Tatum Hardt,  

Sponsor or Client: 

Title:

Sedimentary Analysis of Eklutna Lake, Alaska, to Understand Glacier Fluctuations Over the Past 9,600 Years

Abstract:

Evidence from proglacial lake sediments was used to reconstruct changes in Eklutna Glacier size over the past 9,600 years. Anchorage, AK depends on freshwater and hydropower provided by Eklutna Glacier, which is rapidly retreating. Eklutna Lake sediment cores were used to create an age-depth model based on 14C ages and volcanic ash layers to understand glacier fluctuations using proxies. Biogenic silica measures diatom productivity, which is determined by glacier cover. Larger glaciers generate more rock flour that increases lake water turbidity and sediment accumulation rate at the lake floor, limiting growing conditions in the photic zone that reduces diatom abundance. The results indicate that Eklutna Glacier was smaller before 5000 years ago and larger thereafter, agreeing with other studies in the region. This study provides insight into how glaciers responded to past temperature changes and can help infer how glaciers will change in the future due to human-induced warming.