Summer heatwave impacts on the European kelp Saccharina latissima across its latitudinal distribution gradient – raw data to temperature-amplitude experiment with field material from five different locations
2021
Diehl, Nora | Roleda, Michael Y | Bartsch, Inka | Karsten, Ulf | Bischof, Kai
Temperature is a major factor for the global biogeographic pattern of marine benthic algal species and their loss has serious consequences for ecosystems. Local adaptation and phenotypic plasticity of species can result in intraspecific differences of thermal tolerance, and population loss might not only occur at thermal trailing edges. Understanding the underlying physiological and biochemical response mechanisms is from major importance. Therefore, we run the same short-term experiment with field sporophytes of Saccharina latissima from five locations along the European coast (Spitsbergen, Bodø, Bergen, Helgoland, Locmariaquer). We increased each respective mean summer temperature (control, ±0°C) by +2, +4 and +6°C to mimic realistic local heatwave events. The maximum photosynthetic quantum yield of photosystem II (Fv/Fm; Imaging-PAM, Walz GmbH Mess- und Regeltechnik, Effeltrich, Germany) was monitored every day. For growth, the size of the algal discs was photographed every second day, analyzed with ImageJ (Version 1.52a). Absolute concentrations of all pigments were analyzed using a HPLC. Afterwards, the pool sizes, the de-epoxidation state of the xanthophyll cycle (DPS), and the ratios were calculated. The C:N ratio, total nitrogen and total carbon content were analyzed with an elemental analyzer. Mannitol concentration was also analyzed in a HPLC. Phlorotannins were analyzed using the photometric Folin-Ciocalteu method.
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