## 3 Results and Discussion
### Isotopic Analysis in Modern Mammals
#### 3.2.2 \(\delta^{34}\)S Values of Various Mammals
Figure 9: Median of \(\delta^{15}\)N vs. \(\delta^{34}\)S isotopic data for (1) cattle from Chalkidiki; (2) cattle from Crete; (3) sheep from Chalkidiki; (4) sheep from Crete; (5) cows from Sparta; and (6) sheep from Sparta. Sulfur Isotope Analysis in Modern Terrestrial, Marine, and Freshwater Environments: Contribution of the Paleo Diet and Paleo Mobility Studies  
In order to assess the paleo diet reconstruction, \(\delta^{13}\)C, \(\delta^{15}\)N, and \(\delta^{34}\)S isotopic values have been plotted (see Figures 11 and 12), along with relevant conversions used in this (paleo) diet study (Table 6), illustrating the modern terrestrial, freshwater, and marine reservoirs, as derived from this research. It is noteworthy to mention herein that the findings are constrained by either a lack of sample size or a lack of samples from various locations, while all modern carbon isotopic values are calibrated to ancient ones [90] in order to compare them with available archaeological data. In fact, the geological complexity of Greece can lead to variations in isotopic signatures due to differences in local rock composition, soil chemistry, and water sources. These variations can make it difficult to establish clear baselines for ecological and nutritional reconstructions. However, to mitigate these challenges, we used multi-isotopic approaches, including carbon, nitrogen, and sulfur and compared the results with the data of archaeological specimens (Table 5). Furthermore, because the comparison between modern and ancient samples may overlook temporal changes in dietary practices and environmental conditions, potentially leading to misinterpretations of ancient diets, we compared modern samples and samples from archaeological and historical contexts with known environmental and dietary characteristics [68; 69; 70]. Findings document that all the fish species analyzed here are carnivores that consume herbivorous fish, crustaceans, and mollusks. The results show that recent marine fish, as a dietary resource, exhibit variable isotopic compositions, i.e., a total range of 6.4% for \(\delta^{13}\)C, 7.1% for \(\delta^{15}\)N and 4.7% for \(\delta^{34}\)S. The observed range of \(\delta^{15}\)N values indicates that the studied fish species live at different trophic levels, with the grouper existing at the highest level (each successive step in the food chain corresponds to an increase of about 3% in \(\delta^{15}\)N values, [46]). In principle, the increase in \(\delta^{15}\)N content during assimilation from one trophic level to another depends on the number of steps in the food web. Figure 10: Median of \(\delta^{34}\)S vs. \(\delta^{15}\)N data for mammals from different areas of Greece. Moreover, the modern results were compared to the bibliographical data referring to the \(\xi^{13}\)C and \(\xi^{15}\)N of fish bones' values from the archaeological sites (Table 4) [69; 71]. Even if a correlation between the recent and the ancient fish species leads to the conclusion that  
Figure 11: The boxes, \(\xi^{34}\)S versus \(\xi^{15}\)N, indicate terrestrial (brown—mammals; green–plants), freshwater (light blue), and marine (deep blue) reservoirs. The black box represents C4 plants [72; 73; 80; 81]. Figure 12: The boxes, \(\xi^{34}\)S versus \(\xi^{13}\)C values, indicate terrestrial (brown—mammals; green—plants), freshwater (light blue), and marine (deep blue) reservoirs. The black boxes are C4 plants. All modern carbon isotopic values have been calibrated to ancient ones [72; 73; 80; 81]. both groups fall into the same range, a detailed comparison of each species emphasizes significant isotopic differences between them. The recent Sparidae specimen shows the highest \(\delta^{13}\)C values, \(-13.1\%\) (\(\delta^{15}\)N = 6.3%, \(\delta^{34}\)S = 18.5%), whereas the recent Scombridae specimen exhibits the lowest \(\delta^{13}\)C values, \(-17.8\%\) (\(\delta^{15}\)N = 10.5%, \(\delta^{34}\)S = 17%).