2021 Research News

Ph.D. Student Publishes Article on Marine Sponges in Frontiers of Marine Science

May 3, 2021 - Sponges are now the dominant animal life on Caribbean reefs, and they pump huge volumes of seawater through their bodies as they feed. Now, a new research paper authored by UNCW PhD student Lauren Olinger and her colleagues demonstrates that organic compounds are retained as sponges feed, and some of these compounds are organohalides, a class that incorporate the elements chlorine and bromine. The paper is forthcoming in Frontiers of Marine ScienceBarrel Sponge

Organohalides include many important toxic pollutants, including polychlorinated biphenyls (PCBs), insecticides such as DDT, and industrial byproducts, such as dibenzofurans. Equally surprising, only sponge species that had microbes living symbiotically in their tissues could absorb organic compounds; species that did not have microbial symbionts lacked this ability. 

Olinger’s study was conducted on samples from a coral reef off the coast of Belize, using SCUBA diving to carefully collect seawater before and after it passed through the bodies of vase- and barrel shaped sponges. Water samples were analyzed at UNCW’s Center for Marine Science under the supervision of Dr. Wendy Strangman (Dept. of Chemistry and Biochemistry), employing the same untargeted metabolomics techniques used in pharmaceutical research and to detect chemical pollutants in drinking water. 

The organohalide compounds absorbed by sponges have only tentatively been identified, but they are likely naturally occurring metabolites of other marine organisms. Many unusual organohalides have been isolated from the tissues of seaweeds and soft corals, and some of these have been studied for potential uses as new drugs. It remains to be determined whether the sponges themselves, or their microbial symbionts, absorb the organohalides, and whether they simply metabolize these compounds, or somehow incorporate them into their tissues. 

Olinger's work and Dr. Pawlik's lab was featured in a story in CoastalReview.org on May 19th.

Olinger LK, Strangman WK, McMurray SE, Pawlik JR. 2021. Sponges with microbial symbionts transform dissolved organic matter and take up organohalides. Front. Mar. Sci. | doi: 10.3389/fmars.2021.665789 

https://www.frontiersin.org/articles/10.3389/fmars.2021.665789/abstract

Image caption: A baby giant barrel sponge (Xestospongia muta) pumps fluorescein dye in a glass jar.