SUBFOSSIL AND MODERN ENCRUSTING REEFAL BRYOZOANS ON MIDWAY ATOLL, CENTRAL PACIFIC OCEAN: PRELIMINARY OBSERVATIONS
Midway has inconspicuous hard-skeletal bryozoans (PMNM permit 2011-017) which could fossilize and contribute to its reefs, seen on WANT expedition (A Hivekovics leader; PMNM permit 2010-015 to J Pociask; J Beatty snorkel guide; L Logue breakwater guide). Earlier workers found mostly soft-bodied zoaria along its island shores instead (De Felice et al ’98; See Godwin & Menza ’09).
Dredged fill in breakwaters is subfossil reef-rock, mostly Porites. Locally, those are encrusted by algal sheets, interlayered with recrystallized encrusting cheilostomes (Fenestrulina? aff malusii) or ctenostome traces (Terebripora? sp).
Back-reef rubble, shell, wreckage, and floating trash exhibit modern encrusting bryozoans, mostly cheilostome sheets. Abundant (number of colonies) are delicate lacy crusts, Cranosina coronata, the most numerous bryozoan on Enewetak Atoll. Common (skeletal volume) are sturdy solid crusts on ship hulls, Schizoporella errata, in warm waters world-wide. Others are rare: tiny crusts on shells (Parasmittina nitida [common on Okinawa], Fedora dactylus [Philippines], Watersipora sp [Coral Sea]), low domes on raised propellor (“Cellepora”? sp), threads on rubble and shells (cheilostome Aetea anguina; cyclostome Stomatopora sp)[last 3 tropicopolitan].
In-shore pilings support soft-bodied seaweed- or tuft-like living bryozoans noted previously: ctenostomes Amathia distans, Zoobotryon verticillatum; cheilostomes Bugula neritina, Scrupocellaria sinuosa, Savignyella lafontii; cyclostomes Diaperoecia sp, Crisia circinata.
The bryozoan species found here also occur further west in the Pacific. Wartime ship traffic, as well as longer-term currents and winds, explain such distribution.