LOCAL-DISTRIBUTION AND SEASONAL-VARIATION OF FE, PH, ZN, CU, CD, NA, K, CA, AND MG CONCENTRATIONS IN THE SEAGRASS CYMODOCEA-NODOSA (UCRIA) ASCHERS - IN THE ANTIKYRA GULF, GREECE

The local distribution and seasonal variation of Fe, Pb, Zn, Cu, Cd, Na, K, Ca, and Mg concentrations in Cymodocea nodosa (UCRIA) ASCHERS., one of the most abundant seagrasses of the area, as well as their concentrations in the sediment and seawater were studied in the Gulf of Antikyra (Greece). The gulf is characterized by a bauxitic substrate and waste discharges from an aluminium-producing factory. Many of the metals investigated constitute components of the two above-mentioned metal sources. The mean metal concentrations (+/-SE) in the seagrass decreased in the order: Ca > Na > K > Mg > Fe > Pb > Zn > Cd > Cu. At the sampling stations A(1), A(2), A(3), B-3, and C-1, where sufficient data was available for statistical analysis, the concentrations of metals in the plant did not vary significantly among stations (P > 0.05). Metal concentrations in C. nodosa revealed two patterns of significant seasonal variation. The first pattern involved Fe, Cd, Na, and Ca and was characterized by high mean concentrations in summer and autumn. A reverse pattern was shown by Pb, Cu, and Mg. These patterns are discussed in relation to the growth dynamics, and leaf age of the seagrass, the metal concentrations in the environment, the intermetal correlation, etc. Cu, Cd, Pb, and Ca concentrations in the seagrass were significantly correlated with those in the sediment, whereas a direct relation of plant and seawater concentrations was obtained only for Ca and Mg. The intermetal correlation matrices in C. nodosa showed synergistic interactions between Cd-Ca, Pb-Mg, Fe-Ca, Cu-Pb, Na-K, and Na-Ca and antagonistic interactions between Cd-Pb, Cd-Mg, and Pb-Ca. The Cu, Cd, and Pb concentrations and the maximum Fe concentration in C. nodosa in the Antikyra Gulf are high compared with species belonging to the Cymodoceoideae subfamily from other geographical areas.