Ep 3. Freshwater

In Planet Earth season 1 episode 3, titled Freshwater, viewers are taken on a journey through the diverse ecosystems that make up our planet's freshwater systems. Narrated by Sir David Attenborough, the episode explores the vital role that freshwater plays in shaping the lives of various animal species, and how humans have affected these ecosystems over time.

The episode begins in the frozen wilderness of the Arctic, where we witness the mystical beauty of one of the Earth's largest lakes – the Baikal. Here, viewers gain insight into how this magnificent natural wonder has remained untouched by human interference, and how animals such as the Baikal seal have adapted to its unforgiving environment.

Moving on, we head to Africa's Great Rift Valley, where viewers are introduced to a unique species - the African fish eagle, whose diet is entirely dependent on the abundance of freshwater. The episode highlights the impact of droughts on this ecosystem, and shows how animals like the African fish eagle are forced to migrate in search of sustenance.

Transitioning to the Amazonian freshwater systems, the episode showcases the incredible diversity of life that exists in these complex ecosystems. From the mighty Amazon River, which is home to the world's largest freshwater fish - the arapaima - to the blackwater forests of the Amazon's tributaries, viewers are treated to an array of incredible sights.

As the episode progresses, viewers are introduced to the impacts of human activities such as damming in freshwater ecosystems. This is exemplified by the Colorado River, where viewers see the devastating effect of its damming on the natural balance of its ecosystem. Additionally, the episode provides insight into how the Amazon Rainforest's demise could lead to catastrophic effects on the entire planet, as it is one of the primary carbon sinks on Earth.

Towards the end of the episode, viewers are taken on a journey to hidden underground rivers. Here, plants and animals have evolved unique adaptations to survive and thrive in pitch-black environments with no access to sunlight. The episode ends with a reminder of how critically important freshwater is, and how necessary it is to protect these fragile ecosystems.

Overall, Planet Earth season 1 episode 3 – Freshwater- provides a window into the invisible worlds and diverse ecosystems that make up our planet's freshwater systems, and underscores the prudence of preserving them for future generations. It is a must-watch for nature enthusiasts who want to gain insight into some of the planet's most unique environments and the organisms that call them home.