Light, Alkalinity, Nutrients.

[bubbaque]

I was told that if corals are kept in high alkalinity with no nutrients that the skeleton will go faster but there isn't enough nutrients to support the faster growth, this causes tip burn.

Dana, what do you believe causes tip burn if this is not it?

 

[mcarroll]

the amount of pellets I have running at any given time is a joke. It has got to be only barely making a difference.

+1

I wish we had a way to quantify this though!

I don't know how they do it for science experiments, but they report C levels all the time. Wish there was a way for us to at least know that much about our own C levels.

(Sorry for the side-track....for those interested in the burt-tips angle, I do have some posts on my blog with articles that talk about some features of this. Read there or PM me if this is interesting.)

why do some recommend raising nutrient levels to keep them inline with a given alkalinity level?

I literally started hearing this with frequency after your now-famous appearance at MACNA that was widely publicized on BRS/Youtube and much-linked here on R2R. :)

I'm honestly not sure if that was a coincidence of timing or not though. I just know those conversations posts and threads seemed isolated before.

Before I recall that we mostly talked about N and P levels with regards to light levels. Flow and chemistry were mostly presumed to be "good" in those conversations (or blamed if there were problems, then corrected), at least as I recall.

 

[chefjpaul]

We were beta testing some of Knop's giant calcium reactors (not sure if these monsters ever made it to market) and, if my recollection is correct of circumstances some 20 years ago, the dKH jumped about 2 full units (that is, ~7 to 9) overnight. We didn't see any stress reactions (polyp withdrawal, mucus production, bleaching, etc.) My point is that we didn't lose any of perhaps 20 coral genera (hundreds of frags, perhaps a 100 species) we had in this system. All I am suggesting is that a sudden jump in alkalinity didn't cause any adverse effects that we could determine visually, and certainly no tip burning. Do I recommend doing this - of course not. But we did and it was part of our learning curve.

Were you guys testing nutrient levels as well in this calcium reactor experimenting?
I see you may have shown no issues with the sps, but were the nutrients not running naturally higher 20 years ago?
Henceforth the corals probably were
1). Acclimated to it
&
2). They Wouldn't be affected negatively with an Alk spike, as opposed to today where carbon / nutrient stipping is a common occurrence.

 

[madweazl]

I dont really know what to think. My tank was looking good and my parameters have been very stable in the range considered "good" (e.g. dKH 8-8.5, NO3 5, PO4 .03, Ca 440, Mg 1335) for the past six months; I had no complaints. About a month ago I did a full set of tests along with taking samples for Triton. I had PO4 .049 on a Hanna ULR and my Triton results came back 0 (P and PO4). Last weekend I ran some tests and my PO4 .153! I did a larger than normal water change (20g vice my typical 10g) and it dropped the PO4 by roughly 30%. A couple days later and it had dropped a little bit more but today it was back up to .126 (NO3 dropped to 0 during the same period and it has always been right around 5). After thinking about it a while, the SPS have never looked better so I said to hell with it and decided to make that my new baseline.

I have no idea what "good" or "bad" is when it comes to measurements anymore but when my corals look happy, I'm happy. Oh yea, forgot about light and alkalinity. After the water change, my alkalinity was 9.9 dKH. Before adding the pair of T5s, I was providing about 125 PAR to the higher SPS and about 90 PAR to the lower SPS. Alkalinity nor lighting seems to make any difference with the "elevated" (I dont much trust the test right now) PO4 and non-existent NO3.

 

[CodyRVA]

Great convo here. In regards to lighting, i'd love to know if higher PAR or more intense lighting throws another wrench into all of this. My system is very high light ranging from 450 to 250 on the sand bed. I'm starting to think my shallow lagoon tank is as much higher risk for ALK burning because of how intense and how shallow my water is.

 

[Dana Riddle]

Were you guys testing nutrient levels as well in this calcium reactor experimenting?
I see you may have shown no issues with the sps, but were the nutrients not running naturally higher 20 years ago?
Henceforth the corals probably were
1). Acclimated to it
&
2). They Wouldn't be affected negatively with an Alk spike, as opposed to today where carbon / nutrient stipping is a common occurrence.

This 1,500 gallon system was filtered by 3 algal turf scrubbers (totaling about 3 m2 surface area) plus protein skimming, so we were in constant danger of nutrient deficiency (ala Adey.) The system was lighted by 8 400-watt 6500K lamps in high bay fixtures with PAR values (at the corals) of 800-900. No nuisance algae were growing. This was 20 years ago, and I haven't had access to the log books for a while (although I *might* have some notes in my personal diary. I'll try to find that book.)

 

[Nano sapiens]

In 20+ years of keeping stony corals, I have yet to observe this phenomenon. My systems are basic (chemical media and mechanical filtration are not used), but have the full mix of SPS, LPS, Zoas, etc.

My personal supposition in regards to tip burning: When SPS in a ULNS environment do not have the energy reserves to support the growing tips with enough ATP (when the higher than NSW alkalinity level triggers a growth spurt), tip burning can occur. In a sense, the coral withholds it's limited resources from the tip areas to limit/halt the growth spurt that it can't maintain and makes sure that the main body stays nourished. When conditions return to NSW levels, more normal slower growth can continue and the tips 'recover'.

Link: https://link.springer.com/article/10.1007/BF00397270

Why does the white tip of stony coral grow so fast without zooxanthellae?

The photosynthesis of zooxanthellae in a coral polyp greatly enchances the calcification rate of a coral. However, the white tip of a coral branch is free of zooxanthellae yet still has a very high calcification rate. Furthermore, the reason for the difference is not clear. In this study, the amount of photopigment, total protein (TP), total organic carbon (TOC), ATP, and lipid in polyps from the white tip and brown stalk of a branch of stony coral were measured. Samples of Acropora hyacinthus and A. formosa were collected from southern Taiwan between 1985 and 1987. The results showed that the ATP concentration in polyps of the white tip was much higher than that in polyps of the brown stalk. Conversely, the amount of TP, TOC and measured lipids in polyps of the brown stalk were all higher than those of the white tip. It was the high concentration of ATP in cells that gave these polyp tips the vitality to sustain the energy requirements of such a rapid calification rate. Facilitated diffusion, due to the high metabolite gradient created by cell activity, could be the major driving force for the transport of photosynthetic product from stalk to tip.


The very low nutrients as well as the reduced bacterial counts (bacteria are consumed by corals) of ~1/10 of natural coral reef levels based on the study below when a skimmer and GAC are used) in a ULNS reef aquarium, can cause energy reserve issues:

Link: http://www.advancedaquarist.com/2011/3/aafeature

Bacterial Counts in Reef Aquarium Water: Baseline Values and Modulation by Carbon Dosing, Protein Skimming, and Granular Activated Carbon Filtration

(excerpt): The observation that, at least among this small set of aquaria examined, the water within the skimmed/filtered tanks had only ~ 1/10th of the population of bacteria that the unskimmed/unfiltered tanks had was a real surprise.


Ralph.

 

[Dana Riddle]

I was told that if corals are kept in high alkalinity with no nutrients that the skeleton will go faster but there isn't enough nutrients to support the faster growth, this causes tip burn.

Dana, what do you believe causes tip burn if this is not it?

We know that increasing alkalinity will increase the rate of photosynthesis in at least one zooxanthella clade (C15 found in Pacific Porites.)Photosynthesis (along with respiration) will produce harmful oxygen radicals and hydrogen peroxide which are destructive if not detoxified by dismutase enzymes. Now the question is the 'shelf life' of these enzymes - are they 'used up' after one bout, or are they good to go for several rounds. Someone might know, I don't. So, this is my hypothesis - unnaturally high alkalinity levels turbocharge photosynthesis and production of harmful oxygen species, and natural enzyme defenses are overwhelmed, thus tissue is destroyed. This happens at the tips of SPS corals because a.) the tips receive the most light and b.) the tips are likely exposed to the most water flow (which also boosts photosynthesis.) This probably happens in soft corals too, but the amount of tissue makes the damage less apparent. But I still don't get what nutrients have to do with it. Some please offer a hypothesis...

 

[Dana Riddle]

In 20+ years of keeping stony corals, I have yet to observe this phenomenon. My systems are basic (chemical media and mechanical filtration are not used), but have the full mix of SPS, LPS, Zoas, etc.

My personal supposition in regards to tip burning: When SPS in a ULNS environment do not have the energy reserves to support the growing tips with enough ATP (when the higher than NSW alkalinity level triggers a growth spurt), tip burning can occur. In a sense, the coral withholds it's limited resources from the tip areas to limit/halt the growth spurt that it can't maintain and makes sure that the main body stays nourished. When conditions return to NSW levels, more normal slower growth can continue and the tips 'recover'.

Link: https://link.springer.com/article/10.1007/BF00397270

Why does the white tip of stony coral grow so fast without zooxanthellae?

The photosynthesis of zooxanthellae in a coral polyp greatly enchances the calcification rate of a coral. However, the white tip of a coral branch is free of zooxanthellae yet still has a very high calcification rate. Furthermore, the reason for the difference is not clear. In this study, the amount of photopigment, total protein (TP), total organic carbon (TOC), ATP, and lipid in polyps from the white tip and brown stalk of a branch of stony coral were measured. Samples of Acropora hyacinthus and A. formosa were collected from southern Taiwan between 1985 and 1987. The results showed that the ATP concentration in polyps of the white tip was much higher than that in polyps of the brown stalk. Conversely, the amount of TP, TOC and measured lipids in polyps of the brown stalk were all higher than those of the white tip. It was the high concentration of ATP in cells that gave these polyp tips the vitality to sustain the energy requirements of such a rapid calification rate. Facilitated diffusion, due to the high metabolite gradient created by cell activity, could be the major driving force for the transport of photosynthetic product from stalk to tip.


The very low nutrients as well as the reduced bacterial counts (bacteria are consumed by corals) of ~1/10 of natural coral reef levels based on the study below when a skimmer and GAC are used) in a ULNS reef aquarium, can cause energy reserve issues:

Link: http://www.advancedaquarist.com/2011/3/aafeature

Bacterial Counts in Reef Aquarium Water: Baseline Values and Modulation by Carbon Dosing, Protein Skimming, and Granular Activated Carbon Filtration

(excerpt): The observation that, at least among this small set of aquaria examined, the water within the skimmed/filtered tanks had only ~ 1/10th of the population of bacteria that the unskimmed/unfiltered tanks had was a real surprise.


Ralph.

Interesting. I have the first paper in my library, and I need to review the referenced Advanced Aquarist article. So, we could test the latter hypothesis - has anyone seen alkalinity burn in an unskimmed tank?

 

[Robthorn]

Hey Dana, I am pretty much a self proclaimed idiot but I have noticed things have changed over the last 20 years. I cannot run my tank like I did back then with Iwakis and URI vho's. Huge Euroreef skimmers and very low flow compared to todays standards.
Our alkalinity was 4.5 meq/l and higher. Now if I get much above 2.5 I have corals start to shed tissue.
Millis have always been one of the harder acros for me.
I am at a loss for what is going on these days.

 

[CodyRVA]

We know that increasing alkalinity will increase the rate of photosynthesis in at least one zooxanthella clade (C15 found in Pacific Porites.)Photosynthesis (along with respiration) will produce harmful oxygen radicals and hydrogen peroxide which are destructive if not detoxified by dismutase enzymes. Now the question is the 'shelf life' of these enzymes - are they 'used up' after one bout, or are they good to go for several rounds. Someone might know, I don't. So, this is my hypothesis - unnaturally high alkalinity levels turbocharge photosynthesis and production of harmful oxygen species, and natural enzyme defenses are overwhelmed, thus tissue is destroyed. This happens at the tips of SPS corals because a.) the tips receive the most light and b.) the tips are likely exposed to the most water flow (which also boosts photosynthesis.) This probably happens in soft corals too, but the amount of tissue makes the damage less apparent. But I still don't get what nutrients have to do with it. Some please offer a hypothesis...

You guys are clearly more educated on the matter, but i'll continue to raise questions in hopes that it will generate a "smarter" question and maybe an answer haha.

My understanding is coral will halt or slow the rate of photosynthesis when nutrients are too high right? Or I can at lest hypothesize that when coral are subjected to a sudden spike of nutrients the rate of photosynthesis will slow or stop entirely. That being said; if we have a daily dosing regiment that we follow, our systems would by default over dose because our corals are not utilizing essential components required for "growth" like ALK, CA, MG, etc. If this is true, then you would see an ALK swing at the very least right? Seems like the burnt tips, or the starting point, question has been addressed.

So if you expose a coral to high ALK, with low nutrients... the photosynthesis process is supercharged, but has no fuel to do what it's trying to do and the tissue recedes. This may have been answered, but i'd love a more clear understanding as to why this can cause the entire coral to die out. Why can you frag a tip off the same coral colony and it survive. Does the size of the colony have anything to do with this? Are smaller colonies more likely to survive vs larger ones?

Hope i'm not rambling...:eek:o_O

 

[Donovan Joannes]

I dont really know what to think. My tank was looking good and my parameters have been very stable in the range considered "good" (e.g. dKH 8-8.5, NO3 5, PO4 .03, Ca 440, Mg 1335) for the past six months; I had no complaints. About a month ago I did a full set of tests along with taking samples for Triton. I had PO4 .049 on a Hanna ULR and my Triton results came back 0 (P and PO4). Last weekend I ran some tests and my PO4 .153! I did a larger than normal water change (20g vice my typical 10g) and it dropped the PO4 by roughly 30%. A couple days later and it had dropped a little bit more but today it was back up to .126 (NO3 dropped to 0 during the same period and it has always been right around 5). After thinking about it a while, the SPS have never looked better so I said to hell with it and decided to make that my new baseline.

I have no idea what "good" or "bad" is when it comes to measurements anymore but when my corals look happy, I'm happy. Oh yea, forgot about light and alkalinity. After the water change, my alkalinity was 9.9 dKH. Before adding the pair of T5s, I was providing about 125 PAR to the higher SPS and about 90 PAR to the lower SPS. Alkalinity nor lighting seems to make any difference with the "elevated" (I dont much trust the test right now) PO4 and non-existent NO3.

Other than test kit error (either your kit or triton test :P), the absent of PO4 reading from triton could be due to being consumed by bacteria during transit. Off course this is just my 2 cents :D

 

[mcarroll]

Interesting. I have the first paper in my library

Any tips on how an ordinary knucklehead can get access to a university library with resources like that without paying for a sheepskin?

Springer is notoriously stingy. ;)

(Thank goodness for the likes of JSTOR, ALSO and others that provide access. Research Gate too, of course. ;))


P.S. Off-topic I know, but I can't be the only one cursing at the screen when I can't read the rest of an article like that from the 1980's.

P.P.S. BTW, here's a more modern article (a review) by Dr R Gates that covers some of the same ground: The future of coral reefs: a microbial perspective (PDF available)

 

[mcarroll]

Link: https://link.springer.com/article/10.1007/BF00397270

Why does the white tip of stony coral grow so fast without zooxanthellae?

Very interesting indeed – can't believe this is the first time I've seen that posted anywhere! :) :) :)

Dated since it doesn't mention microbes though....which means now I have more digging and reading to do!!!!! :) :) :) :)

A quote from the link I posted just a min ago:

Only recently have the role of microbial diversity and host–microbe interactions in the response of reef ecosys- tems to environmental change been explored.

 

[mcarroll]

Growth is there but not explosive.

Maybe contrary to what seems like common knowledge, but...

There are indications that fast-growing coral might not be as healthy as slow-growing ones....or not as resilient.

For example: Fast Growth May Impair Regeneration Capacity in the Branching Coral Acropora muricata

And on the flip side I'm not aware of any evidence showing that fast growth indicates better health, but maybe someone can link some! :)

File this under "Nothing good happens fast in a reef tank." :) :) :)

 

[mcarroll]

with the "elevated" (I dont much trust the test right now) PO4 and non-existent NO3.

PO4 started to accumulate due to exhaustion of the N supply IMO.*

Since the tank looks fine there's not much call for action – not even the water changes you did.

But if at some point you wanted to do "something" you should add nitrates up to around 5-10 ppm and restore some balance....you'll find P will drop on its own when it gets used up.

My guess is that if the system is well and consistently fed you may never have an issue....but if you do have an issue it might be paling/losing color on your stony corals. (Zero N isn't a desirable state in the long run.)

* This change was quite possibly brought on by the added light. :)

 

[mcarroll]

#reefsquad Haven't I seen one or more of the reefsquad folks talking about setting nutrient levels according to light levels?

 

[bubbaque]

Dana, you said at un-naturally high alk, photosynthesis is turbo charged and you believe the defensive enzymes can't keep up so you get burnt tips. Do you believe it has nothing at all to do with nutrient levels? Why do you believe some tanks run into issues when alk starts to go above natural sea level and other tanks are just fine running high alk?

 

[Salty1962]

Awesome discussion!
My "HYPOTHISIS" is that with the accelerated growth due to elevated Alk, corals need a nutrient source for soft tissue growth.
I have noticed in my years that when I ran higher Alk, @9-10, I had tremendous growth. I noticed that my SPS tips were pale to white but no soft tissue growth on the tips. I never have been a UNLS person but my tank was very low in No3, @4ppm, and Po4, @.01 with a heavy Bio-Load. I incorporated night time feeding of my corals 2-3 times a week. My No3 did got up, @12ppm but I noticed soft tissue growing onto my SPS tip growth. I did heavy skimming, wet, and I had very strong alternating water flow in my tank.
So that's my $.02 of info for what's worth;Yawn

 

[reeferfoxx]

I don't know, I might just be tired now and I may regret saying this in the morning but...

For example, I've seen recommendations to adjust nutrient levels upwards if running high alkalinity, which seems to defy Liebig's Law of the Minimum which states the rate of photosynthesis is regulated by the least available nutrient, not the most abundant.

I wasn't aware of Liebig's law until now. The definition might be a little ambiguous at least according to Wiki stated here:
It states that growth is controlled not by the total amount of resources available, but by the scarcest resource (limiting factor).
Situational factor should be considered. Meaning for example, your salt mix is at 12dkh. Your tank tests at 11dkh. Your nutrients are low to non detectable. At this point your nutrients would be the limiting resource. We see this with bleaching, tissue recession, or death. The suggested fix or the easiest fix is to increase nutrients. We see these threads a lot on R2R.

On the other hand, (more suiting to my situation, though not my parameters) your salt mixes at 7dkh. Your tank tests 7dkh. Nutrient are detectable but not high or low. Since going any lower than 7dkh can lower ph and cause calcium carbonate to dissolve thus lowering growth, your new limited resource would now be alkalinity and not nutrients. It this point it would be more conventional to dose alkalinity and not nutrients.

I don't think either route defies the law.

Another perspective; If your alk were stable around 7dkh though your no3 is at say, 20ppm and po4 is around the higher end, say 0.15+, you will notice your coral turning brown from mass zoox production. With tens of thousands of reefers making threads pertaining to this very topic, eventually you see trends turn to experiences turns to advice and seen as a "balance". Many SPS threads discuss this a lot but mostly in regards to pushing colors.

Furthermore, how Redfields ratio came into the mix earlier is a mystery to me. Though, some new reefers come across it at some point while learning, I think.