Interactive Effect of UVR and Phosphorus on the Coastal Phytoplankton Community of the Western Mediterranean Sea: Unravelling Eco-Physiological Mechanisms
Some of the most important effects of global change on coastal marine systems include increasing nutrient inputs and higher levels of ultraviolet radiation (UVR, 280–400 nm), which could affect primary producers, a key trophic link to the functioning of marine food webs. However, interactive effects of both factors on the phytoplankton community have not been assessed for the Mediterranean Sea. An in situ factorial experiment, with two levels of ultraviolet solar radiation (UVR+PAR vs. PAR) and nutrients (control vs. P-enriched), was performed to evaluate single and UVR×P effects on metabolic, enzymatic, stoichiometric and structural phytoplanktonic variables. While most phytoplankton variables were not affected by UVR, dissolved phosphatase (APAEX) and algal P content increased in the presence of UVR, which was interpreted as an acclimation mechanism of algae to oligotrophic marine waters. Synergistic UVR×P interactive effects were positive on photosynthetic variables (i.e., maximal electron transport rate, ETRmax), but negative on primary production and phytoplankton biomass because the pulse of P unmasked the inhibitory effect of UVR. This unmasking effect might be related to greater photodamage caused by an excess of electron flux after a P pulse (higher ETRmax) without an efficient release of carbon as the mechanism to dissipate the reducing power of photosynthetic electron transport.
Instituto del Agua, Universidad de Granada, Granada, Spain;Departamento de Ecología, Facultad de Ciencias, Universidad de Granada, Granada, Spain;Instituto del Agua, Universidad de Granada, Granada, Spain;Departamento de Ecología, Facultad de Ciencias, Universidad de Granada, Granada, Spain;Instituto del Agua, Universidad de Granada, Granada, Spain;Instituto del Agua, Universidad de Granada, Granada, Spain;Departamento de Ecología, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain;Centro Oceanográfico de Málaga, Instituto Español de Oceanografía Fuengirola, Málaga, Spain;Centro Oceanográfico de Málaga, Instituto Español de Oceanografía Fuengirola, Málaga, Spain;Departamento de Ecología, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain;Departamento de Ecología, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain;Centro Oceanográfico de Málaga, Instituto Español de Oceanografía Fuengirola, Málaga, Spain
Recommended Citation:
Presentación Carrillo,Juan M. Medina-Sánchez,Guillermo Herrera,et al. Interactive Effect of UVR and Phosphorus on the Coastal Phytoplankton Community of the Western Mediterranean Sea: Unravelling Eco-Physiological Mechanisms[J]. PLOS ONE,2015-01-01,10(11)