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]

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]

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]

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]

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]

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:

Randy's Elements to Dose

In a previous article I discussed my thoughts on trace elements https://www.reef2reef.com/ams/randys-thoughts-on-trace-elements.951/ This article expands on that discussion by providing specific guidance for all elements one might dose. First...

www.reef2reef.com

And

Randy's thoughts on trace elements

Randy's thoughts on trace elements in reef aquaria.

www.reef2reef.com

 

[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.