In the coastal temperate rainforests of the Tongass National Forest, one of the largest migrations of biomass from sea to land occurs as Pacific salmon return to their home rivers to spawn. Salmon bring an immense flux of marine-derived nutrients into the terrestrial system, nourishing animals, forests, and the Lingít people for thousands of years. Such an intense annual nutrient pulse can quickly increase plant-available nutrients, but evidence is mixed on how those nutrient inputs affect terrestrial plant community composition. Despite the importance of mycorrhizal and saprotrophic fungi in mediating nutrient cycling, even less is known about how fungi are affected by marine-derived nutrients from salmon returns. The main purpose of this project is to understand how salmon nutrient inputs in coastal temperate rainforests affect soil microbial communities and how those microbes might affect plant community composition in a changing climate. In particular, we will focus on the abundance and diversity of mycorrhizal fungi that associate with culturally important and vulnerable plants such as Yellow cedar, hemlock, and several types of berries. Ultimately, this study will yield key insights into the microbial role of marine-derived nutrient cycling in these highly productive old growth forests.

Funded by the Society for the Protection of Underground Networks

Supported by the Sitka Sound Science Center