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Glossary of Chemical Oceanography Terms
Photons: The packets of light energy emitted by the sun or the quantum of electromagnetic
radiation.
Photosynthetic Pigments: Pigments that absorb the photons contained in the chromatophores (i.e., chlorophyll).
Photosynthetic Quotient (PQ): Molecules of oxygen liberated/ molecules of carbon dioxide assimilated.
Photosynthetic Zone: The portion of the water column in which there is adequate light
penetration for photosynthesis to occur. Usually, 100 m is the maximum depth.
Phototrophic Organisms: Organisms whose primary form of obtaining energy is
photosynthesis.
Phytoplankton: Free- floating microscopic animals moving mostly in the confines of the
water column. They are responsible for the greatest amount of primary production in the sea.
Primary Productivity: Rate of inorganic carbon fixed photosynthetically per unit time
per unit volume or unit surface area. It is the result of the growth of organisms
from photosynthesis.
Productive Waters: Waters found in areas of high primary productivity; often highest in
coastal upwelling areas.
Radiant Energy: The energy produced by the sun’s light (measured in cal cm –2 min –1 ).
Reflection: One of the controlling factors in the amount of light that reaches the surface
of the earth. It involves a beam hitting a surface and being bounced back at a different angle, not adsorbed.
Respiration: The process by which energy required for metabolic process is obtained by
the oxidation of the photosynthesized organic compounds.
Respiration Quotient (RQ): Molecules of carbon dioxide liberated/ molecules of oxygen
assimilated.
Retardation Phase: The phase in the life cycle of an organism when a reduction occurs in
the growth rate because of depletion of nutrients, the presence of growth inhibitors, and reduction of photosynthesis brought about by shading.
Scattering: The diffusion of light in the ocean produced by particulate matter.
Solar Energy: Radiant energy in the form of photons obtained from the sun.
Spectral Composition: The wavelengths of the light present in the atmosphere.
Standing Crop: The amount of cells or phytoplankton in a given amount of seawater
(10 6 cells/ cm 3 ).
Stationary Phase: The phase in which metabolic activity is maintained yet there is no net
increase in living cells.
Ultraplankton: Phytoplankton ranging in size between 0.5 and 10 μm.
Upwelling: The process that brings nutrient- rich waters to the surface. The areas where
this occurs usually have the highest primary productivity.
Organic Compounds
Alcohols: Compounds with a hydroxyl group on a nonaromatic carbon atom. Low molecular weight alcohols are found in natural waters because of their large solubility.
Isoprenoid alcohols such as phytol are also widespread in marine waters.
Aldehydes: Contain the carbonyl group (H- C = O). Are very easily oxidized. Both aliphatic and aromatic aldehydes have been isolated from seawater and marine
sediments. Biogenic and photochemical oxidations of humic substances are the
primary origins of this class of organic compounds.
Glossary of Chemical Oceanography Terms
Photons: The packets of light energy emitted by the sun or the quantum of electromagnetic
radiation.
Photosynthetic Pigments: Pigments that absorb the photons contained in the chromatophores (i.e., chlorophyll).
Photosynthetic Quotient (PQ): Molecules of oxygen liberated/ molecules of carbon dioxide assimilated.
Photosynthetic Zone: The portion of the water column in which there is adequate light
penetration for photosynthesis to occur. Usually, 100 m is the maximum depth.
Phototrophic Organisms: Organisms whose primary form of obtaining energy is
photosynthesis.
Phytoplankton: Free- floating microscopic animals moving mostly in the confines of the
water column. They are responsible for the greatest amount of primary production in the sea.
Primary Productivity: Rate of inorganic carbon fixed photosynthetically per unit time
per unit volume or unit surface area. It is the result of the growth of organisms
from photosynthesis.
Productive Waters: Waters found in areas of high primary productivity; often highest in
coastal upwelling areas.
Radiant Energy: The energy produced by the sun’s light (measured in cal cm –2 min –1 ).
Reflection: One of the controlling factors in the amount of light that reaches the surface
of the earth. It involves a beam hitting a surface and being bounced back at a different angle, not adsorbed.
Respiration: The process by which energy required for metabolic process is obtained by
the oxidation of the photosynthesized organic compounds.
Respiration Quotient (RQ): Molecules of carbon dioxide liberated/ molecules of oxygen
assimilated.
Retardation Phase: The phase in the life cycle of an organism when a reduction occurs in
the growth rate because of depletion of nutrients, the presence of growth inhibitors, and reduction of photosynthesis brought about by shading.
Scattering: The diffusion of light in the ocean produced by particulate matter.
Solar Energy: Radiant energy in the form of photons obtained from the sun.
Spectral Composition: The wavelengths of the light present in the atmosphere.
Standing Crop: The amount of cells or phytoplankton in a given amount of seawater
(10 6 cells/ cm 3 ).
Stationary Phase: The phase in which metabolic activity is maintained yet there is no net
increase in living cells.
Ultraplankton: Phytoplankton ranging in size between 0.5 and 10 μm.
Upwelling: The process that brings nutrient- rich waters to the surface. The areas where
this occurs usually have the highest primary productivity.
Organic Compounds
Alcohols: Compounds with a hydroxyl group on a nonaromatic carbon atom. Low molecular weight alcohols are found in natural waters because of their large solubility.
Isoprenoid alcohols such as phytol are also widespread in marine waters.
Aldehydes: Contain the carbonyl group (H- C = O). Are very easily oxidized. Both aliphatic and aromatic aldehydes have been isolated from seawater and marine
sediments. Biogenic and photochemical oxidations of humic substances are the
primary origins of this class of organic compounds.