Lake Tahoe and Global Warming?

Question

I just read where Global Waming is responsible for hindering the "deep mixing" of the lake's waters. And that in about a decade the blue lake will turn green.

Some please explain to me HOW THIS HAPPENS. What does the evil global warming have to do with it???

Answer 1

If it turns green, I would suspect it would be from pollutants, i.e. nitrates and phosphate, that would increase the plankton.  That is what the green is.

Answer 2

water mixes in winter. in hot weather the top water warms and this means it tends to stay at the top and you get stratification and stagnation. warmer it gets, more this will happen.

http://www.ingentaconnect.com/content/kl...

Answer 3

It's discussed in the article.

"What we expect is that deep mixing of Lake Tahoe's water layers will become less frequent, even nonexistent, depleting the bottom waters of oxygen," said Geoffrey Schladow, director of the Tahoe Environmental Research Center at U.S. Davis.

On average, water in Lake Tahoe — at 1,644 feet deep — mixes every four years, the researchers said.

The water circulation brings nutrients from the bottom to the surface where they promote algae growth. Oxygen from the surface, meanwhile, is spread through the lake and supports aquatic life.

The new study showed that, if global greenhouse-gas emissions continue at current levels, mixing could become less frequent and less deep, and possibly stop as early as 2019.

"While we expected that the lake would mix less in the future, learning that we may be only a decade or two from the complete shutdown of deep mixing was very surprising." Schladow said.

"If mixing shuts down, then no new oxygen gets to the bottom of the lake, and creatures that need it, such as lake trout, will have a large part of their range excluded," Schladow said.

When the oxygen is gone, the study said phosphorus contained in lake-floor sediments would be released and spur algae growth, further damaging the lake's clarity and water quality."