Microbe abundance and biomass in the euphotic zone of the Aegean Sea at Station SEPT-1997-GN36199704605MSB04

10-30 ml subsamples were concentrated on 25 mm black polycarbonate filters (0.6 µm for NF, 0.2 µm for B), stained with DAPI for 10 min and filtered. NF were counted using UV and blue excitation and enumerated. Heterotrophic B were counted using UV excitation. NF were classified in size categories and biovolume was calculated. NF abundance data were converted into C biomass using 220 fgC µm**-3. Bact abund data were converted into C biomass using 20 fgC cell**-1. BP C was estimated by the 3H-leucine approach according to Kirchman et al. (1986) and Kirchman D.L., 1993. Leucine incorporation as a measure of biomass production by heterotrophic bacteria. In: Kemp P.F. et al. (eds), 1993. Handbook of methods in aquatic microbial ecology. Lewis Publishers, Ann Arbor, 509-512). At each depth duplicate samples and a control one were incubated with 1 nM L-[4,5 3H]-leucine (specific activity 128 Ci/mmol) and 18 nM non-radioactive leucine. Samples were incubated in the dark at in situ temperature.

将10~30 mL的子样品浓缩至25 mm黑色聚碳酸酯滤膜（纳米浮游生物（NF）使用孔径0.6 µm滤膜，异养细菌（B）使用孔径0.2 µm滤膜），经DAPI（4',6-二脒基-2-苯基吲哚）染色10 min后完成过滤。采用紫外与蓝光激发模式对NF进行计数统计，异养细菌则采用紫外激发模式完成计数。将NF按尺寸类别进行分组，并计算其生物体积。基于220 fgC·μm⁻³的转换系数，将NF丰度数据转换为碳生物量；基于20 fgC·cell⁻¹的转换系数，将细菌丰度数据转换为碳生物量。细菌生产碳量（BP C）采用³H-亮氨酸法进行估算，参考Kirchman等（1986）以及Kirchman D.L. 1993年的研究：《以亮氨酸掺入量作为异养细菌生物量生产的检测指标》，收录于Kemp P.F.等主编的1993年《水生微生物生态学实验方法手册》，Lewis出版社，安阿伯，第509-512页。在每个采样深度下，设置平行样品与空白对照，加入1 nM L-[4,5-³H]-亮氨酸（比活度128 Ci/mmol）与18 nM非放射性亮氨酸，将样品置于暗处，按照原位温度进行培养。