WENDT, D.E.*; JOHNSON, C.H.; Cal Poly, San Luis Obispo; Harvard University: Availability of dissolved organic matter (DOM) reduces carryover performance consequences for the marine bryozoan Bugula neritina

For marine invertebrates with complex life-cycles physical stresses during the larval stage can often have dramatic and long-lasting effects on postmetamorphic performance. The cheilostome bryozoan Bugula neritina is an ideal model system for investigating such carryover performance consequences. For B. neritina an extended larval swimming phase results in postmetamorphic individuals that are on average smaller and slower growing, causing a decrease in the production of offspring over a given time period when compared to individuals that develop from larvae that do not undergo protracted larval swimming. We sought to determine if the availability of dissolved organic matter (DOM) could offset the known carryover effects that result from extended larval swimming by comparing the performance of animals in the presence and absence of DOM during larval swimming and metamorphosis. Indeed, for nearly a century researchers have investigated the uptake and utilization of dissolved organic matter (DOM) by marine invertebrates however the extent to which DOM transport contributes to the overall growth, reproduction and survival of animals remains largely unknown. Animals in a DOM-enriched condition had a higher rate of successful metamorphosis when compared to animals in the DOM-reduced condition. In addition, animals in the DOM-enriched condition had larger post-metamorphic size compared to animals in DOM-depleted seawater. The results from these experiments in conjunction with known carryover consequences for B. neritina suggest that the ability to utilize DOM during swimming and metamorphosis may ultimately result in increased reproductive fitness.