Is there new evidence to support dosing trace elements?

[Punchanello]

...That is my question. Randy, if you are reading, I'd be grateful if you tell us if your views have changed on this over the past decade.

I keep returning to Randy's article @ http://www.reefkeeping.com/issues/2007-04/rhf/index.php

It contains the following helpful advice:

Necessary Supplements in Nearly All Reef Aquaria

• Calcium
• Alkalinity

Useful Supplements in Many Reef Aquaria

• Magnesium (if not maintained by calcium addition methods and water changes)
• Iron (for aquaria growing macroalgae)
• Silicate (for aquaria with sponges, snails, etc.)

Possibly Useful Supplements in Reef Aquaria

• Certain amino acids (e.g., aspartic acid)
• Fatty acid supplements

Generally Unnecessary or Undesirable Supplements in Most Reef Aquaria

• Iodine
• Strontium
• Borate
• Trace element mixtures

I keep returning to it because I can't find any new information about the usefulness or otherwise of trace elements and other substances. None that I trust anyway.

 

[Randy Holmes-Farley]

It's a complicated situation.

Many trace elements are depleted in many tanks (including mine), as this fact is clearly evidenced by ICP testing that has become widely available and we have a lot more data than we previously did.

Also, some trace element dosing is clearly and immediately useful in some cases (such as iron when growing macroalgae).

But, many tanks, even those with depletions of some trace elements, may have other elements at elevated levels. For that reason, I still do not think trace element mixtures is the best way to go for folks who can afford ICP testing.

Two final complications are that

1. ICP testing does not reveal the form of the chemical present, and different forms may have greatly different bioavailability and potential toxicity. I recently posted an article which detailed that the bioavailability of the various different forms of iron is still not well known (Fe++, Fe++ bound to organics, free Fe+++, Fe++ bound to organics)

2. Even for a given form (say, free Fe+++) we really do not have much useful data on what levels are desirable (not too low to becoemlimitign to growth, and not so high to become a toxicity concern).

 

[Randy Holmes-Farley]

As to the elements I list above as likely not useful

• Iodine
• Strontium
• Borate

(they are not actually trace elements, but rather minor elements), I am still not convinced they are useful.

That said, it is generally pretty easy for folks to dose them and see if they see benefits. When recently asked what I would do if I was restarting from scratch, possibly carefully testing in my system if they have a benefit might be one of the things I'd do.

 

[Randy Holmes-Farley]

There is (IMO) even less generality on the utility of organic additives, such as vitamins, amino acids, fatty acids, etc.

I think some may well be useful in some scenarios (like amino acids when other sources of N are very low). Amino acids may even be useful in most reef tanks. Especially aspartic acid. But there is relatively little evidence to show utility for any given organic in reef tanks.

 

[Randy Holmes-Farley]

Here's an article with my Triton test results and my commentary on each and the potential for dosing of specific trace elements:

http://www.reefedition.com/my-triton-testing-results-by-randy-holmes-farley/

 

[Reef Stu]

I don’t do a lot of water changes even though I feed very heavily (water parameters are all in check). I noticed one of my of my hermit crabs acting lethargic for weeks. I started dosing iodine, he molted the first night, and became very active again. I also saw many other molts from copepods. I think if your like me and don’t do many water changes, it’s important to add supplements.

 

[Randy Holmes-Farley]

I don’t do a lot of water changes even though I feed very heavily (water parameters are all in check). I noticed one of my of my hermit crabs acting lethargic for weeks. I started dosing iodine, he molted the first night, and became very active again. I also saw many other molts from copepods. I think if your like me and don’t do many water changes, it’s important to add supplements.

OK, that's certainly a fair conclusion of yours. I just look at your result and have a different conclusion.

We've seen the result of molting crabs and shrimp immediately after dosing iodine for decades. Many of us do not see that as evidence of a desirable effect.

It is well known, for example, that compounds most would deem deterimental to crustaceans (e.g., the pesticide DDT) also cause accelerated molting:

Effects of Pollutants on Molting and Regeneration in Crustacea
https://academic.oup.com/icb/article/32/3/495/1992364
"Exposure of regenerating U. pugilator to10 and 25 /ug/liter DDT produced an acceleration of regeneration and molting (Weis and Mantel, 1976)."

One place to look for evidence of utility is the aquaculture of shrimp. There's no evidence that I have ever seen that aquaculture farms dose any iodine into the water for the purposes of supplying a need, even though they dose many things and even use some forms of iodine to disinfect their equipment.

 

[Reef Stu]

Is there iodine in the synthetic sea salt at the aquaculture shrimp farms? Do they do frequent water changes? I don’t know. I don’t believe that the specific immediate molt response to my adding iodine was and undesirable effect. Just because of the fact that the red legged hermit crab had not moved much in weeks. Then the molt, then happy crab again. Also I add Iodine weekly now, and it’s not like the crabs are molting after every application. I will concede that you have a much better grasp on chemistry then me. I can only speak as to what I have seen in my own very small piece of the ocean. [emoji1303]

 

[Randy Holmes-Farley]

Is there iodine in the synthetic sea salt at the aquaculture shrimp farms? Do they do frequent water changes? I don’t know. I don’t believe that the specific immediate molt response to my adding iodine was and undesirable effect. Just because of the fact that the red legged hermit crab had not moved much in weeks. Then the molt, then happy crab again. Also I add Iodine weekly now, and it’s not like the crabs are molting after every application. I will concede that you have a much better grasp on chemistry then me. I can only speak as to what I have seen in my own very small piece of the ocean. [emoji1303]

Just to be clear, while I think dosing iodine is not likely useful, I am certainly open to hearing of evidence that it is.

I understand what you are saying, and the molting effect has been used for decades by some as a justification for dosing iodine. But I do not agree that it is, and many of us who stopped dosing iodine after doing so for years saw no change in our ability to keep shrimp, crabs, etc.

If it was so important, I would expect it would not be hard to find articles on shrimp and crabs that indicated such a need, but despite extensive googling over the years, I've never seen any such articles except by hobbyists.

FWIW, seafoods and especial seaweeds (e.g., nori) have a lot of iodine already in them, and is likely a substantial source of iodine to reef tanks for any organisms that might need it.

Aquaculture shrimp farms often use freshwater or brackish water, and they supplement with some minerals that do not generally report iodine as an ingredient:

http://www.ciba.res.in/Books/Brochure 4.pdf

Supplementation of potassium, magnesium and sodium chloride in practical diets for the Pacific white shrimp, Litopenaeus vannamei, reared in low salinity waters
https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2095.2007.00460.x

 

[Reef Stu]

So are you saying in your opinion that dosing iodine is a waste of time and money? Or do you think it’s actually detrimental?

 

[Daniel@R2R]

Good discussion already! I'm curious about this as well. Following

 

[Randy Holmes-Farley]

So are you saying in your opinion that dosing iodine is a waste of time and money? Or do you think it’s actually detrimental?

If you dose iodide (I-) or iodate (IO3-) and maintain NSW levels, I would contend that it is just a waste of time and money. That has been my opinion for about a decade, despite dosing both forms at one time or another, and having dosed iodide for many years. But if there was compelling evidence of a benefit, I'd certainly change that opinion. If it is beneficial, my money would be on making algae (macro and micro) grow faster since the main place in the natural world where iodine accumulates is in algae. My tests didn't show a statistically significant effect, but I only tested two species (chaeto and caulerpa racemosa).

If you dose Lugols (it has I2 in it, which is reactive with organics including living tissues and trace elements such as ferrous iron), then I'm not sure if it is detrimental or not, or maybe even beneficial for reasons unrelated to iodine itself, but to the the bioavailability of trace elements (which Lugols can alter by changing the oxidation state of the metals by oxidizing them.

 

[Randy Holmes-Farley]

FWIW, there are some organisms that do have a demonstrated need for iodine, and this has been known for a long time. It isn't always clear that they necessarily get their iodine from the water as opposed to in foods, but they do have a need. It's just that I do not think most reefers keep these.

I documented what was known to the point I wrote this article in 2003 :

Chemistry And The Aquarium: Iodine in Marine Aquaria: Part I ? Advanced Aquarist | Aquarist Magazine and Blog
https://web.archive.org/web/20050405045820/https://www.advancedaquarist.com/issues/mar2003/chem.htm

Chemistry And The Aquarium: Iodine In Reef Tanks 2: Effects On Macroalgae Growth ? Advanced Aquarist | Aquarist Magazine and Blog
https://web.archive.org/web/20030419082711/http://www.advancedaquarist.com/issues/april2003/chem.htm

some examples from the first one:

Who uses iodine: Gorgonia and antipatharian corals (black coral)

Another set of creatures of the deep that use iodine are certain gorgonia, such as Plexaura flexuosa.42 They have 3,5-diiodotyrosine in their bodies, to the tune of 0.1 to 2.6% of the total dry weight as iodine. This iodoamino acid is presumably incorporated into proteins in the skeleton (stem), but the benefit is unclear. Again, it may be largely an antipredatory effect that is desired. The iodine incorporation in gorgonia seems to increase with age.43,44 The proteins of many different gorgonia species contain substantial iodine: Eunicella otenocalloides 6.5-8.9% by weight%, Gorgonia verrucosa 4.2-9.0, G. lamarcki 3.3-6.8, G. scirpearia 0.4-0.6, Rhipidigorgia flabellum0.6-1.1, Euplexora maghrebensis 0.19-0.23, and Plexaura kukenthali 1.9-2.2.44 It has also been demonstrated that at least one gorgonia (E. verrucosa) takes up iodine in the form of inorganic iodine from the water column.45

One study showed that the organoiodine compound thyroxine, and some related compounds, are localized to certain parts of the gorgonia L. virgulata.46 Most interestingly, one of the places it is localized to are scleroblasts (spicule-forming cells) and on the spicules themselves. Further, the addition of thyroxine to these cells impacted the uptake of calcium, and it is suggested that the thyroxine functions in spicule formation.

The antipatharian corals (the black corals) also seem to incorporate a lot of iodine. The basal regions of these corals are especially loaded with iodine, with more than 23% iodine by dry weight recorded in two species.43, 45 Again, the specific purpose is not known.

Who uses iodine: Tunicates

The known story of iodine in tunicates also appears to be complex. Tunicates apparently use the iodinated amino acids to make proteins, like the gorgonia, but they also make some very complicated organoiodine compounds.47-49 Since some of these molecules are vertebrate hormones (e.g., thyroxine) it has been suggested that tunicates use them in this fashion, while most lower invertebrates do not.48 Others of these iodoorganics are even more complex, such as lukianol B, a cytotoxic compound that might be made as a deterrent to predators.47 Like all of the species discussed above, tunicates have also been shown to take up iodine as dissolved inorganic iodine from the water column.49


Who uses iodine: Sponges

Sponges are also known to produce a wide variety of potentially toxic organoiodine compounds.50 One sponge of the genus Geodia is known to make cyclic peptides (geodiamolides A and B) that contain iodine, and these toxic compounds are expected to exert a protective effect of some type.51

Overall, the sponges do incorporate large amounts of iodine An analysis of 12 species of sponges from the Andaman Sea showed iodine contents that range from 0.001 to 0.085% iodine.52 I have not, however, seen any studies about where sponges get iodine, whether from inorganic iodine in the water column, or from ingested food.


Who uses iodine: Worms

The marine worm Glossobalanus minutus has been shown to take up iodine from the water column, but it is not clear what it does with it as no iodinated proteins were detected.53 A different marine worm, Lineus rubber, accumulates iodide from the water column and stores it mostly as iodide, with a smaller amount of thyronine (an organoiodine hormone).54, 55

Who uses iodine: Shrimp

As one moves up the food chain to more sophisticated organisms, data on their ability to take up iodine from the water column becomes very sparse. Shrimp are known to have a need for iodine to grow, but that is only known in terms of a dietary requirement. The shrimp, Penaeus chinensis O'sbeck, for example, grows optimally when the diet contains 0.003% iodine.56

Shrimp apparently incorporate substantial amounts of iodoorganics into their bodies. The shrimp Pandalus borealis, for example, incorporates between 0.04 and 2 ppm iodine as iodoorganic compounds depending on the particular body tissues examined. Their roe were somewhat higher, up to 4 ppm iodine as iodoorganic compounds.57 Shrimp shells and other parts can contain up to 17 ppm by dry weight iodine, the majority of which is iodoorganic compounds58, but the values are still far lower than for other inverts like macroalgae, sponges, or gorgonia.

Still, the amount contained says nothing about whether iodine is an important requirement. I could find no scientific studies that showed that shrimp need iodine from the water column, but neither could I find any that demonstrates that they do not.

Who uses iodine: soft corals such as Xenia

Surely, you say, there must be studies showing that Xenia and other soft corals need iodine from the water column? Well, I could find none. There may be studies that I could not find, and regardless of whether there are studies, iodine in the water column may or may not have a significant impact on these organisms. Nevertheless, there is no published basis (that I could find) for many of the claims about iodine.

There are studies that show that Xenia does contain substantial iodine, and it is likely that it got it from the water column, but what good, if any, that iodine serves is unknown. In a recent publication, Ron Shimek showed that a wild specimen of Xenia sp. contained 350 ppm iodine on a wet basis and a captive specimen showed 270 ppm on a wet basis and 1350 ppm on a dry basis.29 Those values are as high as some of the macroalgae, and lend some support to the idea that Xenia accumulate iodine (and presumably have a use for it at such high accumulations).


Of course, accumulating iodine from the tank somehow, and showing that supplemental inorganic iodine is beneficial are very different. I am in the planning stages of running experiments on the possible benefits of iodine supplementation to certain soft corals, but the technical challenges are significant (much more so than similar tests on macroalgae), and I’m not certain that they will be successful.

 

[Reef Jeff]

I agree that supplements are important, but we don’t have the testing technology that allows us to know what to add and when. Blanketly adding a trace element mix is worse than not adding because you may add what is not needed or what is detrimental just to get something else in check. Even if you add the specific trace element, it’s hard to know if you added enough without another Triton test. Triton tests are a big improvement over those limitations, but too expensive to do with any regularity.

I liked Randy’s article though. It clearly shows usefulness of the Triton test to see what’s going on and to give some clarity to existing husbandry practices.

 

[vetteguy53081]

Generally, regular water changes replenish/refreshes the lost elements which are used up through evaporation and coral absorption. I have always used additives for elements and see nothing but benefits. The two I use are Kent and Fluval trace elements

 

[Punchanello]

Thanks Randy and everyone else for the comments.

I'm not overly sceptical about the use of "trace" elements in and of themselves. I certainly haven't got the experience to make a judgement based on personal observations. The pursuit of NSW composition makes sense, or at least probably wouldn't do any harm.

I'm more sceptical of the specific claims being made like "X ingredient is known to improve Y" when there is no real science to back that up. That's a huge turn-off. A dosing regime that simply includes substances in a bottle without any publicly available baseline water chemistry target (this seems to be 90% of these products) raises all sorts of questions.

 

[L Sean Hubbard]

The Red Sea trace element pack includes iodine. The box claims that it's necessary for corals that have certain colors.

 

[Punchanello]

The Red Sea trace element pack includes iodine. The box claims that it's necessary for corals that have certain colors.

This was one of the products I was thinking about.

 

[Randy Holmes-Farley]

I'm more sceptical of the specific claims being made like "X ingredient is known to improve Y" when there is no real science to back that up. That's a huge turn-off. A dosing regime that simply includes substances in a bottle without any publicly available baseline water chemistry target (this seems to be 90% of these products) raises all sorts of questions.

The claims along those lines greatly stretch the proven facts, IMO.

 

[Stigigemla]

I have a lot of customers using the Balling method. Normally they begin with the sodium bicarbonate when kH is sinking and then Calcium when that is needed.
When the consumption raises i recommend them to switch to the full Baliing method. After a while some of them are complaining about the colors of stone colors. Specially the pink birdsnest (very popular beginners coral in Sweden) often pale off to a more orange color. With iodine supplement in the Balling method it is normally fixed in less then a week. So weak color in pink birdsnest can be reset with iodine. That has happened so many times so i am totally convinced. But i cant say if the corals fare well of it. Maybe it is us liking the color of a coral struggling with a light poisoning. But i like to guess it is good for the coral.
If the corals miss green i recommend the heavy metal complex (most iron) and that has helped many times. There are many that claims strontium is good for red color but i have not observed that.
Maybe strontium sometimes can increase red color without having another effect on corals.

It is a problem for us in the hobby that the research of corals only look on their well being not the colors as we hobbyists. (Or maybe the opposite)