Benthic macroinvertebrate collection protocols
Download 1.35 Mb.
|
| see Figure 4). If the substrate is removable, pull it up and hold it underwater in front of the center of the net while brushing all surfaces so that dislodged organisms flow into the net. Cleaned substrate should then be set aside. In low flow situations, these rocks can be placed at the edge of the net in a manner that increases the amount of water flowing through the net. Large substrate that is partially in the kick sample area should only be brushed on that portion which resides in the 0.25 m2 kick area.
Figure 4. Photograph of the Brushing process in front of the net. Hold the net handle securely while kicking the substrate vigorously for 20 seconds to a depth of 10 cm in an area of about 0.25 m2 (0.5m wide net x 0.5m upstream) in front of the net (see Figure 5). At this time it may be possible to remove large objects (e.g., cobble, large gravel) from the net while the water is still sweeping through the net. 
Figure 5. Photograph of the Kicking process in front of the net. Remove the net from the water with a quick upstream motion to wash the organisms to the bottom of the net ( Directory: WWE WWE -> Chapter 12 Designing and Delivering WWE -> Course Objectives WWE -> Learning Objectives Download 1.35 Mb. Share with your friends:
|