Distribution and seasonality of the marine macrophytes from Antikyra Gulf (Viotia, Greece)

The Gulf of Antikyra (Viotia) with a bauxitic substrate was aggravated by wastes discharged from an Aluminium factory where the Parnassos bauxite is treated Seasonal collections of macrophytes from stations selected inside the Antikyra Gulf were carried out. 85 species of macroalgae were totally collected, out of which 16 belonged to Chlorophyceae, 12 to Phaeophyceae and 57 to Rhodophyceae. There has been no obvious difference in the qualitative composition of the macroalgae as we move away from the area where the wastes are being discharged. Moreover, the stations where depths are greater exhibit different qualitative composition that those with smaller depths. The presence of phanerogams and especially that of Halophila stipulacea, the Lessepsian immigrant, encountered for the first time in the Korinthiakos Gulf, was also evident. The biomass of the three phanerogams decreased with the order: Posidonia oceanica>Cymodocea nodosa>Halophila stipulacea. The biomass of C. nodosaand P. oceanica was higher in July, while that of H. stipulacea was lower in July and higher in March and September

Effects of cadmium, zinc and nitrogen status on non-protein thiols in the macroalgae <i>enteromorpha spp.</i> from the Scheldt estuary (SW Netherlands, Belgium) and Thermaikos Gulf (n Aegean Sea, Greece)

Enteromorpha prolifera (Scheldt Estuary) and E. linza (Thermaikos Gulf) were incubated at three salinities with 100 and 200 µg L-1Cd and Zn. The objective was to measure effects of Cd, Zn and nitrogen (N) status on the pools of metal-binding non-protein thiols: glutathione and phytochelatins, (?-glutamyl-cysteinyl)n-glycine (PC). In E. linza, ammonium pools were higher, but amino acid pools, total N and protein contents were lower than in E. prolifera. Reduced glutathione (GSH) pools were positively correlated with free glutamate and protein contents. In E. linza GSH pools increased and the ratio of reduced to oxidized glutathione (GSH:(GSH + 0.5GSSG)), an indicator of oxidative stress, decreased with Cd contents, indicating Cd-induced glutathione oxidation. Total glutathione pools (reduced plus oxidized) ranged from 16 nmol S gdwt-1 in controls (at 0.5 µmol Cd gdwt-1) to 179 nmol S gdwt-1 (at 1.9 µmol Cd gdwt-1) at the highest cadmium dosage. Cadmium stimulated PC synthesis in E. prolifera which suggests that in N-rich algae, glutathione pools were high enough for PC synthesis. In both species GSH and protein increased with Zn contents, whereas GSH:(GSH + 0.5GSSG) decreased, which would indicate Zn-induced oxidative stress; in E. linza, at the highest salinity the glutathione redox ratio decreased from 0.61 (at 2.9 µmol Zn gdwt-1) to 0.26 (at 4.9 nmol S gdwt-1) (at 0.5 mol Cd gdwt-1). PCs were not synthesized in response to Zn, which may have resulted in Zn-induced GSH oxidation. The presence of both oxidative effects (Cd, Zn) and detoxification (Cd) could be identified by observing the responses of glutathione and PC pools to metal stress

Effects of cadmium, zinc and nitrogen status on nonprotein thiols in the macroalgae Enteromorpha spp. from the Scheldt Estuary (SW Netherlands, Belgium) and Thermaikos Gulf (Greece, N Aegean Sea)

Enteromorpha prolifera (Scheldt Estuary) and E. linza (Thermaikos Gulf) were incubated at three salinities with 100 and 200 µg L-1Cd and Zn. The objective was to measure effects of Cd, Zn and nitrogen (N) status on the pools of metal-binding non-protein thiols: glutathione and phytochelatins, (?-glutamyl-cysteinyl)n-glycine (PC). In E. linza, ammonium pools were higher, but amino acid pools, total N and protein contents were lower than in E. prolifera. Reduced glutathione (GSH) pools were positively correlated with free glutamate and protein contents. In E. linza GSH pools increased and the ratio of reduced to oxidized glutathione (GSH:(GSH + 0.5GSSG)), an indicator of oxidative stress, decreased with Cd contents, indicating Cd-induced glutathione oxidation. Total glutathione pools (reduced plus oxidized) ranged from 16 nmol S gdwt-1 in controls (at 0.5 µmol Cd gdwt-1) to 179 nmol S gdwt-1 (at 1.9 µmol Cd gdwt-1) at the highest cadmium dosage. Cadmium stimulated PC synthesis in E. prolifera which suggests that in N-rich algae, glutathione pools were high enough for PC synthesis. In both species GSH and protein increased with Zn contents, whereas GSH:(GSH + 0.5GSSG) decreased, which would indicate Zn-induced oxidative stress; in E. linza, at the highest salinity the glutathione redox ratio decreased from 0.61 (at 2.9 µmol Zn gdwt-1) to 0.26 (at 4.9 nmol S gdwt-1) (at 0.5 mol Cd gdwt-1). PCs were not synthesized in response to Zn, which may have resulted in Zn-induced GSH oxidation. The presence of both oxidative effects (Cd, Zn) and detoxification (Cd) could be identified by observing the responses of glutathione and PC pools to metal stress. [KEYWORDS: Cadmium ; Enteromorpha ; Glutathione ; Macroalgae ; Phytochelatins ; Zinc]