The majority of the ocean floor is sedimentary, and marine sediments play a key role in the flux of nutrients and organic matter in the ocean. Via their feeding and other activities, organisms living in marine sediments influence benthic-pelagic coupling by processing and redistributing organic matter supplied from the water column and influencing the supply of nutrients. These activities also influence recruitment and competitive interactions. Thus, factors that impact infaunal activity can secondarily impact sediment biogeochemistry and benthic communities. Non-lethal loss of body tissue is a common event for marine infauna such as polychaetes, and numerous studies have investigated the immediate effects of injury on individuals and predicted indirect effects on ecological interactions in marine soft-sediment habitats. Accurate predictions of the effect injury has on marine infaunal communities require knowing the frequency at which infaunal organisms are injured, whether injured individuals can regenerate and the speed at which they do so. But comprehensive, accurate assessments of injury rates among soft-bodied infauna are difficult because current methods underestimate injury rates by counting only individuals that are visibly regenerating lost tissue. Past injury may be masked by rapid regeneration in some species.
RESEARCH SUMMARY & INTELLECTUAL MERIT: This project will use a novel approach using a histological stain in conjunction with field surveys to answer several important ecological questions: How frequently are marine worms injured? How variable is the incidence of injury in space and time? Are there species differences in the frequency of injury? Surveys of infaunal injury will be repeated during the spring and summer months over three years at two sites in Maine. This project will also investigate the effect of repeated injury on infauna, an aspect of injury that has been largely ignored. Comprehensive measurements relating sediment activity, regeneration status and nutritional condition of infauna are rare. Laboratory experiments will compare the effect of repeated injury on survival, growth, fecundity, nutritional condition and sediment disturbance by different functional groups such as spionid polychaetes (shallow tube-dwelling interface deposit feeders with rapid regeneration rates), maldanid polychaetes (head-down tube-dwelling conveyor-belt feeders), and arenicolid polychaetes (head-down burrowers that subduct surface sediments to depth to feed). This project will then use the data gathered in the proposed experiments and surveys to create a more realistic model of the interacting effects injury has on infaunal populations, sediment bioturbation, recruitment, and predator populations. Effects of predation intensity on bioturbation and infaunal populations will be explored.
BROADER IMPACTS: The project includes a significant effort to improve ocean science literacy across the nation by collaborating with the Centers for Ocean Sciences Education Excellence-Ocean Systems team (COSEE-OS) to develop educational resources describing the ways marine infauna link sediment and water column processes in the ocean. Two graduate students and three undergraduates will receive diverse training in marine organismal biology, physiology and ecology. All participants will work with COSEE-OS educational experts to develop content and educational activities that will be added to interactive concept maps of Oceans and Climate and Ocean Diversity. Undergraduate and graduate students will be introduced to the process of translating the knowledge and experience they gain during their research into larger key concepts to be presented to a general audience. Educational activities will be tested in the PI's marine science class and interactive concept maps and ocean science educational activities will be widely distributed by COSEE-OS via the internet. Materials will align with Ocean Literacy Essential Principles and National Science Education Standards. After internal evaluation at the University of Maine to evaluate student learning, the materials will then be widely distributed by COSEE-OS and evaluated using standard evaluation protocols for technology usability and end-user effectiveness. By working directly with both a national network (COSEE) and a national ocean literacy campaign with proven success, we can ensure that our deliverables will reach a broad spectrum of learners, including those traditionally underrepresented in ocean sciences.
