Sempéré Richard, Para J., Tedetti Marc, Charriere B., Mallet M. (2015). Variability of solar radiation and CDOM in surface coastal waters of the northwestern Mediterranean sea. Photochemistry and Photobiology, 91 (4), p. 851-861. ISSN 0031-8655.
Titre du document
Variability of solar radiation and CDOM in surface coastal waters of the northwestern Mediterranean sea
Sempéré Richard, Para J., Tedetti Marc, Charriere B., Mallet M.
Source
Photochemistry and Photobiology, 2015,
91 (4), p. 851-861 ISSN 0031-8655
Atmospheric and in-water solar radiation, including UVR-B, UVR-A and PAR, as well as chromophoric dissolved organic matter absorption [a(CDOM)()] in surface waters were monthly measured from November 2007 to December 2008 at a coastal station in the Northwestern Mediterranean Sea (Bay of Marseilles, France). Our results showed that the UVR-B/UVR-A ratio followed the same trend in the atmosphere and at 2m depth in the water (P<0.0001) with an increase (eight-fold higher) during summer. The low diffuse attenuation coefficients for downward irradiance [K-d()] of UVR-B, UVR-A and PAR indicated that the waters were highly transparent throughout the year. The relationships between a(CDOM)() and K-d() in this oligotrophic system suggested that CDOM contributed to UVR attenuation in the UVA domain, but also played a significant role in PAR attenuation. Mean UV doses received in the mixed layer depth were higher by a factor 1.4-33 relative to doses received at fixed depths (5 and 10m) in summer (stratified period), while the inverse pattern was found in winter (mixing period). This shows the importance of taking into account the vertical mixing in the evaluation of UVR effects on marine organisms.
