| Abstrakt: |
This is the first report of long-distance transoceanic dispersal of coastal, shallow-water benthic foraminifera by ocean rafting, documenting survival and reproduction for up to four years. Fouling was sampled on rafted items (set adrift by the Tohoku tsunami that struck northeastern Honshu in March 2011) landing in North America and the Hawaiian Islands. Seventeen species of shallow-water benthic foraminifera were recovered from these debris objects. Eleven species are regarded as having been acquired in Japan, while two additional species (Planogypsina squamiformis (Chapman, 1901) and Homotrema rubra (Lamarck, 1816)) were obtained in the Indo-Pacific as those objects drifted into shallow tropical waters before turning north and east to North America. Four species were acquired after the debris came ashore in Hawaii and in North America. As previously shown for the Japanese species Trochammina hadai Uchio, 1962 and the Indo-Pacific species Amphistegina lobifera Larsen, 1976, introduced foraminiferal species may rapidly proliferate and disperse, negatively impacting native species. In the geologic past, panoceanic rafting must have been relatively infrequent, as it would have floating pumice and vegetation with relatively limited potential for multiyear survival at sea. In modern times, the ever-increasing abundance of floatable plastic artifacts emplaced along tectonic coastlines provides a greater abundance of more permanent materials for tsunami- and storm-generated rafts that can introduce foraminifera and other marine biota to distant shorelines. [ABSTRACT FROM AUTHOR] |
