[taricha]

Originally Posted by 34cygni

Poking around in Google Scholar turned up a link between the B12 economy and the Roseobacter bacteria clade, which you may recall from page 101. Turns out rosies are big into B12 synthesis. As of 2015, of the >50 rosies that have had their DNA sequenced, every single one had the genes for making B12. This makes sense given how tight rosies are with algae, and since rosies are involved, naturally that means organic sulfur is part of the B12 economy.

heh. Been telling myself for a while I ought to actually read your whole megapost on p101. Lots of ideas I've toyed with came from searches that flagged small sections of the megapost.

Originally Posted by 34cygni

Have you tried Fe + B12 to see if that moves the needle on N or P? Colimitation by B12 and Fe has been observed in "high nitrate low chlorophyll" regions of the ocean. You might also try playing around with different combinations of B12, Fe, and Si to see if you can trigger diatom growth, as HNLC regions are typically low in dissolved Si, too.

Haven't tried B12+Fe, until yesterday. Co-limitation is complicated. :-)
funny you mention high nutrient low chlorophyll (HNLC) research. a couple of weeks ago, I realized how relevant HNLC was. It's what I've been aiming to create in my water column - available macronutrients and light, but with some crucial micronutrient(s) removed actively by chaeto/caulerpa leading to low dino growth.
It's cool to find what I was doing was well researched in big sections of the ocean - once I realized what it was that I was doing. :-)
The HNLC phenomena is still debated, but Fe or Fe+something are the overwhelmingly favored explanations. That lit helped me narrow my trace element search list.

Originally Posted by 34cygni

And by any chance, are you using OTC vitamin pills as a source for B12? I suggested this back on page 111...


...because dinos make their armor out of cellulose -- and as it turns out, cellulose is commonly used in vitamins and other pills to fill out the bulk of each pill when the active ingredient is present only in small quantities. I can't help but wonder if your second B12 run demonstrated proof of concept.

yep. OTC B12 supplements with various forms of cellulose and other fillers. I googled every ingredient because I wondered if I had Fe hiding in my B12, (nope) but I now looking back on the ingredient list, I did find Si in one of the fillers which seems possibly meaningful now. Wasn't thinking those lines at the time unfortunately, so I didn't examine that beaker under right power/light combo to track diatom growth. A revisit of B12+Si with added Fe is certainly worth a look.
B12 vitamin #1 (NatureMade)
1000mcg Cyanocobalamin
Dibasic Calcium Phosphate (CaHPO4)
Stearic Acid (C₁₇H₃₅CO₂H)
Cellulose Gel (C6H10O5)n
Magnesium Stearate Mg(C18H35O2)2
Croscarmellose Sodium - Na and a bunch more cellulose

B12 vitamin #2 (Sundown Naturals)
1500mcg Cyanocobalamin
Vegetable Cellulose
Vegetable stearic acid
Silica (!) - didn't catch that on first glance.
Vegetable Magnesium Stearate

Originally Posted by 34cygni

Are you using a chelated iron supplement? You might look into complexed iron (...chelation is technically a type of iron complex, I believe, but as I've said, chemistry is not my thing)

yes Iron EDTA. and I thought complexed and chealated were interchangeable. My Chem Kung-Fu is weak. I'll go back to chealators in a moment...

Originally Posted by 34cygni

I've read that scrubbers sometimes go through a dino phase before settling on green algae, which perhaps explains emerald crab's cautionary tale, and the phrase "oversized scrubber syndrome" was used by Floyd R Turbo on Santa Monica's web site to describe the tendency of scrubbers to grow dinos instead of green algae when their screens are too big

Another recurring theme. Nature may abhor a vacuum, but dinos sure love uncontested real estate.

Originally Posted by 34cygni

You might try adding a UV unit. If you knock back your ostis, maybe the amphidiniums that won't come out of the sand will pop up again.

I have a UV that I've been waiting on using, I'll start it after I get done with this line of experiments.

Originally Posted by 34cygni

AIO systems ... have teeny-tiny fuges, which means there isn't a lot of heft behind the algal holobiont. The tank:sump ratio looks way too high, if it isn't actually a divide by zero error.

Love the analogy. I wish I had a larger sump every day. I feel like I'd have so much more punch behind passive remediation options to create stability.

Originally Posted by 34cygni
I'd bet good money that coralline is the canary in the coral mine signalling that the bacteria population in an aquarium is shifting away from the coral-friendly bunch that we want and towards dino-friendly types.

I can certainly cite the flip side.
Once dinos essentially vanished from my tank in the last 2-3 weeks, Coralline growth exploded - completely covering the back glass, alk has now dropped precipitously. The dino months prior showed only a trickle of Coralline growth in spite of abundant Ca/Alk levels throughout. It never got so bad as to have coralline turn white and die, as others have reported. There was no dosing that could be credited for the change.

Originally Posted by 34cygni

IRON RELEASE BY GFO STIMULATES DINOS?????????????????????????

Obnoxious CAPS and ????s were me making a note to myself, not part of Budman422's post.

When trying to limit Fe in my tank, after I ran across this info from RHF, I ripped my very exhausted (many months old) small amount of GFO out of my system....

In other cases, the organic/iron complex can be absorbed and used, and in some of the most interesting cases, these ligands are specifically designed by organisms to “go out and collect iron” [siderophores].
...
For example, one research group recently claimed in the journal Nature that “Dissolved Fe(III) in the upper oceans occurs almost entirely in the form of complexes with strong org. ligands presumed to be of biol. origin.” 1

The chelators that bind iron in seawater (and by analogy, reef tank water) are many, and come from many sources that are present in our reef tanks. One researcher, for example, details the concern: “The present report shows that both inorganic Fe(III) in the presence of oxygen, and humic Fe(III) which stimulates lipid peroxydation, trigger or stimulate the release of chelators from green algae, red algae, and cyanobacteria.” 2 Consequently, we should anticipate that we have such chelators in our tanks.
...
“This review focuses on how cyanobacteria respond to growth-limiting levels of available iron and on how siderophores potentially alter the biological availability of iron in the system thereby allowing the cyanobacteria to exist at low iron availabilities.”

So yeah. It's possible that although GFO adds biologically unavailable forms of Fe, due to cyano, algae & co, it may not all stay that way.

Also this paper on Fe in seawater is unintentionally hilarious in that it's several dozen scientists basically throwing up their hands repeatedly at the complexity of trying to say what forms of Fe really constitutes "bioavailable" and who uses what, and how once in an organism it changes and is used by the rest of the system.

...this task presently is largely beyond our capability. The perspective that developed during the workshop is that iron availability will be a function of: (1) the various chemical forms of iron in seawater, (2) the preference of the uptake mechanism of each organism for one or another of these forms, and (3) the balance between the reaction kinetics of iron
exchange among chemical species, the iron uptake kinetics of a given organism, and the iron demand of each member population within the phytoplankton assemblage. Clearly, the complexity of the natural seawater system frustrates attempts to define a general “biological availability” of iron...
..Moreover, our present ignorance of many aspects of iron chemistry in seawater makes it unlikely that we can accomplish this task within the near future.

Basically the whole paper is like that - interspersed with fascinating examples of organisms going to heroic lengths ("Fe-siderophore pirates" is an awesome phrase) to capture Fe that you wouldn't expect they could uptake. Granted, that was 20 years ago. But it still suggests that the notion that we could put bunches of GFO in our tanks and say it's totally unavailable biologically seems an unsupported premise.