Community structure of low rocky intertidal zones is strikingly different on the Oregon coast. This project will examine why an intertidal zone with high sessile recruitment and phytoplankton availability supports the highest levels of prey production, which in turn supports high abundance of carnivores and herbivores. The postulated result of high consumer abundance is stronger predation on, and weaker competition among, sessile organisms. For contrast, an intertidal zone with high nutrients and macroalgal abundance, and low phytoplankton availability will also be examined. Dr. Menge hypothesizes that higher nutrient uptake by the more abundant macroalgae and/or shorter residence time of nutrients and phytoplankton in nearshore is due to stronger offshore currents. To tests these hypotheses, research scientists will quantify: (1) nutrients, chlorophyll and productivity on- and offshore, (2) current/upwelling regimes, (3) recruitment rates and larval abundance, (4) prey and macroalgal growth rates, and (5) intensities of predation, grazing, and competition at both sites. The project will also evaluate the generality of the influence of nearshore water column processes on intertidal community processes by quantitative surveys of community structure and dynamics, and oceanographic conditions at other locations along the Oregon coast. The results from the project will provide considerable insight into the influence of nearshore oceanographic conditions on community structure in low rocky intertidal habitats.
