Marine Ecology Progress Series
Biochemical and traditional analyses were used to characterize the microbial food resources and digestive efficiency of Ptychodera bahamensis, an enteropneust hemichordate. Sediment was collected from freshly extruded fecal casts and adjacent feeding depressions. There were no significant differences between casts and depressions in median grain size, percent silt-clay, density of total meiofauna and of nematodes, and concentrations of chlorophyll a and phaeophytin. Nematodes in casts had a median diameter greater than those in depressions. Measures of total, viable microbial biomass were 30% (total phospholipid, ester-linked fatty acids) and 49% (extractible phospholipid phosphate) lower in casts. Concentrations of 33 fatty acids were lower in casts, indicating that the hemichordate digests a wide variety of microorganisms. Only 18:1w7c (cis-vaccenic acid) was not lower in casts than in depressions. This fatty acid is characteristic of eubacteria having the anaerobic-desaturase pathway, many of which are Gram-negative organisms. P. bahamensis either cannot digest this functional group of bacteria or contributes gut microbes containing 18:1w7c to sediment passing through its alimentary canal.
Original Publication Citation
Dobbs, F.C., & Guckert, J.B. (1988). Microbial food resources of the macrofaunal-deposit feeder Ptychodera bahamensis (Hemichordata: Enteropneusta). Marine Ecology Progress Series, 45(1-2), 127-136. doi: 10.3354/meps045127
Dobbs, Fred C. and Guckert, James B., "Microbial Food Resources of the Macrofaunal-Deposit Feeder Ptychodera bahamensis (Hemichordata: Enteropneusta)" (1988). OES Faculty Publications. 25.