Foraminiferal recolonization on the continental shelf

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Abstract
Boxes filled with defaunated sediment were placed on the shelf floor at a site 90 miles east of Atlantic City, New Jersey [USA], at a depth of 65 m. After 10 wk, 4 boxes were recovered and after 43 wk, 4 additional boxes were recovered to assess biologial changes, including recolonization by foraminifera. The natural community of foraminifera also was sampled at 4 times between Feb. and Dec., 1977. The densities of foraminifera in all recolonization boxes were remarkably similar and surpassed the mean density observed in the natural community within 10 wk. Significant numbers of living foraminifera were observed as deep as 3 cm in the sediment, suggesting that horizontal and vertical colonization proceed simultaneously. Species richness in the recolonization boxes exceeded that observed in the natural community. With the exception of the agglutinated foraminifer Reophax atlantica the dominant species of foraminfera of the natural community and in the 10-wk recolonization boxes were basically the same. A nonequilibrium model of recolonization following an ecologic disturbance best fits the data obtained in this study.