Resende Julia Fanny de Jesus, Bezerra Jadna Nayara de Souza, Borburema Henrique D S, Oliveira Vinícius Peruzzi de
Graduate Program in Biological Sciences/Botany, Federal University of Rio de Janeiro, Brazil.
Graduate Program in Biological Sciences/Botany, Federal University of Rio de Janeiro, Brazil.
Mar Environ Res. 2025 Sep;210:107262. doi: 10.1016/j.marenvres.2025.107262. Epub 2025 May 31.
Climate change has increased ocean temperature and salinity, and increasing nutrient inputs into the sea have intensified coastal eutrophication worldwide. These factors directly affect ephemeral marine macroalgae, whose excessive blooms raise significant ecological and economic concerns. Based on climate scenarios, this study analyzed the combined effects of temperature (23, 25, 26, and 28 °C), salinity (36 and 38), and nutrient availability on the growth, photosynthetic performance, and biochemical composition of the bloom-forming green macroalga Ulva lactuca. Thalli were cultured in fully crossed factorial experiments of warming and increased salinity and nutrients. Current conditions (23 and 25 °C, salinity of 36) and RCP8.5 future scenarios (26 and 28 °C, salinity of 38) were evaluated. Three nutrient levels were defined by adding von Stosch nutrient solution (VSES) to the seawater (control: 0 % VSES, natural eutrophication: 10 % VSES, and anthropogenic eutrophication: 50 % VSES). The highest macroalgal performance occurred under higher salinity and nutrient conditions at 25 °C. In contrast, the macroalgal growth reduced at 23 °C, salinity of 36, and lowest availability of nutrients. Under warming conditions (26 and 28 °C), U. lactuca showed thermal tolerance, stable growth rates, and high photosynthetic performance. Increasing nutrient availability enhanced photosynthetic pigments and N content of U. lactuca, as well as decreased the C:N ratio. These findings suggest that U. lactuca has a high potential to thrive under future environmental scenarios, potentially intensifying green tides and their negative ecological and economic impacts.
气候变化导致海洋温度和盐度上升，而海洋营养物质输入的增加加剧了全球沿海地区的富营养化。这些因素直接影响着短暂性海洋大型藻类，其过度繁殖引发了重大的生态和经济问题。基于气候情景，本研究分析了温度（23、25、26和28°C）、盐度（36和38）以及营养物质可利用性对形成水华的绿色大型藻类石莼生长、光合性能和生化组成的综合影响。藻体在温度升高、盐度增加和营养物质增加的完全交叉因子实验中进行培养。评估了当前条件（23和25°C，盐度36）和RCP8.5未来情景（26和28°C，盐度38）。通过向海水中添加冯·施托希营养液（VSES）来定义三种营养水平（对照：0%VSES，自然富营养化：10%VSES，人为富营养化：50%VSES）。在25°C、较高盐度和营养条件下，大型藻类表现最佳。相比之下，在23°C、盐度36和营养物质可利用性最低的条件下，大型藻类生长减缓。在变暖条件下（26和28°C），石莼表现出耐热性、稳定的生长速率和较高的光合性能。营养物质可利用性的增加提高了石莼的光合色素和氮含量，同时降低了碳氮比。这些发现表明，石莼在未来环境情景下具有很高的生长潜力，可能会加剧绿潮及其负面的生态和经济影响。
