THREE YEARS OF HIGH-RESOLUTION OBSERVATIONS FROM AN ARCTIC ESTUARY NEAR KOTZEBUE, ALASKA

The Arctic is warming faster than the rest of the planet, resulting in dramatic changes to freshwater flows, sea ice extent and duration, and nutrient availability to support primary production. These changes are, in turn, altering the food web, which threatens subsistence food systems and cultural integrity in Indigenous Arctic communities, largely though emergent threats such as Harmful Algal Blooms (HABs). Kotzebue, Alaska (Qikiqtaġruk) is one such community that relies on marine food sources, so understanding these changes there is critical. As part of a community-led sampling project, we deployed a moored YSI EXO-2 sonde at the entrance to Kobuk Lake in the summers of 2022, 2023, and 2024. The sonde measured temperature, salinity, oxygen, turbidity, dissolved organic matter, chlorophyll and phycocyanin fluorescence every 10 minutes. Across the three seasons, we documented several distinct salinity spikes, up to 27 ppt, in the surface waters of Kobuk Lake. Analysis of temperature, dissolved organic matter, and other water characteristics showed that the spikes were consistent with water originating in the Chukchi Sea. Analysis of wind speed and direction obtained from the nearby PAOT weather station showed no direct correlation between wind speed or direction and salinity, though high-speed winds (>10 knots) were found to precede all spikes. A Sentinel-3 satellite time series for the same location is being developed to compare with the in-situ mooring data. We will present our analysis of the mooring data and the larger scale changes observed in the satellite data.

Presentation Preference: Poster

Primary Presenter: Eilidh MacLeod, Columbia University Lamont Doherty Earth Observatory (ejm2242@columbia.edu)

Authors:

Eilidh MacLeod, Columbia University  (ejm2242@columbia.edu)

Ajit Subramaniam, Lamont Doherty Earth Observatory  (ajit@ldeo.columbia.edu)

Alex Whiting, Native Village of Kotzebue  (alex.whiting@qira.org)