Can BTAs pull nutrients directly from the water column?

[Tigé21v]

I've looked around on the net for the answer, but I'm not having much luck finding an answer. Tried searching on RC also, but no luck. I'm probably not asking the question correctly.
Can BTAs absorb nutrients (NO3, PO4) from the water like giant clams do? Or does all of their fuel come from either photosynthesis or any food they eat?

TIA