Lakes release large amounts of CO2, now we know why

We do not even understand all the natural sources of CO2 very well!

Global Warming is a hoax and Climate Change is a religion!

"A new study has uncovered the missing science behind why some lakes around the world emit such large amounts of carbon dioxide (CO2).

Lakes are unlikely sources of substantial amounts of greenhouse gas emissions. But the exact mechanisms at work hadn’t been fully understood ...

The study was based around Lake Geneva, which borders France and Switzerland, and is one of western Europe’s largest lakes.

“Our results not only explain the carbon cycle in Lake Geneva, they also reveal a universal process that applies to several of the world’s great lakes,” ...

They found that when bedrock in Lake Geneva’s catchment is exposed to rainwater it releases bicarbonate and calcium ions, which flow into the lake.

In the summertime, heat and algal growth change the pH of the water and catalyse a chemical reaction which turns these ions into microparticles of calcium carbonate. This is known as calcite precipitation, and the reaction also releases CO2. ..."

From the abstract:

"Lakes emit substantial amounts of carbon dioxide (CO2) into the atmosphere, but why they do remains debated. The long-standing vision of lakes as solely respirators of the organic matter leaking from the soils has been challenged by evidence that inorganic carbon produced by weathering of the catchment bedrock could also support lake CO2 emissions. How inorganic carbon inputs ultimately generate lake CO2 outgassing remains a blind spot. We develop and introduce a calcite module in a coupled one-dimensional physical-biogeochemical model that we use to simulate the carbon cycle of the large Lake Geneva over the past 40 years. We mechanistically demonstrate how the so-far neglected process of calcite precipitation boosts net CO2 emissions at the annual scale. Far from being anecdotal, we show that calcite precipitation could explain CO2 outgassing across various lakes globally, including some of the largest lakes in the world."

Lakes release large amounts of CO2, now we know why

Calcite precipitation: The forgotten piece of lakes’ carbon cycle (open access)

Fig. 3. CO2 supersaturation as a function of alkalinity level.