Headcanon: the 'Dragon Pulse' in FMA:B is the movement of groundwater.
lbr, the only reason Ed/Al let the 'dragon pulse' explanation fly was because they had other shit to worry about at the time. you know Ed would be all over that shit any other time.
If Edward "I met god and came out of that an atheist" Elric heard about the mystic sounding dragon's pulse, he would crack open the whole crust of the earth to get to the bottom of that shit.
I think it's groundwater movement bc:
A) groundwater is, by necessity, closer to the surface of the earth than the tectonic plates where alchemists get their energy from, which means it would be faster to draw on and also could bypass the philosopher stone layer under amestris. (you know those stones needed to be buried deep so that no one could just... accidentally dig up a Philospher's Stone.)
B) I don't remember if it's explicitly stated in the show, but decently popular fanon has alkahestry as having a basis in healing and the body, and sense of self. Groundwater movement is way less rigid and would also symbolically link well with healing and life.
C) Mei can do alkahestry at a distance so long as something she has used, something she sees as an extension of herself, is at the point and both she and that point are connected to the ground in some way. What if that extension of self actually comes from the fact that, if you carry something for long enough, you'll sweat on it or bleed on it, and you can sense the remnants of that through the alkahestry.
C.1) the idea that all you need is a vague connection and a bodily fluid to do alkahestry at a distance opens up all sorts of fun avenues tbh. Using blood or spit probably doesn't work well unless you're setting traps on non-porous material. Trap won't work if the snare got absorbed by the nearby trees... although... could you water a plant using your blood for long enough that the tree could be used as an alkahestric target/anchor/whatever they call it? (I can just imagine Ed learning alkahestry just so he can spit in somone's face, quick clap, and break their nose without touching them. That would be sick as hell.)
It would also make sense if alkahestry and qi sense in FMA is based on water. Humans = mostly water, so if qi sense is just a sense a person can develop to see how the water (plus the hormones and reactions that make up emotional responses) move throughout another person then it would go well with alkahestry and the dragon pulse also being water based. (This is also why all of the homunculi are strange to qi sense, even Bradley, bc he was human who became homunculus ,while the others don't really have blood or normal bodily functions/systems.)
Plus, it's called the Dragon's 'pulse' which implies liquid. If the dragon is the earth, then it's pulse would be groundwater, or really just water, movement. (... if it's just water, imagine the damage a Pirate alkahestrist could do.)
