Turbulence induces metabolically costly behaviors and inhibits food capture in oyster larvae, causing net energy loss

Planktotrophic invertebrate larvae require energy to develop, disperse, and settle successfully, and it is unknown how their energetics is impacted by turbulence. Ciliated larvae gain metabolic energy from their phytoplankton food to offset the energetic costs of growth, development, and ciliary activity for swimming and feeding. Turbulence may affect the energetic balance by inducing behaviors that alter the metabolic costs and efficiency of swimming, by raising the encounter rate with food particles, and by inhibiting food capture. We used experiments and an empirical model to quantify the net rate of energy gain, swimming efficiency, and food capture efficiency for eyed oyster larvae (Crassostrea virginica) in turbulence. At dissipation rates representative of coastal waters, larvae lost energy even when food concentrations were very high. Both feeding activity and turbulence-induced behaviors incurred high metabolic costs. Swimming efficiency was concave up versus dissipation ...