Nitrogen and phosphorus co‐limitation of bacterial productivity and growth in the oligotrophic subtropical North Atlantic
Nitrogen and phosphorus co‐limitation of bacterial productivity and growth in the oligotrophic subtropical North Atlantic
复制标题
DOI：
10.4319/lo.2008.53.2.0824
复制
发表时间：
2008-03
影响因子：
4.5
通讯作者：
M. Mills;C. M. Moore;R. Langlois;A. Milne;E. Achterberg;K. Nachtigall;K. Lochte;R. Geider;
中科院分区：
文献类型：
--
作者：
M. Mills;C. M. Moore;R. Langlois;A. Milne;E. Achterberg;K. Nachtigall;K. Lochte;R. Geider;
细菌生产力和生物量被认为受到世界上大部分海洋中溶解有机碳(DOC)的限制。然而，稀有营养海洋的混合层通常会耗尽溶解的无机氮和磷，这增加了大量营养素也可能限制异养细菌生长的可能性。我们使用营养生物测定实验来确定无机营养(N、P、Fe)和/或DOC是否会限制2004年春季(3-4月)北大西洋中部的细菌生产力和生物量。我们观察到，在营养稀少的北大西洋，异养细菌的生产力和生物量都受到N和P的共同限制，除非同时添加N和P，否则添加不稳定的DOC(葡萄糖)不会提供任何刺激。流式细胞术结果表明，只有一小部分高核酸含量的大细胞才能提高组合NP修饰剂的生产率。相比之下，营养添加没有引起细菌种群的主要组成部分的净变化，这些细菌种群由相对较低的核酸含量的小细胞组成。在NP组合处理中，细菌产量的相对增加大于浮游植物生产力解除氮素限制时的测量结果。这些结果表明，细菌群落中N和P的共限制导致北大西洋中部表层群落异养和自养成分之间的竞争加剧，并可能影响浮游细菌对有机质的循环。
Bacterial productivity and biomass are thought to be limited by dissolved organic carbon (DOC) in much of the world's oceans. However, the mixed layer of oligotrophic oceans is often depleted in dissolved inorganic nitrogen and phosphate, raising the possibility that macronutrients may also limit heterotrophic bacterial growth. We used nutrient bioassay experiments to determine whether inorganic nutrients (N, P, Fe) and/or DOC could limit bacterial productivity and biomass in the central North Atlantic during the spring of 2004 (Mar‐Apr). We observed that both heterotrophic bacterial productivity and biomass were co‐limited by N and P in the oligotrophic North Atlantic, and additions of labile DOC (glucose) provided no stimulation unless N and P were also added. Flow cytometry results indicated that only a small subset of large cells high in nucleic acid content were responsible for the increased productivity in the combined NP amendments. In contrast, nutrient additions elicited no net change on the dominant component of the bacterial population, composed of small cells with relatively low nucleic acid content. In the combined NP treatments the relative increase in bacterial production was greater than that measured when phytoplankton productivity was relieved of nitrogen limitation. These results suggest that N and P co‐limitation in the bacterial community results in increased competition between the heterotrophic and autotrophic components of the surface communities in the Central North Atlantic Ocean, and potentially impacts the cycling of organic matter by the bacterioplankton.