Mixotrophic uptake of organic compounds by coccolithophores
Mixotrophic uptake of organic compounds by coccolithophores
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DOI：
10.1002/lno.11396
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发表时间：
2020-06-01
影响因子：
4.5
通讯作者：
Balch, William M.
中科院分区：
文献类型：
--
作者：
Godrijan, Jelena;Drapeau, David;Balch, William M.
渗透营养是浮游植物兼养获取碳的主要模式之一，但历史上一直未得到充分研究，其生理和生态相关性仍然知之甚少。在这里，我们调查营养球石藻。颗石藻是海洋生物量的主要来源之一，分布于海洋环境中的真光层和亚真光层。颗石藻展示了在黑暗中利用各种有机化合物的潜力。在BioLog Ecoplates的实验中，我们筛选了大量有机化合物作为潜在的碳源，并观察到颗石藻吸收的主要类型的有机化合物主要是碳水化合物沿着一些氨基酸和聚合物。此外，在随后的放射性示踪剂实验中，（14）C-标记的溶解的有机碳化合物在黑暗中的吸收率相对较低的最大速率光合碳固定在光。一些化合物的摄取时间过程表明其运输的组成能力，而对于其他化合物，运输似乎被激活。尽管如此，集体缓慢的吸收率在海水中发现的有机化合物的大阵列，可能是唯一的方式，营养可以燃料显着的颗石藻生长在深真光和次真光区的海洋。
Osmotrophy is one of the main modes of mixotrophic acquisition of carbon by phytoplankton, but historically it has been under-investigated and its physiological and ecological relevance remains poorly understood. Here, we investigate osmotrophy in coccolithophores. Coccolithophores are one of the major contributors to the ocean biomass inhabiting both euphotic and subeuphotic depths in the marine environment. Coccolithophores demonstrate the potential to utilize a wide array of organic compounds in darkness. In experiments with BioLog Ecoplates, we screened a wide array of organic compounds as potential carbon sources, and observed that the major types of organic compounds taken up by coccolithophores were primarily carbohydrates along with a few amino acids and polymers. Furthermore, in subsequent radiotracer experiments, the uptake rates of(14)C-labeled dissolved organic carbon compounds in the dark were low relative to the maximal rates of photosynthetic carbon fixation in the light. The time course of uptake for some compounds suggests constitutive capacity for their transport, while for others the transport appears to be activated. Nonetheless, the collective slow uptake rate of a large array of organic compounds found in seawater, might be the only way that osmotrophy could fuel significant coccolithophore growth in the deep euphotic and subeuphotic zones in the sea.