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The iron cycle is an important component of the terrestrial ecosystems. The ferrous form of iron, Fe 2+, is dominant in the Earth's mantle, core, or deep crust. The ferric form, Fe 3+, is more stable in the presence of oxygen gas. [22] Dust is a key component in the Earth's iron cycle.
The human body needs iron for oxygen transport. Oxygen (O 2) is required for the functioning and survival of nearly all cell types. Oxygen is transported from the lungs to the rest of the body bound to the heme group of hemoglobin in red blood cells. In muscles cells, iron binds oxygen to myoglobin, which regulates its release.
Iron-60 has a half-life of 2.6 million years, [12] [13] but was thought until 2009 to have a half-life of 1.5 million years. It undergoes beta decay to cobalt-60 , which then decays with a half-life of about 5 years to stable nickel-60.
Iron can also be oxidized by marine microbes under conditions that are high in iron and low in oxygen. [53] Iron can enter marine systems through adjoining rivers and directly from the atmosphere. Once iron enters the ocean, it can be distributed throughout the water column through ocean mixing and through recycling on the cellular level. [54]
Archaeological materials, such as bone, organic residues, hair, or sea shells, can serve as substrates for isotopic analysis. Carbon, nitrogen and zinc isotope ratios are used to investigate the diets of past people; these isotopic systems can be used with others, such as strontium or oxygen, to answer questions about population movements and cultural interactions, such as trade.
In geochemistry, paleoclimatology and paleoceanography δ 18 O or delta-O-18 is a measure of the deviation in ratio of stable isotopes oxygen-18 (18 O) and oxygen-16 (16 O). It is commonly used as a measure of the temperature of precipitation, as a measure of groundwater/mineral interactions, and as an indicator of processes that show isotopic fractionation, like methanogenesis.
Of the different isotopes that exist, one common classification is distinguishing radioactive isotopes from stable isotopes. Radioactive isotopes are isotopes that will decay into a different isotope. For example, 3 H is a radioactive isotope of hydrogen. It decays into 3 He with a half-life of ~12.3 years.
Trace metal stable isotope biogeochemistry is the study of the distribution and relative abundances of trace metal isotopes in order to better understand the biological, geological, and chemical processes occurring in an environment. Trace metals are elements such as iron, magnesium, copper, and zinc that occur at low levels in the environment ...