The green you see in the Thames River is a cyanobacteria, or blue green algae, bloom.
According to the Lower Thames Valley Conservation area the bloom seems to be focused on central Chatham-Kent, with staff noting that samples at Kent Bridge didn’t show the bacteria, or the telltale colour.
Officials with the MOECC say there is also some algae in McGregor Creek, but the two appear to be unrelated.
Blue Green Algae is what caused the Lake Erie water intakes to be closed in years past.
So far no fish kills have been recorded, however officials are asking people to avoid the river.