Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Front view of direct sampling apparatus, where the gray section is the sampling filter (30 cm by 10 cm) supported by a cage that filters macroscopic material while providing housing for the sampling material. The cylindrical floats position the sampler so that the water surface transects the filter material.
