TABLE 3.
Relative percent change (mean ± SE) over the season (shown under Control) and relative percent difference (mean ± SE) with the interactive effects of season and fertilization (as shown under Fertilized) in the measured parameters in rhizome and leaf tissues of seagrass plants in control (n = 6) and fertilized (n = 6) plots from the anthropogenically impacted sites (Baia, Gulf of Pozzuoli) and low impacted sites (Ischia) in June compared to control (n = 6) and fertilized (n = 6) plots in September.
| Traits | Site | Changes until September 2019 (%) |
|
| Control | Fertilized | ||
| Population level | |||
| Cover | Baia | −54.05 ± 2.70 | −65.15 ± 2.80 |
| Ischia | −2.04 ± 5.70 | −24.76 ± 2.72 | |
| Shoot density | Baia | +29.71 ± 15.48 | +0.60 ± 8.00 |
| Ischia | −6.24 ± 8.23 | −4.12 ± 15.43 | |
| Epiphytes | Baia | −11.03 ± 8.77 | +86.16 ± 41.86 |
| Ischia | +55.65 ± 13.25 | +82.23 ± 27.71 | |
| Morphological | |||
| No. leaves per shoot | Baia | −32.65 ± 3.32 | −36.28 ± 4.07 |
| Ischia | +1.62 ± 7.86 | −7.32 ± 6.56 | |
| Leaf height | Baia | −6.18 ± 4.66 | +0.16 ± 4.84 |
| Ischia | +1.15 ± 4.56 | −1.75 ± 4.11 | |
| Max. leaf canopy height | Baia | −38.92 ± 4.46 | −39.52 ± 3.99 |
| Ischia | −14.93 ± 5.75 | −26.36 ± 6.69 | |
| LAI | Baia | −49.73 ± 6.39 | −55.75 ± 4.69 |
| Ischia | −47.76 ± 8.59 | −55.05 ± 6.73 | |
| Leaf width | Baia | +10.28 ± 2.30 | + 12.00 ± 2.16 |
| Ischia | +7.94 ± 3.64 | +6.40 ± 4.29 | |
| Leaf area | Baia | −6.85 ± 4.54 | +0.16 ± 4.84 |
| Ischia | +1.27 ± 4.86 | −1.78 ± 4.32 | |
| Leaf area per shoot | Baia | −56.45 ± 5.16 | −55.95 ± 4.37 |
| Ischia | −42.82 ± 8.34 | −53.48 ± 6.54 | |
| Biochemical | |||
| Leaf C | Baia | +11.51 ± 2.33 | +9.05 ± 1.67 |
| Ischia | +6.05 ± 1.27 | +9.13 ± 1.34 | |
| Rhizome C | Baia | +7.14 ± 3.70 | −0.72 ± 0.63 |
| Ischia | +3.14 ± 0.97 | +6.55 ± 3.84 | |
| Leaf N | Baia | +15.71 ± 13.80 | +23.09 ± 11.21 |
| Ischia | −9.05 ± 9.15 | +5.41 ± 8.19 | |
| Rhizome N | Baia | +70.80 ± 12.82 | +15.37 ± 11.92 |
| Ischia | +65.66 ± 13.10 | +71.01 ± 21.21 | |
| Leaf δ13C | Baia | +10.10 ± 3.75 | +5.98 ± 2.31 |
| Ischia | −5.35 ± 4.08 | −3.49 ± 2.24 | |
| Rhizome δ13C | Baia | −0.38 ± 0.85 | +0.27 ± 1.44 |
| Ischia | −4.66 ± 1.68 | −1.11 ± 0.91 | |
| Leaf δ15N | Baia | −9.60 ± 4.34 | −27.23 ± 3.46 |
| Ischia | −12.45 ± 9.50 | −38.48 ± 5.08 | |
| Rhizome δ15N | Baia | −4.10 ± 1.07 | −12.67 ± 3.24 |
| Ischia | −8.95 ± 2.31 | −14.15 ± 4.07 | |
| Leaf C:N ratio | Baia | +1.04 ± 10.65 | −9.32 ± 7.77 |
| Ischia | +12.73 ± 9.26 | +3.92 ± 8.03 | |
| Rhizome C:N ratio | Baia | −44.33 ± 5.53 | −13.23 ± 10.71 |
| Ischia | −45.50 ± 4.42 | −36.07 ± 7.94 | |
| Leaf P | Baia | −11.64 ± 29.78 | −30.93 ± 19.48 |
| Ischia | +10.54 ± 11.73 | +12.15 ± 10.41 | |
| Rhizome P | Baia | +310.39 ± 50.21 | +74.47 ± 29.96 |
| Ischia | +130.64 ± 14.61 | +167.31 ± 31.95 | |
| Leaf sucrose | Baia | +13.53 ± 9.75 | −1.97 ± 8.87 |
| Ischia | +31.81 ± 20.74 | +9.77 ± 14.98 | |
| Leaf starch | Baia | −40.17 ± 9.81 | +57.07 ± 27.03 |
| Ischia | −13.22 ± 7.59 | −26.09 ± 4.30 | |
| Rhizome starch | Baia | +11.07 ± 14.38 | −26.98 ± 7.14 |
| Ischia | +25.43 ± 16.53 | +26.60 ± 13.99 | |
| Rhizome sucrose | Baia | −20.89 ± 5.58 | +1.29 ± 5.52 |
| Ischia | −12.69 ± 6.91 | −9.83 ± 12.33 | |
Statistically significant values are in bold.