From Land to Sea: How Will Shifts in Stream Flow Influence Delivery of Nutrients, Organic Matter, and Organisms to Alaska and Hawai‘i Nearshore Marine Ecosystems?

Nearshore marine ecosystems in Alaska and Hawai‘i rely heavily on organic materials and nutrients delivered by rivers and streams. It is hypothesized that the magnitude and timing of stream flows influences this delivery of materials to coastal ecosystems. However, despite previous research on the topic, there is still considerable uncertainty about how stream flow may influence these land-to-water (“ridge-to-reef") linkages, and how climate change induced shifts in runoff may ripple across ecosystem boundaries to influence estuary and nearshore marine ecosystems and species of cultural and commercial importance (e.g., Pacific salmon, gobies, and coral reefs).  

This project is a collaborative study to examine how patterns of stream flow in AK and HI influence the delivery of materials to nearshore ecosystems, how climate-driven changes influence these fluxes, and how these changes will be expressed differently in southeast Alaska versus Hawai’i. The research team will quantify dissolved organic and inorganic carbon, nutrients, particulate organic matter, and organism exports (e.g., terrestrial and aquatic invertebrates, and fish larvae) in Peterson Creek just outside of Juneau, Alaska and in the Wailuku River in Hilo, Hawai‘i. These river systems are also part of on-going Alaska CASC-funded research to which the results from this project can be linked: a project to examine the structure and dynamics of river food webs that support salmon, and a project that will examine how stream flows influence the foraging and growth of juvenile salmon. 

The resulting data from this project will allow the construction of a model that can be used to predict the effects of stream flow patterns on the magnitude and composition of transported materials. This model can be used to further examine how future stream flow conditions may influence ridge-to-reef linkages in each stream. The direct products from this project will help generate a series of hypotheses that can extend research on the ridge-to-reef theme not only in Alaska and Hawai‘i, but also other locations where stream flow change may dramatically alter nearshore ecosystems.