Seawater levels of trace elements?

[Superlightman]

Hello , question, do we have measurements of the seawater trace elements ? I want to compare them with the recommended level in the ICP. I think the recommended level in ICP are much higher than what we find in reefs?

 

[Randy Holmes-Farley Verified Community Expert]

Hello , question, do we have measurements of the seawater trace elements ? I want to compare them with the recommended level in the ICP. I think the recommended level in ICP are much higher than what we find in reefs?

Yes, but unlike the major ions, trace elements vary considerably by depth and location. Some are depleted in deeper water, some depleted at the surface, and some have more complex variation.

I’d also advise that icp cannot determine the chemical form of the ions, and that form can greatly impact the toxicity and bioavailability of ions. Something most of these companies don’t mention. Both the oxidation state (e.g. ferrous vs ferric iron) and the binding by organics can have a big effect.

 

[Hans-Werner]

Hello , question, do we have measurements of the seawater trace elements ? I want to compare them with the recommended level in the ICP. I think the recommended level in ICP are much higher than what we find in reefs?

In the MBARI Periodic Table of Elements in the Ocean you find data and graphs on all elements.

Do you know how to calculate the concentration by weight as given by ICP labs from the molar concentration in the PTEO?

 

[Superlightman]

In the MBARI Periodic Table of Elements in the Ocean you find data and graphs on all elements.

Do you know how to calculate the concentration by weight as given by ICP labs from the molar concentration in the PTEO?

thanks, unfortunately I don't know :-(

 

[Superlightman]

Yes, but unlike the major ions, trace elements vary considerably by depth and location. Some are depleted in deeper water, some depleted at the surface, and some have more complex variation.

I’d also advise that icp cannot determine the chemical form of the ions, and that form can greatly impact the toxicity and bioavailability of ions. Something most of these companies don’t mention. Both the oxidation state (e.g. ferrous vs ferric iron) and the binding by organics can have a big effect.

Thanks for this clarifications.On which basis they then made their trace elements recommendations in the ICPs?

 

[Randy Holmes-Farley Verified Community Expert]

Thanks for this clarifications.On which basis they then made their trace elements recommendations in the ICPs?

I do not know what each company did, but I do know they do not always try to match natural levels of all elements.

 

[Hans-Werner]

thanks, unfortunately I don't know :-(

If you click on an element in the PTEO a window like this one opens

Multiply the average (or else) concentration in ocean with atomic weight to get the concentration in g/kg: 5.4 nmol/kg x 65.39 = 353.106 ng/kg = 0.353106 µg/kg (ppb) or ca. 0.35 µg/kg (ppb).

The average concentration in the ocean by weight of Zn is 0.35 µg/kg or ppb. Now you can compare it with the ICP result and the level recommended by the lab.

 

[GARRIGA]

Fair to say not all salts created equal as to trace elements therefore we might be putting more emphasis on meeting strict ICP levels vs just being the ball park?

 

[Superlightman]

If you click on an element in the PTEO a window like this one opens

Multiply the average (or else) concentration in ocean with atomic weight to get the concentration in g/kg: 5.4 nmol/kg x 65.39 = 353.106 ng/kg = 0.353106 µg/kg (ppb) or ca. 0.35 µg/kg (ppb).

The average concentration in the ocean by weight of Zn is 0.35 µg/kg or ppb. Now you can compare it with the ICP result and the level recommended by the lab.

thanks that is very usefull :-)
How is the concentration in your salt? do you try to match the natural levels or not?

 

[Superlightman]

I do not know what each company did, but I do know they do not always try to match natural levels of all elements.

yes exactly because of this I ask. I believe some company may have put higher levels in their ICP recommandation than needed to increase their sales... I would know at which level coral thrive in the natural environment

 

[Randy Holmes-Farley Verified Community Expert]

thanks that is very usefull :)
How is the concentration in your salt? do you try to match the natural levels or not?

Which natural levels? As I noted, and such links make clear, it varies a lot.

 

[Randy Holmes-Farley Verified Community Expert]

yes exactly because of this I ask. I believe some company may have put higher levels in their ICP recommandation than needed to increase their sales... I would know at which level coral thrive in the natural environment

No. This is just not true. It entirely ignores the chemical form present which changes the availability a lot.

There just is no single perfect answer.

 

[Superlightman]

No. This is just not true. It entirely ignores the chemical form present which changes the availability a lot.

There just is no single perfect answer.

Although it may vary from place to place, there should be a range of values in which each trace element is present and we should be able to take averages. What interests me is the average, it will already give an indication. For example if an element is present between 2-4 and ICP advice 8 I know that even below the ICP I am comfortable. What bothers me about the ICPs from one brand to another, the recommendations can sometimes go from single to double. How do you know who is right?And they are not able or willing to tell you why these levels are the best, you just have to believe them that is the best level.

 

[Randy Holmes-Farley Verified Community Expert]

Although it may vary from place to place, there should be a range of values in which each trace element is present and we should be able to take averages. What interests me is the average, it will already give an indication. For example if an element is present between 2-4 and ICP advice 8 I know that even below the ICP I am comfortable. What bothers me about the ICPs from one brand to another, the recommendations can sometimes go from single to double. How do you know who is right?And they are not able or willing to tell you why these levels are the best, you just have to believe them that is the best level.

There’s no reason to assume natural levels are necessary or optimal. Coupled with the unknown chemical forms present, and there’s a whole lot of guessing involved that is not answered by knowing seawater values.

This may be helpful:
https://www.reef2reef.com/ams/randys-elements-to-dose.952/
And


https://www.reef2reef.com/ams/randys-thoughts-on-trace-elements.951/

 

[Hans-Werner]

thanks that is very usefull :)
How is the concentration in your salt? do you try to match the natural levels or not?

Yes, we do. We try to match the average concentrations in natural seawater.

 

[Dan_P]

Although it may vary from place to place, there should be a range of values in which each trace element is present and we should be able to take averages. What interests me is the average, it will already give an indication. For example if an element is present between 2-4 and ICP advice 8 I know that even below the ICP I am comfortable. What bothers me about the ICPs from one brand to another, the recommendations can sometimes go from single to double. How do you know who is right?And they are not able or willing to tell you why these levels are the best, you just have to believe them that is the best level.

Do we know the accuracy of the ICP results? In your example, if the ICP result is 2-4, the real value could be 0 or 16.

 

[Superlightman]

Do we know the accuracy of the ICP results? In your example, if the ICP result is 2-4, the real value could be 0 or 16.

so your saying icp are useless?

 

[Dan_P]

so your saying icp are useless?

Not useless, but making the point that as we think about getting the trace element concentration right, we can't be too fussy about getting the target right because we don’t know the accuracy of the ICP measurement, and therefore, we can’t know with much confidence whether we are hitting the target.

 

[CoralsComeInMoreColors]

If the ICP doesn't detect what chemical form the elements are in, how do we determine what is toxic? For example, my SPS dominated tank has been running high zinc 7.8-10ug/l and ive seen growth on some acros and the death of many more. same thing with Sn at the level of 5 ug/l and aluminum at 11 ug/l. Thanks in advance!

 

[Randy Holmes-Farley Verified Community Expert]

It’s impossible to know with some elements and the sources of them, such as tin which can be in many forms that will require different levels to become toxic. For others, even with just one form, we have little reliable tox data on many trace elements for the wide variety of organisms we keep, all of which may have different tox thresholds.