Assessing the influence of lithology on the temporal-spatial variability of sediment transport and its relation to primary production in mountain streams

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Primary production provides the fundamental source of energy for most life on earth, and therefore understanding what controls primary production is key to understanding ecosystems. In streams, relevant research has focused mainly on the influence of light and nutrients. The role of underlying geology and sediment transport has not been as well explored. The algae that dominate primary producers in headwater streams live on rocks. Flow events that mobilize those rocks can scrape algae away and reset the system to low production levels. Understanding controls on the frequency of sediment scour and abrasion in a stream is therefore fundamental to understanding the dynamics of primary production. This research project will contribute to a better understanding of the coevolution of ecosystems and landscapes.This interdisciplinary research project links fluvial geomorphology and stream ecology. The goal is to determine: (a) how spatial variability in velocity and shear stress affect sediment transport in gravel-bedded streams, (b) how these affect primary productivity at reach and patch scale, and (c) what control underlying bedrock lithology exerts on these processes. This project will couple the use of a 2D model and the collection of field measurements in four sites in the Oregon Coast Range. The sites have been selected based on similar climate, light, nutrients, and temperature, but different lithology to isolate the controls it exerts. The project is led by an early career Hispanic female investigator. Collaboration with a local high school will provide a research experience for teachers and involve Native American high school students.