#deep lakes

[mumblelard]

grains of paradise reversed or bitrot waning

last night i dreamt of the job i had thirty years ago at the check processing center. when i woke up i could remember the names of the different jobs we ran and how the machines felt when they ran, but i couldn't remember the names of the four coworkers that died in the four years i worked there. still though, i could see the face of that red headed kid talking through the last hours of a friday shift about taking his motorcycle out for the first time after a long ohio winter and what he did instead was go home and kill himself with a shotgun. when i finally did fall back to sleep, all my dreams were filled with the lost

this post may self destruct

[mikeo56]

Mixing Is the Heartbeat of Deep Lakes. At Crater Lake, It’s Slowing Down. | Quanta Magazine

The physics of mixing water layers — an interplay of wind, climate and more — makes lakes work. When it stops, impacts can ripple across an

As the planet warms, summers are growing longer and winter nights aren’t getting as cold as they used to. As a result, the surfaces of many deep, temperate lakes are warming even faster than the air. This shift to the energy flux of the top layer of water can set in motion a series of physical changes that add up to a breakdown of lake mixing — a fundamental process that acts like a heartbeat for deep, temperate lakes that don’t freeze in winter. Lake mixing is driven by physical properties such as wind, air temperature, water temperature and salinity, and on seasonal or annual cycles it circulates water between the surface and the depths. When mixing stops, oxygen and nutrients don’t get distributed throughout the water column, which can kill fish, trigger unsightly and dangerous algal blooms and invite invasive species to take over.

From Italy to New Zealand and beyond, scientists have been alarmed to observe reduced lake mixing. In 2021, Chandra and his colleagues published evidence in Nature (opens a new tab) of greater stratification in the water column over time — an indicator of weaker mixing — in 84% of 189 temperate lakes for which they could find sufficiently long and robust datasets. Some lakes had stopped mixing altogether. “While each system is unique, the endgame is generally the same: a lack of mixing for these large, deep lakes,” Chandra said.

Of the world’s millions of lakes, Crater Lake is one of very few with a monitoring program that stretches back more than 40 years. Scientists are now beginning to realize how crucial those datasets are for unraveling lake physics and how climate change is altering it. “Because local weather can be extremely variable from year to year, it takes many years to capture the range in conditions and measure ‘normal,’” Girdner said. “Hence the advantage of long-term datasets.”

Crater Lake is therefore at the center of the first efforts by researchers, including Girdner and Chandra, to compare lake systems to get to the bottom of their breakdown, so they can prepare for the future and perhaps even ward off the most extreme impacts.

“Historically, people have studied lakes one at a time,” said Stephanie Hampton (opens a new tab), director of the Tahoe Environmental Research Center at the University of California, Davis. In light of how quickly things are changing, that siloed approach no longer works, she said. “We need to learn from each other and synthesize these data to understand what’s happening globally.”