Water Resources Research Act Program

Details for Project ID 2016AK131B

Initiating a network of long-term records of lake-level fluctuations in interior Alaska in relation to climate change

Institute: Alaska
Year Established: 2016 Start Date: 2016-03-01 End Date: 2017-02-28
Total Federal Funds: $15,000 Total Non-Federal Funds: $30,000

Principal Investigators: Matthew Wooller

Abstract: Many of the lakes in interior Alaska serve as important water resources for recreational use including sport fishing, water sports, subsistence resource aquisition and fresh water sources for their local communities. However, some of these lakes are exhibiting lake level decreases, possibly resulting from high-latitude climate changes. Despite these lakes having been present on the landscape for tens of thousands of years, there are very limited records of how lake levels at these sites have changed in the past in response to climate changes. Fortunately, lakes have sediments that have been laid down over thousands of years since the lakes first appeared on the landscape. A core extracted from down through these layers of sediment near the deepest point in a lake provides a time-line of a lake’s history, which can yield information on how the lake and its surrounding environment changed over time. We have previously taken, dated and archived sediment cores from near the deepest locations in Blair and Quartz lakes in interior Alaska. We propose here to analyze samples from various depths in these sediment cores for the remains of diatoms. Diatoms are microscopic single-celled algae that have a cell wall of silica (called a frustule), which preserves well over very long periods of time. The characteristic ornamentation of the frustules makes it possible to identify them to species level. Different species are also favored in shallow lakes compared with deep lakes. Therefore, changes in the diatom assemblages and in their abundance along a dated core can be interpreted qualitatively and also used in a statistical model to infer quantitative changes in past lake depth over time. This is an approach that has recently been successfully applied to Grizzly Lake in Alaska. By conducting diatom analyses of cores from Quartz and Blair lakes, we will be able to construct two unique and new long-term records of lake-level changes from interior Alaska. In 2014 we also initiated an intensive field and laboratory project (NIWR funded) to investigate long-term, lake-level changes at Lost Lake in interior Alaska. At Lost Lake we used a complementary, but different, approach that is more favourable for shallower and more accessible lakes. This alternative approach involved taking mutiple cores from the lake mud across a bathymetic gradient. The multiple cores taken from this transect, going from the deepest part of the lake to the shallow edge, were radiocarbon dated and lined up. The result illustrated the rate and timing of when the lake filled in over time and also illustrated when lake levels decreased. We now propose combining the data that will be acquired from Blair and Quartz lakes (the present proposal), along with our collected data from Lost Lake and additional published lake-level records from other lakes in interior Alaska (Harding and Birch) into a spatial network of regional historical lake-level records. We propose initiating and using this network to examine the extent of regional vs. local lake-level signals over the last 10,000 years and in relation to past climate changes over this period. This project will support the research and training of a graduate student at UAF.