Changes

In order to assess the level of crude oil biodegradation, a scale has been developed by Peters and Moldowan.<ref name="13Moldowanetal" /> The scale is called the PM scale. The PM scale ranges from 1 to 10, with 10 to be the most altered i.e. most biodegraded. This scale is efficient and can be evaluated in conjunction with observation of the corresponding gas chromatography traces of crude oil samples. This scale illustrates very clearly that microbes favor consumption of simple hydrocarbons starting from n-alkanes and proceed to heavy aromatics at higher levels of biodegradation ([[:File:GeoWikiWriteOff2021-Aljezen-Figure5.jpg|Figure 5]]).

In order to assess the level of crude oil biodegradation, a scale has been developed by Peters and Moldowan.<ref name="13Moldowanetal" /> The scale is called the PM scale. The PM scale ranges from 1 to 10, with 10 to be the most altered i.e. most biodegraded. This scale is efficient and can be evaluated in conjunction with observation of the corresponding gas chromatography traces of crude oil samples. This scale illustrates very clearly that microbes favor consumption of simple hydrocarbons starting from n-alkanes and proceed to heavy aromatics at higher levels of biodegradation ([[:File:GeoWikiWriteOff2021-Aljezen-Figure5.jpg|Figure 5]]).

Other authors have proposed their own biodegradation scales, e.g. Another biodegradation scale is Wenger et al. although that scale only describes the oil based on very slight, slight, moderate, heavy and severe biodegradation levels. The scale is based on the presence or absence of specific compound classes ([[File:GeoWikiWriteOff2021-Aljezen-Figure6.jpg|Figure 6]]). The main problem with these scales is that, there are insufficient changes observable in chemical classes at very high biodegradation levels (heavy to severe) thus biodegradation between PM 5-8 on the PM scale and heavy to severe on Wenger et al. scale.

Other authors have proposed their own biodegradation scales, e.g. Another biodegradation scale is Wenger et al. although that scale only describes the oil based on very slight, slight, moderate, heavy and severe biodegradation levels. The scale is based on the presence or absence of specific compound classes ([[:File:GeoWikiWriteOff2021-Aljezen-Figure6.jpg|Figure 6]]). The main problem with these scales is that, there are insufficient changes observable in chemical classes at very high biodegradation levels (heavy to severe) thus biodegradation between PM 5-8 on the PM scale and heavy to severe on Wenger et al. scale.

[[File:GeoWikiWriteOff2021-Aljezen-Figure6.jpg|thumbnail|Figure 6 shows the Wenger 2002 scale with the corresponding PM scale and the key compounds altered or removed. (Steve et al., 2012)<ref name="15Larteretal" />]]

[[File:GeoWikiWriteOff2021-Aljezen-Figure6.jpg|thumbnail|Figure 6 shows the Wenger 2002 scale with the corresponding PM scale and the key compounds altered or removed. <ref name="15Larteretal" />]]

==What are the effects of biodegradation on crude oil economically?==

==What are the effects of biodegradation on crude oil economically?==