As shown in Figure 2, considerable heat is transferred towards north in the northern hemisphere, and towards south in the southern hemisphere by atmospheric flows and oceanic currents. Heat transport is more effective by the atmospheric flows than oceanic currents. This is because, in the atmosphere, heat is transferred by both the heat energy of air (sensible heat) and latent-heat energy of water vapor.
As we can see from the explanation above, the physical properties (large specific heat and evaporation-latent-heat) of water and its mobility equate the global thermal environment, and reduce the geographical variations. Through these functions, water contributes to form and to maintain the earth environment suitable for inhabitation of lines. This implies that water is not merely a resources but a factor to form the global environment. Therefore, water is the habitat itself for organisms.
3. Production of Plants/Foods and Water
1) Productivity of Natural Vegetation and Global Environment
Plant production is the fundamental basis of lives of all organisms on the Earth. This principle has been true for nearly 4 billion years of history of lives, and is considered to be true in future as well. This is why the chlorophytes, being the "plant producers", are called "Green Atlas" that quietly have supported and will continue to support all lives on the Earth.
The Green Atlas (Giant) receives the force to maintain all organisms from the solar radiation constantly supplied through the distance of 150 million kilometers in the space. The quantity of force is expressed as a net primary productivity (NPP, ton dry matter/ (ha・year)) calculated from the following equation.
NPP = GPP - R ... (3)
where GPP and R are the gross net primary productivity of plants and its respiration losses, respectively.
