The Atmosphere and The Oceans
                                     
   
Our Biosphere
  
Blue Hotel
  
               
       
                             
               
                             
        Arctic ice shelf splits
       
                       
 
                       
   
                       
 
                       
  Origin of the Earth's Atmosphere
                       
     
             
                                         
        Origin of atmospheric oxygen

    Free oxygen is never more than a trace component of most planetary atmospheres. Thermodynamically, oxygen is much happier when combined with other elements as oxides; the pressure of O2 in equilibrium with basaltic magmas is only about a ten millionth of an atmosphere. Photochemical decomposition of gaseous oxides in the upper atmosphere is the major source of O2 on most planets. On Venus, for example, CO2 is broken down into CO and O2. On the earth, the major inorganic source of O2 is the photolysis of water vapor; most of the resulting hydrogen escapes into space, allowing the O2 concentration to build up. An estimated 20 billion grams of O2 per year is generated in this way. Integrated over the earth’s history, this amounts to less than 3% of the present oxygen abundance. The partial pressure of O2 in the prebiotic atmosphere is estimated to be no more than 0.001 atm, and may have been several orders of magnitude less. The major source of atmospheric oxygen on the earth is photosynthesis carried out by green plants and certain bacteria: 		     
                                         
                 
                                         
      The Cells that Rule the Seas
Sallie Chisholm
The Invisible Forest

Prochlorococcus
    
                                         
            Flow cytometry is the measurement (meter) of characteristics of single cells (cyto) suspended in a flowing saline stream. A focussed beam of laser light hits the moving cell and light is scattered in all directions. Detectors placed forward of the intersection point or side-on (with respect to the laser beam) receive the pulses of scattered light and they are converted into a form suitable for computer analysis and interpretation. The total amount of forward scattered light detected is closely correlated with cell size, whereas the amount of side scattered light can indicate nuclear shape or cellular granularity.



Exxon rep: CO2 output to rise 50 percent by 2020  from Tim Nau 		   
                                         
Structure of the Atmosphere  
               
In large measure, the atmosphere has evolved in response to and controlled by life processes. It continues to change as a consequence of human activities, but at a rate that is far in excess of the rate of previous evolutionary change. The atmosphere controls the climate and ultimately determines the quality of life on Earth.
 
               
                                 
                                 
GreenHouse Effect
    The gases in the atmosphere that help retain heat are called greenhouse gases. These gases, primarily carbon dioxide (CO2), absorb heat instead of allowing it to escape into space. This "greenhouse effect" makes the planet a hospitable place. However, greenhouse gases can have negative effects, too. Human activity has increased the amount of CO2 in the atmosphere.
     Since the 1800s, industrialized societies have burned fossil fuels such as coal, oil, and natural gas; these processes all give off CO2. During the past 25 years, the amount of CO2 in the atmosphere has increased by about 8 percent. With more CO2 in the atmosphere, more heat is absorbed and retained, causing global temperatures to rise. Some scientists project that by the next century, CO2 levels in the atmosphere could be twice what they are today, causing a global temperature increase of about 3 degrees. Three degrees may not seem like much, but even a few degrees can have serious consequences. Tropical diseases could increase, since mosquitoes and other disease-carrying insects thrive in a warmer climate. Sea levels could rise, and coastal cities such as New Orleans and Washington, D.C., could be battered by storm surges. Prosperous farmland could dry up and agricultural regions could shift, wreaking havoc on the global economy.
   
               
    It is possible that the recent warming trend is due more to natural cycles of cooling and warming than to human activity. Global climate change occurs on a scale of tens or hundreds of thousands of years, but scientists have only begun to study these effects in the last 150 years. Still, most scientists agree that just as climate affects our lives, we can affect the climate. Just how much we can influence it remains to be seen.
               
                                         
The climatic effects of water vapour
Physics World
by Ahilleas Maurellis and Jonathon Tennyson		  
The Earth Radiation Budget Experiment (ERBE)
. . .but, I thought it was the CO2 that was the culprit?
   
                 
                    

     
   
Solar Energy