摘要
采用荧光显微镜直接计数和分级培养的方法对黄海冷水团水域的浮游细菌分布及其摄食压力来源进行了研究,结果表明:在所研究水域聚球(Synechococcusspp.)蓝细菌生物量的变化是0.78～33.49mgCm3(平均为6.26mgCm3,n=197),最高值是最低值的40多倍;异养细菌生物量的变化是1.58～21.25mgCm3(平均为5.79mgCm3,n=197),最高值是最低值的13倍。在垂直方向上聚球蓝细菌生物量表现为中层>表层>底层,异样细菌生物量表现为表层>中层>底层。聚球蓝细菌对浮游植物总生物量的贡献(CBPB)为2%～99%(平均为42.5%),而异养细菌生物量与浮游植物生物量的比值为0.05～6.37(平均为0.85)。在浮游细菌的昼夜变化中,聚球蓝细菌的最高值是最低值的8.8倍,异养细菌最高值是最低值的2.8倍,但二者的昼夜变化规律不明显。浮游细菌的分布与水温和盐度变化基本一致,且浮游细菌生物量最低值出现在冷水团水域。另外在冷水团区域聚球蓝细菌的主要摄食者是小型浮游动物(Microzooplankton,20～200μm),摄食率约为0.20～0.42d。
The Yellow Sea Cold Water Mass （YSCWM） is very important phenomena in the southern Yellow Sea, especially prominent in summer and autumn. It is renewal in winter every year and the boundary and temperature-salinity structure remain almost unchanged one year comparing to another. The primary characters of YSCWM are low temperature with a remarkable variation （5 ～ 12℃） and a rather constant salinity （31.5 ～ 32.5）. The particular physico-chemical parameters of YSCWM represent a very attractive model system to study the impact of environmental changes on the biomass of bacterioplankton which is composed mainly of heterotrophic bacteria and two types of photosynthetic prokaryotes cyanobacteria, Prochlorococcus and Synechococcus. These prokaryotes are basic components of microbial loop, and play an important role in the marine food web.
In this paper, the author described the distribution of bacterioplankton and the preying pressure. At the same time, the author discussed the effect of Yellow Sea Cold Water Mass （YSCWM） on the distribution of bacterioplankton.
Four special surveys were carried out in Aug. 2001, and Aug., Sep., Oct. 2002 in the southern Yellow Sea, China.Bacterioplankton abundance and biomass were quantified along the transect from Qingdao of China to Jeju island of Korea. Samples for bacterioplankton were collected from a SeaBird CTD-General Oceanic Rosette assembly with 10 1 Go-Flo bottles, and preserved with buffered glutaraldehyde at a concentration of 1%. Synechococcus cyanobacteria abundance was determined by directly counting cell numbers using epifluorescence microscopy method; and heterotrophic bacteria after acridine organge staining. The biomass of Synechococcus cyanobacteria and heterotrophic bacteria were calculated with a carbon conversion factor of 294 fg/cell and 20 fg/cell, respectively. Concentrations of Chl-a were measured on a Turner fluorometer. Phytoplankton biomass was calculated by a conversion factor of 50 mg C/mg chlorophyll.
The results showed： the rang of Synechococcus biomass was 0.78 ～ 33.49 mg C/m^3 （average was 6.26 mg C/m^3 ）, and heterotrophic bacteria biomass was 1.58～21.25 mg C/m^3 （average was 5.79 mg C/m^3, n = 197）. In the vertical direction, the distribution of Synechococcus biomass was shown as the mid-layer 〉 surface 〉 bottom, and heterotrophic bacteria biomass was surface 〉 mid-layer〉 bottom. The contribution of Synechococcus to the total phytoplankton biomass （CB/PB） was from 2% to 99 % （average vaule was 42.5 % ）, but the ratio of heterotrophic bacteria biomass to phytoplankton biomass was from 0.05 to 6.37 （average vaule was 0.85 ）. Daily variations of bacterioplankton biomass at anchor stations showed the Synechococcus maximal biomass was 8.8 times of the minimum value, and 2.8 times of heterotrophic bacteria. All in a word, the distribution of bacterioplankton was accorded with temperature and salinity, the minimum value of bacterioplankton biomass occurred in YSCWM waters. At same time, the microzooplankton （20 ～ 200μm） were the grazer who prey on Synechococcus in this waters, and the ingesting rate was about 0.20 ～ 0.42/d
出处
《生态学报》
CAS
CSCD
北大核心
2006年第4期1012-1020,共9页
Acta Ecologica Sinica
基金
国家自然科学基金资助项目(40376048)
国家重点基础研究专项经费资助项目(G19990437)~~
