Lightweight Corer Designed for Sampling Very Soft Sediments

An underwater corer has been developed capable of taking 10-cm diam cores up to 1 m long from unconsolidated, fine-grained fluvial and lacustrine sediments including organic-rich (gyttja-like) deposits. The corer is lightweight and compact for transport and hand operation from float planes and small boats. It is of the piston type and has a sphincter valve for core retention. A miniature optical sensor triggers the corer when the sediment–water interface is penetrated. The corer is compatible with a system to subdivide the cores by vertical extrusion.