Oceans, Seas, and Glaciers: Earth’s Water Systems
Oceans and Seas
Oceans are large bodies of water separating the continents. Planet Earth has five oceans; the largest is the Pacific, with its 180 million km2, larger in extent than all the continents combined. The other four are the Atlantic, Indian, Southern, and Arctic. Within the oceans, seas are areas near the coast, almost always located on the continental shelf.
Seafloor Relief
The average depth of the oceans is about four or five kilometers. This depth varies depending on the area:
- Continental
Human Health and Environmental Impact: A Comprehensive View
Human Health and Disease
The World Health Organization (WHO) defines health as a state of complete physical, mental, and social well-being, not merely the absence of disease. Given the agent that causes disease, diseases can be classified into:
- Infectious
- Non-infectious
Infectious Diseases
Infectious diseases are caused by a pathogen that enters the body and, in most cases, can spread to other people.
Non-infectious Diseases
In non-infectious diseases, a living organism is not directly involved in their
Read MoreWater Resources: Management and Industrial Applications
Water Supply
The oceans store 97.6% of natural water (water alone, in solid, liquid, or gas). The water available to organisms of terrestrial life represents only 0.5% of the total, most of it groundwater. While the amount of atmospheric water is relatively small, its rate of recycling in the atmosphere is relatively high, with an average atmospheric residence time of nine days. Therefore, atmospheric water vapor is renewed 40 times a year. The two human activities that consume more water are industrial
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Classification of Materials
Classification of materials: The most general classification of materials is as follows:
- Metal: Ferrous, Nonferrous
- Nonmetallic: Organic, Inorganic
Ferrous Metals
Ferrous metals, as its name suggests, its main component is iron. Its main features are its high tensile strength and hardness. The principal alloys are obtained with tin, silver, platinum, manganese, vanadium, and titanium.
The main products of representatives of metallic materials include gray iron castings, malleable
Read MoreEarth’s Dynamic Systems: Atmosphere, Tectonics, and Life’s Origins
The Earth: Atmospheric Changes
Some minor gases control climate and life. For example, water vapor, carbon dioxide, and methane are greenhouse gases, transparent to visible radiation from the sun but opaque to infrared. These gases trap heat emitted from the Earth, raising the Earth’s surface temperature over 30ºC. Without them, half of the atmosphere’s temperature would be -18ºC.
- Main components of the atmosphere: Nitrogen 78.1%, Oxygen 20.9%, and Argon 1%.
Why is There Liquid Water on Earth’s Surface?
Read MoreEarth’s Structure, Composition, and Geological Processes
Direct and Indirect Methods of Studying the Earth
Direct methods of study are those that provide testable data on what is being investigated. On the other hand, indirect methods are applied to obtain information when material objects cannot be manipulated directly.
Indirect Methods
Seismic Method
The seismic method involves the study of earthquakes and seismic waves, which are vibrations of the Earth’s crust recorded as waves on a seismograph. The waves that can be recorded are:
- P-waves: Primary or longitudinal