Monday, November 5, 2012

Climate change impacts on Lake Tahoe

As a sailor on Lake Geneva over the last 7 years, I have noticed the warmer water temperatures, lower water levels, increased vegetation. Has anyone else noticed the effects of climate change here?

National Geographic reports on a study published about the climate changes impacts on Lake Tahoe. Given the similar characterics of Leman and Tahoe, I imagine the findings would be similar in Geneva. Has any work been done locally? The study also discusses measures to increase the lake's resilience to climate change.


Sailing on Lake Tahoe

Here is are two main impacts that the UC Davis scientists at Tahoe observed with their instruments.

1. Change in "stratification"
During a typical summer the lake becomes stratified, with warmer waters on top and cooler water at depth. In the winter these layers mix, a process that refreshes the lake and keeps it healthy.
The extended stratification season on Lake Tahoe has major implications for water quality. “A longer stratification period increases the risk of losing oxygen at the bottom of the lake,” Schladow explained, “and this can release a huge, almost infinite supply of phosphorus to the lake in a process known as internal loading.” Phosphorus is the limiting nutrient in Lake Tahoe. The more there is, the more algae can grow, causing a decline in water clarity.

Figure: Lake Tahoe Stratification Season. Source: TERC.

Figure: Lake Tahoe Stratification Season. Source: TERC.
2. Declining water clarity in the summer due to increased algae growth

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