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H1 East Transect – March 2017

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Detailed Description

Permanent Site: H1 East Transect; Depth: 5.9 Meters (19.5 Feet); Distance from river mouth: 2.4 Kilometers (1.5 Miles) east; Pre/Post Dam Removal: 6 years post-dam removal; Lat/Long: 48.1479177,-123.53472865; Site Description: This is a shallow site and one of the farthest removed from the effects of the sediment plume outside of the control sites. Substrate remains mainly gravel with some sand, cobble and an occasional boulder. In 2017 surveys were conducted monthly for 6 months (Feb-July) to observe seaweed growth throughout the main growing season. As compared to February, larger red seaweeds were now growing (0:31, 0:34, 0:37 seconds) as well as the annual brown seaweeds Alaria marginata (0:14, 0:49, 1:00 seconds) and Saccharina spp. (0:59 seconds). Leaf growth on the perennial seaweed Pterygophora californica (0:32, 0:41, 0:55 seconds) was healthy. Horse clams (Tresus capax) are always abundant at this site but rarely seen on the videos during that summer due seaweed coverage. One clam siphon can be seen next to the tape on the right at 1:19 seconds (oval shape with two small holes) and an empty horse clam shell is at 2:11 seconds. A boulder at 2:07 seconds is covered with orangish-yellow fan hydroids.




Public Domain.