, concerns regarding the production and occurrence of blue-green algal toxins has grown in Indiana and nationally.  Reports of potentially-toxic blue-green algae in Indiana include Geist, Morse, and Eagle Creek in Marion County, Ball Lake in Steuben County, Lake Lemon and Monroe Reservoir in Monroe County, and at least 20 other lakes and reservoirs statewide.