MEPS 258:161-169 (2003)  -  doi:10.3354/meps258161

Structures and concentrations of surfactants in gut fluid of the marine polychaete Arenicola marina

J. C. Smoot1,3, L. M. Mayer2, M. J. Bock2,4, P. C. Wood1, R. H. Findlay1,5,*

1Department of Microbiology, Miami University, Oxford, Ohio 45056, USA
2Darling Marine Center, University of Maine, Walpole, Maine 04573, USA
3Present address: Department of Civil and Environmental Engineering, University of Washington, Seattle, Washington 98195, USA
4Present address: ARCADIS, Portland, Maine 04101, USA
5Present address: Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama 35487, USA
*Corresponding author. Email:

ABSTRACT: Marine invertebrate deposit feeders secrete surfactants into their gut fluid in concentrations sufficient to induce micelle formation, enhancing solubilization of sedimentary lipids. We isolated and identified 3 related surfactant molecules from the deposit-feeding polychaete lugworm Arenicola marina. Surfactants were isolated and separated by a combination of solvent extraction and thin-layer and gas chromatography. Identification was performed using mass and infrared spectrometry, coupled to various derivatization and hydrolysis reactions. A. marina produces a mixture of related yet distinct anionic surfactants composed of branched, C9, saturated and unsaturated fatty acids that are amide linked to leucine or glycine residues, showing some similarity to crustacean surfactants. The critical micelle concentration of the mixture of these surfactants in gut fluid was about 2 mM, and total concentrations ranged from 5.5 to 19.5 mM. The hydrophilic amide linkage helps to explain previous observations that gut surfactants do not adsorb onto sediment transiting the gut.


KEY WORDS: Digestive physiology · Surfactant · CMC · GC-MS · Gut fluid · Sediment


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