Answer
The energy flow system in the lakes is controlled by the manner aquatic organisms interact with each other.
Explanations
In lakes and ponds there is transfer and flow of energy that depends on the manner aquatic organisms interact with each other. For example, In a simple aquatic food web, phytoplankton in form of algae and aquatic macrophytes in form of plants obtain energy from the sun and convert it to energy they can use through photosynthesis. During this process, carbon dioxide, water, sugars and energy from the sun is utilized to form organic compounds in form of chemical energy. This chemical energy is then utilized for growth and reproduction.