I read a 'Last Man on Earth' short story in an SF anthology with, essentially, this premise. At the end of the story, the exhausted person dies while sitting on the edge of the sea... only to seed the next round of life from all of the lifeforms and organic materials contained therein. Creepy, heady stuff for a preteen. This was the 70's, so the idea has been around awhile.
VerDeTerre came through, above. I read it in an anthology in the children's section of the public library (another good reason for public libraries), but the anthology title is long lost to /dev/null.
Killer, killer anthology. The anthology I read was shorter, but that's ignorable... everybody should go find a copy of 'Adventures in Time and Space', it's a classic full of classics.
