The tom-tom corer: a new design of the Kajak corer for use in meiofauna sampling

Abstract

A new corer, the tom-tom, is a modification of the basic Kajak design. New modifications increase the efficiency of the corer in soft muds and increase the stability of the corer during ascent and descent. A stepped release trigger mechanism allows the corer to trip easily in even the softest muds, and a Phleger “bomb’ weight adds stability to the device. The corer can be deployed in a slow, controlled descent from small as well as large boats to reduce bow-wave. Four cores (4.50 cm inner diameter) are taken simultaneously in a fixed spatial pattern. Limited comparative sampling revealed that the tom-tom collected more meiofauna than a Van Veen grab and attained numbers statistically indistinguishable from diver-collected cores (only small sample sizes were available however). The corer will be most efficient in sediments without an extremely well-developed, suspendable layer, and most practical for smaller vessels in environments where diver collected cores are precluded by depth, strong currents or poor visibility. Although used in meiofauna collection, the corer should be appropriate for any sampling needs requiring a relatively undisturbed core.