A320FOX: I'm not a marine biologist (although I do have a PhD in biology), but I could imagine scenarios in which impact with the ocean & aircraft disintegration yielded leaked pools of floating oil, hydraulic fluid, residual fuel in APU feeds, etc.
If some (but not necessarily all) bits of airframe debris floated off in such pools, encrustation or colonisation by marine creatures may be significantly delayed.
Components forward of ruptured reservoirs or tanks (eg. flaperon) may become colonised, whereas empennage aft (e.g. HS) may not be.
For an authoritative answer, you would need a....marine biologist!
Additionally, Ppruners who could offer an opinion on the water-solubility or durability of such oily fluids may also provide guidance (eg. how long can oil slicks persist?)
Dean