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It looks like the paper you quoted has results that are contradictory to the results in the article I am referring to. These are both experiments with similar parameters and goals but with completely opposite results. There would have to be much more work done to support either conclusion. What I can say is there are examples of tanks where nutrient parameters are never checked and the system runs fine. @Paul B is an example of such a system. Is his tank heavy sps? No.Hi.
I occasionally read comments like your PO4 recommendations above & wonder what evidence there is to back them.
0.1ppm PO4 may be fine for some, or several corals? but it is well over typical coral reef levels, & above the level typically suggested to hobbyists >> 0.03 ppm to 0.07 ppm, a level many have success with. I also wonder where in nature corals are subjected to much higher levels than 0.1ppm PO4?
You also mentioned - "The scenario you want to avoid is high nitrates and low phosphates:"
I don't know if you have any specific N-P ratio you believe one should stay below, but I've seen some misinterpret, or misrepresent what the science says on this, claiming that a P-N ratio above 10:1 is detrimental to coral health. Consider, no3 @ 2 ppm & po4 @ 0.04 ppm is a P-N ratio of 50:1.
The science mentions a threshold level of phosphate, & below this phosphate starvation can occur, exacerbated by high nitrogen levels. But if phosphate is above this threshold, the N-P ratio is unimportant.
e.g. In this paper Phosphate deficiency promotes coral bleaching and is reflected by the ultrastructure of symbiotic dinoflagellates
it states the following points.
1. " We exposed corals to imbalanced N-P ratios in long-term experiments and found that the undersupply of phosphate severely disturbed the symbiosis, indicated by the loss of coral biomass, malfunctioning of algal photosynthesis and bleaching of the corals."
2. "In our experiments, a phosphate concentration of ~ 0.3 μM (0.0285 ppm) at a N/P ratio of >> 22:1 << yielded an overall healthy phenotype."
3. *** "Accordingly, it is likely that the absolute N/P ratio becomes also less critical for the proper functioning of the symbionts when phosphate concentrations exceed a vital supply threshold > 0.3 μM (0.0285 ppm), even when the symbionts are rapidly proliferating."
=================================
So if PO4 is kept at 0.03ppm or above, so corals are not starved of phosphate to begin with, N to P ratios are not a concern, at least relative to the levels hobbyists typically target.
Thoughts?
I know 10 ppm is way too high for corals.We're both reading some of same research papers. 10 ppm PO4 is too high, it does interfere with calcification and at some point will kill corals. But reef aquarists have been told to keep it too low for a long time. I have two threads dealing with nuisance algae on the local forum showing PO4 levels increasing as nuiusance algae dissappeared, so it's not the direct cause of problems as is often advised. Dunn, et al, showed coral growth increase up to .5 mg/l and Richard Ross's acro dominate tank was over 1.0 mg/l at one point. His article "Chasing Numbers" I think helps put things in perspective. Research done by a group of researchers at SOuthampton University in England with corals maintained in a closed system from 2-10 years shows the problems with imbalances in the N/P ratio. Here's some links:
Nutrient enrichment can increase the susceptibility of reef corals to bleaching:
Ultrastructural Biomarkers in Symbiotic Algae Reflect the Availability of Dissolved Inorganic Nutrients and Particulate Food to the Reef Coral Holobiont:
Ultrastructural Biomarkers in Symbiotic Algae Reflect the Availability of Dissolved Inorganic Nutrients and Particulate Food to the Reef Coral Holobiont
Reef building corals associated with symbiotic algae (zooxanthellae) can access environmental nutrients from different sources, most significantly via the uptake of dissolved inorganic nutrients by the algal symbiont and heterotrophic feeding of the coral host. Climate change is expected to...www.frontiersin.org
Phosphate deficiency promotes coral bleaching and is reflected by the ultrastructure of symbiotic dinoflagellates
Phosphate deficiency promotes coral bleaching and is reflected by the ultrastructure of symbiotic dinoflagellates
Enrichment of reef environments with dissolved inorganic nutrients is considered a major threat to the survival of corals living in symbiosis with din…www.sciencedirect.com
Addendum,
I forgot to add in my response above I've been very happy with the maricultured Premium Live ROck I've gotten from GulfLiveRock.com Lots of neat stuff and especially a great source for cryptic sponges.
Yes. But it is one paper Tim has, & others repeatedly cite.It looks like the paper you quoted has results that are contradictory to the results in the article I am referring to. These are both experiments with similar parameters and goals but with completely opposite results.
good point.There would have to be much more work done to support either conclusion. What I can say is there are examples of tanks where nutrient parameters are never checked and the system runs fine. @Paul B is an example of such a system. Is his tank heavy sps? No.
Hi.
I occasionally read comments like your PO4 recommendations above & wonder what evidence there is to back them.
0.1ppm PO4 may be fine for some, or several corals? but it is well over typical coral reef levels, & above the level typically suggested to hobbyists >> 0.03 ppm to 0.07 ppm, a level many have success with. I also wonder where in nature corals are subjected to much higher levels than 0.1ppm PO4?
You also mentioned - "The scenario you want to avoid is high nitrates and low phosphates:"
I don't know if you have any specific N-P ratio you believe one should stay below, but I've seen some misinterpret, or misrepresent what the science says on this, claiming that a P-N ratio above 10:1 is detrimental to coral health. Consider, no3 @ 2 ppm & po4 @ 0.04 ppm is a P-N ratio of 50:1.
The science mentions a threshold level of phosphate, & below this phosphate starvation can occur, exacerbated by high nitrogen levels. But if phosphate is above this threshold, the N-P ratio is unimportant.
e.g. In this paper Phosphate deficiency promotes coral bleaching and is reflected by the ultrastructure of symbiotic dinoflagellates
it states the following points.
1. " We exposed corals to imbalanced N-P ratios in long-term experiments and found that the undersupply of phosphate severely disturbed the symbiosis, indicated by the loss of coral biomass, malfunctioning of algal photosynthesis and bleaching of the corals."
2. "In our experiments, a phosphate concentration of ~ 0.3 μM (0.0285 ppm) at a N/P ratio of >> 22:1 << yielded an overall healthy phenotype."
3. *** "Accordingly, it is likely that the absolute N/P ratio becomes also less critical for the proper functioning of the symbionts when phosphate concentrations exceed a vital supply threshold > 0.3 μM (0.0285 ppm), even when the symbionts are rapidly proliferating."
=================================
So if PO4 is kept at 0.03ppm or above, so corals are not starved of phosphate to begin with, N to P ratios are not a concern, at least relative to the levels hobbyists typically target.
Thoughts?
A simple search shows upwelling can expose corals to ~.3 mg/l (3.0 µM) From my own expereince I realized over 2 decades ago PO4 was not a major factor with problems in reef systems and stopped worrying about it.. I was not seeing high PO4 cause nuisance algae issues, quite the opposite in fact. When remediateing tanks wiht algae issues I would see inmprovet growth and apperance of corals and might also see PO4 increase as algae dissappeared.
The problem with high nitrates to low phosphates goes beyond the levels documented by D' Angelo, Wiedeneman, Rosset and others with at Southampton.
I did get that book. I got about half way through then got distracted by all the pretty pictures in @najer twins thread. I will get to finishing it eventually. Tank is still a month or 2 from being salty so I have time.
I did find that interesting that all these reefers following something that isn't just not doing anything but is actually detrimental to their balanced ecosystems.
. . . With po4 at or above the threshold it is incorrect to suggest that a P-N ratio at or below 10:1 is necessary for coral health (I haven't seen you recommended this ?). At typical aquarium levels the P-N ratio is of no concern. . . .
. . . it can become a number chasing exercise. . . .
. . . but my point is, recommending a phosphate level over a threshold of 0.028 ppm isn't necessary, & it can become a number chasing exercise. At that threshold PO4 is way above typical NSW levels. I live at the ocean, test NSW often, have tested water directly from Hook Island at the GBR, & PO4 never registers on a hobby kit.
In the research I have read a couple of things stood out. 1. Phosphate assimilation by coral rises during heat stress.
. . .
. . . 2. Phosphate starvation can occur when nitrogen rises but this P-N ratio imbalance is only a problem in the ocean with typically super low phosphate levels to begin with.
When phosphate is at or above the threshold - 0.028 ppm, which is typical in an aquarium, P-N ratio is unimportant. . . .
You always ask for the evidence when you cite it yourself.Hi.
I occasionally read comments like your PO4 recommendations above & wonder what evidence there is to back them.
0.1ppm PO4 may be fine for some, or several corals? but it is well over typical coral reef levels, & above the level typically suggested to hobbyists >> 0.03 ppm to 0.07 ppm, a level many have success with. I also wonder where in nature corals are subjected to much higher levels than 0.1ppm PO4?
You also mentioned - "The scenario you want to avoid is high nitrates and low phosphates:"
I don't know if you have any specific N-P ratio you believe one should stay below, but I've seen some misinterpret, or misrepresent what the science says on this, claiming that a P-N ratio above 10:1 is detrimental to coral health. Consider, no3 @ 2 ppm & po4 @ 0.04 ppm is a P-N ratio of 50:1.
The science mentions a threshold level of phosphate, & below this phosphate starvation can occur, exacerbated by high nitrogen levels. But if phosphate is above this threshold, the N-P ratio is unimportant.
e.g. In this paper Phosphate deficiency promotes coral bleaching and is reflected by the ultrastructure of symbiotic dinoflagellates
it states the following points.
1. " We exposed corals to imbalanced N-P ratios in long-term experiments and found that the undersupply of phosphate severely disturbed the symbiosis, indicated by the loss of coral biomass, malfunctioning of algal photosynthesis and bleaching of the corals."
2. "In our experiments, a phosphate concentration of ~ 0.3 μM (0.0285 ppm) at a N/P ratio of >> 22:1 << yielded an overall healthy phenotype."
3. *** "Accordingly, it is likely that the absolute N/P ratio becomes also less critical for the proper functioning of the symbionts when phosphate concentrations exceed a vital supply threshold > 0.3 μM (0.0285 ppm), even when the symbionts are rapidly proliferating."
=================================
So if PO4 is kept at 0.03ppm or above, so corals are not starved of phosphate to begin with, N to P ratios are not a concern, at least relative to the levels hobbyists typically target.
Thoughts?
First of all I most certainly have not said N-P ratios above 10-1 are detrimental anywhere. It would be pretty stupid as I am on the record using Southampton's results.
One additional item to note is that potential N enrichment stunting coral growth does not arise from micro algae simply growing and absorbing the available phosphate, it also interferes with the symbiotic process of the coral passing trace nitrate to the zooxanthallae and receiving sugars, aminos, and carbs in return.First of all I most certainly have not said N-P ratios above 10-1 are detrimental anywhere. It would be pretty stupid as I am on the record using Southampton's results.
I am curious where you heard that ratio of 10-1 N-P being bad? Thurber, et al, did find ratios close to your supposed 10-1 N-P did increase disease incidence on a reef. However, I think it's important to keep in mind that was the result of fertilizer being dosed in addition to the plankton the reef was receiving it. Very different than the controlled conditions used by Southampton. (For refference Delbeek and Sprung on pg 377 and 378 of "The Reef Aquarium" V. III discuss plankton on reefs and give numbers of 2 gm to 5 gm dry weight per 100 gallons daily.)
I certainly agree on not chasing numbers. I was curious and went back to when I first started using that phrase and it was almost 7 years ago. And here's a qoute of mine from 9 years ago:
"Some people advocate frequent testing and some people (myself) are more lax and use the ol' eyeball, I would point out that corals can over time acclimate to conditions that will kill new corals so at least periodic testing is suggested once you are familiar with your tanks moods."
10 years ago Delbeek wrote this:
"Our crystal-clear aquaria do not come close to the nutrient loads that swirl around natural reefs. And so when we create low-nutrient water conditions, we still have to deal with the rest of a much more complex puzzle. Much like those who run their aquarium water temperature close to the thermal maximums of corals walk a narrow tight rope, I can't help but think that low-nutrient aquariums may be headed down a similar path." Charles Delbeck, Coral Nov/Dec 2010, pg 127
It's not at all surprising to me you have very little PO4 in the reef close to you. Kleypas, et al, 1999 gives minimums and maximums and some reefs are very low. Average PO4 is ~.012 mg/l (.13 µM). Maximum given by Kleypas is ~.0512 mg/l (.54 µM). Sooooo, I have to disagree with your assertion .028 mg/l is " is way above typical NSW levels"
If we only had to deal with the risk of uric acid crystals forming and rupturing coral cell walls it really wouldn't bother me to say stick to .028 like you seem to be saying. Keeping PO4 low can be done for years. D' Angelo and Wiedenmann at Southampton University set up a very typical reef system and maintained it for years before they started running thier experiements. (I've posted several of thier papers already but here's thier paper where they initially describe thier system.) But as you've read when temperatures rise PO4 demand rises also. One of the biggest problems I see is AC failure. Keeping PO4 higher than the threashold identified by Southampton reduces the risk of bleaching corals due to a phosphate deficiency should aquarium temperatures rise unexpectidly.
I guess you didn't read all the papers done by Southampton I posted. Thier experiments were done on corals maintained in a typical reef setup. Not conducted on corals in situ. Thier research applies just as much to corals maintained in our systems as much, if not more so, than corals on reefs.
OK Tim, I tried to send you a private message to discuss the points you've raised by quoting me. This wasn't possible as it seems you have placed me on your ignore list, for some reason? That's very interesting, & also perplexing as you quote me here, looking for interaction. . . .