News Articles
The Green Slime is Coming
Posted on Aug 20th, 2022
Coming to a river near you!
Yipes, first it was a WWTP discharge into the river now it’s a strange substance seen floating on the river. This gooey green substance was spotted today heading downriver flowing over the salt water dam that’s located just north of Hwy 35 near West Columbia. Hope this isn’t like the horror movie “Green Slime” where a mysterious fungus invades a space station and turns the inhabitants into monsters.
Photos Tom Ronayne
First seen a week ago, on Sat 13Aug22, a solid covering of green substance floats on a creek that enters the river a short distance from the salt water dam.
Photo taken a week later on Sat 20Aug22 shows the green slime starting to break apart as it flows downriver.
The green slime passes over the salt water dam.
Some sort of algae or other type of bloom has been penned up by the tide from Hwy 35 bridge up to the dam. Looks sort of like miniature shamrocks. Been there several weeks. Assuming heat, salt, low O2, and stagnant water, or any combination of those unusual conditions this summer, are responsible. Now the rain and some water over the dam is pushing it downriver.
Colleen Roco, retired Coastal Ecologist says...
"Although the closeup photo is a bit blurry, this plant appears to be common duck weed. It proliferates under low flow, high heat, and high nutrient conditions. See this website for more information. Common Duckweed - AquaPlant: Management of Pond Plants & Algae (tamu.edu)
As a result of the bloom conditions could especially be right for a fish kill in the tributary stream due to the total shading and the consumption of oxygen in the water column as the plants die and break down. Dissolved oxygen (DO) levels likely are already depressed due to the heat and sluggish flow, but the bloom and subsequent die-back can exacerbate those conditions. While we generally do not see low DO fish kills on the San Bernard, they could occur upstream and the carcasses wash down. If it occurs, it is a natural phenomenon, although rather unpleasant."
Comment By: Tom Ronayne
Posted on Aug 20, 2022
Colleen’s diagnosis sounds exactly right. Just have never seen such a huge amount of it up here. Glad to see enough rain to give the river a good flushing.