Holobiont is an organism with all of its associated microorganisms called microbiota. Microbiota affects growth, development and health of its host. Sponges (Porifera) are multicellular organisms with undifferentiated tissue. Sponges are an important member of benthic habitats because of their large biomass and the capacity for filtering water. This paper describes several characteristics of a sponge holobiont and its effect on the ecosystem. Some of the common microorganism taxa found in the sponge microbiota are Proteobacteria, Chloroflexi, Cyanobacteria, Crenarchaeota and Acidobacteria. In a healthy holobiont, relationships in the microbiota are at equilibrium. This balance breaks down by changing biotic and abiotic factors. When is the sponge holobiont healthy it provides nutrients for other organisms. In the deep sea near the hydrothermal vents metatropic bacteria from microbiota by chemiosmosis assimilate carbon by which they provide nutrients. While coral reefs of warm and cold seas depend on sponge loop to acquire enough nutrients and energy. Sponge loop uses both microbiota and the host to convert DOM into POM which is then returned to higher trophic levels. This are just some of the reasons why is sponge holobiont important which is getting more endangerd because of the negative impact of climate change on it.