TED-Ed: Scientists are obsessed with this lake | Nicola Storelli and Daniele Zanzi

The video explores the impact of oxygen on Earth's atmosphere, leading to the Great Oxygen Catastrophe. It highlights environments where oxygen-averse microorganisms thrive, such as Lake Cadano in the Swiss Alps. This lake is unique due to its meromictic nature, with two distinct layers that never mix. The video delves into the chemical composition and ecological interactions within the lake, providing insights into early life evolution and the role of microorganisms. Scientists study these ecosystems to model pre-oxygen Earth and understand ancient biological processes.

What was the initial impact of oxygen on early life forms on Earth?

• It was a poisonous gas.

• It had no effect.

• It was a source of energy.

• It was a vital nutrient.

What is unique about the structure of Lake Cadano?

• It is a single body of water.

• It is completely oxygenated.

• It has a saltwater top layer.

• It consists of two distinct layers.

How does rainwater contribute to the formation of the anoxic layer in Lake Cadano?

• By directly entering the lake's top layer.

• By mixing with ocean water.

• By evaporating quickly.

• By seeping through dolomite and losing oxygen.

What role do anaerobic microorganisms play in Lake Cadano?

• They live in the top layer.

• They consume fish.

• They emit toxic sulfide.

• They produce oxygen.

Why is the study of Lake Cadano's ecosystem important for scientists?

• It helps model the world before the Great Oxygen Catastrophe.

• It offers a habitat for endangered fish species.

• It is a popular tourist destination.

• It provides a new source of drinking water.

What is bioconvection and why is it significant?

• A type of water pollution.

• A process of water evaporation.

• A phenomenon of microorganism movement.

• A method of fish migration.

How do Chromatium okani bacteria survive in Lake Cadano?

• By feeding on fish.

• By relying on oxygen.

• By living in the top oxygenated layer.

• By using sulfur for photosynthesis.