[eng] Marine intrusion is a major threat for wetland ecosystems, mainly inhabited by
macrophytes. Increase in salinity levels due to marine intrusion can cause an increase in
Reactive Oxygen Species (ROS) production in macrophytes. ROS react with
biomolecules causing oxidative damage, which is prevented by both enzymatic and nonenzymatic antioxidant mechanism. Macrophyte response to salinity has been proposed
for monitoring marine intrusion. Ceratophyllum demersum, a subcosmopolitan
submerged macrophyte reported to be salinity sensitive, inhabits the brackish waters of
s’Albufera de Mallorca, the highest wetland of the Balearic Islands. Enzymatic
antioxidant activities, malondialdehyde (MDA) concentration and photosynthetic
pigments content were measured in C. demersum following a salinity gradient through
five stations in s’Albufera de Mallorca. Salinity triggered superoxide dismutase (SOD),
glutathione peroxidase (GPx) and glutathione reductase (GRd) activities, but they failed
to avoid oxidative damage (MDA concentrations increased) at the highest salinity levels.
Evolution of photosynthetic pigments contents and ratios did not follow the salinity
gradient, suggesting they would depend on other environmental factors. The parameters
measured in C. demersum were not robust enough to be used as biomarkers for monitoring
marine intrusion. Reviewing the literature, M. spicatum coverage would be a better
parameter for monitoring marine intrusion. Further studies at local level should be carried
out to a better understanding of macrophyte and wetland ecosystems response to marine
intrusion.