Marine microbial symbionts - Sponges

Sponges host diverse microbial symbiont communities that contribute to digestion and nutrient release from the filtered organics. In some species cyanobacterial (or dinoflagellate) endosymbionts can supply fresh photosynthate to meet a substantial fraction of the sponge energy requirements. N fixation, denitrification, and annamox are also known to occur Sponges contribute to explain Darwin’s paradox through the generation of inorganic nutrients for the reef.