Water Study Questions

[SteveN]

Don't know if y'all want to kick it around, but I would be interested if there are biologically significant uses for Strontium and/or Manganese as it seems I have none. Also are there any non-professional tests for these two metals?

[tatuvaaj]

SteveN,

I guess Randy somehow missed this question so I'll bring it up by giving some basic information I have about manganese.

Mn (as MnO2) is used in anoxic sediment by bacteria for the oxidation of organic matter yielding almost exactly as much energy as using nitrate as electron acceptor (and even close to energy yield from O2). So it seems that MnO2 should be quite important element in anoxic sediment.

MnO2 is reduced to Mn++ which is soluble and can diffuse upwards into regions where O2 is present and be oxidized back to MnO2.

[SteveN]

It sounds like it could go undetected if ti binds quickly. I could still have some and it would be doing its job. I have also heard that Strontium has few uses in our aquariums. Is this true?

[Randy Holmes-Farley]

Manganese is very important for many biological processes in plants and animals. In people it is, among other things, critical for the use of vitamin B1.

Strontium is more complicated. Some have suggested that it is important for calcification of corals, and have some experimental evidence that it is present at calcifying surfaces. Others, like Ron, think of it only as a toxin. I am not familiar with any other biological uses.

What values did you get in the water study for these two?

[SteveN]

The Manganese was below the detection level of 0.0005 ppm and the Strontium was way low at 5.8 ppm. I am very interested to hear a response.Could you point me in the direction of a good site for the biochemistry involved? Are the any goo sources for these two elements, and good test kits?

[tatuvaaj]

Steve,

I wouldn't worry about your Sr level, it is pretty close to NSW levels (7.7 mg/l). Do you add Sr into your aquarium (for example some of those 2-part Ca+Alk additives?)

Seachem and Salifert make strontium test kits. I have only used the Salifert test and I must say that it isn't very accurate. But it's still usable to make sure you are not overdosing Sr.

[SteveN]

I was under the impression that Sr had a NSW concentration of 13ppm. To answer your question, no, I just dose kalk at the moment. So far, it has been able to maintain Ca and alk pretty well. My Ca has stayed at about 400 and my alk is consistently above 3, both measured with Salifert. I think I will probably get a Hach Mn test. I know that thier tests are pretty good. Their web site doesn't show a Sr test.

[Randy Holmes-Farley]

I agree with Tatu: the values that I see for NSW strontium are more like 7.9 ppm. I wouldn't worry about your strontium value.

Manganese is a bit trickier, but looks clearly depleted in your tank. It is enriched in ocean surface water from the input of rivers and release from sediments, and depleted lower down. Typical surface values are around 0.2 ppm [NO, calculator error; change this to 0.0002 ppm], but quickly drop to about 0.02 to 0.05 ppm [No; change this to 0.00002 to 0.00005 ppm].

No, I don't think Hach has a Sr++ kit.

I think there are plenty of sources of strontium. I'm not sure about manganese. I'll look around.

I don't off hand know of any good on line sources for biochemistry. I typically use biochemistry textbooks.

[SteveN]

Thanks for the response, Randy. What is a good book for coral / reef animal biochemistry? Or what do you use as a reference. I'm not afraid to buy reference material. Guess I'll be ordering some test kits and supplements. It will be wierd to add something to the tank other than kalk. TIA

[rshimek]

Hi Steve et alia,

This is a long post, and for that I apologize, but there really is no short answer.

First, the only organisms that I know of with a demonstrated physiological need for strontium are 1) early larvae of Aplysia, 2) early larvae of Octopus, and Acantharean Radiolarians which have a skeletacal capsule of strontium sulfate. There has been no demonstrated need for strontium in corals, indeed, just the opposite has been noted.

My reasons for considering Strontium a weak toxin are given below. There is no ambiguity for that conclusion. It is supported by several research papers all published in peer-reviewed professional journals. The only paper suggesting that strontium benefits corals is Swart’s 1980 paper, and it is this paper which is cited by Delbeek and Sprung as evidence that corals need strontium. Unfortunately, Delbeek and Sprung must have missed Swart’s 1981 paper where he explained that his 1980 conclusions were incorrect and based on incomplete research - the “publish or perish� syndrome strikes again. Delbeek and Sprung have also missed all of the other references on strontium and corals.... Good literature researchers, these guys ain’t...

There is no specific book on the biochemistry or physiology of coral reef animals, and will not likely be, as most physiologists consider them as perfectly normal invertebrates, so why do something specific for them? Probably the most widely used text on the physiology of invertebrate animals is:

Prosser, C. L. 1991. Comparative Animal Physiology, 4th ed.. Environmental and metabolic animal physiology. Wiley-Liss, New York, 578 pp.

There are a lot of papers investigating the concentration of strontium in coral skeletons. Without exception, these papers were looking at the relative amount of strontium as related to calcium as an indicator of temperature. If this could be done, then paleontologists could use the Sr/Ca ratio in fossil corals to determine the temperature of ancient seas. Unfortunately, after a lot research, it has become evident that this ratio is simply too variable to be of much use.

Relatively few papers have looked at Strontium metabolism in corals. Only one research paper, by a fellow named Swart, published in 1980 has shown any beneficial attributes of strontium.

Swart’s 1980 study indicated that strontium supplementation enhanced skeletal formation. He added large amounts of several chemicals, including strontium and calcium, to sea water elevating their relative ionic concentrations significantly above those found in normal sea water. When he added enough strontium to raise the strontium concentrations by a factor of 10, from 7 ppm to 77 ppm, he found that this massive addition of strontium caused a significant increase in skeletal growth. Interestingly, he found an identical increase with the addition of calcium.

The results presented in Swart’s 1980 paper indicate that strontium stimulates the formation of coral skeletons. Unfortunately, such a conclusion would be in error. These data were published prematurely (and Swart admitted as such), and were from the initial phase of a longer study. In the final results, Swart(1981), noted that increases in three factors: total strontium concentrations, strontium/calcium ratios, and increased calcium concentrations, ALL caused a growth increase. Additionally, there was a concentration level (approximately 100 ppm above the local �normal� sea water concentrations, or about 520 ppm) above which further increases in calcium concentration ceased to cause an increase in growth.

Here are the references - I suggest you read them.

Swart, P. K. 1980. The effect of seawater chemistry on the growth rates of some scleractinian corals. In: R. Tardent and P. Tardent (Editors). Developmental and Cellular Biology of Coelenterates. Proceedings of the Fourth International Coelenterate Symposium. Interlaken. pp. 203-208.

Swart, P. K. 1981. The strontium, magnesium and sodium composition of recent scleractinian coral skeletons as standards for paleoenvironmental analysis. Palaeogeogrraphy, Paleoclimatololy, Paleoecology. 34:115-136.

The results in these papers indicated that there appeared to be an unutilized potential for skeletal formation in natural seawater in the area of his studies. (Calcium concentration varies more than a little bit throughout oceanic waters) If additional ions of a chemically suitable nature are present, either calcium or strontium, the coral will use them to form the skeleton. The increases in the growth seen with the increases in strontium concentrations appear to be due to the substitution of strontium for the �missing� calcium.

Swart’s work indicated that either calcium or strontium will cause increases in skeletal growth provided the total of both ions is less than or equal to about 100 ppm above normal, or a total of 520 ppm. It is important to note that in the results from this study, strontium did not stimulate additional skeletal formation, it simply substituted for �missing� calcium ions. What was necessary was an ion of the right size and shape. In effect, strontium was an acceptable substitute for an unrealized calcium potential. It is also clear, however, is that apparently equivalent increased skeletal growth can be obtained by simply increasing calcium levels.

An examination of the scientific literature subsequent to Swart’s work shows that there is NO other evidence for any beneficial effects of strontium by itself to the corals.

Swart also stated the skeleton formed in the solutions containing higher than normal concentrations of strontium show decreased calcification (Swart, 1981), which he thought was simply due to the substitution of strontium for calcium. In fact, there is a small, but growing body of evidence that indicates that strontium REDUCES calcification rates in corals (Chalker, 1981; Swart, 1981; Ip and Krishnaveni, 1991; Wright and Marshall, 1991).

Here are those references - again, please read them.

Chalker, B. E. 1981. Skeletogenesis in scleractinian corals: the transport and deposition of strontium and calcium. In: Handbook of Stable Strontium. S.C. Skoryna (Ed.) Plenum Press. New York, pp. 47-63.

Ip, Y. K. and P. Krishnaveni. 1991. Incorporation of strontium (90Sr2+) into the skeleton of the hermatypic coral Galaxea fascicularis. Journal of Experimental Zoology. 258:273-276.

Wright, O. P. and A. T. Marshall. 1991. Calcium transport across the isolated oral epithelium of scleractinian corals. Coral Reefs. 10:37-40.

Wright and Marshall (1991) showed that strontium significantly reduced the transport of calcium ions across coral epithelial tissues. All calcium used by corals for either metabolic processes or for calcification comes from within the animal’s tissues, not directly from the sea water surrounding it. So, it has to pass through the epithelium. Thus a reduction in calcium transport into the animal will directly reduce all of these processes, including calcification. The presence of significant amounts of strontium could significantly inhibit and alter all calcium requiring processes, such as muscle contraction, tissue differentiations, growth, and injury repair) by reducing the calcium uptake from the surrounding waters.

Additional calcification reduction may be due to the substitution of strontium for calcium in the enzymatic pathways necessary for calcification. Strontium (and other doubly charged positive ions such as magnesium, barium and zinc) will occasionally substitute for calcium in the chemical processes that a coral uses for skeletogenesis. The substitution of strontium for calcium by corals, mollusks, and fishes appears accidental (Sadovy and Severin, 1992). However, strontium is not a twin of calcium and reacts somewhat differently than calcium, and may significantly slow down the calcification process. Thus, if the conditions are otherwise good for the corals, the addition of strontium would inhibit calcification. However, the deposition of strontium in the coral skeleton may not be due to simple substitution, see below.

Any strontium found in the coral skeleton is tightly bound into that skeleton. Such binding means that the chemical is not available to be utilized by, or influence the animal. Many invertebrate animals deposit wastes or toxins in crystalline matrices as a way of detoxifying their environment (Kozloff, 1990). It is possible that those corals whose skeletons contain relatively large amounts of strontium are selectively depositing it in the skeletons. This would remove that strontium from the metabolic pathways, as materials that are deposited as crystals are unavailable for biologically mediated reactions. In this way, any deleterious aspects of strontium ions in solution would countered. This type of elimination of “problem chemicals� is fairly common.

(See almost any issue of the journal, Marine Pollution Bulletin, for references to such pathways).

There is also some work indicating that strontium is rapidly and efficiently removed from the coral polyp and deposited into the skeleton (Ip and Krishnaveni 1991). They found that strontium was deposited into the skeleton of the coral Galaxea fascicularis by a pathway that appeared to be different from that used by the coral to deposit calcium. This pathway appeared to function when the calcification pathway was not working. This could indicate that natural selection has favored the development of an additional metabolic pathway to remove strontium from the solutions bathing the coral. Such a pathway would ameliorate any toxic effects due to this chemical, and would facilitate across membrane transport of calcium and subsequent skeletal calcification.

[SteveN]

Ron,
Thank you very much for the "dissertation". When school is back in, I will check the library for the reference materials you mentioned, as well as the book. I will aslo be doing a web search for them. If you happen to have a second and could point to the "best" place to look, and it is not one of the aforementioned places, I would appreciate it. The chemistry/biochemistry aspect of this hobby fascinates me to no end. Again, thanks.

[Randy Holmes-Farley]

Thanks for jumping in Ron!

Steve:

On the manganese issue, I found two other references that cite manganese levels substantially lower than those I reported above. One gives 0.002 ppm, and the other gives 0.0002 ppm.

So the range so far is between 0.0002 and 0.00002 ppm [note this was changed from the original post]. Consequently, I'm not sure what values are appropriate. Maybe it's just easiest to leave them alone.

[tatuvaaj]

This handy page also gives NSW Mn level 0.000275 ppm

http://www.dnai.com/~patwilde/ocpertbl.html

[SteveN]

Well, I guess I won't worry about it then. I hadn't done a water change in over a month at the time of the survey, so perhaps there is a miniscule trace amount in IO. I will have to check that out. If so, it could be that there is some use for the element and it was depleted. I will check IO and let you know what i find. Thanks for the assistance.

[tatuvaaj]

Steve,

You might find this page useful : "The Composition Of Several Synthetic Seawater Mixes" http://www.animalnetwork.com/fish2/aqfm/1999/mar/features/1/default.asp

[SteveN]

Man, I was about to post that in case anyone was interested:D . This, however, brings another question to my feeble mind. Tatu, Randy, both of you have found/given different concentrations for Mn, Craig and Marlin Atkinson give the level as .0004 mm/kg. Although I don't have my table of elements and a calculator handy to do the conversion, it doesn't appear at first glance to match up. Is there a difficulty that I have forgotten from my days in qual/quant analysis in accurately breaking out the different salts from their metals? Or do you think it could be local variations in the quantities of the trace elements?

[Randy Holmes-Farley]

Steve:

You're right, Craig gives it as 0.0004 umole/kg (note that is micromole/kg, not millimole).

http://www.animalnetwork.com/fish2/aqfm/1999/mar/features/1/default.asp

That's about 0.00002 ppm.

I slipped a digit on one of my earlier calculations, and went back and changed the values in earlier posts. Here's my best understanding:

My CRC handbook of Chemistry and Physics from 1999 gives 0.0002 ppm, and gives references, but none later than 1988.

Spotte gave a value in "Captive Seawater Fishes". I need to double check it, but I thought it was even higher.

Millero (in "Chemical Oceanography", 1996) gives values of 0.2 - 3 nm for the range and 0.5 nM for the "average". Those correspond to 0.000011 to 0.00016 ppm and 0.000027 ppm, respectively.

In another section, Millero shows a graph of Mn concentration vs depth off of California. The highest value at the surface is over 4 nM (0.00022 ppm) anf the lowest value in the deep ocean as below 0.5 nm (0.000027 ppm).

So I think the ranges of values that we should be thinking of are likely on the order of 0.00001 to 0.0002 ppm.

[SteveN]

Ok, the way it seems to me is that the levels of Mn are naturally low. But IO has 1.2um (wish I could have done that earlier, I really do know the difference :D ), so it would seem that there is something in the tank depleting the Mn. Could it be the rock or sand? I know that rock/sand will "collect" Cu. I wish I knew a little more biochem, but I guess that is why you guys are here, to help me learn :D . Don't worry, I won't put the onus on you :D . I will be getting some reference materials.

[Randy Holmes-Farley]

FWIW, Spotte gives Mn = 0.002 ppm and several references to his source, but they are all from the 80's and earlier. Maybe the lower values represent better quantitation.

[saltshop]

Originally posted by SteveN
Ok, the way it seems to me is that the levels of Mn are naturally low. But IO has 1.2um (wish I could have done that earlier, I really do know the difference :D ), so it would seem that there is something in the tank depleting the Mn.

Manganese is used by almost all photosynthetic organisms as part of PhotosystemII or PSII. Each unit of PSII consists of Mn clusters in the Z proteins that are part of the "electron gate" that allow for synthesis of ADP to ATP. So if you have any growing photosynthetic organisms in your tank, corals included, they will deplete Manganese as they continue to grow.

I was actually going to post a question to Randy regarding any information on both iron and manganese depletion rates when I came accross this in a search. Iron is used as part of PSI as FeS and ferrodoxin (the other half of the Photosystem) that synthesizes NADP.

Anyway..Randy do you have any information regarding the depletion rates of Iron or Manganese in your own tank? I know you add iron so I was wondering if you have tested for it or not? Since reading your thoughts on iron additions to help macro-algae outcompete micro-algaes I have been playing with it with good results. Since adding both iron and manganese at half the recommended dose I have not had any grape or feather caulerpa go sexual like it had been previously....interesting so far and no nuissance algae problems. :)

Did find these ICP water test results from 3high that showed he had zero iron and manganese as well.

http://archive.reefcentral.com/vbulletin/showthread.php?threadid=42483&highlight=manganese

A lack of Fe or Mn would be limiting to zooxanthellae multiplication as well since both are required for photosynthesis. Interested to see the rest of Dr. Ron's water study results when it comes to these two elements.

[Randy Holmes-Farley]

JB:

<< Randy do you have any information regarding the depletion rates of Iron or Manganese in your own tank? >>

No. I expect that until recently it was depleted primarily by removal by skimming (though I'm speculating). The organics in tank water can be very good chelators for metals, and that's why I've dosed so much.

As an experiment, I stopped my skimmer a few weeks ago and am monitoring various tank properties (like water coloration). Since I did that, I've substantially reduce the iron dosing as I expect the removal is less. However, I have no iron testing to say what is actually happening to that element.

I communicated with Craig Bingman a while back about iron in tanks. He said that in most Berlin style tanks that he tested, he was able to detect some (and he pointed out that many of these tanks may have been using the original Combisan that did contain substantial iron), but that in tanks with a lot of growing algae, he couldn't detect any. I don't know what his detection limits are, but that clearly suggests that algae do help to deplete the available iron.

<< Since reading your thoughts on iron additions to help macro-algae outcompete micro-algaes I have been playing with it with good results. Since adding both iron and manganese at half the recommended dose I have not had any grape or feather caulerpa go sexual like it had been previously....interesting so far and no nuissance algae problems>>

Wonderful! I've never had mine go sexual either.

[SteveN]

Very interesting things here. I haven't had a chance to check out that link yet. My mom is in town for my birthday, so I haven't had much time to read. I will get to it, probably Saturday. Thanks for all the discussion. I think this is my favorite part of the boards. Getting links to more reading. My wife hates it.