Maragos and Jokiel 1986

scientific article | Coral Reefs

Reef corals of Johnston Atoll: one of the world's most isolated reefs

Maragos JE, Jokiel PL


Johnston Atoll lies 800 km southwest of the nearest reefs of Hawaii and over 1,500 km from other shallow reefs to the south and west. Only 33 species and 16 genera and subgenera of shallow water stony corals have been reported from the atoll. Endemic species are absent despite Johnston's great age and favorable environment. With few exceptions, only species with broad geographic distribution are represented. Factors contributing to the low number of species are remoteness, the atoll's small size, lack of favorable currents to transport larvae from the southwest Pacific, lack of reef “stepping stones” in the region since the Cretaceous, possible defaunation during eustatic sea-level rise and fall, and possible drowning from tectonic subsidence or tilting. The species list shows strongest affinity with that of Hawaii, but some unexpected discontinuities occur. Despite low species diversity, coral coverage is extremely high in most environments.

Research sites
Depth range
20- 400 m

Mesophotic “mentions”
0 x (total of 5520 words)

* Presents original data
* Focused on 'mesophotic' depth range
* Focused on 'mesophotic coral ecosystem'

Community structure

Scleractinia (Hard Corals)

USA - Johnston Atoll

Manned Submersible
SCUBA (open-circuit or unspecified)
SCUBA (open-circuit or unspecified)

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