Phosphate vs skeletal growth by corals

[Thales]

Yes. Here's the blurb from the other thread, focus on the bolded section at the end. It looks like 11% decline for continuous high N and P and 8% rise in calcification for pulsing high/low:

This paper from 2021 shows that the calcification of coral frags at elevated N and P calcified at nearly the same rate as controls (Figure 2a):

https://link.springer.com/content/pdf/10.1038/s41598-021-92276-y.pdf

The concentrations they used:

High N and P: "ammonium and phosphate were both permanently elevated to 14 and 10 µmol L−1 respectively."

That is 0.2 ppm ammonia and 0.95 ppm phosphate

Control N and P:
"During this study, seawater concentrations of ammonium and phosphate averaged 0.55 and 0.32 µmol L−1 respectively across the experimental period,"

That is 0.009 ppm ammonia and 0.03 ppm phosphate.

This is exactly the range of phosphate values one might consider normal for a reef tank (0.03 ppm) and high (0.95 ppm), and yet the drop in skeletal surface area at the end of the study was quite small (23.23 cm2 for the high NP and 26.14 cm2 for the control). Even more striking, the pulsed high N and P (as opposed to the continuous high NP) was even HIGHER than control at 28.27 cm2).

Ah! Thanks. 11%. Seems to me that the juice is not worth the squeeze for the majority of the hobby. I. Am see farmers trying to cut frag turn around time at scale, but for keeping a nice display, not so much.

if I sell 1000 in coral frags a month, spending money and time and resources to get an 11% increase might be worth it, if it costs less than 50$ a month to bring phos down (I can’t see it costing that little, but maybe). For a pleasure tank, not so much.

I said the same thing twice!

 

[ceaver]

I've strived for higher nutrients because I like a fish population. And not trying, ended up with large fish, that cause high nutrients. Right now averaging .05 ppm phosphates and 35 ppm nitrates.

One question I have is a) what types of corals were studied, LPS vs. SPS - is there a difference in growth rates based on availability of P & N?

b) Is there a difference in growth patterns based on P & N concentrations. I've noticed my SPS, growing thicker skeletal mass instead of growing upward or outward. Branches that average 1/8" thick (probably standard for many branching SPS), I have thick calcium based branches that are easily 1/2" thick, maybe thicker. They grew thicker when nutrients are high, and grew outward when nutrients were low. There was a 6-8 months where I ran with just one fish in 340 gallons due to fish dieing off due to electrocution. I let it go fallow and nearly gave up then. I had the issues of low nutrients spaghetti bacteri growing all over the sand bed, my algae turf scrubber stopped growing algae during that time. Nutrients bottomed out. My SPS grew thin branches and the space they took up quadrupled in size. Now, over the past year of running high P & N the branches stopped growing longer and it stopped growing new branches, but the existing branches grew extremely thick.

Obviously I don't have a control to scientifically attribute thickness is determined by levels of nutrients. It's one factor. Could be lighting, could be alk and calcium concentrations, could be trace elements, could be feeding levels. I have no idea.

Wanted to throw that out there as growth is growth, I agree, I would have preferred my SPS get bigger with new branches so, I can frag them more easily. With thicker branches it's much harder to frag them. I'm to a point I may need a band saw to cut them without damaging the flesh.

This last part of what I assume is the article abstract seems to provide the evidence and explanation for your observations. Very interesting!

"Skeletal surface area increase in the present study was reduced under elevated phosphate concentrations (10 μmol L−1), despite no observed changes in net CaCO3 accretion. This indicates a shift towards higher skeletal density and lower skel- etal expansion, thus reducing the competitive ability of A. intermedia to occupy new territory, while gaining improved tolerance to physical damage and fragmentation68. Such shifts are notably beneficial in upwelling areas characterized by high nutrients but also intensified wave energy.”

 

[Treefer32]

This last part of what I assume is the article abstract seems to provide the evidence and explanation for your observations. Very interesting!

"Skeletal surface area increase in the present study was reduced under elevated phosphate concentrations (10 μmol L−1), despite no observed changes in net CaCO3 accretion. This indicates a shift towards higher skeletal density and lower skel- etal expansion, thus reducing the competitive ability of A. intermedia to occupy new territory, while gaining improved tolerance to physical damage and fragmentation68. Such shifts are notably beneficial in upwelling areas characterized by high nutrients but also intensified wave energy.”

Good catch! Absolutely what I'm seeing! I had a branching Acro where 80% of the branches died off, however, two branches survived and thickened. It's really weird looking. The rest of the structure has dead skinny branches and two branches full colorful skin and extending polyps on thick. It literally looks like sore thumbs sticking out. I need to break the two living branches off and throw the rest. I wanted to see if it would grow down and encompass the existing skeleton, but so far, all it has done is thicken up. Heh.

 

[areefer01]

Ah! Thanks. 11%. Seems to me that the juice is not worth the squeeze for the majority of the hobby. I. Am see farmers trying to cut frag turn around time at scale, but for keeping a nice display, not so much.

if I sell 1000 in coral frags a month, spending money and time and resources to get an 11% increase might be worth it, if it costs less than 50$ a month to bring phos down (I can’t see it costing that little, but maybe). For a pleasure tank, not so much.

A part often overlooked by hobbyist. And since we are talking about a number everyone should also try and visualize it to put it into perspective.

I said the same thing twice!

For emphasis!!!!

 

[Palegic]

Thank you. I was starving mine at 0.03 Phopshates and < 5 nitrates with stn taking out 50% of my SPS and Euphyliia death. Increased it to 20 ppm NO3 and 0.12 PO4 and it has never been better. I don’t know if the lower levels were the reason behind stn but I see growth tips now that indicates starving.

Pretty sure lighting, flow, and nutrients all have to be within ratio. If your lighting is high you need to increase No3 and Po4. At least that's what I have always been taught. Generally your coral will tell you when it's happy.