Rapid depletion of dissolved organic sulphur (DOS) in freshwaters
Rapid depletion of dissolved organic sulphur (DOS) in freshwaters
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DOI：
10.1007/s10533-020-00669-4
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发表时间：
2020-05
期刊：
影响因子：
4
通讯作者：
F. Brailsford;H. Glanville;D. Wang;P. Golyshin;P. Johnes;C. Yates;D. Jones
中科院分区：
文献类型：
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作者：
F. Brailsford;H. Glanville;D. Wang;P. Golyshin;P. Johnes;C. Yates;D. Jones
硫(S)是所有生物体的关键常量营养素，其细胞需求与磷(P)相似。对S循环的研究往往集中在无机部分，但有强有力的证据表明，淡水微生物也可能接触到溶解的有机S(DOS)化合物(如含S的氨基酸)。本研究的目的是比较有机~(35)S标记的氨基酸(半胱氨酸、蛋氨酸)和无机的S(Na_(235)SO_4)在低营养输入和中等营养输入的河水中的相对浓度和耗竭速率。结果表明，无机SO42-−存在于水体中的浓度远高于游离氨基酸。然而，与SO_4~(2-)−相反，中营养化和贫营养化水体中的半胱氨酸和蛋氨酸都在1h内迅速耗尽，减半时间为1小时。从溶液中去除的−中只有一小部分被矿化并以SO_4~2 DOS的形式排出(约占总吸收总量的16%)，这表明DOS可以满足对碳(C)和硫的需求。
Sulphur (S) is a key macronutrient for all organisms, with similar cellular requirements to that of phosphorus (P). Studies of S cycling have often focused on the inorganic fraction, however, there is strong evidence to suggest that freshwater microorganisms may also access dissolved organic S (DOS) compounds (e.g. S-containing amino acids). The aim of this study was to compare the relative concentration and depletion rates of organic35S-labelled amino acids (cysteine, methionine) with inorganic S (Na235SO4) in oligotrophic versus mesotrophic river waters draining from low nutrient input and moderate nutrient input land uses respectively. Our results showed that inorganic SO42−was present in the water column at much higher concentrations than free amino acids. In contrast to SO42−, however, cysteine and methionine were both rapidly depleted from the mesotrophic and oligotrophic waters with a halving time < 1 h. Only a small proportion of the DOS removed from solution was mineralized and excreted as SO42−(< 16% of the total taken up) suggesting that the DOS could be satisfying a demand for carbon (C) and S. In conclusion, even though inorganic S was abundant in freshwater, it appears that the aquatic communities retained the capacity to take up and assimilate DOS.