ANTHROPOGENIC REEF EXPANSION AND POSSIBLE HABITAT MODIFICATION AT KWAJALEIN ATOLL, REPUBLIC OF MARSHALL ISLANDS

Located in the southwest Pacific basin, Kwajalein Atoll is part of the Marshall Islands. After cessation of World War II hostilities, this island was littered with abandoned machinery and equipment. Until recent times, a period of rebuilding and construction occurred. Much of the unwanted equipment from the invasion and the rebuilding effort was discarded and disposed of by being dumped at the edge of the atoll.

Today, in the shallow, submerged areas of the reef, machinery, equipment and concrete structures are present. Carbonate is being precipitated from seawater directly onto these old, abandoned artifacts, cementing coral, beach fragments and orphaned metal. In an attempt to prevent erosion, man-made cement was poured, affixing the island to the equipment. The overall effect was to create an artificial reef and expand the size of the island.

In the southwest corner of Kwajalein Island, in an area called the Shark Pit, the iron content in the sediment is higher than in other beaches. The higher iron content is probably derived from the eroding, rusting machinery visible along the beach. In addition, traditional burrowing organisms are less abundant at this locality and species presumably unique to Kwajalein are present. The reason for this ecological difference is not understood, but may be associated with the erosion and disintegration of exposed and buried equipment.