The response of Lake Tahoe to climate change

Abstract

A temperate deep lake, Lake Kuttara, Hokkaido 148 m depth at the deepest point was completely frozen in winter in the 20 th century. However, non-freezing of the lake over winter occurred four times in the 21 st century, which is probably due to global warming. In order to understand how thermal regime of the lake responds to climate change, its heat storage was calculated by estimating heat budget of the lake and monitoring water temperature at the deepest point for 1 June 2014-31 May 2016. As a result, the temporal variation of heat storage from the heat budget was very consistent with that from the direct temperature measurement the determination coefficient R 2 = 0.903. A sensitivity analysis was conducted by numerically changing main meteorological factors air temperature, solar radiation, wind speed, precipitation for the heat storage obtained from the heat budget estimate. The increase in air temperature and precipitation was very effective to increase the heat storage. It is noted that, considering the increasing rate of air temperature 0.024°C/yr , the lake could be permanently unfrozen in about two decades.

Refractory dissolved organic nitrogen accumulation in high-elevation lakes

“…With this in mind, the production flux for refractory proteins was calculated and compared with annual atmospheric N loading (148,000 kg; ref. 56). Using LT SPE-DOM recoveries and C:N values, the lake's DON inventory is estimated at B5 Â 10 6 kg N (Table 1; Supplementary Table 4).…”

“…There is considerable evidence that lake environments will be impacted under future climate change scenarios 12,56 . Changes in seasonality and characteristics of hydraulic inputs could alter the quality and quantity of terrestrial organic matter reaching highelevation lakes, with potential repercussions for DOM cycling as well as ecosystem health.…”

“…Changes in seasonality and characteristics of hydraulic inputs could alter the quality and quantity of terrestrial organic matter reaching highelevation lakes, with potential repercussions for DOM cycling as well as ecosystem health. Projections for LT also show that increased stratification will likely reduce nutrient entrainment from depth into surface waters 56 , which may further alter phytoplankton and bacterial community composition. Future investigations of the response of aquatic and terrestrial ecosystems to global change should consider the potential for DOM dynamics to impact nutrient availability and carbon storage.…”

“…Samples are regularly collected in close proximity to the LT TB-4 collection site and measured for nitrate and chlorophyll concentrations by the UC Davis Tahoe Environmental Research Center 15,56,70 .…”

Climate Change Impacts on US Water Quality Using Two Models: HAWQS and US Basins

“…Evidence of rising river and lake temperatures [3,4] (pp. 1-5), and decreased mixing of lakes and reservoirs (i.e., increased stratification) [5,6] have already been observed. There is an economic value associated with these changes in water quality, measured in terms of changes in the quality of recreation opportunities and commercial activity.…”