Notable books in the design pattern genre include: 1  Gamma, Erich; Helm, Richard; Johnson, Ralph; Vlissides, John (1995). 2  Brinch Hansen, Per (1995). 3  Buschmann, Frank; Meunier, Regine; Rohnert, Hans; Sommerlad, Peter (1996). 4  Schmidt, Douglas C.; Stal, Michael; Rohnert, Hans; Buschmann, Frank (2000). 5  Fowler, Martin (2002).
Answer 1: The oxygen that we currently find in the air has two main sources. The first, and major, source is that oxygen is liberated as a by-product of photosynthetic chemical reactions. The second source occurs in the atmosphere itself when water molecules are split apart after being struck with ultraviolet radiation. This process is called photolysis. The molecule is broken down into one diatomic hydrogen molecule and one free oxygen. The hydrogen molecule is light, and has a quick thermal velocity,so it can escape Earth's atmosphere leaving behind the free oxygen to form a diatomic oxygen molecule. The main source of this atmospheric water was volcanic eruptions and outgassing. Basically before photosynthesis began on large scales, free oxygen molecules in the atmosphere were drawn down in oxidation reactions with free metal ions on the Earth's surface, mainly iron.
An adequate supply of dissolved oxygen gas is essential for the survival of aquatic organisms. A deficiency in this area is a sign of an unhealthy river. There are a variety of factors affecting levels of dissolved oxygen. The atmosphere is a major source of dissolved oxygen in river water.Waves and tumbling water mix atmospheric oxygen with river water. Oxygen is also produced by rooted aquatic plants and algae as a product of photosynthesis. There are physical factors that can lessen the amount of oxygen dissolved in the Cuyahoga.aves and tumbling water mix atmospheric oxygen with river water. Oxygen is also produced by rooted aquatic plants and algae as a product of photosynthesis. There are physical factors that can lessen the amount of oxygen dissolved in the Cuyahoga.