Dissolved Organic Carbon and Coral Disease

[robert]

In reply to a poster seeking help to address STN in his SPS - I may have inadvertanly derailed his thread as a considerable discussion ensued which although only only slghtly tangental to his problem - did not focus on his specific situation - My apologies. I though the topic however an important one so I moved it here to clean up his thread and to open it to a more general discussion.

Please read post: https://www.reef2reef.com/threads/why-is-my-sps-peeling-and-turning-white.211149 for context.

In reply to a question as to cause and cure of STN, I replied:

Here is an alternate thought...

We only talk of two basic nutrients - Nitrate and phosphate. We ignore and do not test for dissolved organic carbon.

Our tanks and corals are loaded with bacteria - held in check by the lack of organic carbon sources.

Corals themselves harbor the bacteria which causes this condition, kept in check by the slime coat which renders DOC unavailable to residing bacteria.

If the coral resident bacteria gains access to DOC, either through excess dosing, excess suspended particulate carbon or damage - the bacteria already present kills the coral -

It does not have to be an introduced pathogen. A bactriostatic which could penetrate the slime coat coud stop its progression but other wise once out of hand the bacteria has access to all the C,N,P it needs from the coral tissue itself. Fragging is the only defense.

Carbon dosing - in one form or another - either deliberate or inadvertant or a system shift which destabilizes the slime coat is in my opinion the the most probable cause.

Do not carbon dose in any form. Actively strip carbon from the water column by all means at your disposal. Run agressive filteration and active carbon. Hign N or P or ammonia alone or in combination does not cause this - DOC does.

 

[robert]

Chefjpaul posted some invaluable links...well worth the read.

http://www.researchgate.net/profile..._Mortality/links/0deec5266a31792079000000.pdf

http://www.nature.com/ismej/journal/v5/n8/abs/ismej201112a.html

 

[Amoo]

following as I saw this in the other thread and this is one of the more interesting and potentially promising "theories" I've read.

 

[robert]

From chefs first citation

coral surface mucopolysaccharide
layer (SML) = coral slime

Please read the section:
Coral-associated Bacteria augmentation experiment.


"Treatment of corals with phosphorus
or nitrogen sources did not cause significant
mortality in five 30 d experiments
with respect to the seawater controls

Coral mortality caused by DOC treatments
was on average 5-fold higher
(36.6%), and significantly different
compared to controls (p < 0.001

Organic carbon treatments
caused pathologies similar to those reported
for band diseases, with a progressive
loss of tissue starting at the colony
margins, as well as rapid sloughing of
coral tissue. Similar mortality patterns
due to DOC loading were also observed
in 4 previous culturing experiments
using a simpler culturing system in
Panama and Puerto Rico (data not
shown). Naturally occurring reef POM
caused significant bleaching of the corals
in both treatments (Fig. 1, p < 0.005)."

It gets more interesting

"Coral SML was collected and cultured.

The cultured Bacteria were added to 30 l
of fresh seawater in glass aquaria once
every 3 d, to make a final concentration
of ~106 Bacteria ml–1. There were 10 M.
annularis nubbins in each aquaria.

"Addition of ~106 microbes ml–1 of seawater in
(this only a 2x increase over the upper limits of pristine reef water - my comment)
aquaria caused elevated coral mortality in aquaria
experiments as compared with controls (Fig. 3). The
Vibrios caused 100% mortality in 16 d, while the
Enterics caused 90% mortality in 19 d. Both the coralassociated
Enterics and Vibrios had a lethal time until
50% mortality (LT50) of 14 d (Fig. 3)."

Both these bacteria were cultured from the SCM of the corals themselves....
The disease(s) are already resident in the corals - DOC disrupts the function of the slime coat and hence the bacterial balance
Causing the corals to lose tissue and die.






[

 

[chefjpaul]

From that,
I'm really starting to think the correlation of DOC's and an insufficient amount of or diversified supply bacteria is relevant in relation to running low nutrients.

I think the more we strip our systems and not add back bacteria strains to compete with DOC's which in turn inorganic nutrients that slow calcium building leading to RTN / STN.

While LN / ULN systems tend to run with a lower KH, resulting in weaker calcification / slime coat.

I think addition of different strains of bacteria can strengthen the system.
Or
Stop stripping these system so much?

 

[robert]

What this means is there need not be an introduced pathogen...elevated DOC can trigger the death of your corals.
Carbon dosing to reduce Nitrate and Phospahte may be exactly wrong as neither of these in elevated concentration caused the disease.

Have we been chasing numbers and in doing so killing our corals.

I have been practicing low-bac reefing for ~ 8 months now. I have huge nutrient loads and healthy corals - go figure.

 

[robert]

We may have violated our own rules with carbon - if you can't test it don't dose it....

 

[robert]

Adding a "known" bacteria to an established system to consume DOC and reduce N and P may be a good strategy. But dosing organic carbons without a test is probably flirting with trouble.

How many with low N and P continue to dose?

 

[robert]

The next question might be "do corals need adjuvant bacteria at all"?

By way of analogy, we too have bacteria on our skin, in our mouths and gut. It does not mean we consume bacteria as food or that that bacteria is providing some symbiotic function. If we were to suddently lose our immunity, we too might be overcome by some awful flesh eating bacteria.

the SCM is the corals defense - like our skin. The corals need the N and P but the overabundance of C feeds its enemies...

 

[robert]

There may be a simple way to measure bacterial load and DOC using methelene blue. Its along the lines of the "milk quality" experiment done in middle school. I've been fiddling with it but it still isn't right and not calibrated.

It relies on bacterial consumption of oxygen causing methelyne blue to go clear and timing how long that takes.
If your out of any of the three N/P or C it should take monger or it won't change at all.

I have high N (very high N) and unknown P - and the water sits blue indefinately.
If I add C it should fade after a few hours to a day as the aerobic bacteria consume oxygen...it does but not enough.

It could be a neat experiment to run as a community if the protocol were set.

 

[robert]

I'm done...need to go check on a new fish - a poor mans gem tang - a mustard surgeon fish...picked him up today (like I need more bio-load)

 

[chefjpaul]

There may be a simple way to measure bacterial load and DOC using methelene blue. Its along the lines of the "milk quality" experiment done in middle school. I've been fiddling with it but it still isn't right and not calibrated.

It relies on bacterial consumption of oxygen causing methelyne blue to go clear and timing how long that takes.
If your out of any of the three N/P or C it should take monger or it won't change at all.

I have high N (very high N) and unknown P - and the water sits blue indefinately.
If I add C it should fade after a few hours to a day as the aerobic bacteria consume oxygen...it does but not enough.

It could be a neat experiment to run as a community if the protocol were set.

Interested

 

[robert]

I've been think that what may be wrong is that I don't start with enough bacteria - maybe kick start it with a known quantity and if so how much.

 

[chefjpaul]

Maybe look into the SHIMADZU technology methods and techniques they employ.

I will be doing a lot of research on this during my flight to Cairns Monday. And write up some thoughts and questions on the return.

 

[robert]

I will - thanks and have a safe trip...
I look forward to hearing your thoughts.

 

[Mattrg02]

Well, back to my microbacter7 it is!

 

[Randy Holmes-Farley]

FWIW, while I think it is a fine hypothesis that dissolved carbon may be a problem in some reefs, I do not think it is clear that general DOC's have caused an issue in typical aquaria (except cyanobacteria, which is very likely).

 

[Aquaph8]

Only time I have found any issue with carbon dosing relating to coral health is with Alk burn caused by AlK over about 8dkh. Like Randy stated Cyano can also be a small problem from time to time. I've pushed dosing pretty hard at times too.

 

[Mattrg02]

Can anyone recommend a good bacteria supplement that is confirmed to be alive? I'm back to using microbacter7, but read that no one can confirm it has anything alive.

 

[Randy Holmes-Farley]

Can anyone recommend a good bacteria supplement that is confirmed to be alive? I'm back to using microbacter7, but read that no one can confirm it has anything alive.

One of my concerns with these is that people seem to think they contain species that can do all kinds of different things, from nitrifying to denitrifying to consuming whatever organic they may be dosing. That seems a lot to ask from a single product, even if they are alive.