Photosynthesis forests, tropical

When the so-called fossil fuels such as coal and petroleum are used a large amount of carbon dioxide is released, resulting in an increase of carbon dioxide in the atmosphere. As carbon dioxide is a gas with an influence on the greenhouse effect, its increase in the atmosphere results in the raising of the temperature on the surface of Earth. Therefore the increase of carbon dioxide in the atmosphere should be curtailed. It is usually thought that most carbon dioxide in the atmosphere is consumed by plants on the land. Of course this idea is not incorrect the tropical rain forests of the Amazonian area, Kalimantan (Borneo) and some other areas consume much of the carbon dioxide in the atmosphere. However, it should be kept in mind that the consumption of the gas by algae and cyanobacteria in the ocean is also sizable. Some researchers say that 70% of carbon dioxide in the atmosphere is consumed by the photosynthesis of algae and cyanobacteria in the oceans. 

Thiele A, Krause GH and Winter K (1998) In situ study of photoinhibition of photosynthesis and xanthophyll cycle activity in plants growing in natural gaps of the tropical forest. Austr J Plant Physiol 25 189-195... 

Coffee grows naturally In the understory of the wet tropical forest and bears some physiological characteristics of a shade plant (1). Air humidity is certainly an important factor in the devellopment of the plant,but the basic information on this topic is very short. In sequence of previous work ( 2) this, presents more data showing that low air humidity is a stress factor on photosynthesis and suggests that it affects not only stomatal conductance but chemical characteristics of the mesophyll related with photosynthesis. 

Seasonal fluctuations are primarily due to summertime maxima and wintertime minima in the net rate of photosynthesis, which removes CO2 from the atmosphere. The long-term trend, however, is clearly upward, and reflects anthropogenic releases of carbon dioxide from fossil fuel combustion, land alteration (in large part, the clearing and burning of tropical forests for agriculture), and, to a lesser extent, cement production. 

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