Photobiological Effects on Ice Algae of a Rapid Whole-Fjord Loss of Snow Cover during Spring Growth in Kangerlussuaq, a West Greenland Fjord ...

• Main Authors: Sorrell, Brian K, Hawes, Ian, Stratmann, Tanja, Lund-Hansen, Lars Chresten
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 2023
• Subjects: Greenland; ice algae; optics; photobiology; Snow cover; stress; Spectral radiometer; Arctic Biodiversity & Livelihoods FACE-IT; Arctic; Kangerlussuaq; Arctic biodiversity; Sea ice
• Online Access: https://dx.doi.org/10.1594/pangaea.963203; https://doi.pangaea.de/10.1594/PANGAEA.963203

The presence of snow on sea-ice can have dramatic effects on the photosynthetically available radiation (PAR) that reaches the ice algae. To better quantify this effect in the high Arctic, an experiment was conducted in Kangerlussuaq, west Greenland, throughout March 2013 where snow was cleared off the sea-ice and measured parameters were compared to a control area. Samples of under-ice algae were then taken to analyse the species composition. The bottom 30 mm of the sampled ice cores were used to determine the stress on the photosystems of the sea ice algae as they experienced the rapid irradiance via the variable fluorescence of photosystem II (PSII). PSII was measured using pulse amplitude modulated (PAM) fluorometry (Walz Imaging-PAM fluorometer). This provides the effective quantum yield of PSII (Φ_PSII), which is a unitless ratio of ambient (F) and maximum (F_m) fluorescence yields. These measurements were taken every 3 hours over the final day of the study. Periodically over the week of the study, ...