Reef Chemistry Question of the Day #237 Trace Element Riddle

[Randy Holmes-Farley]

Reef Chemistry Question of the Day #237

I am a trace metal in reef aquaria.

In a boxing analogy, I'd be considered a flyweight of the trace metal world.

I can exist in many different oxidation states (e.g., +2, +3, +4, etc.).

In my different oxidation state(s) in seawater, I may be one of the main chemicals that interact with an ORP (redox) probe to determine what mV reading the probe reports.

I play a critical, but often unheralded role in photosynthesis, where I help oxidize water to O2.

My archenemy is superoxide (O2-)

I am the most macho of the trace metals in seawater.

Who am I?

A. Iron
B. Chromium
C. Molybdenum
D. Manganese
E. Vanadium

 

[Pongo]

A. Iron

 

[Randy Holmes-Farley]

In case you don't know what a flyweight is, one of these guys is a heavyweight, the other is a flyweight.

http://boxrec.com/media/index.php/Weight_divisions

 

[nautical_nathaniel]

I'm gonna say D.

 

[Pongo]

Little guy D. Manganese

 

[Beardo]

Based solely on the "flyweight" reference, I'm going to say the answer is E. Vanadium as it has the lowest atomic number of the elements listed.

 

[saltyfilmfolks]

;Bookworm
A

 

[BZOFIQ]

I'm going with D - Manganese

 

[MnFish1]

Vanadium is the lightweight. Manganese is the next littlest. Is required in photosynthesis and has the most oxidation states. As far as the superoxide enemy. That is close with Iron but I guess D

 

[rushbattle]

Vanadium is the lightweight. Manganese is the next littlest. Is required in photosynthesis and has the most oxidation states. As far as the superoxide enemy. That is close with Iron but I guess D

Agreed, D-Manganese.

 

[rkpetersen]

D.

Because of its many many oxidation states and its catalytic role in photosynthesis.

Did not know about its influence on ORP; I believe I've seen some opinions that artificial (i.e. ozone) ORP increase in aquaria is largely due to ferric/ferrous redox reactions.

 

[IonicBond]

Considering the macho reference, Manganese!

 

[rushbattle]

Considering the macho reference, Manganese!

Is that a Randy Savage reference?

 

[Randy Holmes-Farley]

Is that a Randy Savage reference?

That's not what I intended.

 

[rushbattle]

That's not what I intended.

Macho Man @Randy Holmes-Farley ?

 

[rushbattle]

Double post.

 

[Randy Holmes-Farley]

And the answer is...

Who am I?

D. Manganese

I am a trace metal in reef aquaria.

All of the choices fit.

In a boxing analogy, I'd be considered a flyweight of the trace metal world.

Manganese is pretty light as metals go, but so are some of the other choices.

I can exist in many different oxidation states (e.g., +2, +3, +4, etc.).

This choice mostly rules out iron, unless you want to look to rare compounds.

In my different oxidation state(s) in seawater, I may be one of the main chemicals that interact with an ORP (redox) probe to determine what mV reading the probe reports.

Some of the choices fit here, perhaps especially manganese and iron:

ORP and the Reef Aquarium - Reefkeeping.com
http://reefkeeping.com/issues/2003-12/rhf/feature/index.htm


Oxidizers:

• 
  
  
  O2 (singlet oxygen), 3O2 (triplet oxygen), O3 (ozone), H2O2 (hydrogen peroxide), OH (hydroxide radical)
  
  
  
  Metals: Fe+++ (iron), Mn++++ (manganese), many others
  
  • 
    

Reducers:

• 
  
  
  Metals: Fe++ (iron), Mn++ (manganese), many others

I play a critical, but often unheralded role in photosynthesis, where I help oxidize water to O2.

https://en.wikipedia.org/wiki/Photosynthesis

"the oxidation of water is catalyzed in photosystem II by a redox-active structure that contains four manganese ions and a calcium ion; this oxygen-evolving complex binds two water molecules and contains the four oxidizing equivalents that are used to drive the water-oxidizing reaction."

My archenemy is superoxide (O2-)

Iron and manganese form the cores of different types of superoxide dismutatse, which destroye superoxide in living organisms.

https://en.wikipedia.org/wiki/Superoxide_dismutase

"Superoxide dismutase is an enzyme that alternately catalyzes the dismutation (or partitioning) of the superoxide (O2−) radical into either ordinary molecular oxygen (O2) or hydrogen peroxide (H2O2). "

"
Manganese – Nearly all mitochondria, and many bacteria, contain a form with manganese (Mn-SOD): For example, the Mn-SOD found in human mitochondria. The ligands of the manganese ions are 3 histidine side-chains, an aspartate side-chain and a water molecule or hydroxy ligand, depending on the Mn oxidation state (respectively II and III)."

I am the most macho of the trace metals in seawater.

Macho: showing aggressive pride in one's masculinity.

It's hard to do that more than Manganese.

Happy reefing!