Randy's thoughts on trace elements

[Lasse]

Magnesium and strontium are incorporated into deposited aragonite, even abiotic aragonite, in ratios that do not reflect the seawater concentration.

How about calcite?

If I look at the figures in Hans-Werner:s paper - the ratio between Ca and Sr is nearly the same in both sea water and skeleton - around 50:1 What would happen if the ratio Ca/Sr in the tank water rise to 100:1 (1/2 natural Sr concentration). Would there still be the same ratio in the skeleton? - and if so - does it cost energy? If a biological process - it should IMO.

Sincerely Lasse

 

[Randy Holmes-Farley]

How about calcite?

If I look at the figures in Hans-Werner:s paper - the ratio between Ca and Sr is nearly the same in both sea water and skeleton - around 50:1 What would happen if the ratio Ca/Sr in the tank water rise to 100:1 (1/2 natural Sr concentration). Would there still be the same ratio in the skeleton? - and if so - does it cost energy? If a biological process - it should IMO.

Sincerely Lasse

If you raise the level of one ion, there's more driving force for that ion to enter the crystal and more will end up there, assuming it is not carefully controlled by an organism.

The Sr/Ca ratio has been studied endlessly because folks use it as a record of the paleo temperature, since the ratio depends on temperature, whether in a skeleton or simple precipitation.

THis recent paper discusses how the chemistry controls the incorporation of ions into calcium carboante, not just the concentrations:

https://www.sciencedirect.com/science/article/pii/S0016703723004064

"or in other words the preferred Me2+ affinity for the solid or the fluid, is controlled by the structural parameters in the two phases. As such Cd2+, Co2+, and Ni2+, that coordinate to six oxygens both in calcite and the fluid phase, and obtain ionic radii close to that of calcium in calcite, exhibit a preferential affinity for the solid under near equilibrium conditions "

and here's a more general discussion:

Incorporation of Incompatible Strontium and Barium Ions into Calcite (CaCO3) through Amorphous Calcium Carbonate

Calcite is a ubiquitous mineral in nature. Heavy alkaline-earth elements with large ionic radii such as Sr2+ and Ba2+ are highly incompatible to calcite. Our previous study clarified that incompatible Sr2+ ions can be structurally incorporated into calcite through crystallization from amorphous...

www.mdpi.com

Calcium carbonate exists mostly as calcite and aragonite in the natural environment. It is known that the structures of carbonates depend on the ionic radii of divalent metal ions [6]. Divalent ions with an ionic radius smaller than that of Ca2+ (1.00 Å) form a carbonate with the calcite structure. On the other hand, divalent ions with an ionic radius larger than that of Ca2+ form a carbonate with the aragonite structure. The incorporation of impurity ions into structures of carbonates also depends on the radii of impurity ions. Carbonates with the calcite structure tend to capture impurity elements of which the ionic radius is smaller than that of calcium ion. In contrast, carbonates with the aragonite structure tend to capture impurity elements of which the ionic radius is larger than that of Ca2+. From the above, divalent metal ions such as Sr2+ and Ba2+ are incompatible to calcite.

 

[Lasse]

and here's a more general discussion:

From the linked article My bold

Heavy alkaline-earth elements with large ionic radii such as Sr2+ and Ba2+ are highly incompatible to calcite. Our previous study clarified that incompatible Sr2+ ions can be structurally incorporated into calcite through crystallization from amorphous calcium carbonate (ACC).

In addition to these three anhydrous polymorphs, amorphous calcium carbonate (hereafter amorphous calcium carbonate (ACC); CaCO3·nH2O, n < 1.5) is known to exist [1]. In living organisms, ACC is mainly used as a precursor for the formation of crystalline calcium carbonate and either has an aragonite-like short-range order or a calcite-like short-range order.

If I understand this right - during non biological circumstance Sr and Ba will not be incorporated into calcit. And as I understand it - calcit is the CaCO3 form that calcification by coral animals create. The Sr and Br in coral skeletons is therefore a result of biomagnification? Please correct me if I´m wrong. I do not try to argue here - I try to understand. Any argumentation will come when I understand how it works :)

Sincerely Lasse

 

[Randy Holmes-Farley]

If I understand this right - during non biological circumstance Sr and Ba will not be incorporated into calcit. And as I understand it calcit is the CaCO3 form that calcification by coral animals create. The Sr and Br in coral skeletons is therefore a result pf biomagnification. Please correct me if I´m wrong. I do not try to argue here - I try to understand. Any argumentation will come when I understand how it works :)

Sincerely Lasse

Coral skeletons are primarily aragonite, which takes in more Sr and Ba.

 

[Lasse]

Coral skeletons are primarily aragonite, which takes in more Sr and Ba.

OK - I rest my case for the moment

My normal way to understand during a discussion is to seek information among scientific papers on the net - sometimes I find other useful information. Have you seen this article?

Sincerely Lasse

 

[rtparty]

I'm assuming it must have. Went to CO.

Point and case, without a standard in shipping/handling we can't be sure that our samples are received in good condition. Not pointing fingers at the companies conducting the tests - but I think the amount of variance is something that needs to be accounted for and should be considered before individuals react.

I won't be changing my routine or buying up additives needless to say.

I think these testing procedures can be helpful when certain protocols are established and coupled with definitive research that provides supporting evidence that trace element supplementation is necessary. Until then, I'm out.

After seeing your initial post, I knew it was ICP Analysis running the test just based on the "less than ideal" results.

Your experience is more common than many want to accept and what is sad is how many would have blindly started trying to fix things that didn't need any fixing. Thank you for sharing. It is another data point in the collective.

This isn't to bash any company but we as a hobby need to call out the bad actors and help others to avoid them. Only one ICP company is even attempting to test their procedures and share their results openly. It is very likely they may be the only ICP company worth using as time goes on.

 

[PocketGoose]

After seeing your initial post, I knew it was ICP Analysis running the test just based on the "less than ideal" results.

Your experience is more common than many want to accept and what is sad is how many would have blindly started trying to fix things that didn't need any fixing. Thank you for sharing. It is another data point in the collective.

This isn't to bash any company but we as a hobby need to call out the bad actors and help others to avoid them. Only one ICP company is even attempting to test their procedures and share their results openly. It is very likely they may be the only ICP company worth using as time goes on.

Exactly. I really believe there is some
great work to be accomplished from these procedures and I didn’t want to come across as bashing anybody at all. The main idea was as consumers I think we need to be realistic in our approach of what we do with the data we receive and ask the appropriate questions to make informed choices for our tanks.

I guess you can say we’re essentially just scratching the surface in this whole thing.

 

[GuppyHJD]

Do you have questions that you would like to see addressed?

Randy, thank you for the reply and if/when I get a logical question, I will not hesitate to ask. I have learned so much reading your forum and you have saved me from some dumb mistakes. I have been tracking my tank with ICP's for about 8 months and find some of Moonshiner's information and some of Reef BluePrint conflict and some makes sense (who knows yet if such will actually help the tank). Focusing on the majors stability now and fighting a case of dinoflagelents with silicate dosing. Again - thank you for your reply and the countless hours you give to the community.

I am excited with the direction the science is heading...hopefully the ICP tests will start to agree and we will learn what is fact vs what is just a number. Like the medical community for humans, it is hard to believe some of the claims from the chemical merchants and frightening when I read some answers offered to less informed beginners. Not to mention some of the salt differences and/or the Vibrant story.

 

[Hans-Werner]

Zitations from ALLISON, Nicola, et al. Strontium in coral aragonite: 3. Sr coordination and geochemistry in relation to skeletal architecture. Geochimica et Cosmochimica Acta, 2005, 69. Jg., Nr. 15, S. 3801-3811.:

"Our data indicate
that the Sr composition of COCs is affected by biological or
kinetic processes, as well as temperature."

"The Sr/Ca composition of skeletal COCs is significantly
different from that of adjacent fasciculi (Cohen et al., 2001;
Allison and Finch, 2004) and Cohen et al. (2001) suggest that
biological and kinetic effects may be minimised in the COCs.
In this study, we observe Sr heterogeneity within both COCs
and fasciculi and we conclude that there are similar challenges
in reconstructing SST records from both of these skeletal
structures."

COC = centres of calcification
SST = sea surface temperature

Figures in the article show higher Sr/Ca ratios in COCs. The ratios vary from ca. 11.2 mmol/mol at COCs to 8.3 mmol/mol for Porites lobata in Fig. 5. and from ca. 10 mmol/mol at COC to 9.3 mmol/mol for Acropora palmata in Fig. 3.

The Sr/Ca ratios of Table 5 are 8.9 to 10.2 mmol/mol, average 9.2 mmol/mol

Pavona: Sr/Ca 9.0 mmol/mol at fasciculi - 10.2 mmol/mol at COC, avg. 9.4 mmol/mol
Montastrea: Sr/Ca 9.0 mmol/mol at fasciculi to 9.4 mmol/mol at COC, avg. 9.2 mmol/mol
Porites: Sr/Ca 8.9 mmol/mol at fasciculi to 9.2 mmol/mol at COC, avg. 9.0 mmol/mol

From Millero I have calculated a Sr/Ca ratio 8.7 mmol/mol, from data of the PTEO of the MBARI I also get a Sr/Ca ratio of 8.7 mmol/mol for NSW.

This means Sr/Ca ratios of analysed skeletons are slightly higher (or strontium is elevated) relative to NSW ratios, especially at the COCs.

Reefers that did experimentation with strontium chloride addition reportet increased (longitudinal?) growth with strontium addition but brittle growth tips when Sr++ additions where high. If I recall it right Treuheit reported this in a German marine aquarium magazine in the early 90s I think.

@Randy Holmes-Farley , is there any hard evidence that Sr++ and Ba++ have no effect?

 

[Lasse]

I found this when I try to gather information about calcification. It is 157 pages - I have only read around 30 of them till now - but I will read the rest as soon as possible. It was very interesting reading

https://edoc.ub.uni-muenchen.de/26077/1/Conci_Nicola.pdf

Sincerely Lasse

 

[Randy Holmes-Farley]

OK - I rest my case for the moment

My normal way to understand during a discussion is to seek information among scientific papers on the net - sometimes I find other useful information. Have you seen this article?

Sincerely Lasse

I had not seen that particular paper, but I'm concerned about the conclusion. I'm not sure that anyone since has noted a dependence of coral calcification rate on calcium levels, but certainly on pH and/or carbonate levels, yes.

IMO, they ignore an important contributor to their measured rates (which they base on the need for alk and calcium dosing rather than any observation of corals), which is ANY abiotic precipitation of calcium carbonate. That rate surely will be impacted by calcium, and I think it skews their data in a way that makes it seem that coral calcification relates to calcium concentration, when in fact, it may not be.

On the carbonate issue...

Despite the mention of carbonate, it is very hard to distinguish whether corals calcify faster at higher alk or pH due to which of these two effects:

1. More carbonate at higher pH or at higher alkalinity makes it easier to take up directly. That explains higher alkalinity and higher pH effects by direct impact on carbonate concentrations.

or

2. Bicarbonate is the ion taken up, not carbonate. Higher alkalinity means higher bicarbonate so calcification and process faster, and the pH effect is only a small change in bicarbonate around pH 8, but the ability of the corals to excrete the excess proton after converting HCO3- into CO3-- and H+ is much easier as the pH rises (lowering the external H+ concentration against which the coral has to fight to pump out that proton).

Since an increase in pH and a separate increase in alkalinity both increase calcification in both of these possible mechanisms, it is very hard to distinguish them by experiments on calcification, and would require, IMO, molecular level analysis of transporters.

 

[Randy Holmes-Farley]

Zitations from ALLISON, Nicola, et al. Strontium in coral aragonite: 3. Sr coordination and geochemistry in relation to skeletal architecture. Geochimica et Cosmochimica Acta, 2005, 69. Jg., Nr. 15, S. 3801-3811.:

"Our data indicate
that the Sr composition of COCs is affected by biological or
kinetic processes, as well as temperature."

"The Sr/Ca composition of skeletal COCs is significantly
different from that of adjacent fasciculi (Cohen et al., 2001;
Allison and Finch, 2004) and Cohen et al. (2001) suggest that
biological and kinetic effects may be minimised in the COCs.
In this study, we observe Sr heterogeneity within both COCs
and fasciculi and we conclude that there are similar challenges
in reconstructing SST records from both of these skeletal
structures."

COC = centres of calcification
SST = sea surface temperature

Figures in the article show higher Sr/Ca ratios in COCs. The ratios vary from ca. 11.2 mmol/mol at COCs to 8.3 mmol/mol for Porites lobata in Fig. 5. and from ca. 10 mmol/mol at COC to 9.3 mmol/mol for Acropora palmata in Fig. 3.

The Sr/Ca ratios of Table 5 are 8.9 to 10.2 mmol/mol, average 9.2 mmol/mol

Pavona: Sr/Ca 9.0 mmol/mol at fasciculi - 10.2 mmol/mol at COC, avg. 9.4 mmol/mol
Montastrea: Sr/Ca 9.0 mmol/mol at fasciculi to 9.4 mmol/mol at COC, avg. 9.2 mmol/mol
Porites: Sr/Ca 8.9 mmol/mol at fasciculi to 9.2 mmol/mol at COC, avg. 9.0 mmol/mol

From Millero I have calculated a Sr/Ca ratio 8.7 mmol/mol, from data of the PTEO of the MBARI I also get a Sr/Ca ratio of 8.7 mmol/mol for NSW.

This means Sr/Ca ratios of analysed skeletons are slightly higher (or strontium is elevated) relative to NSW ratios, especially at the COCs.

Reefers that did experimentation with strontium chloride addition reportet increased (longitudinal?) growth with strontium addition but brittle growth tips when Sr++ additions where high. If I recall it right Treuheit reported this in a German marine aquarium magazine in the early 90s I think.

@Randy Holmes-Farley , is there any hard evidence that Sr++ and Ba++ have no effect?

Several comments,

1. First is the idea that both you and Lasse keep throwing out that because the ratio of Sr to Ca in a skeleton is seemingly similar to the ratio in the water, or maybe higher than the ratio, that somehow that implies it is needed or useful. I fail to understand that logic at all. The incorporation of strontium (and even different isotopes of strontium) into precipitating calcium carbonate is known and published to depend on many factors, including the strontium concentration, the temperature, and the rate of calcium carbonate precipitation. The published incorporation rates are about the same level in corals and in abiotic precipitation.

If you wanted to help support a claim that Sr was being intentionally deposited because it was useful, I think that you would need to show that it is significantly higher in a coral skeleton than in abiotic precipitation taking place under similar conditions.

This entire discussion is not new. I published this exact discussion in 2003, and while there have been a huge number of studies on the Sr/Ca ratios (even ratios of individual isotopes), the goal has almost always been to get a paleo thermometer from fossil corals, and not answering whether Sr is useful.

Aquarium Chemistry: Strontium and the Reef Aquarium

This article on strontium is the second of several that delve into a variety of issues involving magnesium and strontium.

reefs.com

from that article of mine:


Organisms That Use Strontium: Corals and Calcerous Algae
Organisms that calcify (that is, deposit calcium carbonate skeletons) are known to incorporate strontium into them. This deposition may be:

Intentional for positive reasons. That is, the strontium serves a useful purpose. Perhaps the purpose is to initiate or maintain calcium carbonate precipitation in some fashion. Some organisms described above clearly fall into this category.

Intentional for negative reasons. That is, the organism wants to get rid of potentially toxic strontium and depositing it into a CaCO3 skeleton is one way to accomplish that task).

Accidental. That is, the deposition of strontium serves no real purpose for the organism, but is simply the result of the fact that strontium looks rather like calcium, and gets into pathways intended for calcium and becomes deposited into the skeleton. This is obviously the way that strontium gets into abiotically deposited calcium carbonate.
In the abiotic precipitation of calcium carbonate from seawater (by the slow addition of carbonate), strontium is incorporated into the growing crystal at almost the same ratio to calcium that is present in the seawater. That is, about 103:1, Ca:Sr (at 25 °C).25 Interestingly, he amount of strontium incorporated is slightly lower at higher temperatures (105:1 at 30 °C), and slightly higher at lower temperatures (97:1 at 10 °C).13,25

This temperature dependence has lead many researchers to investigate, and find largely true, the idea that the strontium to calcium ratios in corals might be used as a temperature probe for ocean temperatures. Most interestingly, it has been extended into ancient coral skeletons, where actual temperature measurements are lacking.26 Many factors have complicated these studies, such as

....Different corals incorporate different ratios at the same seawater temperature and strontium levels,
....The same corals can deposit different ratios during the day and the night
....Different parts of the skeleton of a single coral may have different ratios
....The presence of zooxanthellae can significantly perturb the ratio.25
....The incorporation of strontium is strongly dependent on the strontium concentration in solution (which may vary over geologic time, with depth, and with salinity)

Other related measurements (such as the incorporation of various oxygen isotopes into the calcium carbonate) may ultimately turn out to be more useful for temperature estimation. The ratio of the different strontium isotopes (molecular weight 87 and 86) in deposits has also been suggested to be a measure of the weathering of land, since the ratio in rivers is different than in the ocean.27

In any case, there are many fascinating studies reported related to strontium in corals and other calcium carbonate deposits. While many of these are only tangentially related to aquarium issues, some of the basic issues are important for understanding the strontium balance in aquaria.

In an old (1957) study28 of 900 samples of calcium carbonate from many different organisms, it was noted that:

“Analyses of limestones, reef cores, limestone precursors, and fossils indicate that replacement and recrystn. lower the Sr/Ca ratio”. This fact is important because if calcium carbonate is the ultimate basis for calcium additives to aquaria (such as CaCO3 in CaCO3/CO2 reactors, or CaCO3 heated to form lime that is later used to make limewater), then the amount of strontium present in these ancient deposits will control the amount getting into aquaria. If these deposits are deficient in strontium, then an aquarium using them may also become deficient.
“…reef corals, and green aragonite algae all have high Sr/Ca ratios that may be related to rapid deposition of carbonates associated with photosynthesis processes”. Again, if reef corals are not the ultimate source of CaCO3 used to make calcium supplements, then the levels in the aquarium may drop over time, just as in (1).
“The Sr/Ca ratio is characteristic of a species or a taxonomic group…”
In this case, if the organisms used to make the original CaCO3 are not the same species that are depositing CaCO3 in the aquarium, then the relative amount of strontium in the supplement may be too high or too low, allowing the aquarium to become enriched or depleted over time. The same could be said for the deposition temperature.

Many recent studies have shown the Ca:Sr ratio for many corals at typical tropical reef temperatures and at normal seawater strontium concentrations to be in the range of 100:1 to 120:1. When looked at very closely, it has been noted that corals do actually seem to incorporate slightly more strontium than happens abiotically under the same temperature and ambient strontium conditions (about 103:1 (at 25 °C).25 Is that because the corals “want” the strontium? Or just an artifact of the pathway that corals use to get calcium deposited29 into calcium carbonate? The answer is unknown, but there are a few clues buried in other studies, and these are described below.

Do Corals Need Strontium?
Over the past decade, a number of advanced aquarists have indicated that certain calcifying corals in their aquaria have responded positively when they have added strontium. Julian Sprung, for example, indicated that in one of his aquaria, strontium boosted growth considerably. Unfortunately, he does not report strontium levels from that aquarium.1

The several possible reasons for corals to take up strontium were presented earlier in this article. These reasons range from needing strontium for some purpose, through not caring one way or the other about strontium, to depositing it only as a means of eliminating it from their bodies. What does the scientific literature have to say on this subject? Unfortunately, not enough. There has never been a published study that showed exactly what happens to the health of corals (as measured via calcification rates or any other means) when strontium is absent.

There have been numerous studies that have shown what happens when strontium is raised above natural levels. In those studies, the amount of strontium incorporated rises linearly with strontium concentration up to at least 300 ppm in Stylophora pistillata.30 It has also been shown that calcium and strontium uptake may use the same pathways, since they are both inhibited by the same organic molecules that block certain protein transporters.30 Depending on the conditions, calcification can increase on adding extra strontium, as it does with added calcium.31,32 Nevertheless, these studies say little about whether natural levels of strontium are important for normal calcification.

Another study examined in microscopic detail where the strontium is located in Galaxea fascicularis.33 They found that strontium was significantly enriched in the mucous layers. They propose that the strontium is used to neutralize (thanks to its +2 charge) the highly anionic (that is, negative charged) individual mucin glycoproteins. Once neutralized, the mucin can condense into functional mucin granules. These glycoproteins are highly sulfated, and if one were selecting a cation to bind to and neutralize the mucin, one might well select a divalent ion with a preference for binding sulfate. That is exactly what strontium provides, recalling the fact mentioned above that strontium sulfate is much less soluble than either calcium or magnesium sulfate.

The authors also go on the state that the mucin layer itself may play an important role in ensuring that calcium is delivered to the ectodermal cells. That is, it helps maintain an artificially high calcium concentration near the surface of the ectodermal cells. This process would help what is otherwise believed to be a limiting factor in calcification: the active transport of calcium. Whether this hypothesis is valid or not remains to be established. Nevertheless, it has, for the first time, provided a plausible mechanism for corals to benefit from strontium.

 

[Randy Holmes-Farley]

@Randy Holmes-Farley , is there any hard evidence that Sr++ and Ba++ have no effect?

No. Is there evidence that the well known incorporation of uranium is not useful?

Is there evidence that either is useful? No.

 

[Randy Holmes-Farley]

I'll just add that it is the role of a scientist to be skeptical of claims without convincing evidence.

That may not be the easiest way to maintain a reef tank. Showing whether barium is useful or not takes a lot of effort. Maintaining a natural level is not particularly difficult.

Thus, if the goal is easily maintaining a great reef tank, taking the approach of maintaining all or many or some elements at natural concentrations, regardless of evidence of utility, may be the easiest way forward.

But in my role as scientist, I require more. :)

 

[Hans-Werner]

No. Is there evidence that the well known incorporation of uranium is not useful?

Is there evidence that either is useful? No.

Ok, but there are no reports on any effects of uranium either. In strontium there are.

In fact both, the report on increased growth, brittle tips at elevated concentrations and scientific findings of elevated concentrations on the COCs may point to a role in crystal nucleation.

As I mentioned at least there is a long time of experimentation and mentioning strontium as useful or necessary. In the 2000s, when transition metals had no good reputation, many reefers regarded only strontium and iodine as necessary or useful trace elements.

In fact for most reef aquarists strontium (maybe besides iodine) was the most important trace element in the 90s, in the 2000s and for many still it is.

I have learned at least to take experiences serious but to check the explanations and to look for more plausible explanations if there is scientific evidence that the explanation is wrong, like the nutrient vs. oxidant explanation of nitrate effects. :)

 

[Thales]

I think the reports by many reefers over the years that adding strontium had no effect or that no change was seen after stopping strontium addition also need to be taken seriously.

 

[Lasse]

In those studies, the amount of strontium incorporated rises linearly with strontium concentration up to at least 300 ppm in Stylophora pistillata.30 It has also been shown that calcium and strontium uptake may use the same pathways, since they are both inhibited by the same organic molecules that block certain protein transporters.30 Depending on the conditions, calcification can increase on adding extra strontium, as it does with added calcium.31,32 Nevertheless, these studies say little about whether natural levels of strontium are important for normal calcification.

With other words - higher concentration of strontium (compared with today's normal concentrations) in the water column will lead to higher strontium and calcium incorporation (read higher calcification rate) - even if calcium concentrations is not increased in the water column - if I understand it right.

What's happen if the strontium gets lower than "natural concentrations" ....... will this lead to lower strontium and calcium incorporation (read lower calcification rate) ......

Sincerely Lasse

 

[Celestion]

Not to sound rude, but this trace element thread was hijacked and is mostly a debate about nitrates and phosphates. Seems like it should be in its own thread.

Yup , that's cuz actual trace element theory(understanding is just beginning) dosing is much more complex than nitrate and phosphate

 

[michealprater]

Hans, Lasse, What trace elements do you dose in your own aquariums?

 

[Hans-Werner]

Hans, Lasse, What trace elements do you dose in your own aquariums?

All that are mentioned in this article and a few more.

I dose all trace elements of the Tropic Marin All-For-Reef or of the K+ and A- Elements: "strontium and trace elements (barium, boron, bromine, chrome, iron, fluorine, iodine, cobalt, copper, lithium, manganese, molybdenum, nickel, selenium, strontium, vanadium and zinc)"

I developed these products, so I know what I am adding.