Party-pooper fact-check in the next comment, but here's the story as it was told to me when I was on Iceland:
There is a lake some ways from Akureyri called MΓ½vatn ("mosquito water"), and the island in the middle is a flourishing green only because mosquitoes fly out there, breed and die, their bodies fertilizing and contributing to the topsoil over the volcanic rock.
It's in effect a vampire island.