FA signatures of the diatom Skeletonema cf. marinoi: just how natural is culturing anyway?

Abstract

Spatial subsidies including particulate organic matter (POM) play an important role in near-shore food web ecology. Fatty acid (FA) analysis has proven an effective tool for constructing these food webs, although the FA profiles of many marine autotrophs and the validity of culturing is still unknown. We cultured the diatom Skeletonema cf. marinoi using dialysis tubes and compared the FA profile to published batch culture FA profiles and to POM FA profiles. PERMANOVA analysis showed that FA profiles of dialysis replicates were not significantly different from each other (p=0.14) but were different from batch culture (p=0.001) and POM data (p=0.0001). FA suites from cultured phytoplankton may delineate specific phytoplankton taxa, but further studies are necessary to determine the most accurate culturing method.