Iron uptake by algae in seawater?

[shardakar]

I'm having an disagreement with my friend,

He contends that Iron does not have to be soluble because certain bacteria will secrete siderophores and chelate the iron and thus make it soluble and then algae can use up the siderophore chelated iron. Either that or the bacterium will absorb the chelated iron and eventually die releasing iron and then be used up by the algae

My understanding is that iron first has to be in a soluble form before that kind of chelation can occur. Iron has to be dissolved and its ions freely floating in the water before chelation by bacteria can happen. If its just sitting as a precipitate at the bottom, no chelation will occur. Further more, Siderophores form some of the strongest chelates and most algae would be unable to break the chelating molecule to absorb the iron ions.

Could someone with a chemistry background help clear this up?

 

[sk8rdn]

Dude, I have no clue. I just take my Flintstones vitamins once a day for all my iron needs...


But welcome to RS!
...."Fish" Happens!....

 

[Basile]

Wow , thats heavy, no punt intended, i was just looking for iron related posts. All i can tell you is that for a 75 gallon display refugium full of macroalgaes you have to dose every second day because the intake is phenomenal . I test , and its always low, the algaes specially the red ones consume huge amounts of it. So much so i've set up an experiment with a second fuge with only green algae to see if the intake is as much.

 

[Snid]

I'm not sure about the precipitate vs. soluble debate you guys are having, but the answer is probably out there somewhere on the Interwebs. As for Chelates being too strong, Micro Alga produces a special enzyme that dissolves Chelated Iron so that is can compete against bacteria for iron consumption.

 

[Creekview]

In the other iron thread, I posted that I use Seachem Flourish Excel, which is a liquid carbon that converts ferrous iron to ferric iron. Ferric is what the plants can use.