ST. PETERSBURG — The City Council has approved an agreement with the second of three additional artists commissioned to create pieces for the new Pier District.The council approved an agreement with Nick Ervinck of Belgium, who will create a waterlike sculpture in bronze, with a patina finish, to be installed near the Pier head. The piece, “Olnetopia,” will cost $140,000. According to the artist, the organic form “is linked to hollowed rocks and the wild waters.” As well, he said, it “represents the dynamic power of life and provides a warm welcome” to the Pier. Late last year, the council also approved a contract with American artist Xenobia Bailey, who specializes in mosaics and fibers. She will design and install a piece called “Morning Stars” on a screen wall edging the Pelican parking lot. It will face north toward Spa Beach and cost $200,000. Another agreement is expected to be signed with California artist Nathan Mabry, who will create a 13-foot, red origami pelican sculpture for the 26-acre Pier District’s entry plaza. The piece will cost $140,000. The three pieces will join one of Janet Echelman’s billowing net sculptures at the Pier. The council has already approved a $1.5 million contract with the internationally acclaimed Echelman. Her lighted artwork is being planned for an area east of the Dolphin parking lot.