Inorganic and organic carbon and nitrogen uptake strategies of picoplankton groups in the northwestern Atlantic Ocean
Inorganic and organic carbon and nitrogen uptake strategies of picoplankton groups in the northwestern Atlantic Ocean
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DOI：
10.1002/lno.11909
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发表时间：
2021-08-13
影响因子：
4.5
通讯作者：
Cassar, Nicolas
中科院分区：
文献类型：
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作者：
Berthelot, Hugo;Duhamel, Solange;Cassar, Nicolas
微浮游生物种群在表层少营养化海洋浮游生物群落中占主导地位。然而，它们在氮(N)和碳(C)的有机和无机来源的获取和分配方面的策略描述得很少。在此，我们测量了西北大西洋6个低氮站的色素和非色素浮游生物对溶解无机C（固定C）、C-亮氨酸、n -亮氨酸、硝酸盐（NO3-）、铵（NH4+）和n -尿素的单细胞吸收。我们的研究强调了原绿球藻、聚藻球菌、光合微真核生物和非色素原核生物在营养策略上的重要差异。非色素原核生物的特点是亮氨酸摄取率高，碳固定不显著，NH4+、n -尿素和NO3-摄取率相对较低。非色素原核生物对NH4+、NO3-和n -尿素的吸收分别贡献了7% +/- 3%、2% +/- 2%和9% +/- 5%。相比之下，色素组表现出相对较高的碳固定率、NH4+和n -尿素摄取率，但亮氨酸摄取率低于非色素组。聚球藻和光合微真核生物对NO3-的吸收率高于原绿球藻。微尺度色素组在群落固碳（63% +/- 27%）、NH4+吸收（47% +/- 27%）、NO3-吸收（62% +/- 49%）和n -尿素吸收（81% +/- 35%）中占显著比例。有趣的是，原绿球藻和光合微真核生物对C-亮氨酸和N-亮氨酸的平均依赖程度高于聚球菌，这表明它们对有机C和N来源的依赖程度更高。综上所述，我们的单细胞结果破译了海洋浮游生物群体之间和内部C和N营养策略的广泛多样性，但在色素和非色素群体之间仍然存在明确的划分。
Picoplankton populations dominate the planktonic community in the surface oligotrophic ocean. Yet, their strategies in the acquisition and the partitioning of organic and inorganic sources of nitrogen (N) and carbon (C) are poorly described. Here, we measured at the single-cell level the uptake of dissolved inorganic C (C-fixation), C-leucine, N-leucine, nitrate (NO3-), ammonium (NH4+), and N-urea in pigmented and nonpigmented picoplankton groups at six low-N stations in the northwestern Atlantic Ocean. Our study highlights important differences in trophic strategies between Prochlorococcus, Synechococcus, photosynthetic pico-eukaryotes, and nonpigmented prokaryotes. Nonpigmented prokaryotes were characterized by high leucine uptake rates, nonsignificant C-fixation and relatively low NH4+, N-urea, and NO3- uptake rates. Nonpigmented prokaryotes contributed to 7% +/- 3%, 2% +/- 2%, and 9% +/- 5% of the NH4+, NO3-, and N-urea community uptake, respectively. In contrast, pigmented groups displayed relatively high C-fixation rates, NH4+ and N-urea uptake rates, but lower leucine uptake rates than nonpigmented prokaryotes. Synechococcus and photosynthetic pico-eukaryotes NO3- uptake rates were higher than Prochlorococcus ones. Pico-sized pigmented groups accounted for a significant fraction of the community C-fixation (63% +/- 27%), NH4+ uptake (47% +/- 27%), NO3- uptake (62% +/- 49%), and N-urea uptake (81% +/- 35%). Interestingly, Prochlorococcus and photosynthetic pico-eukaryotes showed a greater reliance on C- and N-leucine than Synechococcus on average, suggesting a greater reliance on organic C and N sources. Taken together, our single-cell results decipher the wide diversity of C and N trophic strategies between and within marine picoplankton groups, but a clear partitioning between pigmented and nonpigmented groups still remains.