Light, Alkalinity, Nutrients.

[mcarroll]

"liquid" nutrients can feed the tissue as much as capturing "live" food. Or is it more "liquid" than "live".

Corals are omni-feeders to be sure – you know they are even known express chitonase on their skin so they can digest (e.g.) bug shells??!! :D So amazing.

But dissolved nutriets are known to first benefit the microbes such as their zooxanthellae, and secondarily benefit the host. This is why it's possible to over-do dissolved nutrients and bleach a coral. (Not too easy in a home setting as I've not seen it, but possible.)

Particulate nutrients are the opposite – they first benefit the coral host and the zooxanthellae sencondarily.

 

[mcarroll]

Forgot to answer this part...

The nitrogen cycle on the reef must be hidden low within the reef, low as in decaying matter surrounding the corals, rock and sand. Low as in the oceans flow is impeded by the corals structure, thus reducing removal of nitrates surrounding the corals to the point of not starving them?

Yes! :)

Has there been any studies of this?

I've got a few here:

• Extracoelenteric zooplankton feeding is a key mechanism of nutrient acquisition for the scleractinian coral Galaxea fascicularis
• Impacts of nutrient enrichment on coral reefs: new perspectives and implications for coastal management and reef survival
• Limited phosphorus availability is the Achilles heel of tropical reef corals in a warming ocean
• Results of the 1991 United States-Israel Workshop, “Nutrient Limitations in the Symbiotic Association between Zooxanthellae and Reef-building Corals”

Ignore the titles – each article has some relevant goodies. :) :)

@Lasse I think you were talking about something like this? Heat + Nutrients? (Someone! LOL)

• The response of the scleractinian coral Turbinaria reniformis to thermal stress depends on the nitrogen status of the coral holobiont

@Dana Riddle (and everyone) Have you seen this one?

• The in situ light microenvironment of corals ;Jawdrop

(I tried to make some useful comments and quotes from the article on the link page as usual.)

It seems to cover in detail at least some of the lighting aspects that have come up here.

 

[Diesel]

Forgot to answer this part...



Yes! :)



I've got a few here:

• Extracoelenteric zooplankton feeding is a key mechanism of nutrient acquisition for the scleractinian coral Galaxea fascicularis
  
• Impacts of nutrient enrichment on coral reefs: new perspectives and implications for coastal management and reef survival
  
• Limited phosphorus availability is the Achilles heel of tropical reef corals in a warming ocean
  
• Results of the 1991 United States-Israel Workshop, “Nutrient Limitations in the Symbiotic Association between Zooxanthellae and Reef-building Corals”

Ignore the titles – each article has some relevant goodies. :) :)

@Lasse I think you were talking about something like this? Heat + Nutrients? (Someone! LOL)

• The response of the scleractinian coral Turbinaria reniformis to thermal stress depends on the nitrogen status of the coral holobiont

@Dana Riddle (and everyone) Have you seen this one?

• The in situ light microenvironment of corals ;Jawdrop

(I tried to make some useful comments and quotes from the article on the link page as usual.)

It seems to cover in detail at least some of the lighting aspects that have come up here.

Dang, I can't navigate myself through that in one night :rolleyes:
But there's always some one who can. ;)

 

[Randy Holmes-Farley]

So if fast growth/thin tissue is the cause of 'burn', why don't we see the same occur to rapidly growing encrusting bases (often seen in recently fragged SPS corals, where the widened base acts as an 'anchor' before the corals can grow tall)?

I don't know if the hypothesis is correct, or if it may apply to some corals and not others (not all seem to get burnt tips) but if it is, then corals that have adapted to grow tissue to match their skeletal growth at normal alkalinity (no matter how fast that is) may do fine while the "abnormally" fast skeletal growth at high alkalinity is the primary thing that pushes some corals over the edge of growing tissue fast enough when nutrients are not sufficiently available.

 

[Dana Riddle]

Thanks for the comments! And I haven't seen the 'scalar irradiance' paper. I just this morning picked up a 120-gallon system for the lab, and other duties have put a strain on my spare time. Will try to look at all these comments while flying to Wyoming for the eclipse later this week. And then there's the family wedding to attend in Jacksonville. Who said retirement was boring?!

 

[Diesel]

Lol, that's the reason I won't retire cause ppl taking up your free time.

 

[CodyRVA]

All good input, great thread! I keep pointing back to the current state of my system because i'm experiencing everything this thread is discussing; Here. A few things i'd like to report all from my "learning experience."

All corals are not made the same, duh. My point, some of the "easiest to keep" coral were the first ones to bite the dust when I experienced a spike in PO4 and then a spike in ALK. My Green ORA Birdsnest was bleached within 2 days, it was just larger than a softball. Same thing happened to my bali green slimer. I'm really starting to buy into the link between ALK and growth rates. These two corals for example are relatively fast growers IME. Is it fair to assume the faster the growth rate of a coral, the faster it will bleach out and die given this situation? Do these easy to keep corals have a much smaller window for survival, in this particular situation, because of they're fast growers?

SPS vs LPS. No intention on getting into the category debate, but corals like cyphastrea and leptos that are commonly sold as LPS and IMO should absolutely be classified as SPS. My justification is these types of corals reacted the exact same way as my SPS colonies. They are a lot of skeleton and very little flesh. Ultimately it's irrelevant what you call them; the point is in the unfortunate condition my system was in, the fleshy/soft corals were naturally the least affected. Hammers, Candy Canes, etc also had no sign of ailment, softies entirely unaffected (shocker).

Any claim that high ALK has no affect on burnt tips is simply false unless you can somehow validate many other conditions like nutrients, flow, lighting, etc. If you maintain low nutrients and drive your ALK up, I promise you will have trouble with stony coral. If you don't, then pray tell how... Totally possible to have an ALK of 11 dKH with happy stony coral. Farfetched to believe you can have an ALK of 11dKH with NO3 and PO4 at 0 with happy stony coral, however, i'm sure there are other "things" at play here that contribute to this.

Lastly, lighting and flow play a crucial part in this. IME coral exposed to higher light and higher/more direct flow suffering from "burning" died much much faster in comparison to those exposed to lower light or lower/indirect flow. My guess based on what others have mentioned is less light and flow will naturally cause little to no additional damage to a coral vs coral that's already suffering in addition to being blasted with high light and flow. The ironic part is most SPS demand such parameters; this makes me wonder if this is the explanation to why a "burnt" coral will ultimately die regardless if parameters are corrected... flow and light. Could a potential solution be to move a burnt stony coral to low light and flow until parameters are corrected?

 

[reeferfoxx]

My Green ORA Birdsnest was bleached within 2 days, it was just larger than a softball.

Not arguing your point and I know this thread isn't coral specific but I dont think birdsnest is a easy to keep coral. It's a fast grower because has thin branches compared to other sps. Because they grow fast, they are one of the cheapest corals. Though, great identifiers of unstable parameters. A true easy to keep sps in my experience is the green or purple stylophoras. Stylos can absorb a lot of swings.

Could a potential solution be to move a burnt stony coral to low light and flow until parameters are corrected?

Moving an encrusted coral from one spot to another alone can cause issues so I don't think that would fix the issue either. That said, nutrient swings are an indicator that the tank isn't ready for more sensitive coral. Taking that into consideration, we urge hobbyists to take it slow. Let the tank mature, be consistent with husbandry, and feeding.

 

[Diesel]

Stress factor comes also in place.
How often we say if a SPS going down fast as in a RTN from top to bottom or vise versa not for getting left to right as depends how you look to the coral to frag it as to salvage some of it
That said not all is related to parameters, light or flow.
A quick water change in this case or many cases if we talking SPS won't help now LPS will have some sort reaction on a water change.
Is it not the docometaries we see of a reef dying in most cases we see only SPS corals.
That's why I think stress factors on a SPS plays a big roll in from being perfect even we hold them under different parameters to bad conditions.
Most of us experienced the fact why one collony just decide to say goodbye like it or not while others look perfect.
As I say many times "if you go slow, slow down even more, never seen a 1" frag turn into a colony over night but have seen and experienced that a colony turned into a frag over night"

 

[CodyRVA]

A true easy to keep sps in my experience is the green or purple stylophoras. Stylos can absorb a lot of swings.

I've got a green and purple right next to each other and during this debacle the purple has maintained its resiliency, the green has almost bleached entirely... I believe this to be the case because stronger/direct flow comes in from the same side as the green stylo; which is why i called light and flow into question in my previous post.

Moving an encrusted coral from one spot to another alone can cause issues so I don't think that would fix the issue either. That said, nutrient swings are an indicator that the tank isn't ready for more sensitive coral.

Nutrient swings and swings in general can happen in even the most established systems. Agreed, moving a coral is a gamble under even the best conditions, but honestly seeing colonies die out so fast IMO it's worth the gamble. That said, it truly is a gamble... if you leave it, it might rebound assuming your chemistry is corrected in a timely manner; if not then it might be worth relocating and or fragging.

Reducing flow might be a better option; I have done this and seen success. I also tried reducing lighting, unfortunately this has an adverse affect since ALK tends to swing over night periods. Reducing my ALK dosage and cutting my lights back resulted in a rise in ALK, not decline.

 

[reeferfoxx]

Nutrient swings and swings in general can happen in even the most established systems.

Yes, but husbandry or common maintenance is typically the catalyst in maintaining stable nutrients. For example, dead fish not found, dying or dead snails staying in the tank, not cleaning detritus, or over feeding and thinking the tank can absorb it. I'm not a fan of chemical filtration so I won't add that to maintaining stable parameters.

 

[hart24601]

So if fast growth/thin tissue is the cause of 'burn', why don't we see the same occur to rapidly growing encrusting bases (often seen in recently fragged SPS corals, where the widened base acts as an 'anchor' before the corals can grow tall)?

This could be a surface area ratio item. That is the surface ratio to volume (or mass here) - growth tips have a far greater surface area than the encrusting base per skeleton unit as they are only lit from the top as the bottom is on the plug or rock and the sides are not lit either is the coral is encrusting evenly. Now what is interesting is if alk, nutrient or flow is encouraging the base widening and via what feedback mechanism.

 

[Hans-Werner]

These two corals for example are relatively fast growers IME. Is it fair to assume the faster the growth rate of a coral, the faster it will bleach out and die given this situation? Do these easy to keep corals have a much smaller window for survival, in this particular situation, because of they're fast growers?

I have always tried to see a mechanism behind the way corals react to certain parameters and I have come to the conclusion that somehow growth and phosphate need/phosphate consumption on the one side and phosphate and alkalinity on the other side are connected. In this way the corals with the fasted growth are most sensitive to low phosphate and high alkalinity. I think Acropora spp. are the most sensitive corals to this kind of problems. One or my first experiments 24 years ago with my three part method was how much calcium and alkalinity I can add and how the corals react. The first reaction I saw was that a Acropora frag showed tissue lesions at the base as soon as alkalinty rose at 9° dKH or higher. Ever since I found this reproducible.

 

[Hans-Werner]

So if fast growth/thin tissue is the cause of 'burn', why don't we see the same occur to rapidly growing encrusting bases (often seen in recently fragged SPS corals, where the widened base acts as an 'anchor' before the corals can grow tall)?

I think the growth on the tips and fast growth of frags at the base are different biochemical growth mechanisms. In skeletal growth different calcification mechanisms are involved like the well know removal of H+ from bicarbonate turning it into carbonate but also the hydrolysis of urea or glutamin realeasing ammonia and raising the pH in this way. The proportions of the different mechanisms at the white tips of Acropora and at the brown base are different. I guess in the white tips far away from zooxanthellae the proportion of urea hydrolysis is higher.
I hope my English is understandable.

 

[Nano sapiens]

Any claim that high ALK has no affect on burnt tips is simply false unless you can somehow validate many other conditions like nutrients, flow, lighting, etc. If you maintain low nutrients and drive your ALK up, I promise you will have trouble with stony coral. If you don't, then pray tell how... Totally possible to have an ALK of 11 dKH with happy stony coral. Farfetched to believe you can have an ALK of 11dKH with NO3 and PO4 at 0 with happy stony coral, however, i'm sure there are other "things" at play here that contribute to this.

In my very mature, well fed system (NO3=0.5, PO4='0'...Salifert) a few years ago I had alkalinity rise from 9.5 to 14 dKh in the matter of hours due to reef keeper error (checked alkalinity with two separate kits just to make sure). SPS specific corals (Montipora, Stylophora, Pavona, Leptoseris and one Acropora granulosa) showed only one aftereffect which was a temporary loss of polyp extension that returned to normal in 2-3 days. LPS and Shrooms...no visible effect. No mechanical or chemical filtration. The corals are not blasted with an overabundance of light (SPS range 140 - 280 PAR of 'full spectrum' LEDs) and flow is moderate.

The exact reason(s) why one system experiences 'tip burn' and another doesn't? While I have my hunches, I can't say for sure without controlled experimental studies.

Ralph.

 

[CodyRVA]

In my very mature, well fed system (NO3=0.5, PO4='0'...Salifert) a few years ago I had alkalinity rise from 9.5 to 14 dKh in the matter of hours due to reef keeper error (checked alkalinity with two separate kits just to make sure). SPS specific corals (Montipora, Stylophora, Pavona, Leptoseris and one Acropora granulosa) showed only one aftereffect which was a temporary loss of polyp extension that returned to normal in 2-3 days. LPS and Shrooms...no visible effect. No mechanical or chemical filtration. The corals are not blasted with an overabundance of light (SPS range 140 - 280 PAR of 'full spectrum' LEDs) and flow is moderate.

The exact reason(s) why one system experiences 'tip burn' and another doesn't? While I have my hunches, I can't say for sure without controlled experimental studies.

Ralph.

I've had my ALK spike by 3 dKH in the past, but I wasn't running ULNS then and I had the same result. It ticked the coral off, but everything leveled out and all was well in the world again, no burning. Recorded no change in my softies. A clear back draw to running low nutrients.

In addition, my tank is very shallow, 6 bulb ATI, from sand to top i've got 250 - 450 PAR with high flow in the top half of the tank. Again, clearly not ideal if something like this goes amiss.

 

[chefjpaul]

Forgot to answer this part...



Yes! :)



I've got a few here:

• Extracoelenteric zooplankton feeding is a key mechanism of nutrient acquisition for the scleractinian coral Galaxea fascicularis
  
• Impacts of nutrient enrichment on coral reefs: new perspectives and implications for coastal management and reef survival
  
• Limited phosphorus availability is the Achilles heel of tropical reef corals in a warming ocean
  
• Results of the 1991 United States-Israel Workshop, “Nutrient Limitations in the Symbiotic Association between Zooxanthellae and Reef-building Corals”

Ignore the titles – each article has some relevant goodies. :) :)

@Lasse I think you were talking about something like this? Heat + Nutrients? (Someone! LOL)

• The response of the scleractinian coral Turbinaria reniformis to thermal stress depends on the nitrogen status of the coral holobiont

@Dana Riddle (and everyone) Have you seen this one?

• The in situ light microenvironment of corals ;Jawdrop

(I tried to make some useful comments and quotes from the article on the link page as usual.)

It seems to cover in detail at least some of the lighting aspects that have come up here.

Very great stuff here as always, spent a couple days reading these, as one article would lead me on many more searches.
So from this:

1. Under constant nutrient concentration, light intensity determines the onset of nutrient limitation; as light increases, C : N ratios exceed Redfield ratios.
2. The availability of other nutrients, mainly nitrogen, determines the fate of photo-assimilated carbon. Under high C: N ratios, most carbon goes into respiration, calcification, and excreted mucus, whereas low C : N ratios favor increases in zooxanthellae density, reduce translocation, and slow down calcification.
3. Feeding on zooplankton by the coral under low light provides carbon for metabolism. Under high light it supplies both algae and animal with nitrogen.

"Most recently, however, we could demonstrate that corals exposed to elevated nitrogen levels were more susceptible to bleaching when exposed to heat and light stress [28•]. Interestingly, the detrimental effects observed in these experiments could be attributed to the relative undersupply of phosphorus that resulted from the enhanced demand of the proliferating zooxanthellae population rather than to the elevated nitrogen levels themselves (Figure 1 ; Figure 2)".
---
Say If there is an elevated KH, and ULN, meaning the coral is growing faster than the Zoox can reestablish themselves, but what is actually slowing down or stopping Zoox in our aquarium from reproducing, or limiting?
Not enough dissolved nutrients coupled with intense light & they cant reproduce quickly enough within the new growth, / excess Nitrogen?
Coupled with carbon dosing which maybe faster removing the Nutrients then the Zoox can reproduce would seem like sense., especially if there is / most likely a valid user error, like non proper skimmer / skimming, higher temperature, etc..?
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0075049

 

[Dana Riddle]

Aaaarrgghhhh! More references to review ;). Here's an older one of mine about phosphorus in a *lightly* loaded tank - imagine if it was heavily fed! Total P was about 0.5 mg/L and is slowly converted to soluble, reactive orht0phosphate. Hence an aquarium with an anaerobic zone (intentional, passive, whatever) should have a steady supply of P. If it accumulates, of course, is dependent upon the rate of export. So, I'm not seeing any need to add P in the case of *this* tank.

 

[snappa1953]

In my very mature, well fed system (NO3=0.5, PO4='0'...Salifert) a few years ago I had alkalinity rise from 9.5 to 14 dKh in the matter of hours due to reef keeper error (checked alkalinity with two separate kits just to make sure). SPS specific corals (Montipora, Stylophora, Pavona, Leptoseris and one Acropora granulosa) showed only one aftereffect which was a temporary loss of polyp extension that returned to normal in 2-3 days. LPS and Shrooms...no visible effect. No mechanical or chemical filtration. The corals are not blasted with an overabundance of light (SPS range 140 - 280 PAR of 'full spectrum' LEDs) and flow is moderate.

The exact reason(s) why one system experiences 'tip burn' and another doesn't? While I have my hunches, I can't say for sure without controlled experimental studies.

Ralph.

Veerrrryyy interesting! May I ask about your set up Ralph? No mechanical or chemical filtration? A lot of different corals?

 

[Grey Guy]

I'm not there yet.