Stimulated bacterial growth under elevated p CO₂: results from an off-shore mesocosm study.
Stimulated bacterial growth under elevated p CO₂: results from an off-shore mesocosm study.
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DOI：
10.1371/journal.pone.0099228
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发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
Engel A
中科院分区：
文献类型：
--
作者：
Endres S;Galgani L;Riebesell U;Schulz KG;Engel A
海洋细菌是新鲜产生的有机物的主要消费者。先前的研究表明，细菌消化有机化合物的许多酶促过程对 pH 值敏感。由于大气中二氧化碳浓度的持续上升，海水pH值目前正以过去3亿年来前所未有的速度下降，但其对微生物生理学、有机物循环和海洋生物地球化学的影响仍未得到解决。我们在挪威峡湾进行了大规模中生态系统研究，研究了海水 pCO2 升高对自然浮游生物群落的影响。用于未来海洋模拟 (KOSMOS) 的九个基尔近海中宇宙被调整到不同的 pCO2 水平，最初范围从约280 至 3000 µatm，每隔一天采样一次，持续 34 天。第一次浮游植物水华在第 5 天左右形成。第 14 天，无机营养物被添加到封闭的、营养贫乏的水域中，以刺激第二次浮游植物水华，这发生在第 20 天左右。我们的结果表明，海洋细菌直接和间接受益于海水 pH 值的降低。在第一次浮游植物大量繁殖期间，在高 pCO2 中生态系统中形成了 5-10% 的透明外聚合物颗粒。同时，蛋白质降解酶亮氨酸氨肽酶的效率随着 pH 值的降低而增加，导致最高 pCO2/最低 pH 介层中的值比对照高出三倍。一般来说，总氨肽酶活性和细胞特异性氨肽酶活性在低 pH 条件下升高。有机物酶促水解的增强和作为底物的凝胶颗粒可用性的提高相结合，在高 pCO2 处理中使细菌丰度提高了 28%。我们的结论是，海洋酸化有可能刺激细菌群落并促进新鲜产生的有机物的微生物循环，从而加强微生物循环在海洋表面的作用。
Marine bacteria are the main consumers of freshly produced organic matter. Many enzymatic processes involved in the bacterial digestion of organic compounds were shown to be pH sensitive in previous studies. Due to the continuous rise in atmospheric CO2 concentration, seawater pH is presently decreasing at a rate unprecedented during the last 300 million years but the consequences for microbial physiology, organic matter cycling and marine biogeochemistry are still unresolved. We studied the effects of elevated seawater pCO2 on a natural plankton community during a large-scale mesocosm study in a Norwegian fjord. Nine Kiel Off-Shore Mesocosms for Future Ocean Simulations (KOSMOS) were adjusted to different pCO2 levels ranging initially from ca. 280 to 3000 µatm and sampled every second day for 34 days. The first phytoplankton bloom developed around day 5. On day 14, inorganic nutrients were added to the enclosed, nutrient-poor waters to stimulate a second phytoplankton bloom, which occurred around day 20. Our results indicate that marine bacteria benefit directly and indirectly from decreasing seawater pH. During the first phytoplankton bloom, 5–10% more transparent exopolymer particles were formed in the high pCO2 mesocosms. Simultaneously, the efficiency of the protein-degrading enzyme leucine aminopeptidase increased with decreasing pH resulting in up to three times higher values in the highest pCO2/lowest pH mesocosm compared to the controls. In general, total and cell-specific aminopeptidase activities were elevated under low pH conditions. The combination of enhanced enzymatic hydrolysis of organic matter and increased availability of gel particles as substrate supported up to 28% higher bacterial abundance in the high pCO2 treatments. We conclude that ocean acidification has the potential to stimulate the bacterial community and facilitate the microbial recycling of freshly produced organic matter, thus strengthening the role of the microbial loop in the surface ocean.
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影响因子：
56.9
作者：
Azam, F
通讯作者：
Azam, F
影响因子：
2.1
作者：
Engel, Anja;Haendel, Nicole;Riebesell, Ulf
通讯作者：
Riebesell, Ulf
影响因子：
4.9
作者：
Borchard, C.;Engel, A.
通讯作者：
Engel, A.
影响因子：
4.9
作者：
Brussaard, C. P. D.;Noordeloos, A. A. M.;Riebesell, U.
通讯作者：
Riebesell, U.
影响因子：
4.9
作者：
Allgaier, M.;Riebesell, U.;Grossart, H. -P.
通讯作者：
Grossart, H. -P.