AF4-ICP-MS # The amount of Arsenic elements in the collected colloidal fractionations.
Molecular weights # UV254 absorbance, Fluo275/340 (protein-like), and Fluo250/435 (humic-like) signals characterizing the size chromatography of the colloids in groundwater (left three panels), Kinnickinnic river water, and re-dissolved standard humic substances from Mississipi River and Suwannee River. UV absorbance and Fluorescence intensity were calibrated using quinine sulfate. It is worth mentioned that the x-axis is log-axis, which extends the display of smaller-sized colloids.
Abstract # Arctic river basin has been suffering a great impact from climate change. However, dynamics and mechanism of biogeochemical processes in boreal rivers in cold season are still partly out of knowledge. Our study focused on seasonality of the Yukon River, one of the regularly ice-covered Arctic rivers in North America. Water samples were collected monthly from downstream Yukon River (known as Pilot Station) from July 2004 to September 2005. Absorption and fluorescence of dissolved organic matter in two phases: colloids and low molecular weight were measured to examine optical characteristics and size distribution of organic matter. Biological index (BIX) and humification index (HIX) are EEM-derived indicators for bio-activities and humification level in aquatic environments. The trend of BIX implied stronger biological activities in the stable fluvial ecosystem under ice. HIX followed the discharge; large river volume with predominant terrestrial input drained in summer, while low-DOC groundwater mainly contributed in winter. Three fluorescence components were decomposed from Excitation-Emission Matrix (EEMs), including two humic-like components and one protein-like component. The ratio between protein-like component and humic-like components indicates the water chemistry conditions in the Yukon River. Relatively high ratio value in the ice-covered season suggested thriving algae community activity under the ice.
Map of Yukon River drainage # Sampling site: between the Dalton Highway Bridge and the USGS Stevens Village hydrological station
Daily Discharge and Sampling Date # 
Monthly integrated discharge # 