Use of 35S to determine the influence of Hexagenia on sulfur cycling in lake sediments

A new quantitative grab for sampling benthos is described. It is constructed of stainless steel to retard corrosion, and incorporates six features designed to make it outperform other grabs: 1) a frame support; 2) counter-weighted arms; 3) overlapping buckets; 4) upright posts on the frame for addition of weights; 5) a fine mesh cover on each bucket; and 6) a moving elliptical pivot point. These features result in high reliability compared to other grabs, and a somewhat quadrangular bite profile. The model in use digs to 6 cm depth over the entire area sampled, and penetrates to a maximum of 11.5 cm.