Lecture 4 - terrestrial and aquatic environments: aquatic life is defined by the physics of water. So you can only see red light in the first few metres, not after that. That"s why more colourful fish are found near the surface of the water, in coral reefs. The amount of light hitting the water influences temperature. The first 10m are warm because the water hits it directly, then there"s a thermocline where the water temperature changes the quickest. The thermocline is formed depending on the environment, location and conditions, i. e. different seasons. For example, in a stormy season, more water mixes so the temperature stays consistent and the cool water sinks decreasing the level of the thermocline. Thermocline is important because it affects biomass, i. e. the mixing of nutrient rich water. Fall turnover of temperature in lakes is due to loss of the thermocline, which is initiated by surface water cooling and sinking.