Performing PO4 experiment relating to SPS color/growth

[bertoni]

It's interesting that you can increase the lighting. I'll be interested to see how this shapes up.

 

[taricha]

Day 31



Since the last update, I increased lighting from 6 hours to 8 hours a day. When I had low nutrients in the past, everything would bleach out. Now corals seem to be taking the increased lighting with no ill effects.

This paper argues precisely that P out of balance too low makes coral more susceptible to bleaching. Cool that you seem to be confirming this in a tank setting.

"P starvation reduces the photosynthetic capacity (Fv/Fm < 0.5) and renders the corals susceptible to heat/light stress. Alternatively, P starvation might result when zooxanthellae growing under nutrient replete conditions are deprived of P while nitrogen levels remain high."

 

[Magik]

This paper argues precisely that P out of balance too low makes coral more susceptible to bleaching. Cool that you seem to be confirming this in a tank setting.

"P starvation reduces the photosynthetic capacity (Fv/Fm < 0.5) and renders the corals susceptible to heat/light stress. Alternatively, P starvation might result when zooxanthellae growing under nutrient replete conditions are deprived of P while nitrogen levels remain high."

Very interesting! What would happen in high P04, low N03 water? That what I got in my tank, nitrates undetectable (<0.25ppm), phosphates 0.09ppm (Hanna ULR).

 

[greengeco82]

Day 39 comparison

Day 39 comparison

Day 1 by [url=https://flic.kr/p/TgKhpd]Day 39 by
[url=https://flic.kr/p/Taf2gZ]Day 1 by [url=https://flic.kr/p/Uybd8K]Day 39 by
[url=https://flic.kr/p/SLHeVQ]Day 1 by [url=https://flic.kr/p/UybfXx]Day 39 by https://www.flickr.com/photos/145255365@N08/

 

[greengeco82]

Overall a lot of growth. No noticeable color change IMO. Pics are taken under 2 x SE 250w, 14k Hamilton, halides. My frag rack is getting heavy, so I think its time to sell them off.

 

[Timfish]

First, you're seeing if you can make your corals brighter. It takes corals awhile to make new or additional fluorescing proteins so they look brighter. Instead of running your experiment for just a few weeks I think you should consider running it for several months.

Maybe this will help clarify why corals make thier fluorescing protiens, there are at least 4 primary purposes.

1. Photoprotection When the light is too intense for the zooxanthellae the fluorescing oragnelles are placed above them shading them, reducing the amount of light they recieve. As the light levels increase the coral makes more proteins intensifying the colors.
http://www.nature.com/nature/journal/v408/n6814/full/408850a0.html
https://researchonline.jcu.edu.au/4244/1/4244_Salih_et_al_2006.pdf
https://www.academia.edu/9996109/The_role_of_host_based_color_and_fluorescent_pigments_in_photoprotection_and_in_reducing_bleaching_stress_in_corals

2. Photoenhancement. If the light is not bright enough for the zooxantheallae to work at optimum photosynthetic effeceincy the fluorescing organelles are located behind them with respect to the light source so they receive increased light levels.
http://www.nature.com/nature/journal/v408/n6814/full/408850a0.html
https://researchonline.jcu.edu.au/4244/1/4244_Salih_et_al_2006.pdf
https://www.academia.edu/9996109/The_role_of_host_based_color_and_fluorescent_pigments_in_photoprotection_and_in_reducing_bleaching_stress_in_corals
(With ULNS methods starving the corals makes them look brighter because the zooxanthellae numbers are restricted reducing thier brown componet to the corals coloration.)

3. As antioxidants. The fluorescing proteins are used to neutralize the free radicals caused by photosythesis.
https://www.researchgate.net/publication/26873319_Coral_Fluorescent_Proteins_as_Antioxidants

4. As an Immune response. Fluorescing proteins are used by the corals immune system to deal with parasites.
http://www.jstor.org/stable/25470724?seq=1#page_scan_tab_contents

Just an update, I was reviewing some stuff and found a refference link was no longer valid. New link is in red.