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[[File:C-14.png|350px|thumb|right|Carbon-14 atom with 6 protons, 8 neutrons, and 6 electrons [1]]]
[[File:C-14.png|350px|thumb|right|Carbon-14 atom containing 6 protons, 8 neutrons, and 6 electrons]]


==''' Overview '''==
==''' Overview '''==


Carbon-14, also referred to as <sup>14</sup>C or radiocarbon, is one of the three naturally occurring isotopes of carbon in nature. <sup>14</sup>C is unstable, and has a half-life of 5700 +/- 30 years [1]. The other two forms of carbon are <sup>12</sup>C, which is what makes up 98% of all carbon in the atmosphere, and <sup>13</sup>C, which makes up around 1% of atmospheric carbon. Both <sup>12</sup>C and <sup>13</sup>C are stable isotopes, while <sup>14</sup>C is unstable. Within the context of [[ecology]], <sup>14</sup>C is used in two main processes: dating organic materials and tracing carbon pathways within ecosystems.
Carbon-14, also referred to as <sup>14</sup>C or radiocarbon, is one of the three naturally occurring isotopes of carbon in nature. <sup>14</sup>C is unstable, and has a half-life of 5700 +/- 30 years [1]. The other two forms of carbon are <sup>12</sup>C, which is what makes up 98% of all carbon in the atmosphere, and <sup>13</sup>C, which makes up around 1% of atmospheric carbon. Both <sup>12</sup>C and <sup>13</sup>C are stable isotopes, while <sup>14</sup>C is unstable. It only occurs in trace amounts naturally, around 1 <sup>14</sup>C atom for every 7.54 x 10<sup>11</sup> atoms of <sup>12</sup>C in the atmosphere. Within the context of [[ecology]], <sup>14</sup>C is used in two main processes: dating organic materials and tracing carbon pathways within ecosystems [2].


== Uses ==
== Uses ==
[[File:fmicb-09-01636-g002.jpg|thumb|left|EPS works at the smallest levels of soil aggregate formation[Costa et al. 2018]]]
[[File:TreeDating.jpg|300px|thumb|left|Cross dating tree rings [3]]]
===Tree Ring Dating===
===Tree Ring Dating===
The suspected primary role of EPS is to create stable habitat bound to a desired substrate<ref name=Flemming_2016 />. EPS is the matrix structure of biofilms. Biofilms are very effective at retaining water in soils even with very negative water potentials.<ref name=Or_2007 /> This allows microbes to resist desiccation during drought periods. EPS can also stabilize pH and reduce the amount of nutrients lost to runoff by binding to them.
<sup>14</sup>C is found in the atmosphere, and although it occurs in trace amounts, it will be absorbed by trees like any other form of carbon.
The science of dendochronology heavily relies on <sup>14</sup>C. Scientists are able to compare the tree rings of similar species growing in similar environments and match up their ages based on their rings [4]. From there, the <sup>14</sup>C content in each tree ring can be matched to the tree's age and year it was growing. Since the amount of <sup>14</sup>C in the atmosphere changes over time, scientists are also able to use the <sup>14</sup>C content in each tree ring to relate it to the atmospheric conditions at the time the tree was growing. Because of all of this data, it is possible to know the tree-ring chronologies for the past 12,400 years [5].


===Carbon-14 Tracing===
===Carbon-14 Tracing===
EPS provides a stable interface for [[soil]] microbes to chemically work on attached substrate and suspended materials. In addition EPS can act as a store of carbon and other nutrients. The binding nature of EPS also helps reduce nutrient loss in soils from runoff.<ref>Lin, D., Ma, W., Jin, Z., Wang, Y., Huang, Q., Cai, P., 2016. Interactions of EPS with soil minerals: A combination study by ITC and CLSM. Colloids and Surfaces B: Biointerfaces 138, 10–16. https://doi.org/10.1016/j.colsurfb.2015.11.026</ref>
<sup>14</sup>C forms naturally in the atmosphere as a result of cosmic radiation. As it moves through the atmosphere, <sup>14</sup>C reacts with oxygen and forms CO<sub>2</sub>. That CO<sub>2</sub> will then be absorbed by trees to be converted into sugars that the tree uses for energy [6]. The <sup>14</sup>C becomes a part of the tree's tissue as it is absorbed. It may also be shunted to other trees via mycorrhizal fungi. In her book ''Finding The Mother Tree'', Suzanne Simard used this method to track the path of carbon through the trees' root systems, and prove that trees exchange <sup>14</sup>C through micorrhizal pathways [7]. This discovery of the vast networks of mycorrhizal has contributed greatly to forestry as a whole.


[[File:HowTreesTalk.jpg|376px|thumb|right|Theoretical functions of soil EPS<ref name=Costa_2018 />]]
[[File:HowTreesTalk.jpg|376px|thumb|right|Suzanne Simard's drawing of carbon tracking through tree root systems [8]]]
===Hydrology===
EPS affects evaporation and flow of water directly and through alterations to the functional soil structure. EPS resists evaporation and slows flow by absorbing and binding water tightly. Also, the biofilm structures formed with EPS can cause bioclogging of pores which blocks evaporation and mass flow of water by reducing the hydraulic conductivity<ref name=Deng_2015 /><ref name=Or_2007 />. This slows the overall rate of change in soil moisture content making for a more stable environment.


===[[Soil Structures]]===
==Analysis methods==
EPS production fills pore space which reduces the effective [[porosity]] of the soil. Also, the swelling shrinking actions of EPS water intake and loss can alter the pore space but there remains a lack of literature differentiating this effect in bulk soil<ref name=Deng_2015 />.
The majority of <sup>14</sup>C analysis is used in determining ages of organic materials. <sup>14</sup>C can also tell information on [[soil]] carbon cycles find in soil trophic relationships. Analysis of <sup>14</sup>C in atmospheric and terrestrial environments is essential for understanding climate and soil environments. Through this analysis and the use of <sup>14</sup>C, we can predict possible future environmental impacts and global climate change in ecosystems [9].
EPS plays a key role in soil [[aggregate formation]] by working as a cementing agent. This has the added effect of reducing soil slaking and increasing overall stability. This added stability can lower erosion rates and decrease nutrient runoff.


===Plants===
==References==
EPS play a role in holding microbes to roots or in the [[rhizosphere]] and act as the medium for symbiotic microbes to exchange nutrients in exchange for root exudates<ref name=Costa_2018 />. The microbes, through the effects of EPS and release of nutrients, stimulate the the exudate release by the roots which introduces fresh carbon sources to the rhizosphere. There is also evidence to suggest EPS assists in salinity tolerance for some plants.<ref name=Ashraf_2004>Ashraf, M., Hasnain, S., Berge, O., Mahmood, T., 2004. Inoculating wheat seedlings with exopolysaccharide-producing bacteria restricts sodium uptake and stimulates plant growth under salt stress. Biol Fertil Soils 40. https://doi.org/10.1007/s00374-004-0766-y</ref>
<p>[1] Stark, A. M. (n.d.). Atmospheric carbon-14 measurements reveal natural production rate by cosmic rays | Lawrence Livermore
National Laboratory. https://www.llnl.gov/article/42086/atmospheric-carbon-14-measurements-reveal-natural-production-rate-cosmic-rays.


===Agriculture===
<p>[2] Cain, W. F., and H. E. Suess. 1976. Carbon 14 in tree rings. Journal of Geophysical Research (1896-1977) 81:3688–3694.
There is growing interest in using EPS producing bacteria in agricultural settings. EPS improves soil particle aggregation which is an issue common to traditional agricultural practices in may parts of the world. Also, EPS producing bacteria improve nutrient availability to plants, increase water stability, and stimulate root growth.<ref name=Costa_2018 />


==Analysis methods==
<p> [3] NPR/TED, and 2020 10:13am. 1969, December 31. Suzanne Simard: How Do Trees Collaborate? https://www.northcountrypublicradio.org/news/npr/882828756/suzanne-simard-how-do-trees-collaborate.
Cation exchange resin (CER) extraction is currently considered the best method for accurately extracting EPS from soils.<ref name=Redmile-Gordon_2014>Redmile-Gordon, M.A., Brookes, P.C., Evershed, R.P., Goulding, K.W.T., Hirsch, P.R., 2014. Measuring the soil-microbial interface: Extraction of extracellular polymeric substances (EPS) from soil biofilms. Soil Biology and Biochemistry 72, 163–171.</ref>This method shows the highest efficency with the least amount of modification to the original EPS composition when compared to other methods. This method works by replacing cations in the material being sampled. This destabilizes the structure and allows for separation through filtration and/or centrifuge.


<p>[4] Douglass, A. E. 1941. Crossdating in Dendrochronology. Journal of Forestry.


<p>[5] Guibal, F., and J. Guiot. 2021. Dendrochronology. Pages 117–122 Paleoclimatology. Springer, Cham.


<p>[6] When trees “talk:” Researchers probe ancient wood for clues about massive solar storms | Arizona International. 2024, December 2. . https://international.arizona.edu/news/when-trees-talk-researchers-probe-ancient-wood-clues-about-massive-solar-storms.


<p>[7] Simard, S. 2021, May 4. Finding the Mother Tree : Discovering the Wisdom of the Forest. https://web-p-ebscohost-
com.gate.lib.buffalo.edu/ehost/ebookviewer/ebook?sid=3722a8f8-2b62-4b46-a151-54e5a387ffd8%40redis&vid=0&format=EK.


<p>[8] Quaternary paleoenvironments - methods. (n.d.). . https://microsite.geo.uzh.ch/alpecole/static/course/lessons/28/28c.htm.


 
<p>[9] Staddon, P. L. 2004. Carbon isotopes in functional [[Soil Ecology|soil ecology]]. Trends in Ecology & Evolution 19:148–154.
==References==
{{reflist}}

Latest revision as of 14:27, 30 March 2025

Carbon-14 atom containing 6 protons, 8 neutrons, and 6 electrons

Overview

Carbon-14, also referred to as 14C or radiocarbon, is one of the three naturally occurring isotopes of carbon in nature. 14C is unstable, and has a half-life of 5700 +/- 30 years [1]. The other two forms of carbon are 12C, which is what makes up 98% of all carbon in the atmosphere, and 13C, which makes up around 1% of atmospheric carbon. Both 12C and 13C are stable isotopes, while 14C is unstable. It only occurs in trace amounts naturally, around 1 14C atom for every 7.54 x 1011 atoms of 12C in the atmosphere. Within the context of ecology, 14C is used in two main processes: dating organic materials and tracing carbon pathways within ecosystems [2].

Uses

Cross dating tree rings [3]

Tree Ring Dating

14C is found in the atmosphere, and although it occurs in trace amounts, it will be absorbed by trees like any other form of carbon. The science of dendochronology heavily relies on 14C. Scientists are able to compare the tree rings of similar species growing in similar environments and match up their ages based on their rings [4]. From there, the 14C content in each tree ring can be matched to the tree's age and year it was growing. Since the amount of 14C in the atmosphere changes over time, scientists are also able to use the 14C content in each tree ring to relate it to the atmospheric conditions at the time the tree was growing. Because of all of this data, it is possible to know the tree-ring chronologies for the past 12,400 years [5].

Carbon-14 Tracing

14C forms naturally in the atmosphere as a result of cosmic radiation. As it moves through the atmosphere, 14C reacts with oxygen and forms CO2. That CO2 will then be absorbed by trees to be converted into sugars that the tree uses for energy [6]. The 14C becomes a part of the tree's tissue as it is absorbed. It may also be shunted to other trees via mycorrhizal fungi. In her book Finding The Mother Tree, Suzanne Simard used this method to track the path of carbon through the trees' root systems, and prove that trees exchange 14C through micorrhizal pathways [7]. This discovery of the vast networks of mycorrhizal has contributed greatly to forestry as a whole.

Suzanne Simard's drawing of carbon tracking through tree root systems [8]

Analysis methods

The majority of 14C analysis is used in determining ages of organic materials. 14C can also tell information on soil carbon cycles find in soil trophic relationships. Analysis of 14C in atmospheric and terrestrial environments is essential for understanding climate and soil environments. Through this analysis and the use of 14C, we can predict possible future environmental impacts and global climate change in ecosystems [9].

References

[1] Stark, A. M. (n.d.). Atmospheric carbon-14 measurements reveal natural production rate by cosmic rays | Lawrence Livermore National Laboratory. https://www.llnl.gov/article/42086/atmospheric-carbon-14-measurements-reveal-natural-production-rate-cosmic-rays.

[2] Cain, W. F., and H. E. Suess. 1976. Carbon 14 in tree rings. Journal of Geophysical Research (1896-1977) 81:3688–3694.

[3] NPR/TED, and 2020 10:13am. 1969, December 31. Suzanne Simard: How Do Trees Collaborate? https://www.northcountrypublicradio.org/news/npr/882828756/suzanne-simard-how-do-trees-collaborate.

[4] Douglass, A. E. 1941. Crossdating in Dendrochronology. Journal of Forestry.

[5] Guibal, F., and J. Guiot. 2021. Dendrochronology. Pages 117–122 Paleoclimatology. Springer, Cham.

[6] When trees “talk:” Researchers probe ancient wood for clues about massive solar storms | Arizona International. 2024, December 2. . https://international.arizona.edu/news/when-trees-talk-researchers-probe-ancient-wood-clues-about-massive-solar-storms.

[7] Simard, S. 2021, May 4. Finding the Mother Tree : Discovering the Wisdom of the Forest. https://web-p-ebscohost- com.gate.lib.buffalo.edu/ehost/ebookviewer/ebook?sid=3722a8f8-2b62-4b46-a151-54e5a387ffd8%40redis&vid=0&format=EK.

[8] Quaternary paleoenvironments - methods. (n.d.). . https://microsite.geo.uzh.ch/alpecole/static/course/lessons/28/28c.htm.

[9] Staddon, P. L. 2004. Carbon isotopes in functional soil ecology. Trends in Ecology & Evolution 19:148–154.

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