Seems to me since diatoms and dinoflagellates are simialr eukaryotic species, they would compete for the same nutrients and elements with diatoms dominating when silca was abundant, while dinofalgelates need more cellulose. I don't think dinofalgellates need diatoms to sequester nutreints and trace elements for them or to produce organic C for them;dinos shuld beable to get them on their own if they are in the water.
That competition from diatoms keeps dinos in check is reasonable and quite likely, and I think most of us are aware of it. It's why many people in these dino threads are now experimenting with dosing water glass in their tanks.
But I have not heard of any positive results back from silicate dosing yet. It could be too early. We shall see.
Still, it behooves us to consider alternative theories. If you look at the graph of North Atlantic phytoplankton populations, you'll see that mixotrophic dinos peak shortly after diatoms are at maximum abundance and well before diatoms are gone. They are just behind the curve. And, while the exhausting of silicates corresponds to a competitive advantage for dinos, dinos really only drop off the map shortly after diatoms have done so. In other words, these dinos do not really die off when diatoms are present. They really only die off when ALL primary and secondary food sources are gone and their decline follows somewhat behind the disappearance of both diatoms AND measured nutrients.
To be honest, I do not even know what kind of dinos are common in reefs tanks or precisely what these common species eat. I've been asking that question for years. So I couldn't tell you how worthwhile this is to even consider.
The reason I am willing to consider alternative theories at this point is just the number of reefers who report experiences related to silicates. Posters are extremely dismissive of them so far -- "Ah, they must be confusing diatoms with dinos". But are they? According to Pants, reefers have been surprisingly competent so far at diagnosing their own dinos. And isn't that just a bit unfair to immediately jump to that conclusion? The number of reports is quite high. Do diatoms also stretch toward the light and bubble up? If so, maybe it really is misdiagnosis on a large scale.
I would love nothing more, though, than to be able to beat dinos by dosing silica and generating a competitor diatom population. That would be, in all honestly, COMPLETELY AWESOME.
But I suspect the truth could also be more complicated. I am starting to wonder if dinos don't have multiple food sources, some of which gradually go away in a reef tank and some of which we also can add on our own. So, the reason they may be tricky is that a single strategy (i.e., heavy nitrate/phosphate reduction) works much more slowly. Multiple energy sources may have to be contained, perhaps.
...
But I have obtained a giant bottle of water glass and some silica-related testing kits. I'm going to try some experiments shortly. It will be interesting to see what happens.
