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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.
The main elements that comprise the human body (including water) can be summarized as CHNOPS. Element Symbol percent mass percent atoms Oxygen O 65.0 24.0 Carbon C 18.5 12.0 Hydrogen H 9.5 62.0 Nitrogen N 2.6 1.1 Calcium Ca 1.3 0.22 Phosphorus P 0.6 0.22 Sulfur S 0.3 0.038 Potassium K 0.2 0.03 Sodium Na 0.2 0.037 Chlorine Cl 0.2 0.024 Magnesium Mg
If an animal (or human) eats only C3 plants, their δ 13 C values will be from −18.5 to −22.0‰ in their bone collagen and −14.5‰ in the hydroxylapatite of their teeth and bones. [16] In contrast, C4 feeders will have bone collagen with a value of −7.5‰ and hydroxylapatite value of −0.5‰.
The different isotope ratios for the two kinds of plants propagate through the food chain, thus it is possible to determine if the principal diet of a human or an animal consists primarily of C 3 plants (rice, wheat, soybeans, potatoes) or C 4 plants (corn, or corn-fed beef) by isotope analysis of their flesh and bone collagen (however, to ...
An increase in primary productivity causes a corresponding rise in δ 13 C values as more 12 C is locked up in plants. This signal is also a function of the amount of carbon burial; when organic carbon is buried, more 12 C is locked out of the system in sediments than the background ratio.
Carbon is a primary component of all known life on Earth, and represents approximately 45–50% of all dry biomass. [1] Carbon compounds occur naturally in great abundance on Earth. Complex biological molecules consist of carbon atoms bonded with other elements , especially oxygen and hydrogen and frequently also nitrogen , phosphorus , and ...
A gram of carbon containing 1 atom of carbon-14 per 10 12 atoms, emits ~0.2 [7] beta (β) particles per second. The primary natural source of carbon-14 on Earth is cosmic ray action on nitrogen in the atmosphere, and it is therefore a cosmogenic nuclide. However, open-air nuclear testing between 1955 and 1980 contributed to this pool.
The metal, or various compounds, can be toxic to humans. [13] In plants, aluminum can be the primary limitation on growth in acidic soils. [14] antimony: 51: 2c: Has no known biological role, but has a variety of uses in medicine, e.g. antibacterial. [15] Some compounds are highly toxic to humans. [11] argon: 18: 2: None known. [11] None known ...