Large Diversity in Nitrogen- and Sulfur-Containing Compatible Solute Profiles in Polar and Temperate Diatoms
Large Diversity in Nitrogen- and Sulfur-Containing Compatible Solute Profiles in Polar and Temperate Diatoms
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DOI：
10.1093/icb/icaa133
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发表时间：
2020-12-01
影响因子：
2.6
通讯作者：
Young, J. N.
中科院分区：
文献类型：
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作者：
Dawson, H. M.;Heal, K. R.;Young, J. N.
强烈的冰底藻华，通常以硅藻为主，是食草动物的重要食物来源，是海冰融化时出口的有机物和溶解的有机碳的重要来源。海冰硅藻有许多适应能力，包括相容溶质的积累，这使它们能够栖息在这个以极端温度、盐度和光照为特征的高度变化的环境中。除了保护它们免受极端条件的影响外，这些化合物还提供了一种不稳定的、营养丰富的有机物来源，包括气候活性化合物（如二甲基硫化物[DMS]）的前体，这些前体可能受到环境变化的调节。本文对三种海冰硅藻中45种代谢物的细胞内浓度进行了量化，并与两种温带硅藻进行了比较，重点研究了相容溶质和游离氨基酸池。硅藻之间的代谢物浓度差异很大，海冰物种之间没有明确的模式可识别。某些相容溶质（异硫离子酸、甘露碱）在海冰硅藻、白茅藻和perminuta Navicula中浓度接近1 M，但在较大的海冰硅藻、lecointernitzschia和温带硅藻中浓度不接近1 M。海冰硅藻对相容溶质的不同使用表明了不同的适应策略，并突出了在极地生物地球化学循环中哪些小有机化合物可能是重要的。
Intense bottom-ice algal blooms, often dominated by diatoms, are an important source of food for grazers, organic matter for export during sea ice melt, and dissolved organic carbon. Sea-ice diatoms have a number of adaptations, including accumulation of compatible solutes, that allows them to inhabit this highly variable environment characterized by extremes in temperature, salinity, and light. In addition to protecting them from extreme conditions, these compounds present a labile, nutrient-rich source of organic matter, and include precursors to climate active compounds (e.g., dimethyl sulfide [DMS]), which are likely regulated with environmental change. Here, intracellular concentrations of 45 metabolites were quantified in three sea-ice diatom species and were compared to two temperate diatom species, with a focus on compatible solutes and free amino acid pools. There was a large diversity of metabolite concentrations between diatoms with no clear pattern identifiable for sea-ice species. Concentrations of some compatible solutes (isethionic acid, homarine) approached 1 M in the sea-ice diatoms, Fragilariopsis cylindrus and Navicula cf. perminuta, but not in the larger sea-ice diatom, Nitzschia lecointei or in the temperate diatom species. The differential use of compatible solutes in sea-ice diatoms suggests different adaptive strategies and highlights which small organic compounds may be important in polar biogeochemical cycles.