Editing Sponge (section)

=== Endosymbionts ===

Freshwater sponges often host [[green algae]] as [[endosymbiont]]s within [[archaeocyte]]s and other cells and benefit from nutrients produced by the algae. Many marine species host other [[photosynthesis|photosynthesizing]] organisms, most commonly [[cyanobacteria]] but in some cases [[dinoflagellate]]s. Symbiotic cyanobacteria may form a third of the total mass of living tissue in some sponges, and some sponges gain 48% to 80% of their energy supply from these micro-organisms.<ref name="Ruppert_2004"/> In 2008, a [[University of Stuttgart]] team reported that spicules made of [[silica]] conduct light into the [[mesohyl]], where the photosynthesizing endosymbionts live.<ref>{{cite journal |last1=Brümmer |first1=Franz |last2=Pfannkuchen |first2=Martin |last3=Baltz |first3=Alexander |last4=Hauser |first4=Thomas |last5=Thiel |first5=Vera |title=Light inside sponges |journal=[[Journal of Experimental Marine Biology and Ecology]] |volume=367 |issue=2 |pages=61–64 |doi=10.1016/j.jembe.2008.06.036 |year=2008|bibcode=2008JEMBE.367...61B }}
* {{cite news |last=Walker |first=Matt |date=10 November 2008 |title=Nature's 'fibre optics' experts |work=BBC News |url=http://news.bbc.co.uk/2/hi/science/nature/7720836.stm |access-date=11 November 2008 |archive-date=17 December 2008 |archive-url=https://web.archive.org/web/20081217045607/http://news.bbc.co.uk/2/hi/science/nature/7720836.stm |url-status=live }}</ref> Sponges that host photosynthesizing organisms are most common in waters with relatively poor supplies of food particles and often have leafy shapes that maximize the amount of sunlight they collect.<ref name="Bergquist_1998"/>

A recently discovered carnivorous sponge that lives near [[hydrothermal vent]]s hosts [[Methanotrophic|methane-eating]] bacteria and digests some of them.<ref name="Bergquist_1998"/>