providing {HEAD ~ a growing surface} in {TAIL ~ said water} to which said algal spores form an attachment 
providing { HEAD ~ a growing surface } in { TAIL ~ said water } to which said algal spores form an attachment
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH