Blanket weed <i>Cladophora glomerata</i> moving in a wave. It grows on a rusty boat ramp in Govik, Lysekil Municipality, Sweden. In among the <i>Cladophora glomerata</i> are tufts of gutweed (<i>Ulva intestinalis</i>) and top left are a couple of dead man's rope (<i>Chorda filum</i>).
<a href="//commons.wikimedia.org/wiki/User:W.carter" title="User:W.carter">W.carter</a>
<span class="int-own-work" lang="en">Own work</span>