Phosphate vs skeletal growth by corals

[Randy Holmes-Farley]

There is a long history of published literature experiments on coral calcification rates vs phosphate that have warned reefers away from high phosphate, and it is hard to discount those entirely, even if the results showed variable and sometimes contradictory effects, but reefer results have also sometimes been very good even at phosphate levels exceeding 1 ppm (such as Richard Ross' aquarium) described here:

Skeptical Reefkeeping 9: Test Kits, Chasing Numbers and Phosphate

By Rich Ross and Chris Jury There are many standard parameters in the reefkeeping world that aquarists strive to match in their home reefs – water quality,

reefs.com

Since it came up in another thread and might get lost there, I thought I'd copy a section of a recent post of mine related to a recent study in the wild of coral frags that show very little coral skeletal surface area reduction from elevated phosphate, and skeletal surface area was higher than control with nutrients that pulsed up to, but did not stay at the highest levels.

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.

 

[Gumbies R Us]

Useful information!

 

[reefer_87]

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.

 

[Lavey29]

Thanks for sharing this and offering information in my phosphate thread. My tank is 2 years old and over the past couple months my phosphate has crept up slowly. Usual reducing methods would not work. I hit .51 and then tried half doses of phosphate RX which brought my number back to .11 but it slowly rises again with the phosphate bound in rocks and sand.

Although concerned about algae and stunted coral growth, the opposite seems to be in play. I have minimal algae in my tank and my coral growth along with coralline growth has been extremely positive. Tank is thriving so I'm confused on what I should do. Just let phosphate rise naturally and do its thing or try and control it with available chemical methods. I strongly try to avoid chemicals in my water column.

The presented scientific study really makes me want to just sit back and let the tank run its course and see where it balances out with the phosphate level. Although I'm worried about waking up to a huge GHA farm too.

Things like this make this hobby so challenging and fun.

 

[Jbell370]

In 3 years with my current setup I chased numbers on a regular basis, now I don't run GFO or Carbon, just my usual 5g AWC daily and 8ml of NoPox. Nitrates 8-10 and Phosphate 0.13 - 0.28 depending on how often and how much I syphon the sand bed. Works for me.

 

[Treefer32]

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.

 

[Acrofiend]

Only test phosphates here to make sure they’re not at zero.

 

[Randy Holmes-Farley]

It's complicated with two threads at the same time discussing the same topic, but here's an update by Richard Ross on his aquarium with elevated P in the link I posted above

Reef Chemistry Question of the Day #285: Aragonite vs Calcite

For sure I am not recommending anyone specifically target 1 ppm phosphate. I generally recommend 0.03 to 0.1 ppm, with above the range better than below it. The question is how much effort and angst should a reefer expend if the tank is currently at 0.2 or 0.5 ppm. Is it worth lowering? I...

www.reef2reef.com

 

[jmichaelh7]

I’m glad to read this going on 2 years and my sps dominated tank will climb to 0.15 - .20 no matter how much phosphate e I dose or nutrition I starve my tangs

 

[MinnieMouse2]

There is a long history of published literature experiments on coral calcification rates vs phosphate that have warned reefers away from high phosphate, and it is hard to discount those entirely, even if the results showed variable and sometimes contradictory effects, but reefer results have also sometimes been very good even at phosphate levels exceeding 1 ppm (such as Richard Ross' aquarium) described here:

Skeptical Reefkeeping 9: Test Kits, Chasing Numbers and Phosphate

By Rich Ross and Chris Jury There are many standard parameters in the reefkeeping world that aquarists strive to match in their home reefs – water quality,

reefs.com

Since it came up in another thread and might get lost there, I thought I'd copy a section of a recent post of mine related to a recent study in the wild of coral frags that show very little coral skeletal surface area reduction from elevated phosphate, and skeletal surface area was higher than control with nutrients that pulsed up to, but did not stay at the highest levels.

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.

I always like to look at who is paying for the research. If it is a lot of companies that sell phos 4 reducing products, might put in question the science that aims to please.

 

[Eric R.]

Thanks for sharing this and offering information in my phosphate thread. My tank is 2 years old and over the past couple months my phosphate has crept up slowly. Usual reducing methods would not work. I hit .51 and then tried half doses of phosphate RX which brought my number back to .11 but it slowly rises again with the phosphate bound in rocks and sand.

Although concerned about algae and stunted coral growth, the opposite seems to be in play. I have minimal algae in my tank and my coral growth along with coralline growth has been extremely positive. Tank is thriving so I'm confused on what I should do. Just let phosphate rise naturally and do its thing or try and control it with available chemical methods. I strongly try to avoid chemicals in my water column.

The presented scientific study really makes me want to just sit back and let the tank run its course and see where it balances out with the phosphate level. Although I'm worried about waking up to a huge GHA farm too.

Things like this make this hobby so challenging and fun.

If you haven't watched this video yet, I highly recommend it. It suggests that there's little to no direct evidence that controlling nutrients is an effective method of nuisance algae control in a reef tank.

 

[Lavey29]

If you haven't watched this video yet, I highly recommend it. It suggests that there's little to no direct evidence that controlling nutrients is an effective method of nuisance algae control in a reef tank.

Thanks I'll watch it shortly. But doesn't uncontrolled nutrients that bottom out lead to tank problems typically?

 

[Eric R.]

Thanks I'll watch it shortly. But doesn't uncontrolled nutrients that bottom out lead to tank problems typically?

Depends. There's a difference between having lots of uptake and starving a tank. I tend to think low nutrients are more dangerous than high nutrients though, corals can starve and dinos can become a problem.

My previous post was more about trying to reduce high nutrients to control algae, not about dosing or feeding more or getting more fish if you have low nutrients. Though it may also just be excess filtration compared to nutrient levels.

 

[Joekovar]

If I bake a cake, I need relatively exact amounts of each ingredient. If I put too much of one thing in, it screws up the whole cake.

However, if I put too much of everything in at the same ratios, I get a bigger cake.

The pulsed highs are interesting to me. I suspect pulses can trigger other controlled parameters to dose more under the radar, the pulsed high causing coral to use more of other elements, which get replenished automatically as the focused on elements are getting all of the attention.

 

[Bruce Burnett]

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.

I have found that high water flow will make thicker branches, low water flow you get longer thinner branches. But so many variables, light, flow, nutrients, along with calcium, alkalinity, magnesium along with trace elements. I had high phosphates and zero nitrates had cyano. Raised nitrates up cyano went away over night. I test nitrates and phosphates to make sure they don't bottom out. With a mixed tank like mine, sps, lps and even a even a toadstool I started running nutrients a bit higher. I have better colors than I have ever had over the years. Only thing really different is lights and running all for reef. But I am also getting thicker spread on base of acros and thicker branches. So is it the flow, lights or all for reef or I think a combination of things.

 

[djf91]

There is a long history of published literature experiments on coral calcification rates vs phosphate that have warned reefers away from high phosphate, and it is hard to discount those entirely, even if the results showed variable and sometimes contradictory effects, but reefer results have also sometimes been very good even at phosphate levels exceeding 1 ppm (such as Richard Ross' aquarium) described here:

Skeptical Reefkeeping 9: Test Kits, Chasing Numbers and Phosphate

By Rich Ross and Chris Jury There are many standard parameters in the reefkeeping world that aquarists strive to match in their home reefs – water quality,

reefs.com

Since it came up in another thread and might get lost there, I thought I'd copy a section of a recent post of mine related to a recent study in the wild of coral frags that show very little coral skeletal surface area reduction from elevated phosphate, and skeletal surface area was higher than control with nutrients that pulsed up to, but did not stay at the highest levels.

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.

Very interesting Randy. I found it very informative.

However, I felt that the conclusion made by the authors was that elevated N and P did in fact have a negative effect on calcification and health. Sustained high nutrients do indeed hinder stony coral and should be avoided.

Influx’s (pulse) of nutrients do appear to be beneficial to coral, as long as they don’t stick around. This could be compared to our aquariums where we feed heavily but also use heavy filtration to keep N and P low.

After reading that study I would encourage stony coral keepers to maintain low levels of N and P.


“Individual and combined effects of press elevated ammonium and phosphate. Press elevated levels of ammonium or phosphate induced contrasting physiological responses in A. intermedia. Elevated lev- els of ammonium led to a substantial decrease in CaCO3 accretion rates. Primary productivity and tissue lipid concentration were unaffected. By contrast, elevated phosphate did not affect net CaCO3 accretion rates, but it reduced skeletal surface area expansion, a measure of the coral’s potential to expand and occupy new territory. Additionally, elevated phosphate reduced primary productivity rates and tissue lipid concentrations per surface area. We found that ammonium and phosphate rarely produced interactive effects when applied together, and most physiological parameters assessed in this study were individually influenced by one of the two nutrients.
Calcification rates (GTA) of A. intermedia under daytime conditions decreased after 7 weeks of exposure to press elevated ammonium concentrations of 14 μmol L−1. This is consistent with previous studies which found reduced calcification under high concentrations (10–109 μmol L−1) of ammonium20, 29, 32, and nitrate25, 26, 64. Other studies found increased skeletal growth for several coral species reared under mild concentrations of 2 and 5 μmol L−1 of ammonium and nitrate respectively65, or heterogenous effects under 11.3–36.2 μmol L−1 ammonium5. Similarly, studies on coral calcification (mainly linear expansion rates and buoyant weight measurements) under elevated phosphate have reported mixed effects for different coral species, describing both enhancement5, 66, 67 and reduction5, 20, 29, 32 under phosphate concentrations ranging from 0.5 to 13 μmol L−1. 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.”

 

[djf91]

There is a long history of published literature experiments on coral calcification rates vs phosphate that have warned reefers away from high phosphate, and it is hard to discount those entirely, even if the results showed variable and sometimes contradictory effects, but reefer results have also sometimes been very good even at phosphate levels exceeding 1 ppm (such as Richard Ross' aquarium) described here:

Skeptical Reefkeeping 9: Test Kits, Chasing Numbers and Phosphate

By Rich Ross and Chris Jury There are many standard parameters in the reefkeeping world that aquarists strive to match in their home reefs – water quality,

reefs.com

Since it came up in another thread and might get lost there, I thought I'd copy a section of a recent post of mine related to a recent study in the wild of coral frags that show very little coral skeletal surface area reduction from elevated phosphate, and skeletal surface area was higher than control with nutrients that pulsed up to, but did not stay at the highest levels.

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.

Also, it seems this study was conducted in aquariums in a lab or maybe the aquariums were outdoors. It’s hard to tell from the paper. I also can’t tell if these aquariums were directly linked to the ocean or if the sea water was collected.

If these were isolated systems then what effect did the absence of wild planktonic foods have on the coral growth rates.

 

[Randy Holmes-Farley]

I always like to look at who is paying for the research. If it is a lot of companies that sell phos 4 reducing products, might put in question the science that aims to please.

The references I was referring to was not generally sponsored by companies, but by governments. The studies were typically aimed at understanding wild corals, not helping hobbyists.

 

[Thales]

Very interesting Randy. I found it very informative.

However, I felt that the conclusion made by the authors was that elevated N and P did in fact have a negative effect on calcification and health. Sustained high nutrients do indeed hinder stony coral and should be avoided.

Can you put that hindering into a percentage? In other words, how much of a hinderance do you feel was demonstrated in the paper? Thanks.

 

[Randy Holmes-Farley]

Can you put that hindering into a percentage? In other words, how much of a hinderance do you feel was demonstrated in the paper? Thanks.

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).