Is Cloudy Water Really A Bacteria Bloom?

[Dan_P]

A report on a recent observation…

I was able to induce the formation of cloudy water in several experimental aquaria by increasing the daily feeding. I thought, “a bacteria bloom, just like in real life”. Under the microscope, instead of seeing a swarm of bacteria, I observed a swarm of the dinoflagellate Amphidinium. Filtering the aquarium water through a 0.45 micron syringe filter until it clogged resulted in a golden colored filter (Possibly a useful method to distinguish a bacteria bloom from a phytoplankton bloom).

I am left wondering if the dinoflagellate benefitted directly from the increase in food, the increase in inorganic nitrogen from bacteria digestion of the food, or from preying on a likely increased bacteria population.

 

[Randy Holmes-Farley]

I would certainly say that I have no idea what organisms are most likely to bloom when conditions are right, and a microorganism bloom might be a better term.

 

[taricha]

Nice, Dan.
To complicate things further, I found that with strong light I could quantify side-scattering from my tank water. But it didn't correlate to dosing phyto or organic carbon additions, which I thought was weird.
Then I found the scattering dropped to undetectable with a drop of HCl. So all the detectable scattering in my tank water was acid-soluble - likely fine CaCO3 particles.
Wonder how many other tanks the majority of particles contributing to the degree of water clarity are actually mineral.

 

[Dan_P]

Nice, Dan.
To complicate things further, I found that with strong light I could quantify side-scattering from my tank water. But it didn't correlate to dosing phyto or organic carbon additions, which I thought was weird.
Then I found the scattering dropped to undetectable with a drop of HCl. So all the detectable scattering in my tank water was acid-soluble - likely fine CaCO3 particles.
Wonder how many other tanks the majority of particles contributing to the degree of water clarity are actually mineral.

Darn, I forgot about this study.

Abiotic and biotic causes of cloudy water. Acid clarification to test for suspended carbonate particulates, and a syringe filter to concentrate organism for color determination.