Diagram of the <a href="https://en.wikipedia.org/wiki/nitrogen_cycle" class="extiw" title="en:nitrogen cycle">nitrogen cycle</a> in an <a href="https://en.wikipedia.org/wiki/aquarium" class="extiw" title="en:aquarium">aquarium</a>.  Drawn in <a href="https://en.wikipedia.org/wiki/Sodipodi" class="extiw" title="en:Sodipodi">Sodipodi</a> by <a href="https://en.wikipedia.org/wiki/User:Ilmari_Karonen" class="extiw" title="en:User:Ilmari Karonen">Ilmari Karonen</a>, <a href="https://en.wikipedia.org/wiki/SVG" class="extiw" title="en:SVG">SVG</a> original available at <a rel="nofollow" class="external autonumber" href="http://vyznev.net/misc/Aquarium_Nitrogen_Cycle.svg">[1]</a>.
Users <a href="https://en.wikipedia.org/wiki/User:Eliashc" class="extiw" title="en:User:Eliashc">Eliashc</a>, <a href="https://en.wikipedia.org/wiki/User:Ilmari_Karonen" class="extiw" title="en:User:Ilmari Karonen">Ilmari Karonen</a> on <a class="external text" href="https://en.wikipedia.org">en.wikipedia</a>
<span class="int-own-work" lang="en">Own work</span>