DIATOMS ONLY. A sediment trap is generally positioned directly over the deepest portion in the lake and secured to the bottom with a weight. The 1998 Green Lake 4 trap aspect ratio of was 4:1, the deployment depth was 3.1 m, and it remained there for approximately two months. The trap consisted of a conical tube connected to a funnel with a mesh 2.5 cm below the opening to keep large objects from clogging the funnel. The trap collected approximately 0.1 g of dry sediment and the sample was freeze-dried promptly after retrieval.