<p xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="first" dir="auto"
id="d16217164e115">The physiological status of Cystoseira compressa, Padina pavonica
and Palisada tenerrima
was studied by in vivo chlorophyll fluorescence, pigment content, stoichiometry (C:N),
accumulation of UV photoprotectors and antioxidant activity; comparing their photosynthetic
response in a coastal lagoon (Mar Menor) and in Mediterranean coastal waters. In general,
the specimens reached their highest ETRmax in spring in the Lagoon, but in summer
in the Mediterranean, coinciding with their maximum biomass peak. The species exhibited
a dynamic photoinhibition. Except C. compressa, they showed a lower decrease in Fv/Fm
and higher recovery rates in the Mediterranean populations when exposed to high irradiance.
The higher salinity and temperature of the lagoon could impair the photoprotection
mechanisms. The acclimation to lagoon environments is species-specific and involves
complex regulatory mechanisms. The results underline the importance of N in repair,
avoidance, quenching and scavenging mechanisms. In general, Lagoon specimens showed
higher pigment concentration. Although xanthophylls play important photo-protective
and antioxidant roles, the observed trend is more likely to be explained by the higher
temperatures reached in the lagoon compared to Mediterranean. Therefore the studied
photosynthetic and biochemical mechanisms can be effective not only for high irradiance,
but also for higher temperatures in a climate change scenario, but are highly dependent
on nutrient availability.
</p>