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Credit: Mike RawlinsOver half of the fresh water and water-borne nutrients flowing from land to the Alaska Beaufort Sea each year are delivered during a two-week period in the spring — earlier than most seasonal Arctic research begins. These inputs are dominated by three large rivers that flow into the central Alaska Beaufort Sea. The… Read more »

Credit: BLE LTERMost consumers in Beaufort Sea lagoons exhibit omnivorous (generalist) feeding strategies. Food web structure shifts with the seasons as food sources change from ice cover to open water. Multiple food sources provide sustenance to consumers including allochthonous (marine and terrestrial/ riverine organic matter) and autochthonous (microphytobenthic and phytoplankton) organic matter.  

Consistent with reports from other regions of the Arctic and the Beaufort Sea Coast, coastal erosion rates appear to have increased along the shores of Elson Lagoon near Utqiaġvik (formerly Barrow) over the last half century. Areas with historically low erosion rates are changing faster, but rates do not exceed those of areas with historically… Read more »

Beaufort Sea lagoons experience large seasonal variations in temperature and salinity related to the Arctic freeze-thaw cycle. In the most extreme cases, lagoons swing from completely freshwater conditions during the spring to hypersaline conditions during the winter. Variations in salinity regimes among lagoons are modulated by ocean exchange characteristics and proximity to river mouths. Water… Read more »

Warming will increase nutrient cycling in soils, increasing its fertility and nutrient supplies to streams and lakes. Data from long term fertilization studies at ARC LTER are used to model tundra responses to climate change and disturbance. Long term phosphate fertilization has altered the Kuparuk River’s structure and function, but lake response to fertilization is… Read more »

Microbial communities decreased from soil, to streams, to lakes. About half of the common lake bacteria detected were rare species in soils and headwater streams. Initial inoculation from soils was followed by species sorting downslope. With warming, microbial trophic structure has become more homogenous across soil horizons, and plant biomass and woody plant dominance has… Read more »

Although air temperature at Toolik Lake is too variable for a warming trend to be statistically significant, several long term measures indicate warming. After 40 years, satellite data indicate “greening,” but plot re-harvesting in 2018 does not indicate an increase in shrub abundance. Alkalinity in Toolik Lake has doubled over 40 years, indicating deeper thaw,… Read more »

Dissolved organic carbon (DOC) released from thawing permafrost soil can be respired by microbes almost twice as fast if the DOC is first exposed to UV light. Arctic LTER long term data indicate that direct photochemical degradation of DOC from land is the dominant mechanism of DOC oxidation in streams and lakes.  

In 2007, a massive tundra fire released ~2 Pg of carbon into the atmosphere. Climate-driven fire may accelerate warming, potentially offsetting the effects of arctic greening. Long term effects of wildfire on tundra were assessed and incorporated into a model simulating recovery from fire and the loss of ~66 Gg of nitrogen. Tundra darkening caused… Read more »

Soil moisture dynamics were modeled using soil moisture data from the long term experimental landscapes at our North Desert Village experimental neighborhood. The relationship between irrigation schedules and plant stress differed by landscape type, which has implications for optimal irrigation regimes.