## 1 Introduction
### \(\delta^{34}\)S in Terrestrial and Aquatic Ecosystems
Sulfur Isotopic Ratios in Archaeology  
Mammals need sulfur-containing biochemical compounds, such as the essential amino acids methionine and cysteine, which can be acquired from their diet. Consequently, the sulfur isotopic composition of plants is transferred through the animal chain to humans who consume animal protein. That is why the baseline for \(\delta^{34}\)S values in bone collagen depends on plant sulfur, soluble sulfate from precipitation, groundwater, microbial activity, and mainly soil. However, as mentioned above, the sulfur isotopic signature may vary significantly in a localized context or exhibit substantial overlaps across different regions. In ancient times, individuals in both rural and urban areas primarily consumed locally obtained food and beverages. Therefore, the \(\delta^{34}\)S values in their tissues primarily reflect those of local terrestrial and/or aquatic ecosystems. Humans living in inland areas generally have lower but more variable \(\delta^{34}\)S collagen values (\(-\)15 to 15%) because their food's \(\delta^{34}\)S values are influenced by the geological context. Humans living in coastal areas usually present high \(\delta^{34}\)S values in their tissues because their sulfur values are more influenced by marine sulfates (sea spray effect) and less by geological context. Apart from the above, there is also the circumstance where individuals from inland areas consume seafood with high \(\delta^{34}\)S values. In such cases, the interpretation of \(\delta^{34}\)S patterns is rather complicated. A very large dataset that includes 187 averaged sulfur isotope values from individual locations was published between 2001 and 2020 [27]. The authors--among others--aim to answer which of the two hypotheses is more closely related to the increase in the \(\delta^{34}\)S: (1) food systems near the coast are influenced by marine sulfates and/or (2) humans living near the coast eat more seafood. The \(\delta^{34}\)S values, in [PERSON] et al. 's study [27], range from \(-\)5.1% to 21.2% and the average is 8.29%. In general, these studies conclude that  
* The association between the deposition of sea salt aerosols and the distance from the coast to \(\delta^{34}\)S values is not linear. At distances greater than 150 km from the coast, the deposition rate of sea salt aerosols decreases significantly, causing \(\delta^{34}\)S values in human collagen to drop rapidly [21]. At distances greater than 200 km, where sea salt aerosol depositions are low, \(\delta^{34}\)S values in human collagen remain unaffected by sea salt deposition, and other factors influence \(\delta^{34}\)S values [27]. * Northwestern Europe receives the highest rate of sea salt aerosols due to strong winds from the North Atlantic that transport sea salt to these regions [28]. * The circum-Mediterranean region exhibits moderately high \(\delta^{34}\)S values, influenced by marine sea salt deposition and Sahara dust aerosols. The \(\delta^{34}\)S values in the Sahara range from 12 to 16%o [29], with particularly high values observed in locations like Crete, where strong sea surface winds contribute to these elevated sulfur values [27]. * The lowest \(\delta^{34}\)S values are observed in the Paris basin, Germany, Poland, and Eastern Europe, which are influenced by the geological context. Archaeological findings from these areas reveal human remains with very low \(\delta^{34}\)S values [27; 30; 31; 32]. Consequently, consumers fed with the products of a particular area should have similar \(\delta^{34}\)S values to those of the surrounding ecosystem, considering the changes in sulfur isotopic compositions from consumption to diet [8; 33]. Experiments indicated that the \(\delta^{34}\)S values of herbivore muscle, meat, and milk-when compared to their diet and between an animal and its offspring--exhibited trophic shifts of approximately 1.5%.. Significant \(\delta^{34}\)S enrichment ranging from 1 to 5%o was observed between the diet and the hair.