The rhodophytes Mastocarpus stellatus and Chondrus crispus occupy the lower intertidal zone of rocky shores along North Atlantic coastlines, with C. crispus generally occurring slightly deeper. Consequently, M. stellatus is exposed to more variable environmental conditions, related to a generally higher stress tolerance of this species. In order to extend our understanding of seasonal modulation of stress tolerance, we subjected local populations of M. stellatus and C. crispus from Helgoland, North Sea, to short-term high-light stress experiments over the course of a year (October 2011, March, May and August 2012). Biochemical analyses (pigments, antioxidants, total lipids, fatty acid compositions) allowed to reveal mechanisms behind modulated high-light tolerances. Overall, C. crispus was particularly more susceptible to high-light at higher water temperatures (October 2011 and August 2012). Furthermore, species-specific differences in antioxidants, total lipid levels and the shorter-chain/longer-chain fatty acid ratio (C14 + C16/C18 + C20) were detected, which may enhance the tolerance to high-light and other abiotic stress factors in M. stellatus, so that this species is more competitive in the highly variable upper intertidal zone compared to C. crispus. Since the high-light tolerance in C. crispus seemed to be affected by water temperature, interactions between both species may be impacted in the future by rising mean annual sea surface temperature around the island of Helgoland.

中文翻译：

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与潮间质红藻Mastocarpus stellatus和Chondrus crispus的高耐光性相关的脂肪酸组成

红藻Mastocarpus stellatus和Chondrus crispus占据了北大西洋沿岸多岩石海岸的下潮间带，C。crispus通常出现在更深的地方。因此，M。stellatus暴露于更多可变的环境条件下，这与该物种的一般较高的胁迫耐受性有关。为了扩展我们对压力耐受性的季节性调节的理解，我们对北海赫尔戈兰岛的斯特雷特氏菌和脆皮梭菌的当地种群进行了为期一年的短期高光胁迫实验（2011年10月， 2012年3月，5月和8月）。生化分析（色素，抗氧化剂，总脂质，脂肪酸组成）可以揭示调节的高光耐受性背后的机制。总体而言，C。在较高的水温下（2011年10月和2012年8月），crispus特别容易受到强光照射。此外，检测到抗氧化剂，总脂质水平和短链/长链脂肪酸比率（C14 + C16 / C18 + C20）的物种特异性差异，这可能增强了对强光和其他非生物胁迫因素的耐受性因此，该物种在高变化的上潮间带中比C. crispus更具竞争性。由于C.crispus的高耐光性似乎受到水温的影响，因此未来两种物种之间的相互作用可能会因Helgoland岛周围的年平均海面温度升高而受到影响。检测总脂质水平和短链/长链脂肪酸比率（C14 + C16 / C18 + C20），这可能增强星状分枝杆菌对强光和其他非生物胁迫因素的耐受性，因此该物种与薄脆衣梭菌相比，在高度变化的上潮间带更具竞争力。由于C.crispus的高耐光性似乎受到水温的影响，因此未来两种物种之间的相互作用可能会因Helgoland岛周围的年平均海面温度升高而受到影响。检测总脂质水平和短链/长链脂肪酸比率（C14 + C16 / C18 + C20），这可能增强星状分枝杆菌对强光和其他非生物胁迫因素的耐受性，因此该物种与薄脆衣梭菌相比，在高度变化的上潮间带更具竞争力。由于C.crispus的高耐光性似乎受到水温的影响，因此未来两种物种之间的相互作用可能会因Helgoland岛周围的年平均海面温度升高而受到影响。