I had a friend who is a biology professor at a local university do an analysis on my 3 acre pond. She found extremely high phosphorous levels, a huge amount of algae (which is why I asked her to look at the pond) and very low dissolved oxygen below three feet.

Questions:

Does excess algae contribute to low O2 levels? Or is the low O2 a byproduct of something else?

Will simply killing the algae help boost the O2 level? I understand that dying plant matter depletes O2, but will the O level bounce up once the decay process ends?

I guess I'm trying to figure out how (if) a high algae count is related to low O2 levels. How do they correlate?

Thanks for any help.

High algae count can limit sunlight penetration, which plants and phytoplankton use to mfg O2.

Floating mats of algae, or phytoplankton? I'm assuming you don't have an aeration system in the pond?

Suspended algae--I assume phytoplankton.

No aeration system.

Killing the algae results in microorganisms feeding on the dead algae. These organisms feeding and multiplying use the available oxygen in the water.

algae like most plants photosynthesis during the days turning co2 into o2.. but at night (and sometimes on cloudy days) do the opposite via cellular respiration.

esshup's is right that if you have a lot of algae the top algae may be photosynthesizing but the algae below it may not be getting light.


The problem is that the algae is feeding on your high phosphorous, but it is also using it up.. well not using more like locking it up.. when your algae decays it's going to release those nutrients back into water, what is going to use it then?