What is photosynthesis, and why does Sir David Attenborough describe it as 'the very basis of life?'. This album explains how the balance of sunlight, water and nutrients are fundamental to the process and how this balance acts to regulate individual ecosystems.  But photosynthesis is only part of the carbon cycle. How is carbon returned to the atmosphere, how do carbon containing gases influence the Earth's climate, and what role do peat bogs play in tackling global warming? This material forms part of The Open University course S396 Ecosystems.