Bacterial abundance, production and organic carbon limitation in the Southern Ocean (39-62°S, 4-14°E) during the austral summer 1997/1998
Bacterial abundance, production and organic carbon limitation in the Southern Ocean (39-62°S, 4-14°E) during the austral summer 1997/1998
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DOI：
10.1016/j.dsr2.2001.01.003
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发表时间：
2004-01-01
影响因子：
3
通讯作者：
Bertilsson, S
中科院分区：
文献类型：
--
作者：
Granéli, W;Carlsson, P;Bertilsson, S
1997/1998 年 12 月至 1 月航行期间，对南大洋不同区域（南纬 39-62 度，东经 4-14 度）的细菌丰度和产量进行了研究。同时研究了由于有机碳（葡萄糖）或无机氮和磷的可用性有限而导致的细菌潜在生长限制的作用。观察到地表水温（-2 至 18 ℃）与细菌丰度（< 0. 1 X 10(6)-1.5 x 10(6) 细胞 ml(-1)）呈正相关。在垂直剖面上对细菌进行了研究，集中在接近东经 6 度的三个区域：前春季冰缘（SIE，南纬 60 度，叶绿素 a 高）、前冬季冰缘（WIE，南纬 56 度，叶绿素 a 低）和南纬 51 度的南极极锋（APF，中等叶绿素 a 水平）。 APF以南的细菌丰度普遍较低，上部50 m处的细菌丰度通常低于0.3 x 10(6)细菌ml(-1)。在更深的水域中，WIE 和 APF 站的细菌丰度急剧下降，但 SIE 站的细菌丰度则不太明显。 APF站混合层中细菌的平均体积产量最高（0.04 μg Cl-1 h(-1)），但SIE站只有该值的一半（0.02 μg Cl-1 h(-1)），而WIE则介于两者之间（大约0.03 μg Cl-1 h(-1)）。在 100 m 以下，细菌产量下降至接近检测限的值。这三个区域均未表现出地表水（2 m）或叶绿素最大值（位于 30 至 66 m 之间）细菌产生的任何系统性昼夜变化。我们观察到细菌产量与体内叶绿素a荧光之间呈正相关，但该参数与细菌丰度之间没有相关性，可能表明这两个参数的控制机制不同。将来自 20 m 深度的未过滤水样在原位温度下孵育，并用铵、磷酸盐或葡萄糖进行修正。在所有三个实验中，从开普敦以南的温暖水域（南纬 38 度，+ 18.6 摄氏度）、APF 北部较冷且无机营养丰富的水域（南纬 45 度，+ 7.0 摄氏度）以及 SIE 寒冷、营养丰富的水域（南纬 61 度，-0.13 摄氏度），有机碳的添加导致细菌数量显着增加。生产。三个地区的细菌生长速率差异很大，并且在低温下细菌群落对碳添加的生长反应非常缓慢。 (C) 2004 Elsevier Ltd. 保留所有权利。
Bacterial abundance and production were studied in different zones in the Southern Ocean (39-62degreesS, 4-14degreesE) during a cruise in December-January 1997/1998. The role of potential growth limitation of bacteria due to limited availability of organic carbon (glucose) or inorganic N and P was studied in parallel. A positive correlation between surface water temperatures (-2 to 18 degreesC) and bacterial abundance (< 0. 1 X 10(6)-1.5 x 10(6) cells ml(-1)) was observed. Bacteria were studied in vertical profiles, concentrated to three areas close to 6degreesE: the former Spring Ice Edge (SIE, 60degreesS, high chlorophyll a), the former Winter Ice Edge (WIE, 56degreesS, low chlorophyll a) and the Antarctic Polar Front at 51degreesS (APF, moderate chlorophyll a levels). Bacterial abundance was uniformly low south of the APF, and for the upper 50 m generally below 0.3 x 10(6) bacterial ml(-1). In deeper water, bacterial abundance decreased dramatically for WIE and APF stations, but less markedly for SIE stations. The average volumetric bacterial production in the mixed layer was highest for APF stations (0.04 mug Cl-1 h(-1)), but only half of this value for SIE stations (0.02 mug Cl-1 h(-1)), with WIE in between (approximately 0.03 mug Cl-1 h(-1)). Below 100 m, bacterial production decreased to values close to the detection limit. None of the three areas demonstrated any systematic diurnal variations in bacterial production in surface water (2 m) or at the chlorophyll maximum (situated between 30 and 66 m). We observed a positive correlation between bacterial production and in vivo chlorophyll a fluorescence, but there was no correlation between this parameter and bacterial abundance, possibly indicating different control mechanisms for these two parameters. Unfiltered water samples from 20 m depth were incubated at in situ temperatures and amended with ammonium, phosphate or glucose. In all the three experiments, from warm waters (relatively poor in inorganic nitrogen and phosphorus) south of Cape Town (38degreesS, + 18.6 degreesC), in the colder and inorganic nutrient-rich waters north of the APF (45degreesS, + 7.0 degreesC) as well as in the cold, nutrient-rich waters at the SIE (61 degreesS, -0.13 degreesC), organic carbon additions resulted in a significant increase in bacterial production. Bacterial growth rates were very different between the three regions, and the growth response in the bacterial communities to the carbon additions was very slow at low temperatures. (C) 2004 Elsevier Ltd. All rights reserved.