ABSTRACT. We present a mechanical method to horizontally section soft bottom sediment cores to minimize the vertical post-sampling redistribution of motile infaunal macroinvertebrates. A clear acrylic core tube for a standard Kajak-Brinkhurst corer was modified by cutting a series of horizontal slits into the side of the core tube to allow the insertion of sectioning plates for physically sealing each section immediately after core retrieval. The modification is simple, inexpensive and easily adapted to any open barrel gravity corer.