## 3 Results
### Sediment Quality
However, the Zn content exhibited seasonal differences (KW = 15.159, \(p\) < 0.001), increasing during summer (55.2 \(\pm\) 12.52 mg/L) compared to winter (38.06 \(\pm\) 10.44 mg/L). The content of total organic matter (TOM) in the first 3 cm of the surface exhibited differences by sector (KW = 7.425, \(p\) < 0.05), observed between Palma Real (19.38 \(\pm\) 4.56%) and Muisne (11.13 \(\pm\) 3.66%), sectors integrated exclusively by natural drainages and modified drainages, respectively. This difference increased when contrasting types of drainages (KW = 17.379, \(p\) < 0.001). Natural drainages averaged a TOM content of 20.52 \(\pm\) 6.09% while modified drainages averaged 11.73 \(\pm\) 4.49%. Seasonal differences (KW = 1.416, \(p\) > 0.05) were not observed. The analysis of 636 sections obtained every 2 cm of depth from 40 columnar sediment samples showed that the OM content differed considerably among sectors (F\({}_{3,560}\) = 52.07, \(p\) < 0.001). Palma real had 18.29 \(\pm\) 6.02% OM content; followed by Tambillo, with 14.68 \(\pm\) 8.02%; Cojimies, 12.31 \(\pm\) 3.78%; and finally, Muisne, with 10 \(\pm\) 4.39%. In all sectors except Muisne, a slight increase in OM was observed with increasing depth. The differences were strengthened when contrasting the type of drainage (F\({}_{1,533}\) = 225.3, \(p\) < 0.001), observing a decrease in organic matter content in modified drainages (10.82 \(\pm\) 4.5%), compared to natural drainages (17.92 \(\pm\) 6.73) (Figure 4). The vertical distribution of the redox potential by type of drainage appears in Figure 5. The redox potential exhibited different vertical patterns according to the type of drainage. Natural drainages, considering all the depth strata (n = 286), had a mean of \(-\)91 \(\pm\) 94 mV and described an inverse correlation of \(-\)0.530 (\(p\) < 0.01) with increasing depth without differing among sectors (F\({}_{2,275}\) = 0.647, \(p\) > 0.05). However, differences were found between sampling locations (F\({}_{9,268}\) = 7.074, \(p\) < 0.001), the ones located towards the interior of the mangroves without connections to freshwater rivers showed values that fluctuate between  
Figure 4: Violin plots of sediment organic matter content in natural drainages (MG) and modified drainages (SF). \(-\)148 to \(-\)158 mV, while sites located closer to the sea or connected to freshwater courses in the headquarters of mangroves presented had reported values in the range \(-\)58 to \(-\)76 mV; sediments from modified drainages (n = 350) showed a redox potential of \(-\)76 \(\pm\) 101 mV. Depth slightly affected the decrease in redox potential, describing a correlation of \(-\)0.135 (\(p\) < 0.05) at these sites. Unlike natural drainages, modified drainages differed among sectors (F\({}_{2,325}\) = 65.18, \(p\) < 0.001) and showed the lowest redox potential values recorded in Cojimies (\(-\)155 \(\pm\) 56 mV), compared to Muisne (\(-\)38 \(\pm\) 102 mV) and Tambillo (\(-\)42 \(\pm\) 83 mV). Cojimies redox potential values showed magnitudes between \(-\)171 and \(-\)176 mV in remnants of internal Cojimies mangroves connected to small watercourses, while locations close to the sea and headwaters of bodies of water showed positive values of 15 mV in T5 and 124 MV in M1.