ABSTRACT: Seagrasses account for approximately 10% of the total carbon stored in the ocean, although photosynthesis of seagrasses is carbon-limited at present oceanic pH levels. Therefore, increasing atmospheric CO₂ concentration, which results in ocean acidification/carbonation, is predicted to have a positive impact on seagrass productivity. Previous studies have confirmed the positive influence of increasing CO₂ on photosynthesis and survival of the temperate eelgrass Zostera marina, but the acclimation of photoprotective mechanisms in this context has not been characterized. We aimed to quantify the long-term impacts of ocean acidification on photochemical control mechanisms that promote photosynthesis while simultaneously protecting eelgrass from photodamage. Eelgrass were grown in controlled outdoor aquaria at different aqueous CO₂ concentrations ranging from ~50 to ~2100 μM from May 2013 to October 2014 and examined for differences in leaf optical properties. Even with daily and seasonal variations of temperature and light, CO₂ enrichment consistently increased plant size, leaf thickness and chlorophyll use efficiency, and decreased pigment content and the package effect while maintaining similar light-harvesting efficiency. These acclimation responses suggest that a common photosynthetic sensory function, such as redox regulation, can be manipulated by CO₂ availability, as well as light, and may serve to optimize photosynthetic carbon gain by seagrasses into the Anthropocene.

中文翻译：

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海洋碳化作用对鳗草 Zostera marina 光收集长期调控的影响

摘要：尽管海草的光合作用在目前海洋 pH 值水平下受到碳的限制，但海草约占海洋中总碳的 10%。因此，预计会导致海洋酸化/碳化的大气 CO ₂浓度增加，将对海草生产力产生积极影响。先前的研究已经证实了增加 CO ₂对温带鳗草Zostera marina 的光合作用和存活的积极影响，但在这种情况下光保护机制的适应尚未得到表征。我们旨在量化海洋酸化对促进光合作用同时保护鳗草免受光损伤的光化学控制机制的长期影响。从 2013 年 5 月到 2014 年 10 月，鳗草在受控的室外水族箱中生长，CO ₂浓度从 ~50 到 ~2100 μM 不等，并检查叶子光学特性的差异。即使温度和光线每天和季节性变化，CO ₂富集持续增加植物大小、叶片厚度和叶绿素利用效率，并降低色素含量和包装效果，同时保持相似的光收集效率。这些驯化反应表明，常见的光合感觉功能，如氧化还原调节，可以通过 CO ₂可用性以及光来操纵，并且可能有助于优化海草进入人类世的光合碳增益。