percent light intensity reduction equation

Photosynthesis varies in proportion to the light intensity up to a limit at which plants become light-saturated, and further increase of illumination produces no further increase of photosynthesis. In high latitudes in summer, the noon compensation depth commonly lies somewhere between 10 and 60 m, reducing to zero during the winter months when virtually no production occurs. In clear water in the tropics, the noon compensation depth may be well below 100 m throughout the year. The compensation depth obviously varies continually with changes of illumination, and must be defined with respect to time and place. Below the compensation depth there is no net production. the depth at which the rate of production of organic material by photosynthesis exactly balances the rate of breakdown of organic material by plant respiration. Photosynthesis is confined to the illuminated surface zone of the sea, and a useful measure of the extent of this productive layer is the compensation depth, i.e. The red and brown colours of many seaweeds are due to these additional pigments and seaweed depth distributions are related to the possession of these pigments. The possession of accessory red and yellowish pigments is important in extending the range of wavelengths which can be absorbed, presumably for energy transfer to chlorophyll a. Red light is rapidly absorbed by water consequently in aquatic plants the absorption of radiant energy by chlorophyll a must be mainly limited to the blue wavelengths. This pigment is green in colour because it absorbs light in the blue and red parts of the spectrum. It appears that chlorophyll a is the essential form for conversion of light energy to chemical energy. Diatoms and dinoflagellates also contain chlorophyll c together with various xanthophyll and carotenoid pigments which give a golden to brownish appearance to their chloroplasts. Chlorophyll occurs in several forms, but only chlorophyll a is common to all photosynthetic organisms. These are contained in organelles known as chloroplasts, except in blue-green algae and photosynthetic bacteria where they are diffused in the protoplasm. The ability of plants to absorb and utilize light in photochemical reactions is due to their possession of the green pigment chlorophyll and certain other accessory photosynthetic pigments. The efficiency of the ocean surface in thisĮnergy transformation must vary with locality and conditions, but is probably on average about 0.1-0.5 per cent overall, an efficiency a little lower than that of the land surface. Anti-reflection coatings are used to diminish the losses.In the process of photosynthesis the energy of solar radiation becomes fixed as chemical energy in organic compounds. The reflection loss at a single surface may seem small, but with multiple lenses, it becomes an unacceptable loss.

Since this contribution is proportional to the square and higher powers of the reflection coefficient, it can often be neglected. This calculation of the transmission is not exactly correct since it neglects the contribution from multiple internal reflections in the medium.

Reflected internally from second surface: % The reflection coefficients can be used to calculate the amount of light transmitted through a medium if the only losses are reflection losses.

Normally incident upon a medium of index n 2 = This normal incidence reflectivity is dependent upon the indices of refraction of the two media. For purposes such as the calculation of reflection losses from optical instruments, it is usually sufficient to have the reflectivity at normal incidence. The general expression for reflectivity is derivable from Fresnel's Equations. The reflectivity of light from a surface depends upon the angle of incidence and upon the plane of polarization of the light. Reflection Coefficient for Light Normal Reflection Coefficient

Percent light intensity reduction equation