Chemical oceanography
Encyclopedia
Chemical oceanography is the study of ocean chemistry
: the behavior of the chemical element
s within the Earth
's ocean
s. The ocean is unique in that it contains - in greater or lesser quantities - nearly every element
in the periodic table
.
Much of chemical oceanography describes the cycling
of these elements both within the ocean and with the other spheres of the Earth system (see biogeochemical cycle
). These cycles are usually characterised as quantitative flux
es between constituent reservoirs defined within the ocean system and as residence time
s within the ocean. Of particular global and climatic
significance are the cycles of the biologically active elements such as carbon
, nitrogen
, and phosphorus
as well as those of some important trace elements such as iron
.
Another important area of study in chemical oceanography is the behaviour of isotopes (see isotope geochemistry
) and how they can be used as tracers of past and present oceanographic and climatic processes. For example, the incidence of 18O (the heavy isotope of oxygen) can be used as an indicator of polar ice sheet
extent, and boron
isotopes are key indicators of the pH
and CO2
content of oceans in the geologic past.
Ocean chemistry
Ocean chemistry, also known as marine chemistry, is influenced by turbidity currents, sediments, pH levels, atmoshperic constituents, metamorphic activity, and ecology...
: the behavior of the chemical element
Chemical element
A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...
s within the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
's ocean
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...
s. The ocean is unique in that it contains - in greater or lesser quantities - nearly every element
Chemical element
A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...
in the periodic table
Periodic table
The periodic table of the chemical elements is a tabular display of the 118 known chemical elements organized by selected properties of their atomic structures. Elements are presented by increasing atomic number, the number of protons in an atom's atomic nucleus...
.
Much of chemical oceanography describes the cycling
Biogeochemical cycle
In ecology and Earth science, a biogeochemical cycle or substance turnover or cycling of substances is a pathway by which a chemical element or molecule moves through both biotic and abiotic compartments of Earth. A cycle is a series of change which comes back to the starting point and which can...
of these elements both within the ocean and with the other spheres of the Earth system (see biogeochemical cycle
Biogeochemical cycle
In ecology and Earth science, a biogeochemical cycle or substance turnover or cycling of substances is a pathway by which a chemical element or molecule moves through both biotic and abiotic compartments of Earth. A cycle is a series of change which comes back to the starting point and which can...
). These cycles are usually characterised as quantitative flux
Flux
In the various subfields of physics, there exist two common usages of the term flux, both with rigorous mathematical frameworks.* In the study of transport phenomena , flux is defined as flow per unit area, where flow is the movement of some quantity per time...
es between constituent reservoirs defined within the ocean system and as residence time
Residence time
Residence time is the average amount of time that a particle spends in a particular system. This measurement varies directly with the amount of substance that is present in the system....
s within the ocean. Of particular global and climatic
Climate
Climate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and other meteorological elemental measurements in a given region over long periods...
significance are the cycles of the biologically active elements such as carbon
Carbon cycle
The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth...
, nitrogen
Nitrogen cycle
The nitrogen cycle is the process by which nitrogen is converted between its various chemical forms. This transformation can be carried out by both biological and non-biological processes. Important processes in the nitrogen cycle include fixation, mineralization, nitrification, and denitrification...
, and phosphorus
Phosphorus cycle
The phosphorus cycle is the biogeochemical cycle that describes the movement of phosphorus through the lithosphere, hydrosphere, and biosphere. Unlike many other biogeochemical cycles, the atmosphere does not play a significant role in the movement of phosphorus, because phosphorus and...
as well as those of some important trace elements such as iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
.
Another important area of study in chemical oceanography is the behaviour of isotopes (see isotope geochemistry
Isotope geochemistry
Isotope geochemistry is an aspect of geology based upon study of the relative and absolute concentrations of the elements and their isotopes in the Earth. Variations in the abundance of these isotopes, typically measured with an isotope ratio mass spectrometer or an accelerator mass spectrometer,...
) and how they can be used as tracers of past and present oceanographic and climatic processes. For example, the incidence of 18O (the heavy isotope of oxygen) can be used as an indicator of polar ice sheet
Ice sheet
An ice sheet is a mass of glacier ice that covers surrounding terrain and is greater than 50,000 km² , thus also known as continental glacier...
extent, and boron
Boron
Boron is the chemical element with atomic number 5 and the chemical symbol B. Boron is a metalloid. Because boron is not produced by stellar nucleosynthesis, it is a low-abundance element in both the solar system and the Earth's crust. However, boron is concentrated on Earth by the...
isotopes are key indicators of the pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
and CO2
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
content of oceans in the geologic past.
See also
- Anoxic eventAnoxic eventOceanic anoxic events or anoxic events occur when the Earth's oceans become completely depleted of oxygen below the surface levels. Although anoxic events have not happened for millions of years, the geological record shows that they happened many times in the past. Anoxic events may have caused...
- Anoxic sea waterAnoxic sea waterAnoxic waters are areas of sea water or fresh water that are depleted of dissolved oxygen. This condition is generally found in areas that have restricted water exchange....
- Hypoxia (environmental)Hypoxia (environmental)Hypoxia, or oxygen depletion, is a phenomenon that occurs in aquatic environments as dissolved oxygen becomes reduced in concentration to a point where it becomes detrimental to aquatic organisms living in the system... - Climate changeClimate changeClimate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...
- Dead zone (ecology)Dead zone (ecology)Dead zones are hypoxic areas in the world's oceans, the observed incidences of which have been increasing since oceanographers began noting them in the 1970s. These occur near inhabited coastlines, where aquatic life is most concentrated...
- Global Ocean Data Analysis ProjectGlobal Ocean Data Analysis ProjectThe Global Ocean Data Analysis Project is a synthesis project bringing together oceanographic data collected during the 1990s by research cruises on the World Ocean Circulation Experiment , Joint Global Ocean Flux Study and Ocean-Atmosphere Exchange Study programmes...
- OceanographyOceanographyOceanography , also called oceanology or marine science, is the branch of Earth science that studies the ocean...
- Physical oceanographyPhysical oceanographyPhysical oceanography is the study of physical conditions and physical processes within the ocean, especially the motions and physical properties of ocean waters.Physical oceanography is one of several sub-domains into which oceanography is divided...
- World Ocean AtlasWorld Ocean AtlasThe World Ocean Atlas is a data product of the Ocean Climate Laboratory of the National Oceanographic Data Center . The WOA consists of a climatology of fields of in situ ocean properties for the World Ocean...