Corals are slowly dying and I can't figure out why??

[jschottenfeld]

I've had my 125G reef running for 3-1/2 years and for most of that time....successfully. During last summer (2010) I had some problems with A) the regulator on my CO2 tank for my calc reactor and B) my pH probe...combined with the fact that it WAS THE SUMMER!! This lead to some wild swings in my alk which I battled to correct but eventually did using 2 part solution.

For the last few months some of my caps and SPS are bleaching out and dying, some of my SPS’s have tissue that is receding from the edges, and some of my zoas are not thriving as much as they previously did or are just remaining closed when they had been doing fine for years. Other zoas and SPS’s in my tank are doing just fine, but generally speaking I don’t appear to be having the same growth that I have had in the past. Also just to mention, my clowns, tangs, wrasses, and gobies are all doing just fine.

First let me describe my system, I'll try to be as complete as possible because I hate when posters forget key facts that could help diagnose their problem. As mentioned above, my display is a 125 gallon bare bottom with 3x250 MH bulbs and 3 Tunze streams on a controller and a Wahoo return pump. I rotate the bulbs out yearly being careful to adjust light periods when the bulbs are new. I am running a Bermuda Aquatic 3C skimmer, an MRC Calc Reactor, Phosban reactor, carbon, filter socks changed weekly, Chiller to keep temp below 81 degrees, 60 gallon sump, 30 gallon fuge with DSB and Chaeto, (fuge also acts as a frag tank). I’m running a RKE controller to keep all devices in line and controlled. Using RO/DI water with 15 gal changes pretty much every week. I feed the tank 2 to 3 times per week with food and toss in BRS Reef Chili once or twice a week at night.

Here are my current tank parameters:
SG 1.025 Mag 1420
Calc 490 Temp 79.8
pH 8.38 NO3 0
Alk 9.6 PO4 0

For the first two years my tank was fairly bulletproof, most of my SPS’s and zoa’s flourished. At that time my Calcium level was keeping stable at around 320-360 and I always wanted it to be higher. After much trial and error my problem was caused by not having a consistent higher level of Mg. I had been adding liquid Mg but could never be consistent with it. At the beginning of this year I purchased a dosing pump for my Mg and from that point on I’ve been keeping a steady 1400-1500 level. Little by little I am tweaking the pump to bring it eventually down to 1350. As soon as I started using the pump for the Mg my calcium stayed consistent in the 500 range and my Alk stayed consistent 9.6-10.0.

As I stated above, I had swings in Alk from 7 to 13dKH during this past summer, but since 1/1/11 my parameters have been fairly consistent with the charted values above.

Two of my very large caps (green and grape), bleached out and died, and not just in my display tank but also frags of the same species in my fuge also bleached. Some Acros that I have are bleaching in spots and the spots are spreading. I do not see any infestation of any kind of worms upon inspection. Overall I do not see the different colored tips of my acros showing new growth.

I know this is a bit lengthy, but would appreciate any help that someone could provide as to why my corals are not thriving.

Thanks!

[HighlandReefer]

I don't see any reason for your bleaching problem from what you have described.

GAC can bleach corals if too much is used at once after not changing it for a long time or if you just start to use it and run too much.

Increasing lighting all at once can bleach coral (for example changing bulbs that are very old or switching bulb types).

Adding to much micro-nutrients (including the heavy metals) can bleach coral.

Allowing water temperature to climb even for short periods above 85 degrees F. can bleach coral.

Sudden increases of copper can bleach corals.

There are viral and bacterial diseases that will bleach coral and can be specific to genus or species.

Just a few possiblilities. Sorry to hear about your problems. :(

[HighlandReefer]

Are you adding anything to your tank except alk, calcium, mag & food?

[jschottenfeld]

I don't run that much activated charcoal. about 1 cup that I change out every couple of months. I did add Brightwell Aquatics Neo Mag Magnesium Media to my calcium reactor in addition to my standard aragonite. Some people on boards mentioned that they did not like that product, although I don't know why.

Mostly dosing a bulk magnesium liquid, running aragonite in my calc reactor, the phosban in my reactor is old (maybe 7 mos).

I checked the calibration on my refractometer.

Lighting isn't the issue because the same corals that died in my display also died in my fuge which is in my basement.

It's just really concerning because i believe that all of my parameters are in line. I do have Kent's Essential elements, but have NOT been adding it to the tank. I use Instant Ocean Reef Crystals for my salt mix.

Has me puzzled??

[HighlandReefer]

Usually diseases like bacteria and virus start at one point on the coral and progress out from the point of infection. You can see bands of infection at the leading edges as it works out. If so, removing badly damaged coral and fragging well beyond the visible diseased parts is best.

[HighlandReefer]

Good quality close-up pics of your coral may help. ;)

[myaerica]

Have you put any new sps in the tank lately that could of some kind of pest?

[tmz]

I've had similar troubles when I used a calcium reactor a couple of years ago and had alk drops. It persisted for a while, I fragged quite a few pieces and the frags survived. Some colonies did too . Seems like once the calcification or growth process is interrupted and the coral starts downhill, it's difficult for the coral to recover.
Alternatively,is it possible a toxin or metal got in there ,somehow? If so some poly filter and/or cuprisorb might help.

[L.R.fisherman]

The only thing that i can tell is maybe bad phosban "the phosban in my reactor is old (maybe 7 mos). " This seems like its really old IMO.

[tmz]

I don't think the phosban would do harm but if it is no longer adsorbing PO4 I'd remove it.. If you haven't changed it in 7 months ,how are you keeping PO4 at 0?

[bertoni]

The PolyFilter sounds like a reasonable idea to me. I'd get second opinions on all the measurements. You've done that for SG, but I'd get the other kits checked as well. Also, I'd consider stopping the magnesium for the moment. What product are you using? What other exact products are going into the system?

[steelhead77]

Man this sucks! In addtion to the previous suggestions, here are some other things to think about that many people don't:

1) Did you fertilze your lawn and then stick your hands in your tank?
2) Do you use any air fresheners?
3) Did you vacuum with any of that carpet fresh stuff?
4) Change the oil in your car?
5) Add gas to your lawnmower?
6) Smoke?
7) Stray voltage?

I'm sure there are many others, but you get the idea. Think of things that you've recently done that might have inadvertantly introduced something into your tank. None of those things I listed would be detectable on a test kit, but could potentially have a deadly impact on your tank.

Good Luck

[jschottenfeld]

I do use poly filter socks and change them out every week.
I post on another board as well and someone came up with the idea of Iodine....or a lack of it. They mentioned that they had a similar problem as I am describing and they found that they were dificient in iodine. They started dosing small qty's of iodine and the corals perked up and healed.
Here's my story regarding Iodine:
I have a lot of xenia in my fuge. From what I understand they are iodine sponges. I have so many xenia that I harvest them like macro algae and trade them at my LFS.

Lately my 2 shrimp have bought the farm. I believe they are consumers of iodine.

My macroalgae has dwindled in my fuge, (TMZ...that's how I was keeping PO4 at low levels)

To me....this points to a low iodine level.

as an aside...I am very careful to not have toxins on my hands when they are in the tank.

[colubrid]

Recently, I went through a similar experience with my corals. It also began with my caps fading and dying. Then my sps tips burned and i had recession and overall bleaching. Most of my sps perished. Interestingly, my fish and many of my lps were fine (couple of chalices receded). I was quite frustrated as you are as all my parameters have been dialed in for years. Eventually, I found that the plastic casing on 4 of my 6 tunze stream magnets made by Algae Free had cracked exposing the neodymium magnets to the water. All were oozing oxidized metals into my tank. I have read that many of these magnets are plated with nickel and possibly nickel-copper alloys making for a heavy metal nightmare. I ran a poly filter and changed water daily for a week and a half to dilute the polution caused by the magnets. Two weeks later and everything is looking much better. Many of the corals that I thought had perished are growing new polyps and are regrowing over skeletons. Check your magnets if you use them!

[jschottenfeld]

Colubrid, I have 3 tunze streams in my tank. What should I look for?

[colubrid]

If you use magnetic mounts, check the seam on the plastic casing on the magnet. Mine were all heavily encrusted with coralline and had to be scraped to notice the split seam. One appeared intact, but I split it open with a hammer and discovered that it was filled with rusty water as well. My magnets were 5 years old. I think that I will be changing mine out every 2.5 years now just to be sure.

[Maivortex]

The one thing that jumps right out at me is the lack of feeding. My tank went thru some similar thing that u explained and I initially blamed it on alk swings. I was being stingy with the food. I started feeding 2 cubes a day and sps did better, no more bleaching , colors improved. Feeding the fish makes food, amino acids for the corals. You also dont have a a very large DSB that would prodcue some coral food as well. I would consider that your corals are starving.

[palyam]

I do use poly filter socks and change them out every week.
I post on another board as well and someone came up with the idea of Iodine....or a lack of it. They mentioned that they had a similar problem as I am describing and they found that they were dificient in iodine. They started dosing small qty's of iodine and the corals perked up and healed.
Here's my story regarding Iodine:
I have a lot of xenia in my fuge. From what I understand they are iodine sponges. I have so many xenia that I harvest them like macro algae and trade them at my LFS.

Lately my 2 shrimp have bought the farm. I believe they are consumers of iodine.

My macroalgae has dwindled in my fuge, (TMZ...that's how I was keeping PO4 at low levels)

To me....this points to a low iodine level.

as an aside...I am very careful to not have toxins on my hands when they are in the tank.

Iodine could be the issue here. Try Kent Lugol's solution, 4 drops once a week after water change, and see if it helps.

[Randy Holmes-Farley]

I do not believe that any corals we keep have a need for supplemental iodine, aside from certian gorgonia. Many if not most experienced reefers that have dosed iodine and stopped noticed no change in their aquaria, including me.

[tmz]

I have dosed iodide on and off with no discernible effect, positive or negative. I am very skeptical that dosing it it would prevent the problems you noted.FWIW ,I suspect it has more to do with alkalinity and PO4 effects on calcification.

[palyam]

I do not believe that any corals we keep have a need for supplemental iodine, aside from certian gorgonia. Many if not most experienced reefers that have dosed iodine and stopped noticed no change in their aquaria, including me.

For every reefer that didn't see any change there is a reefer who saw one. There are many cases (including myself) where reefers added Iodine and saw improvement in coral's condition and colors. Of caurse if you have enough Iodine adding more wouldn't help, but if you have deficiency it will.
The same with Amino acids- you know how many reefers didn't see any change after adding them? so it means AA are useless?

As with any supplement, tetsing is the best advice, and Red Sea has a good testing kit for Iodine.

.

[jschottenfeld]

I just started with a weekly dose of Iodine last night. I think it will be few weeks before I see any discernible results.

I do also believe that my reduced feedings could've weekend some of the corals. I will go back to feeding 2 to 3 x per week as I have done in years past.

[Randy Holmes-Farley]

For every reefer that didn't see any change there is a reefer who saw one.

I don't agree, and I think most highly experienced reefers eventually realize that on their own if they try stopping and observe the tank.

There are many cases (including myself) where reefers added Iodine and saw improvement in coral's condition and colors.

We are talking about bleaching SPS here, not colors. Most such folks add lots of stuff with their iodine, and can't tell what did what, and many color comments aren't even related to supplements even though people attribute them that way. And you did not say you did what I suggested, which was to change nothing else and stop iodine only and see what the effect was. You did the opposite, looking for a positive effect. The placebo effect is quite evident in reefers who add stuff looking for color improvements.

That said, if you think it is helpful for you, then by all means keep doing it, but I don't think it is going to solve anyones dying coral problem.

[palyam]

For every reefer that didn't see any change there is a reefer who saw one.

I don't agree, and I think most highly experienced reefers eventually realize that on their own if they try stopping and observe the tank.

There are many cases (including myself) where reefers added Iodine and saw improvement in coral's condition and colors.


That said, if you think it is helpful for you, then by all means keep doing it, but I don't think it is going to solve anyones dying coral problem.

I'm pretty sure that the situation here isn't just the result of Iodine deficiency, but it might be part of the problem. Since he cannot find (for now) another reason for the condition of the corals, adding Iodine might be a good start towards changing things for the better.

[palyam]

I just started with a weekly dose of Iodine last night. I think it will be few weeks before I see any discernible results.

I do also believe that my reduced feedings could've weekend some of the corals. I will go back to feeding 2 to 3 x per week as I have done in years past.

Make sure that you dose Lugol's and not just Iodine

[HighlandReefer]

Viral communities associated with healthy and bleaching corals
Kristen L. Marhaver1,*, Robert A. Edwards2, Forest Rohwer3Article first published online: 9 MAY 2008
http://onlinelibrary.wiley.com/doi/10.1111/j.1462-2920.2008.01652.x/full

The coral holobiont is the integrated assemblage of the coral animal, its symbiotic algae, protists, fungi and a diverse consortium of Bacteria and Archaea. Corals are a model system for the study of symbiosis, the breakdown of which can result in disease and mortality. Little is known, however, about viruses that infect corals and their symbionts. Here we present metagenomic analyses of the viral communities associated with healthy and partially bleached specimens of the Caribbean reef-building coral Diploria strigosa. Surprisingly, herpes-like sequences accounted for 4–8% of the total sequences in each metagenome; this abundance of herpes-like sequences is unprecedented in other marine viral metagenomes. Viruses similar to those that infect algae and plants were also present in the coral viral assemblage. Among the phage identified, cyanophages were abundant in both healthy and bleaching corals and vibriophages were also present. Therefore, coral-associated viruses could potentially infect all components of the holobiont – coral, algal and microbial. Thus, we expect viruses to figure prominently in the preservation and breakdown of coral health.

Within a coral's skeleton, tissue and mucus, there exists a diverse assemblage of Bacteria, Archaea, algae, fungi and protists (Knowlton and Rohwer, 2003). Endosymbiotic algae, called zooxanthellae, and some Bacteria form relatively stable and species-specific associations with corals (Rohwer et al., 2002; Goulet, 2006). It has been hypothesized that the coral animal can adapt to differing ecological niches by ‘switching’ its algal and microbial associates. In the case of corals and zooxanthellae, this so-called adaptive bleaching may allow the coral animal to adjust to changing water temperatures (Buddemeier et al., 2004). Coral-associated Bacteria can serve as a food source for corals (Sorokin, 1973; Bak et al., 1998) and provide beneficial metabolic capabilities such as nitrogen fixation in at least one coral species (Lesser et al., 2004; 2007). It has been hypothesized that changes in microbe–coral associations will facilitate the survival of corals under future environmental changes (Reshef et al., 2006).

The least-studied constituents in the coral holobiont are the viruses. No cnidarian viruses have been isolated to sufficient purity to be identified genetically prior to this study, although viruses have been observed visually in association with corals and other cnidarians. An observation of virus-like particles (VLPs) in the zooxanthellae of anemones first implicated viruses in coral bleaching (Chapman, 1974; Wilson and Chapman, 2001). VLPs were later observed in the tissues of heat-shocked and control specimens of the scleractinian coral Pavona danai (Wilson et al., 2005) and in the tissue and zooxanthellae of three coral species and one species of zoanthid, all under thermal stress (Davy et al., 2006). The origin of these VLPs was not known. A recent study demonstrated that UV stress induced one type of latent virus in cultures of coral zooxanthellae (Lohr et al., 2007). In sum, observations of VLPs in corals have generally been made under the impression that their presence is an indicator of coral stress or disease (Wilson et al., 2005; Davy et al., 2006). However, given the abundance and diversity of coral-associated microbes, it is expected that these virus populations will consist of abundant and diverse bacteriophages in addition to viruses suspected to target eukaryotic cells, and that viruses will consistently be found in association with corals.

Viral genetic diversity is difficult to characterize because viruses share no single conserved sequence that can be used in a manner analogous to the sequencing of ribosomal RNA from cellular organisms (Rohwer and Edwards, 2002). Individual viruses contain extremely small amounts of DNA (Steward et al., 2000) and often use modified bases, making cloning difficult (Warren, 1980). Viruses also carry genes toxic to bacterial cloning hosts (Wang et al., 2000). Thus, in order to characterize an entire community of coral-associated viruses genetically, the viruses must be physically isolated from bacterial, archaeal, algal and host cells, as well as free DNA, prior to DNA extraction and cloning (Rohwer et al., 2001a). Here, a homogenization and centrifugation technique was developed to purify viruses from the tissues of healthy and partially bleached specimens of the Caribbean coral Diploria strigosa. Shotgun sequencing and metagenomic analyses were then used to determine the genetic content and diversity of these two viral communities. Our results show that coral-associated viruses are extraordinarily diverse and potentially infect all members of the coral holobiont.....................................


................Here we have described the complexity of an under-studied facet of the coral holobiont. Herpes-like viruses occur in both healthy and bleaching corals. This should be a focus for future research on coral holobiont complexity, symbiosis and immunology. The largest identified functional group of coral-associated viruses, cyanophages, may affect the population structure of symbiotic cyanobacteria and endolitic algae, while vibriophages present in coral tissue may affect the pathogenesis of coral-associated Vibrio spp. While these are important structuring forces for the coral holobiont, the prediction that up to 28 600 viral types occur in a healthy coral's viral community indicates that there are myriad functions and interactions still unidentified in this viral assemblage. When compared in the framework of a phage phylogenetic tree, coral-associated phage communities from bleaching and healthy corals are not significantly different from each other, but the coral holobiont as a phage environment is distinct from that of coral reef and oceanic waters. Thus, it appears that a diverse community of viruses continuously occupies coral tissues. With the potential to target animal, algal and microbial cells, viruses are likely to be crucial in maintaining the overall function of the coral holobiont.

[Randy Holmes-Farley]

Make sure that you dose Lugol's and not just Iodine


I presume you mean not just iodide? Or did you really mean iodine (I2)?

In either case, why?

[tmz]

Lugol's is elemental iodine and can be toxic . If you are set on dosing an iodine supplement , iodide is more readily bio availabe and safer.

[HighlandReefer]

The reason for bleaching occuring in coral is related to their symbionts. Iodine is not going to help out in this situation and can cause more bad than any possible good.

You don't know exactly why the bleaching occured and there was a reason for this bleaching to occur. Adding other things to your tank other than maintaining alk, calcium and mag can only complicate the matter in your situation. ;)

I second Randy's post, why dose iodine in this situation.

[HighlandReefer]

FWIW, I have searched the Internet looking for any possible benefit for coral related to iodine as has Randy. Randy's search was much more intensive than I was able to do, since he scoured text books and other articles I don't have access to. When you add things like iodine, interactions occur which can cause problems for many organisms, especially the symbionts within the coral. These symbionts live together and interact with the coral tissues in a delicate balance. You disrupt this balance and the coral will expel the symbionts or if you change water parameters other species of symbionts will become dominate within the coral tissue. In many cases the changed symbiont specie will secrete toxins which kill the coral tissue. Also these changes will cause viruses to take over in some cases which end up killing the coral tissue. The article I posted above did find that there are many virus that also act within a symbiotic way with the coral tissue. Changes in the virus (mutations) can occur as well if you change water parameters.

Scientists are investigating coral bleaching in a big way currently to try and discover why this occurs and looking for possible methods to correct the problem once the bleaching occurs. Iodine has not helped out to correct the problem. Most of the bleaching in coral occurs due to changes in lighting and increased water temperatures. Too much food can lead to bleaching. Too little food results in lack of growth. The amount of food available to coral like dissolved organic carbon is another factor that can cause bleaching. Too much DOC will cause bleaching. Not enough results in poor growth. Heavy metals will do this too.

[HighlandReefer]

Once coral bleaching occurs, there seems to be two things that happen and scientists don't really know why.

1) Coral can recover once the situation that caused it is corrected.

2) Coral do not recover and it ends up dieing.

The current line of thought for the #2 is that disease from bacterial or viral changes occur which are not irreversible. The species of the coral does play into this, with some species more resistant to the disease. ;)

[HighlandReefer]

Measuring iodine in the reef tank is easier said than done. The test kits we have available are very poor IMO to determine what is truly going on with iodine and all the forms it takes. Sending samples off even to a lab, require expertise in understanding how to do it properly in seawater, which many labs can't do. Overdosing will cause problems.

My advice is to take the advice a reef chemist like Randy (with a PhD), who thoroughly understands what is going on rather than simple observations from hobbyists who have not conducted their little experiments in a manor that can exclude many, many other factors which would take a book to write about. Remeber the placebo effect can occur in about 1/3 to 1/2 of hobbyists that try something new. This is where the scientific research helps out.

If someone can post some proper research that proves my statements wrong please enlighten me. I will take no offense to such posts. :lol:

[palyam]

If someone can post some proper research that proves my statements wrong please enlighten me. I will take no offense to such posts. :lol:

I respect what you and Randy wrote, and I agree with most of it.

There is only one little problem- reefing isn't just pure science, and there are many things we still don't know and can only speculate about the corals and other members of our reef.

Let me understand something- you actually insist that Iodine and Potassium Iodide (which are both in lugol's solution) aren't necessary for the corals?.. so if there is deficiency in one of them or both, there won't be any negative effect?

[Randy Holmes-Farley]

There is no I2 in seawater, so aquaria are never "deficient" in it.

It is a bit stronger to say most corals need none than to say they need no supplemental iodine. I strongly believe most do not benefit from supplements, and I think they need none. I've tried adding some several times over the years and never noticed any effect, as have many others, and there is no known biochemical need for iodine by most corals in the scientific literature.

[palyam]

Ok randy, let me ask you these:

Is it possible that adding Iodine to the water will help in treating bacterial infection in corals?

[Randy Holmes-Farley]

By adding I2 at levels around 0.06 ppm or less?

I think that is very unlikely when so dilute, but I can't prove it can't have an effect like that. :)

[Finland]

One thing that crossed my mind was the RO/DI. How old are the cartridges? DI resin exhausted? Aren't there somethings that can go through the RO/DI that aren't filtered out? The reason I mention this is because I have well water and live in close proximity to a landfill. I wonder what sort of chemicals are not removed by RO/DI and don't show up on a TDS meter.

[HighlandReefer]

Even if I2 can kill bacteria, how do you know if it is going to kill the good bacteria or the bad bacteria or perhaps both. Introducing anitbacterial agents can have profound effects on the bacterial populations in the mucal layers and within the coral tissues. You kill the good bacteria with lets say iodine, than the bad bacteria can take over. The problem is it can take long periods of time for this to show up as coral bleaching. I'm begining to wonder if treating coral with iodine dips can potentially cause more problems than good in many cases. Messing with the bacterial, viral and algae sybionts within coral tissues and within their mucal layers is a touchy business and we have not begun to identify all the different bacteria and viruses that cause coral to bleach. :)

For example. You will need to read the entire article to get to the bottom of what I am refering too. ;)

How Microbial Community Composition Regulates Coral Disease Development
Modeling reveals how rapid overgrowth by pathogenic microbes in the mucus layer surrounding corals, which often occurs under temporary stressful conditions, can persist long after environmental conditions return to normal. PLoS Biology, 2010 - dx.plos.org

http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1000345


Abstract

Reef coral cover is in rapid decline worldwide, in part due to bleaching (expulsion of photosynthetic symbionts) and outbreaks of infectious disease. One important factor associated with bleaching and in disease transmission is a shift in the composition of the microbial community in the mucus layer surrounding the coral: the resident microbial community—which is critical to the healthy functioning of the coral holobiont—is replaced by pathogenic microbes, often species of Vibrio. In this paper we develop computational models for microbial community dynamics in the mucus layer in order to understand how the surface microbial community responds to changes in environmental conditions, and under what circumstances it becomes vulnerable to overgrowth by pathogens. Some of our model's assumptions and parameter values are based on Vibrio spp. as a model system for other established and emerging coral pathogens. We find that the pattern of interactions in the surface microbial community facilitates the existence of alternate stable states, one dominated by antibiotic-producing beneficial microbes and the other pathogen-dominated. A shift to pathogen dominance under transient stressful conditions, such as a brief warming spell, may persist long after environmental conditions have returned to normal. This prediction is consistent with experimental findings that antibiotic properties of Acropora palmata mucus did not return to normal long after temperatures had fallen. Long-term loss of antibiotic activity eliminates a critical component in coral defense against disease, giving pathogens an extended opportunity to infect and spread within the host, elevating the risk of coral bleaching, disease, and mortality.

[HighlandReefer]

What are the long term effects of using antibiotics like erythromycin and lugols dips on the coral symbionts? We need more research to determine this, but bad effects are certainly possilbe. The effects on different coral species can be quite different as well. :)

[HighlandReefer]

Another example of what can cause problems for coral, algae in contact with coral tissues:

Algal contact as a trigger for coral disease
Maggy M. Nugues1,*, Garriet W. Smith2, Ruben J. van Hooidonk1, Maria I. Seabra1, Rolf P. M. Bak1Article first published online: 26 AUG 2004

DOI: 10.1111/j.1461-0248.2004.00651.x
http://onlinelibrary.wiley.com/doi/10.1111/j.1461-0248.2004.00651.x/full

Abstract
Diseases are causing alarming declines in reef-building coral species, the foundation blocks of coral reefs. The emergence of these diseases has occurred simultaneously with large increases in the abundance of benthic macroalgae. Here, we show that physical contact with the macroalga Halimeda opuntia can trigger a virulent disease known as white plague type II that has caused widespread mortality in most Caribbean coral species. Colonies of the dominant coral Montastraea faveolata exposed to algal transplants developed the disease whereas unexposed colonies did not. The bacterium Aurantimonas coralicida, causative agent of the disease, was present on H. opuntia sampled close to, and away from diseased corals, indicating that the alga serves as a reservoir for this pathogen. Our results suggest that the spread of macroalgae on coral reefs could account for the elevated incidence of coral diseases over past decades and that reduction of macroalgal abundance could help control coral epizootics.

[HighlandReefer]

AbSeasonal Rainfall and Runoff Promote Coral Disease on an Inshore Reef
tract

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0016893



Background
Declining water quality coupled with the effects of climate change are rapidly increasing coral diseases on reefs worldwide, although links between coral diseases and environmental parameters remain poorly understood. This is the first study to document a correlation between coral disease and water quality on an inshore reef.

Methodology/Principal Findings
The temporal dynamics of the coral disease atramentous necrosis (AN) was investigated over two years within inshore populations of Montipora aequituberculata in the central Great Barrier Reef, in relation to rainfall, salinity, temperature, water column chlorophyll a, suspended solids, sedimentation, dissolved organic carbon, and particulate nitrogen, phosphorus and organic carbon. Overall, mean AN prevalence was 10-fold greater during summer wet seasons than winter dry seasons. A 2.5-fold greater mean disease abundance was detected during the summer of 2009 (44 ± SE 6.7 diseased colonies per 25 m2), when rainfall was 1.6-fold greater than in the summer of 2008. 1Two water quality parameters explained 67% of the variance in monthly disease prevalence in a Partial Least Squares regression analysis; disease abundance was negatively correlated with salinity (R2 = −0.6) but positively correlated with water column particulate organic carbon concentration (R2 = 0.32). Seasonal temperature patterns were also positively correlated with disease abundance, but explained only a small portion of the variance.

[tmz]

Is it possible that adding Iodine to the water will help in treating bacterial infection in corals?


I've used lugol's in dip concentrations on many occassions and while it may stun an asterina star or nudibranch or two.I've never seen it stop a coral infection even in the relatively high concentrations used in a dip.
I don't think even the manufacturer claims antiseptic benefits at the aquarium dosing level of 0.06ppm.. If it were dosed in high enough concentrations to have an anti microbial effect ,the I2 in it would harm desireable organisms including corals,imo. Even when dosed at low levels some localized concentration of the I2 may occur depending on how and where it is dosed and is a cause for concern.

[Maivortex]

Doesnt the iodine get reduced immediately in the aquarium? I recall that it doesnt last in the aquarium for very long, perhaps a few hours at the most..Im not sure on this....

[Randy Holmes-Farley]

Are you referring to I2 reacting quickly with organic matter, or iodide and iodate being taken up by organisms?

[Maivortex]

YEs, the I2 reacting with organics. i guess it depends on the tank....

[Randy Holmes-Farley]

Yes, it will quickly react with organics, some of which becomes iodinated organic matter and some would go back to iodide (I-). I've not see any data on how fast that actually is.

[HighlandReefer]

One thing that may be worth trying once coral start to bleach is to reduce the tank water temperature to what would be the winter low temperature in the regions that the coral come from. There have been quite a few articles including two of the articles I posted above that find that bleached coral recover best at these lower temperatures. The theory is that the beneficial bacteria due better at the lower temperatures than do the disease causing bacteria, thus allowing the beneficial bacteria to make a come-back in the coral mucal layer. :)

[HighlandReefer]

Temperature Stress and Coral Bleaching 2004
Paul L. Jokiel

http://cramp.wcc.hawaii.edu/Downloads/Publications/BC_Jokiel_2004_bleaching_chapter.pdf

From it:

"Most of the O. patagonia colonies bleach annually during the summer months as temperatures reach a maximum of 30–31 °C (Kushmaro
et al. 1996, 1998). The corals recover during the winter months when SST falls to a minimum of 16 °C.The bacterium dies and lyses at the low temperature
and cannot be detected in corals during the winter months. A similar bleaching relationship between the ubiquitous Pacific coral Pocillipora damicornis and the
bacterium Vibrio coralyticus have also been demonstrated (Ben-Haim and Rosenberg 2002). It remains to be seen if such bacterial processes are involved in regional mass bleaching events (see Chap. 25, Rosenberg, this Vol.)."

[tdwright1971]

A few months ago my xenia was looking a bit "tired", withered around the polyps, and started to "melt". When I checked my iodine level was really low, I started dosing to try and get it up to normal levels, and witnessed my xenia come back to life. Coincidence?

[tmz]

Clifff, I've read posts where folks argue for maintaining lower on going temperature ranges in reef tanks as more disease free. I doubt anyone can manage a 61 to 88 degree F range though. A cold water relocation treatment for certain corals might be worth a shot though.

[Randy Holmes-Farley]

A few months ago my xenia was looking a bit "tired", withered around the polyps, and started to "melt". When I checked my iodine level was really low, I started dosing to try and get it up to normal levels, and witnessed my xenia come back to life. Coincidence?

Most likely, yes (IMO), but if you like the effects you observe when dosing iodine, and especially iodide, there's no reason to not do so as long as you are not overdosing. :)

[bertoni]

I agree. Xenia seems to go through phases in a lot of people's tanks with a lot of variation.

[HighlandReefer]

Clifff, I've read posts where folks argue for maintaining lower on going temperature ranges in reef tanks as more disease free. I doubt anyone can manage a 61 to 88 degree F range though. A cold water relocation treatment for certain corals might be worth a shot though.

I don't know of anyone that has tried lowering temperature myself, once bleaching occurs, to say 70 - 73 F. I don't know if you actually have to go to the low of 70 F. It would be nice if the scientists who did the research provided a low end range of temperature where they saw the appropriate bacteria recovering and the other bad bacteria dieing off.

Perhaps shooting for a median temperature may be best to keep tanks at. If you figure a healthy range between 70 - 82 F. That provides a median around 76 F. :) Anything over 85 F. causes problems for sure for coral.

IIRC some of the research was finding slower skeletal growth at the higher Summer temperatures than at the median temperatures. I think (IMHO) 76-78 F. may be the best range if hobbyists can keep it there. ;)

[HighlandReefer]

My Xenia started to die off when I reduced nitrate and phosphate too low. When I allowed both to increase, the Xenia made a come back. I'm not sure if it was the combination of the two or one or the other regarding reducing nitrate and phosphate too low. Xenia do come from higher phosphate/nitrate waters than SPS coral do. ;)

[tmz]

I don't know of anyone that has tried lowering temperature myself, once bleaching occurs, to say 70 - 73 F. I don't know if you actually have to go to the low of 70 F. It would be nice if the scientists who did the research provided a low end range of temperature where they saw the appropriate bacteria recovering and the other bad bacteria dieing off.

Perhaps shooting for a median temperature may be best to keep tanks at. If you figure a healthy range between 70 - 82 F. That provides a median around 76 F. :) Anything over 85 F. causes problems for sure for coral.

IIRC some of the research was finding slower skeletal growth at the higher Summer temperatures than at the median temperatures. I think (IMHO) 76-78 F. may be the best range if hobbyists can keep it there. ;)



The study you cited does give 16C(61F)as a minimum temp were infecting bacteria are affected,unless I misread it. I was thinking of treating corals with persistent infections by chilling them for a day or two . Wonder if that has been tried.I wasn't thinking of lowering the temperature in the whole tank.

[HighlandReefer]

Tom,

If anyone decides to try it I would love to hear the results. ;)

[tmz]

I've kept the same colony of xenia and it's asexual progeny for over 8 yrs in a variety of conditions. It's the first coral I ever kept. My son bought a small frag for me.
As I uderstand it they grow in different areas on the reef ,walking about opportunistically. The strongest suggestions are that they have limited feeding ability and rely on dissolved organics . IME, a new skimmer caused a crash with a subsequent recovery several years ago. In my tanks they now live in low PO4/NO3 water but grow more in a 65 g I have running on a canister filter which has relatively high PO4 and NO3 and weak skimming. I've never seen them respond to iodide dosing.

Eric Borneman notes: "..I have not found iodine to play a role in the sucess of Xenia, nor is its need or uptake documented. I have found it to be detrimental to some, but not all, of my experiences with these coerals...."( Aquarium Corals pgs 152,153)

[Stonerlivin]

I don't run that much activated charcoal. about 1 cup that I change out every couple of months. I did add Brightwell Aquatics Neo Mag Magnesium Media to my calcium reactor in addition to my standard aragonite. Some people on boards mentioned that they did not like that product, although I don't know why.

Mostly dosing a bulk magnesium liquid, running aragonite in my calc reactor, the phosban in my reactor is old (maybe 7 mos).

I checked the calibration on my refractometer.

Lighting isn't the issue because the same corals that died in my display also died in my fuge which is in my basement.

It's just really concerning because i believe that all of my parameters are in line. I do have Kent's Essential elements, but have NOT been adding it to the tank. I use Instant Ocean Reef Crystals for my salt mix.

Has me puzzled??
Are you using RODI water

[Stonerlivin]

Half of one of my frogspawn coral has died while the other corals in the tank are doing very well any thoughts

[jschottenfeld]

This one goes back a while, almost three years.
At this point I don't even remember what caused my corals to bleach out. Yes I always use RO/DI water. Is it just your frogspawn that is affected? What are your tank parameters? Would need to know....

[enb141]

I bet the problem was related to low nutrient (nitrates and phosphates) plus high alkalinity.

If you have a reef with low nutrients the alkalinity must be at 7-8 dKH anything lower or higher will fade or bleach your corals.

[bertoni]

Some people have issues with higher dKH levels; other don't, even with zero measurements for mineralized nutrients. It's not clear to me what is happening.

[enb141]

After reading lots of posts on different forums over internet it seems like in most cases if you have 0 nitrates NO3 and 0 phosphates PO4 your alkalinity must be at 7-8 dKH, people with Zeovit, Carbon dosing, sugar, vodka, GFO, etc. that at the end have low nutrient systems they have bleaching issues when the alkalinity becomes high (above 8 dHK).

I know that SPS need high alkalinity in reef tanks but in the ocean the alkalinity it is 7 dKH so keeping the alkalinity at about 7-8 dKH is your safest bet.

[bertoni]

I don't know whether most tanks running Zeovit or carbon dosing require alkalinity levels that low, but some appear to do better in that range. Lowering the alkalinity definitely is worth trying if a tank is having problems with corals.

[ssick92]

Wow, talk about resurrecting a thread. I was reading from the beginning when I realized the post was from 2011 :eek:

But, I agree that the trend seems to indicate that if a tank has extremely low nturients, then the alk seems like it needs to be lower to avoid any burning or bleaching of the tips...

I've always kept my alk between 8-9dkh and haven't really had any issues at this level.

[tmz]

I tend to agree that acropora kept kept in tanks with undetectable PO4 seem to encounter burnt tips based on a number of anecdotal accounts .
I suspect this effect is related to an imbalance in the calcification process as the coral uses phosphate for a variety of functions .For example, adenosine triphospahte(ATP) mitigates the calcification process while higher alk tends to accelerate it which may lead to more calclium carbonate precipitation without adeqaute control from the coral..

FWIW, with alk around 9dkh and PO4 in the 0.02 to 0.05ppm range I have not seen any burnt tips. I think maintaining some PO4 and NO3 is prudent, generally.when doing so ,alk higher than 7 is fine; though 7 is fine too, but at the low margin there is a greater risk of dropping too low with a risk of stn. Constancy in alk and nutrient levels is key IMO