Hyposaline conditions affect UV susceptibility in the Arctic kelp Alaria esculenta (Phaeophyceae) - results of laboratory experiments at Kongsfjorden, June/July 2014 ...

• Main Authors: Springer, Karin, Lütz, Cornelius, Lütz-Meindl, Ursula, Wendt, Angela, Bischof, Kai
• Format: Dataset
• Language: English
• Published: PANGAEA 2018
• Subjects: Species; Family; Treatment; Maximum photochemical quantum yield of photosystem II; Maximal electron transport rate; Initial slope of rapid light curve; Light saturation point; Chlorophyll a; Chlorophyll c1+c2; Fucoxanthin; beta-Carotene; Violaxanthin + Antheraxanthin + Zeaxanthin; Phlorotannins; Antioxidant capacity, in Trolox Equivalents; Ratio; Experiment; Kongsfjord*; Kongsfjorden; Svalbard; Spitsbergen
• Online Access: https://dx.doi.org/10.1594/pangaea.894853; https://doi.pangaea.de/10.1594/PANGAEA.894853

The kelp Alaria esculenta represents a key species in high Arctic marine fjord ecosystems. However, the European Arctic is currently experiencing extensive environmental change. Glacial fjord systems, such as Kongsfjorden (Spitsbergen, Svalbard), are subjected to rising temperature, increased freshwater inflow from glaciers and melting snow and a changing ultraviolet (UV) radiation regime related to stratospheric ozone depletion. Thus, in addition to natural seasonality, sessile organisms require acclimation in order to adapt to an environment in transition. We examined the physiological and ultrastructural responses of A. esculenta to the combined exposure to hyposalinity and UV radiation. Photosynthetic quantum yield slightly decreased during a low-salinity treatment of 7 d. Exposure to UV radiation also lowered quantum yield, but specimens previously treated with hyposalinity were significantly less susceptible to UV than nontreated individuals. Concomitant with a loss of chlorophyll during the hyposaline ... : ---------Treatment details:---------Initial [ini] => SA 32, 0-4°C, <20 µmol photons m-2 s-1 PARSalinity I, hyposaline conditions (long-term stress treatment) [sal_I] => SA 15, 4°C, 50 µmol photons m-2 s-1 PAR for 7 daysSalinity II, extreme hyposaline conditions (short-term stress treatment) [sal_II] => SA 5, 4°C, 50 µmol photons m-2 s-1 PAR for 6 hoursUltraviolett radiation I (long-term stress treatment) [UV_I] => SA 32, 4°C, 6.8 W m-2 UVA [320-400 nm] and 0.5 W m-2 UVB [280-320 nm] for 7 daysUltraviolett radiation II (short-term stress treatment) [UV_II] => SA 32, 4°C, 7.5 W m-2 UVA [320-400 nm] and 0.8 W m-2 UVB [280-320 nm] for 6 hoursControl conditions [control] => SA 32, 4°C, 50 µmol photons m-2 s-1 PARRecovery conditions (intermediate and final recovery period) [rec. (sal_I), rec. (UV_I), rec. control (sal_II), rec. control (UV_II) ] => SA 32, 4°C, 50 µmol photons m-2 s-1 PAR ...