Coring Tips

This commentary is intended as a practical guide for the non-motorized use of piston corers to obtain undisturbed sections of lake sediments. Good recovery is essential for accurate reconstruction of environmental and limnological history. Emphasis is placed on the square-rod piston corer, which is widely used for acquisition of sediment cores in meter-long sections from lakes as much as 30 m deep. Coring platforms for open water can be easily prepared on pairs of boats or canoes or (in water depth up to 15 m) even a single small rubber raft, but firm anchoring is essenial to maintain the vertical position of the casing and to assure re-entry into a single hole. Incomplete recovery on individual drives is not a result of sediment compaction but rather the build-up of friction on the tube interior, by which the core forms a plug that prevents further recovery.