Photosynthetic capacity of the seagrass Posidonia oceanica was determined in two contrasting nutrient zones along a bathymetric gradient. Photosynthetic capacity was two times higher in the relatively eutrophic zone compared to the highly oligotrophic zone. The same trend was observed in the chlorophyll a+b and tissue nitrogen content. Photosynthetic capacity and chlorophyll a+b decreased with irradiance in the oligotrophic zone while increased in the eutrophic zone. Tissue nitrogen content followed the same trend in the oligotrophic zone and did not present any trend in the eutrophic zone. Overall, this study has shown the importance of large scale sampling when assessing metabolic parameters such as photosynthetic capacity where large differences have been observed associated to the nutrient regime. According to our results, in oligotrophic zones nitrogen seems to govern photosynthetic capacity and there is a coherent pattern between nitrogen content, pigments and photosynthetic capacities. In eutrophic zones, light is the dominant regulator and there is a coherent pattern between light and photosynthetic capacities.

中文翻译：

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海草 Posidonia Oceanica 的光合能力：氮和光的影响

海草 Posidonia Oceanica 的光合能力是在沿测深梯度的两个对比营养区确定的。与高度贫营养区相比，相对富营养区的光合能力高两倍。在叶绿素 a+b 和组织氮含量中观察到相同的趋势。光合能力和叶绿素 a+b 在贫营养区随着辐照度降低而在富营养区增加。组织氮含量在贫营养区遵循相同的趋势，在富营养区没有任何趋势。总体而言，这项研究表明，在评估代谢参数（例如光合能力）时，大规模采样的重要性，其中观察到与营养状况相关的巨大差异。根据我们的结果，在贫营养区，氮似乎控制着光合作用能力，氮含量、色素和光合作用能力之间存在着连贯的模式。在富营养区，光是主要的调节剂，光和光合能力之间存在连贯的模式。