Zebra Mussel Destruction by a Lake Michigan Sponge: Populations, in Vivo 31P Nuclear Magnetic Resonance, and Phospholipid Profiling

Abstract

The sponge Eunapius fragilis (Leidy), that has become abundant in southwestern Lake Michigan, overgrows zebra mussels, Dreissena polymorpha (Pallas). The overgrown mussels die. Population dynamics show that in the presence of zebra mussels, E. fragilis is the dominant species (61% of sponges), with 90% of these sponges being associated directly to the mussels. In vivo 31 P NMR spectroscopy performed on overgrown mussels reveals that mussel ATP is depleted in a manner indicative of a tissue in anoxia (Figure 2). 31 P NMR phospholipid profiles reveal that the phospholipids of such mussels have been degraded to their lyso-phospholipid forms. Phospholipid degradation may be the direct result of the lysosomal chemical action of the sponge or a secondary effect resulting from sponge-induced death by anoxia followed by microbial action on the weakened energy-depleted mussels.