# Natural Versus Anthropic Influence on North Adriatic Coast Detected by Geochemical Analyses
## 2 Materials and Methods  
### Sampling and Analyses  
We investigated the marine area around two fixed observatories (the E1 meteo-oceanographic buoy and the S1-GB dynamic pylon [32; 33]), part of the Italian LTER network (long-term ecological research network, [[https://deims.org/6869436a-80f4-4c6d-954b-a730b348d7](https://deims.org/6869436a-80f4-4c6d-954b-a730b348d7) ce]([https://deims.org/6869436a-80f4-4c6d-954b-a730b348d7](https://deims.org/6869436a-80f4-4c6d-954b-a730b348d7) ce)) deployed to study the ecosystems and the long-term response to environmental, societal and economic drivers [34]. Six sediment cores were collected with a box-cover in 2014, 2016 and 2017 during the oceanographic cruises EL-14, LTER-ANOC16 and INTERNOS17 onboard the R/V Dallaporta (Table 1). Core locations and study areas, namely _S1 (Delta del Po)_ and _E1 (Costa Romagnola)_ (summarized above as S1 and E1, respectively), are shown in Figure 1. Each box-core was subsampled with smaller PVC cores (diameter 8 cm) and stored at 4 \({}^{\circ}\)C [35; 36] directly on the vessel. At the ISMAR-CNR laboratories, each core was described and subsampled at 1 or 2 cm of thickness. The samples were dried at 60 \({}^{\circ}\)C and the porosity was calculated assuming a sediment density of 2.55 g cm\({}^{-3}\)[37]. Dried sediment levels from all six cores were slightly disaggregated and analyzed for the radiotracer \({}^{137}\)Cs, by non-destructive gamma-ray spectrometry using two intrinsic Ge detectors. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Cores** & **Latitude** & **Longitude** & **Site** & **Water Depth (m)** & **Core Length (cm)** \\ \hline
**S1-EL14** & 44.737\({}^{\circ}\) N & 12.447\({}^{\circ}\) E & S1 & 21 & 17 \\
**E1-EL14** & 44.141\({}^{\circ}\) N & 12.573\({}^{\circ}\) E & E1 & 10.5 & 15 \\
**S1-ANOC16** & 44.742\({}^{\circ}\) N & 12.452\({}^{\circ}\) E & S1 & 21 & 17.5 \\
**E1-ANOC16** & 44.148\({}^{\circ}\) N & 12.577\({}^{\circ}\) E & E1 & 10.5 & 16 \\
**S1-INT17** & 44.742\({}^{\circ}\) N & 12.459\({}^{\circ}\) E & S1 & 21 & 18 \\
**E1-INT17** & 44.143\({}^{\circ}\) N & 12.572\({}^{\circ}\) E & E1 & 10.5 & 10.5 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Details of sampling stations. Sediment samples were put into cylindrical transparent plastic jars, pressed and counted for 24 h. Activities were measured following [PERSON] et al. [38] and [PERSON] et al. [39]. Both detectors were connected to an integrated gamma-spectrometry system, the _DSPEC-Ortec_. Output spectra were processed and calibrated by using the _Gammavision-Ortec_ software. All concentrations and activities are relative to dry weight and are expressed in Bq kg\({}^{-1}\). Detector efficiency was estimated using samples of sediment spiked with multipeak standard solutions (QCY58) counted in standard geometry jars (5-10-15-20 ml). Accuracy was checked periodically by using certified reference sediments (IAEA-TEL-2012-03). To assess grain-size distributions, the organic content was firstly removed by treating the samples with H\({}_{2}\)O\({}_{2}\); subsequently, sediments were wet sieved with a 63-\(\upmu\)m-net size to separate coarse- and fine-grained fractions. Finally, the coarse fraction was analyzed using a stack of ASTM sieves, while the finer sediments by an X-ray sedigraph _Micromeritics 5120_, in order to quantify the silt and clay fractions. Results are relative to dry weight and are expressed as percentages of grain-size fractions. Sediments were also analyzed for geochemical composition at the BiGeA laboratories, by means of X-ray fluorescence spectrometry. At least 3 g of each dried sediment layer were ground in an agate mortar and then pressed with 7 g of H\({}_{3}\)BO\({}_{3}\) to obtain powder pellets.