Image of the Day: Cooperative Sponges

Mycale grandis teams up with microbes housed inside it to gather nutrients.

Aug 15, 2019
Nicoletta Lanese
The sponge Mycale grandis overgrowing coral on the reef in Kane'ohe Bay
JOY LEILEI SHIH

The invasive sponge Mycale grandis competes for space with local Hawaiian corals and sustains itself using amino acids produced by microbes living inside it, researchers reported July 17 in Microbial Ecology. The scientists analyzed concentrations of naturally occurring stable isotopes within the sponge to learn if it collected nutrients by catching food from the surrounding seawater, which would produce a distinct isotopic signature. Instead, they found that the sponge and the microbes it plays host to display identical isotopic patterns.  

“The only way to produce the observed amino acid isotopic pattern, or fingerprint, if you will, is through the direct transfer of amino acids from their symbiotic bacteria,” says coauthor Joy Leilei Shih, a marine geochemist and conservationist at the University of Hawai‘i at Manoa, in a press release. The sponge still actively pumps water through itself, suggesting it may collect materials from the water to feed its symbiotic partner.

Jets of green fluorescein dye indicate the active pumping of seawater by the sponge Mycale grandis
JOY LEILEI SHIH

J.L. Shih et al., “Trophic ecology of the tropical pacific sponge Mycale grandis inferred from amino acid compound-specific isotopic analyses,” doi:10.1007/s00248-019-01410-x, Microbial Ecology, 2019.

Nicoletta Lanese is an intern at The Scientist. Email her at nlanese@the-scientist.com.