Could it be iron, the great hidden enemy of reef aquarists?

[Jose Mayo]

So fellows ...

I've done some research on academic articles here and there to identify probable unwanted effects of iron in marine aquariums. I'm amazed!

The increase in the concentration of iron in our aquariums may be the answer to several inquiries about disasters in previously well-established tanks, especially with regard to infestation by harmful algae, cyanobacteria, dinoflagellates and some serious coral diseases such as RTN and STN, for its various metabolic implications, already recognized.

In some studies I read that iron availability is critical to the infectivity of some bacteria, especially Gram negative bacteria and more especially Vibrio vulnificus, a bacterium present on the surface of corals, not usually involved in infections, and that for some strange reason in one high-availability environment of iron multiplies more rapidly and becomes infectious, which may be one of the reasons why, in some assessments of the causes of STN, this bacterium appears to be "only present" and in others it seems to be an active part.

Below is an article on the "phase shifts" in Pacific black reefs, where increasing iron concentration from shipwrecks seems to be the factor involved:

Black reefs: iron-induced phase shifts on coral reefs

In this other article some references on the role of iron in the mechanism of coral infections and what the coral tries to do, to avoid this:

Physiological responses of the scleractinian coral Pocillopora damicornis to
bacterial stress from Vibrio coralliilyticus

Regards

 

[KJ]

Good article.

 

[chefjpaul]

.

 

[Jose Mayo]

Well ... accepting as a null hypothesis that iron imbalances can cause disasters in a reef aquarium (coral bleaching by deficiency and RTN or STN by excess, for example), and may be involved in promoting, when in excess , the uncontrolled development of algae, cyanobacteria and dinoflagellates, I think it would be of great interest for aquarism to determine the optimal range of iron concentration in our aquariums and strive to achieve it.

Increasing iron levels in the aquarium is very easy. There are a number of products today to achieve this aim with greater or lesser efficiency, ranging from the extensive and perhaps abusive use of GFO to control phosphate levels, or even dosages of citrates and other weakly affinity iron chelates, many of them photosensitive, capable of deliver the iron in usable form, especially by autotrophic phytoplankton, organisms for which iron is the most considered limiting, but ... and to remove it?

A product that would be able to perform this task in a reef aquarium could allow the aquarist to try to maintain iron levels within an optimal range in his aquarium, in addition to assisting him in the need to control an outbreak of algae, cyanobacteria, dinoflagellates or even other bacterial diseases, such as STN or RTN, whose protagonists could be iron-limited ... that's what I'm looking for.

Does anyone have the answer?

Regards

 

[wesman42]

Following

 

[Jose Mayo]

Continuing ...
Iron overload diseases are also common in humans and may occur from primary causes (where there are genetic determinants involved) or secondary causes, which are usually due to excessive iron intake or injury to an organ important for the metabolism of iron, such as the liver, for example. When overload is due to excessive intake, control is obvious; dietary measures should be taken to avoid overload by changing eating habits. When the overload is due to genetic causes or to organic lesions, the control is done with chelators.

Chelators are molecules generally water soluble, capable of complexing with metal ions in a variable way, being natural or synthetic. Some chelants dissociate easily, others are very stable and form inert complexes with the metal, neutralizing it.

Natural chelating agents are widely found in living systems and are very important in cell metabolism, however ... many are species-specific, that is, they serve well the purpose of the organism that releases them (usually to get essential ions), but they are not adequate for the others, acting as "facilitators" for that organism, in the sense of obtaining reserve for itself, of a determined ion, in a scarce environment.

That being said, the hypothesis I propose is that if a non-species-specific iron chelator is released in a given environment, it will render iron less available or unavailable to those organisms, which can be a major limiting tool for organisms which depend exclusively on this; Animals in general, for example, could still receive iron through enriched feed, if needed. Algae and bacteria do not.

Any idea?

Regards

 

[Jose Mayo]

In the article below, a good explanation about how microorganisms compete chemically for iron in the natural marine environment:

Chemistry of Marine Ligands and Siderophores

Abstract
"Marine microorganisms are presented with unique challenges to obtain essential metal ions required to survive and thrive in the ocean. The production of organic ligands to complex transition metal ions is one strategy to both facilitate uptake of specific metals, such as iron, and to mitigate the potential toxic effects of other metal ions, such as copper. A number of important trace metal ions are complexed by organic ligands in seawater, including iron, cobalt, nickel, copper, zinc, and cadmium, thus defining the speciation of these metal ions in the ocean. In the case of iron, siderophores have been identified and structurally characterized. Siderophores are low molecular weight iron-binding ligands produced by marine bacteria. Although progress has been made toward the identity of in situ iron-binding ligands, few compounds have been identified that coordinate the other trace metals. Deciphering the chemical structures and production stimuli of naturally produced organic ligands and the organisms they come from is fundamental to understanding metal speciation and bioavailability. The current evidence for marine ligands, with an emphasis on siderophores, and discussion of the importance and implications of metal-binding ligands in controlling metal speciation and cycling within the world’s oceans are presented."

Regards

 

[Dawgvet]

According to the article then, if you have high Fe and are carbon dosing in your tank, you have an increased risk of damaging your corals? Or are the DOCs provided by dosing not high enough? Making an assumption that there is no undesirable algae growth in tank.
Per the article, increased Fe causes increased algal growth, which leads to increased release of DOCs.
p20:
“Here the proposed mechanism is the stimulation of heterotrophic microbes by the dissolved organic carbon released by the benthic algae, which in turn leads to asphyxiation of the coral (Smith et al., 2006). “

 

[Jose Mayo]

According to the article then, if you have high Fe and are carbon dosing in your tank, you have an increased risk of damaging your corals? Or are the DOCs provided by dosing not high enough?
Per the article, increased Fe causes increased algal growth, which leads to increased release of DOCs.
p20:
“Here the proposed mechanism is the stimulation of heterotrophic microbes by the dissolved organic carbon released by the benthic algae, which in turn leads to asphyxiation of the coral (Smith et al., 2006). “

Yes, it seems so; the increased availability of iron may increase the development of algae and bacteria to the extent that by their byproducts they unbalance the holobionte of the coral and may asphyxiate it during the period without light.

Regards

 

[Dawgvet]

One point that is not brought up and I think may be important is the effect of toxins (diesel, oils) being released by the wreck and damaging/weakening the ecosystem which then allows for opportunist organisms to cause a change in the biodiversity.

 

[Jose Mayo]

One point that is not brought up and I think may be important is the effect of toxins (diesel, oils) being released by the wreck and damaging/weakening the ecosystem which then allows for opportunist organisms to cause a change in the biodiversity.

The main point, which acts in the water column and the benthos, is iron. Oils, although toxic, usually float in water and disperse, and their effects are only temporary.

Regards

 

[Dawgvet]

The main point, which acts in the water column and the benthos, is iron. Oils, although toxic, usually float in water and disperse, and their effects are only temporary.

Which makes sense

 

[Paul B]

Wow, great info. So I guess this is bad.

Increasing iron levels in the aquarium is very easy.

Yes it is. I dose one hammer for every 100 gallons of water. I replace the hammer weekly.

 

[DSC reef]

Wow, great info. So I guess this is bad.

The article is meant for info to help others, we've all seen this same photo how many times now?? @Jose Mayo, thanks for taking the time give us great info

 

[Jose Mayo]

Wow, great info. So I guess this is bad.


Yes it is

Kkkkkk ... quiet like that, does not look so bad, but how about experiencing it in the glass?

 

[Paul B]

The article is meant for info to help others, we've all seen this same photo how many times now?? @Jose Mayo, thanks for taking the time give us great info

Yes, you are right, Sorry

 

[Jose Mayo]

One point that is not brought up and I think may be important is the effect of toxins (diesel, oils) being released by the wreck and damaging/weakening the ecosystem which then allows for opportunist organisms to cause a change in the biodiversity.

I am reconsidering that I may have misinterpreted the toxins present in oils ... it seems that accidental or chronic oil and derivative spills can significantly increase the environmental concentrations of heavy metals (because they contain these metals in their composition), producing effects negative effects on the development of coral reefs, as described below:

Heavy metals distribution in the coral reef ecosystems of the Northern Red Sea

But, as the article rightly points out, it is not only the oils and their contents that are the villains of shipwrecks; other alloyed and non-alloyed metal components of the ship itself, and even the paints with which they are painted for conservation, when in service, are extremely toxic components of pollution and are often disregarded when it is decided to sink it.

Regards

 

[Dawgvet]

I am reconsidering that I may have misinterpreted the toxins present in oils ... it seems that accidental or chronic oil and derivative spills can significantly increase the environmental concentrations of heavy metals (because they contain these metals in their composition), producing effects negative effects on the development of coral reefs, as described below:

Heavy metals distribution in the coral reef ecosystems of the Northern Red Sea

But, as the article rightly points out, it is not only the oils and their contents that are the villains of shipwrecks; other alloyed and non-alloyed metal components of the ship itself, and even the paints with which they are painted for conservation, when in service, are extremely toxic components of pollution and are often disregarded when it is decided to sink it.

Regards

I was more thinking along the way of heavy metal (lead primarily) levels that oils pick up from motors etc.
In my search to find some information about high lead levels effects on reefs, I did find this about Iron, which I though was interesting;

https://link.springer.com/article/10.1007/s10152-010-0202-7

" The higher levels of Fe in hard corals than soft corals reflected the incorporation of Fe into the aragonite and the chelation with the organic matrix of the skeleton. The greater abundance of soft corals in metal-contaminated reef sites and the elevated levels of metals in their tissue suggesting that the soft corals could develop a tolerance mechanism to relatively high concentrations of metals. Although the effects of heavy metals on reef corals were not isolated from the possible effects of other stresses, the percentage cover of dead corals were significantly higher as the concentrations of heavy metals increased"

So it looks like soft corals may be able to adapt better ( up to a point) than hard corals.

 

[Jose Mayo]

I was more thinking along the way of heavy metal (lead primarily) levels that oils pick up from motors etc.
In my search to find some information about high lead levels effects on reefs, I did find this about Iron, which I though was interesting;

https://link.springer.com/article/10.1007/s10152-010-0202-7

" The higher levels of Fe in hard corals than soft corals reflected the incorporation of Fe into the aragonite and the chelation with the organic matrix of the skeleton. The greater abundance of soft corals in metal-contaminated reef sites and the elevated levels of metals in their tissue suggesting that the soft corals could develop a tolerance mechanism to relatively high concentrations of metals. Although the effects of heavy metals on reef corals were not isolated from the possible effects of other stresses, the percentage cover of dead corals were significantly higher as the concentrations of heavy metals increased"

So it looks like soft corals may be able to adapt better ( up to a point) than hard corals.

Yes, it's the same article I posted above ... and even suggests ("between the lines") that some soft corals, in addition to adapting better to this pollution, could even "clean" the environment a little, through chemical neutralization.

 

[Dawgvet]

Yes, it's the same article I posted above .

Oops, and so it is. (embarrassed)