Neptune could cause or prevent storms at sea.
As god of the sea many prayed to him to grant a safe voyage to deliver goods and in return Neptune was granted a valuable object.
Neptune was also the god of earthquakes and horses.
"World Book Online Reference Center | Online Reference Book| Online Encyclopedia."
Bespoke Education. "Neptune - Roman Gods." YouTube. YouTube, 29 May 2013. Web. 09 Jan. 2017.