Efectos de la radiación solar sobre el fitoplancton de aguas antárticas y subantárticas

• Main Author: Hernando, M.P.
• Other Authors: Ferreyra, G.
• Format: Thesis
• Language: Spanish
• Published: 2008
• Subjects: Phytoplankton; Taxonomy; Photosynthesis; Ultraviolet radiation; Vertical mixing; Antarctic; Argentina; Potter Cove; The Antarctic; Antarc*; Antártida; Tierra del Fuego
• Online Access: http://hdl.handle.net/1834/2868

The increments in the ultraviolet radiation B (RUVB, 280-320 nm) resultants of the destruction of the ozone layer affect diverse echo-physiologic aspects of the marine phytoplankton. On this study were compared the responses of phytoplankton from an ambient Sub-Antarctic (Channel Beagle, 54º 52´S, 68º 18´W) and another Antarctic (Potter Cove, 62º 14´S, 58º 38´W) to the ultraviolet radiation (RUV). The decrease of the photosynthesis on short term (hours) was observed in both places, however inhibition thresholds were present. In the Beagle Channel, these were for RUVB and ultraviolet radiation A (RUVA, 320-400 nm), respectively, 0,2 and 6,2 Wm-2 for communities with more than 70% diatoms and 0,45 and 14,2 Wm-2, respectively, for communities with more than 70% phytoflagellates. MAA´s were synthesized by the diatoms in response to RUV. These compounds were absent in phytoflagellates. A smaller inhibition of the photosynthesis was observed with bigger concentrations of MAA´s. When the relative abundance of diatomeas was higher, it was determined that those smaller l from the RUVB were more effective in inhibiting the photosynthesis for energy unit. For the Antarctic communities (> 70% phytoflagellates) only was studied normal ozone conditions and it was not photosynthesis inhibition when the doses of RUVB and RUVA were lesser than 0.6 and 13 Wm-2, respectively. In the Channel Beagle there was significant differences when analyzing the photosynthesis inhibition during normal and reduced ozone conditions, being higher in this last. The results of the investigations clearly show a higher sensibility in the communities of ambient Sub-Antarctic regarding the RUVB compared with the Antarctic. The phytoplankton communities from both ambients they use different strategies to adapt to the exposure to RUVB and RUVA The long term effects of exposure in both ambients varied depending on the taxonomic initial composition of the community and the previous light history of the cells. However, a tendency existed to a change in ...