3.1.1 - biosphere  (Page 2/4)

Lithosphere

From: http://www.curriki.org/xwiki/bin/view/Coll_NROCscience/Lesson14TheLithosphereand PlateTectonics_0

The layer of the mantle above the asthenosphere plus the entire crust make up a region called the lithosphere. The lithosphere, and therefore, the earth'scrust, is not a continuous shell, but is broken into a series of plates that independently "float" upon the asthenosphere, much like a raft on the ocean.These plates are in constant motion, typically moving a few centimeters a year, and are driven by convection in the mantle. The scientific theory thatdescribes this phenomenon is called plate tectonics. According to the theory of plate tectonics, the lithosphere is comprised of some seven major plates andseveral smaller ones. Because these plates are in constant motion, interactions occur where plate boundaries meet.

http://www.flickr.com/photos/izzymunchted/3436486360/sizes/l/in/photostream/

Hydrosphere

From Open Source Earth Science Course ( www.opencollegetextbook.org )

The Hydrosphere contains all the water on Earth. As groundwater, the hydrosphere penetrates the soil as far down as bedrock, mostly limestone, or otherimpermeable layers. It is found in aquifers as groundwater and also between soil particles. As surface water, it is found in wetlands, marshes, estuaries,lakes, streams, rivers, lakes, seas, and oceans. In the atmosphere, water is found as a gas throughout the different regions. Water appears to permeate allthe other spheres.

The Hydrosphere extends upward to about 15 kilometers in the Earth's atmosphere and downward to depths on the order of five kilometers in its crust. Indeed,the abundance of water on Earth is a unique feature that clearly distinguishes our "Blue Planet" from others in the solar system. Not a drop of liquid watercan be found anywhere else in the solar system.

Though it cannot be found on any other planet, water is the most abundant inorganic substance at the surface of the Earth. About 1.4 billion cubickilometers of water in liquid and frozen form make up the oceans, lakes, rivers, streams, glaciers, and groundwater.

Atmosphere

The atmosphere, the gaseous layer that surrounds the earth, formed over four billion years ago. The earth's atmosphere extends outward to about 1,000kilometers where it transitions to interplanetary space. However, most of the mass of the atmosphere (greater than 99 percent) is located within the first 40kilometers. The sun and the earth are the main sources of radiant energy in the atmosphere. The sun's radiation spans the infrared, visible and ultravioletlight regions, while the earth's radiation is mostly infrared.

The vertical temperature profile of the atmosphere is variable and depends upon the types of radiation that affect each atmospheric layer. This, in turn,depends upon the chemical composition of that layer (mostly involving trace gases). Based on these factors, the atmosphere can be divided into fourdistinct layers: the troposphere, stratosphere, mesosphere, and thermosphere.