Abstract Coastal phytoplankton assemblages from Potter Cove in Antarctica were exposed to low salinity (S-) and high temperature (T+) conditions to simulate oceanic changes resulting from global warming. The treatments were: low salinity (30) and high temperature (S-T+); low salinity and ambient temperature (1–2 °C) (S-T0); ambient salinity (34) and increased temperature (4–5 °C) (S0T+) and ambient salinity with ambient temperature (control, S0T0). Experiments were conducted in 100-L microcosms and monitored for 6 days. Compared to the control treatment, micro-size diatoms (25–50 μm) dominated the phytoplankton assemblages while prasinophyceae were less abundant at the end of the S-T+ and S0T+ treatments. Nano-size diatoms (10–20 μm) also increased significantly at the end of the experiment but only when exposed to S0T+. In S- treatments, the production of reactive oxygen/ nitrogen species (ROS/RNS) increased while phytoplankton biomass decreased. Under T+ conditions, the production of ROS/RNS was significantly lower than in T0 treatments. Throughout the experiment, α-Tocopherol (α-T) consumption may have prevented lipid damage, allowing for increases in photosynthetic rate and growth when nutrients concentrations were sufficiently high. Our results indicate that an increase in temperature can compensate for the lipid damage produced by low salinity, and stimulate carbon uptake in both conditions. This study demonstrated that the final composition of phytoplankton assemblages in all experimental treatments was strongly influenced by the original composition. Future changes in natural phytoplankton assemblages in Antarctic coastal waters will therefore depend on the planktonic species present at the time of the perturbation, which can strongly impact energy flow along food webs and the magnitude of carbon and nutrient fluxes in Antarctic waters.

中文翻译：

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气候引起的温度和盐度变化对南极沿海浮游植物生理和应激反应的影响

摘要 来自南极洲波特湾的沿海浮游植物组合暴露于低盐度 (S-) 和高温 (T+) 条件下，以模拟全球变暖导致的海洋变化。处理为：低盐度（30）和高温（S-T+）；低盐度和环境温度 (1–2 °C) (S-T0)；环境盐度 (34) 和温度升高 (4–5 °C) (S0T+) 以及环境盐度随环境温度升高（控制，S0T0）。实验在 100 升的微观世界中进行，并监测了 6 天。与对照处理相比，微型硅藻（25-50 μm）在浮游植物组合中占主导地位，而在 S-T+ 和 S0T+ 处理结束时，海藻科植物较少。纳米尺寸的硅藻（10-20 μm）在实验结束时也显着增加，但仅当暴露于 S0T+ 时。在 S- 治疗中，活性氧/氮物种（ROS/RNS）的产生增加，而浮游植物生物量减少。在T+条件下，ROS/RNS的产生明显低于T0处理。在整个实验过程中，α-生育酚 (α-T) 的消耗可能防止了脂质损伤，当营养物质浓度足够高时，可以增加光合速率和生长。我们的结果表明，温度升高可以补偿低盐度造成的脂质损伤，并在两种条件下刺激碳吸收。该研究表明，所有实验处理中浮游植物组合的最终组成受原始组成的强烈影响。