Editing Sponge (section)

=== Sponge microbiome ===
{{main|Sponge microbiomes}}
[[File:The sponge holobiont.webp|thumb|upright=1.8|right|The sponge holobiont as a nested ecosystem. Key functions carried out by the [[Sponge microbiomes|sponge microbiome]] (colored arrows) influence holobiont functioning and, through cascading effects, subsequently influence community structure and ecosystem functioning.<ref name="Pita_2018">{{cite journal |last1=Pita |first1=L. |last2=Rix |first2=L. |last3=Slaby |first3=B. M. |last4=Franke |first4=A. |last5=Hentschel |first5=U. |title=The sponge holobiont in a changing ocean: from microbes to ecosystems |journal=Microbiome |volume=6 |issue=1 |date=2018 |page=46 |issn=2049-2618 |pmid=29523192 |pmc=5845141 |doi=10.1186/s40168-018-0428-1 |doi-access=free}} [[File:CC-BY icon.svg|50px]] Material was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License] {{Webarchive|url=https://web.archive.org/web/20171016050101/https://creativecommons.org/licenses/by/4.0/ |date=2017-10-16 }}.</ref>]]

Besides a one to one [[symbiotic relationship]], it is possible for a host to become symbiotic with a [[microbial consortium]], resulting in a diverse [[Sponge microbiomes|sponge microbiome]]. Sponges are able to host a wide range of [[Marine microorganisms|microbial communities]] that can also be very specific. The microbial communities that form a symbiotic relationship with the sponge can amount to as much as 35% of the [[Biomass (ecology)|biomass]] of its host.<ref>{{cite journal |last1=Egan |first1=Suhelen |last2=Thomas |first2=Torsten |title=Editorial for: Microbial symbiosis of marine sessile hosts- diversity and function |journal=Frontiers in Microbiology |volume=6 |date=16 June 2015 |page=585 |issn=1664-302X |pmid=26136729 |pmc=4468920 |doi=10.3389/fmicb.2015.00585 |doi-access=free}}</ref>

The term for this specific symbiotic relationship, where a microbial consortia pairs with a host is called a [[Holobiont|holobiotic relationship]]. The sponge as well as the microbial community associated with it will produce a large range of secondary [[metabolite]]s that help protect it against predators through mechanisms such as [[chemical defense]].<ref name="Webster_2016">{{cite journal |last1=Webster |first1=N.S. |last2=Thomas |first2=T. |title=The Sponge Hologenome |journal=mBio |volume=7 |issue=2 |pages=e00135-16 |date=April 2016 |pmid=27103626 |doi=10.1128/mBio.00135-16 |pmc=4850255 }}</ref> The sponge holobiont is an example of the concept of nested ecosystems. Environmental factors act at multiple scales to alter microbiome, holobiont, community, and ecosystem scale processes. Thus, factors that alter microbiome functioning can lead to changes at the holobiont, community, or even ecosystem level and vice versa, illustrating the necessity of considering multiple scales when evaluating functioning in nested ecosystems.<ref name="Pita_2018" />

Some of these relationships include endosymbionts within bacteriocyte cells, and cyanobacteria or microalgae found below the pinacoderm cell layer where they are able to receive the highest amount of light, used for phototrophy. They can host over 50 different microbial phyla and candidate phyla, including Alphaprotoebacteria, [[Actinomycetota]], [[Chloroflexota]], [[Nitrospirota]], "[[Cyanobacteria]]", the taxa Gamma-, the candidate phylum [[Poribacteria]], and [[Thaumarchaea]].<ref name="Webster_2016"/>