Evidence supports that all of the molecular oxygen present in Earth’s
atmosphere today could have been produced in the last 2,000 years. Photosynthesis by
green plants, algae and related phytoplankton are the source of this atmospheric
molecular oxygen. Green plants are the “sugar factories of the world” and have
intricate microscopic systems within leaves that use sunlight, water, and carbon dioxide
to produce carbohydrates and oxygen. Capture of photons from sunlight requires a
complex array of pigments that include the green molecule chlorophyll. The photons
are captured via absorption by pigments that are organized sequentially in a specific
order within leaf structures called chloroplasts. Leaves have a complex, organized
macroscopic structure and an even more complex microscopic structure. This
organization begins with the shape and structure of the leaf itself. Leaves have an
aerodynamic shape that allows them to survive in wind and rain and are oriented to
capture sunlight. They have an outer waxy coating which retards water loss but with
provisions (stomata) that regulate entrance and efflux of carbon dioxide, oxygen, and
water vapor. The biosynthesis of carbohydrate from carbon dioxide requires energy
input, and the leaf has intricate mechanisms for capturing sunlight to make chemical
bonds in ATP. Great political turmoil recently has arisen over claims that carbon
dioxide in the atmosphere is the determining factor in increasing the global temperature
by amplifying the “greenhouse” effect. Based on speculation and questionable
computer models, man-made (anthropogenic) carbon dioxide is said to be the cause of
what initially was called “global warming”, but more recently has been changed to
“climate change”. The ability to scientifically measure photosynthesis globally has
become relevant for making intelligent decisions about climate change and atmospheric
CO2 concentration. There is reason to believe that natural (and/or future artificial)
photosynthesis can maintain the balance of atmospheric CO2.
Keywords: Aerobic life, Algae, Antennae, ATP, C3 plants, C4 plants, Calvin
Cycle, CAM plants, Carbon dioxide, Chlorophyll, Climate change, Desert plant, Enzyme, Leaf, Lysozyme, Melvin Calvin, Oxygen, Peroxisomes, Petagram,
Photosynthesis, Photosystem I, Photosystem II, Phytoplankton, RuBisCO, Stomata,
Sunlight, Thylakoid membrane, Transpiration, Water vapor.
