## 2 Results and Discussion  
### Headspace, Volatile, and Semi-Volatile Organic Compounds  
In the present study, two different methods were used to investigate the chemical composition of _C. bursa_ volatiles: headspace solid-phase microextraction (HS-SPME) and hydrodistillation (HD). Two fibers of different polarity (divinylbenzene/carboxylate/polydimethylsiloxane (DVB/CAR/PDMS) and polydimethylsiloxane/divinylbenzene (PDMS/DVB)) were used for HS-SPME to obtain more complete headspace profiles. Different methods were chosen to obtain a comprehensive profile of the headspace, low and medium volatile compounds. First insight into Table 1 reveals meaningful differences among the headspace and distillate composition that was confirmed by statistical analysis. In addition, the composition of fresh and air-dried _C. bursa_ differed notably among the headspace and distillate indicating the strong impact of drying (also confirmed by statistical analysis). \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**No**} & \multirow{2}{*}{**Compound**} & \multirow{2}{*}{**RI**} & \multirow{2}{*}{**RI\({}_{\text{L}}\)**} & \multicolumn{6}{c}{**Area Percentages (\%)**} \\ \cline{6-11}  & & & & \(\pm\) **SD** & \(\pm\) **SD** & \(\pm\) **SD** & \(\pm\) **SD** & \(\pm\) **SD** & \(\pm\) **SD** & \(\pm\) **SD** & \(\pm\) **SD** \\ \hline
1. & 2-Thiappone (DMS) [8] & \textless{}900 & 521 & \(\pm\) 2.45  & \(\pm\) 1.58  & - & - \\ \hline
2. & Butanal [8] & \textless{}900 & 598 & - & - & - & - & - & - & - \\ \hline
3. & Pentan-1-ol [8] & \textless{}900 & 768 & - & \(\pm\) 0.10 [FOOTNOTE:]Footnote : footnotemark: [ENDFOOTNOTE] & - & - & - & - & - \\ \hline
4. & Hexanal [8] & \textless{}900 & 801 & \(\pm\) 0.15  & \(\pm\) 0.01 [FOOTNOTE:]Footnote : footnotemark: [ENDFOOTNOTE] & - & - & - \\ \hline
5. & Dimethyl-sulfoxide [8] & \textless{}900 & / & - & \(\pm\) 0.14  & - & - \\ \hline
6. & Ethylenene [8] & \textless{}900 & 858 & - & \(\pm\) 0.23  & - & - \\ \hline
7. & Hexan-1-ol [8] & \textless{}900 & 867 & \(\pm\) 0.01 [FOOTNOTE:]Footnote : footnotemark: [ENDFOOTNOTE] & - & - & - & - & - \\ \hline
8. & Nonane [8] & 900 & 900 & - & - & - & - & - & \(\pm\) 0.01 [FOOTNOTE:]Footnote : footnotemark: [ENDFOOTNOTE] & - \\ \hline
9. & \textless{}9-Pinene [8] & 940 & 940 & \(\pm\) 0.09  & - & - \\ \hline
10. & Benzaldehyde [8] & 965 & 964 & \(\pm\) 0.15  & \(\pm\) 0.09  & \(\pm\) 0.01  & - \\ \hline
11. & Oct-1-en-3-one [8] & 981 & 980 & - & - & - & - & - & - \\ \hline
12. & Oct-1-en-3-ol [8] & 982 & 982 & \(\pm\) 0.14  & \(\pm\) 0.18 [FOOTNOTE:]Footnote : footnotemark: [ENDFOOTNOTE] & - & - & - \\ \hline
13. & Oct-2-3-dione & 985 & 986 & - & 0.80 & 0.41 & - & - & - \\ \hline
14. & 6-Methyl-hept-5-en-2 one [FOOTNONONOTE:]Footnote : footnotemark: [ENDFOOTNOTE] & 988 & 988 & - & 1.42 [FOOTNONOTE:]Footnote : footnotemark: [ENDFOOTNOTE] & - & 0.41 & - & - & - \\ \hline
15. & 2-Pentyfuran [8] & 992 & 991 & - & 0.30 & - & - & - & 0.60  & - \\ \hline \end{tabular}
\end{table} 
Table 1: The volatile compounds from _Codium bursa_ isolated by headspace solid-phase microextraction (HS-SPME), hydrodistillation (HD), supercritical CO\({}_{2}\) extraction (SC-CO\({}_{2}\)) and analysed by gas chromatography and mass spectrometry (GC-FID and GC-MS). \begin{table}
\begin{tabular}{l c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**No**} & \multirow{2}{*}{**Compound**} & \multirow{2}{*}{**RI**} & \multirow{2}{*}{**RI**} & \multirow{2}{*}{**RI\({}_{\text{L}}\)**} & \multicolumn{6}{c}{**Area Percentages (\%)**} \\ \cline{5-10}  & & & & & **I** & **II** & **III** & **IV** & **V** & **VI** & **VII** \\  & & & & \(\pm\)**SD** & \(\pm\)**SD** & \(\pm\)**SD** & \(\pm\)**SD** & \(\pm\)**SD** & \(\pm\)**SD** & \(\pm\)**SD** \\ \hline
16. & Octanal \({}^{\text{S}}\) & 1003 & 1003 & 0.81 & 0.32 & 0.10 & 0.40 & & & & \\  & & & \(\pm\) 0.02\({}^{\text{a}}\) & \(\pm\) 0.01\({}^{\text{a}}\) & \(\pm\) 0.01\({}^{\text{a}}\) & \(\pm\) 0.01\({}^{\text{a}}\) & - & - & - \\ \hline
17.