Green Hair Algae: Nutrient Sponge

[Dan_P]

Just sharing a quick study of green hair algae nutrient consumption. I had a huge nitrate spike after abruptly stopping carbon dosing (vinegar) in early January and wanted to get rid of it for esthetic reasons. Refugium is a mix of algae, but by the end of carbon dosing only hair algae was growing. I wanted to get an appreciation for how much and how fast GHA could take up nitrate and answer the question will I have to wait a year to lower the nitrate level. Here is the study. For a size reference, the GHA colony is sitting on a 1 cm wide slice of 1 inch PVC in a 2 L vessel.

Besides growing well, the succession of microscopic species living in the GHA colony over the 8 days was interesting to watch. By day 6 the colony was covered with the cyanobacteria Spirulina and dinoflagellates. By the way, I had to dose PO4 to keep it above “not detected” by Hanna Checker. By day five I started dosing nitrate for the same reason.

 

[Big G]

I wonder what the O2 levels were as days progressed and the NO3 & PO4 were consumed.

 

[Dan_P]

I wonder what the O2 levels were as days progressed and the NO3 & PO4 were consumed.

Good question. Never thought to measure the level, but it is something to consider when I ponder the succession of species that occur as the GHA grew.

 

[taricha]

Am I reading right that a 7 day consumption of 100mg PO4 out of 2L is a ~50ppm reduction PO4?

 

[Dan_P]

Am I reading right that a 7 day consumption of 100mg PO4 out of 2L is a ~50ppm reduction PO4?

Sorry for the confusing graph. I payed so much attention to getting the picture lined up that I forgot to label the axes. Use the right hand axis for phosphate.

It looks like ~5.5 mg from about 1500 mL of water. The actual concentration was variable, 0.5 ppm +/-, right after I dosed in the morning. It was gone by the next day. One day I took measurements every several hours. The The PO4 was quite diminished by evening.