The Lost Island of Bikeman
The island shown here is called Bikeman (pronounced "Bik-ee-man"). If you look closely enough on the Flickr map, you'll see it's in the sea in the middle of the atoll.
This island disappeared in the early 1990s, with just a small sandbank remaining at low tide. Many people's kneejerk reaction was to blame climate change and rising sea levels, but the likely cause is changing currents due to a Japanese-funded causeway being built at the north end of the island chain. If the sea level had risen enough to wipe out Bikeman, the rest of the atoll would have disappeared too!
This Time article mentions Bikeman towards the end; this Honolulu Star article contains a photo of a fisherman wading on the remains of Bikeman, and this article talks about the island too, with a contemporary photo featuring the marker tripod visible above.
Taken by my father on Ektachrome, as I was only four at the time.