Carbon-14: Difference between revisions

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[[File:HowTreesTalk.jpg|376px|thumb|right|Suzanne Simard's drawing of carbon tracking through tree root systems []]]
[[File:HowTreesTalk.jpg|376px|thumb|right|Suzanne Simard's drawing of carbon tracking through tree root systems []]]
===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]]===
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 />.
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===
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>
===Agriculture===
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==
==Analysis methods==

Revision as of 15:27, 29 March 2025

Carbon-14 atom with 6 protons, 8 neutrons, and 6 electrons [1]

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. Within the context of ecology, 14C is used in two main processes: dating organic materials and tracing carbon pathways within ecosystems.

Uses

Cross dating tree rings

Tree Ring Dating

The suspected primary role of EPS is to create stable habitat bound to a desired substrate[1]. EPS is the matrix structure of biofilms. Biofilms are very effective at retaining water in soils even with very negative water potentials.[2] 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.

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.[3]

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

Analysis methods

Cation exchange resin (CER) extraction is currently considered the best method for accurately extracting EPS from soils.[4]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.




References

  1. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Flemming_2016
  2. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Or_2007
  3. ↑ 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
  4. ↑ 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.
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