Phytoplankton growth and microzooplankton grazing in high-nutrient, low-chlorophyll waters of the equatorial Pacific: Community and taxon-specific rate assessments from pigment and flow cytometric analyses
Phytoplankton growth and microzooplankton grazing in high-nutrient, low-chlorophyll waters of the equatorial Pacific: Community and taxon-specific rate assessments from pigment and flow cytometric analyses
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DOI：
10.1029/2000jc000744
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发表时间：
2003-10-31
影响因子：
3.6
通讯作者：
Bidigare, RR
中科院分区：
文献类型：
--
作者：
Landry, MR;Brown, SL;Bidigare, RR
[1]在一次法国联合全球海洋通量研究航行中，利用海水稀释技术调查了浮游植物生长和微型浮游动物的摄食率，这次航行的重点是180度赤道太平洋高营养、低叶绿素的摄食过程（1996年10月至11月，赤道区的Broutage研究）。基于荧光分光光度法和高效液相色谱法色素分析的原始速率估计值通常非常接近，但大多数显示出增长和放牧的严重不平衡。流式细胞仪（FCM）分析被用来作为一种替代的方法来区分人群，并作为一种手段来调整色素为基础的增长估计细胞叶绿素含量和生物量的变化。总叶绿素a（Tchla）在30 m和60 m处的平均群落生长速率分别为0.76 d（-1）和0.27 d（-1）。两个深度的平均放牧率分别为0.56和0.15 d（-1），占浮游植物总生长量的69%。对于原核picophytocliter，原绿球藻（PRO），率估计从dv-chl a和FCM细胞计数一般表明平衡的增长和放牧，因此密切放牧控制微型浮游动物。在赤道，根据dv-chl a估算的速率在30米处平均为0.6 - 0.7 d（-1），在60米处平均为0.25 - 0.26 d（-1），这与基于30 - 70米深度范围内昼夜色素变化的推断一致。浮游植物生产的估计，从实验确定的速率和显微镜评估的自养碳在30米（平均值= 19毫克C m（-3）d（-1））同意与同期测量的14 C吸收。硅藻生长速率估计值（1.0 - 1.6 d（-1）），限制了同期测量的硅酸盐吸收，意味着一个相对较小的生物量（10 - 45 nmol C L-1）与高周转率和回收。
[1] Phytoplankton growth and microzooplankton grazing rates were investigated using the seawater dilution technique during a French Joint Global Ocean Flux Study cruise focusing on grazing processes in the high-nutrient, low-chlorophyll equatorial Pacific at 180degrees ( Etude du Broutage en Zone Equatoriale, October - November, 1996). Raw rate estimates based on spectrofluorometric and high-performance liquid chromatography pigment analyses were typically in close agreement, but most showed substantial imbalances in growth and grazing. Flow cytometric (FCM) analyses were used both as an alternate approach for distinguishing populations and as a means for adjusting pigmentbased growth estimates for changes in cellular chlorophyll content and biovolume. Total chlorophyll a (Tchl a) gave mean community growth rates of 0.76 d(-1) at 30 m and 0.27 d(-1) at 60 m. Grazing rates averaged 0.56 and 0.15 d(-1) at the two depths, respectively, and 69% of phytoplankton growth overall. For the prokaryotic picophytoplankter, Prochlorococcus ( PRO), rate estimates from dv-chl a and FCM cell counts generally indicated balanced growth and grazing and therefore close grazing control by microzooplankton. At the equator, rate estimates from dv-chl a averaged 0.6 - 0.7 d(-1) at 30 m and 0.25 - 0.26 at 60 m and were consistent with inferences based on diel pigment variations in the 30 - 70 m depth range. Phytoplankton production estimates from experimentally determined rates and microscopical assessments of autotrophic carbon at 30 m ( mean = 19 mg C m(-3) d(-1)) agreed well with contemporaneous measurements by 14 C uptake. Diatom growth rate estimates (1.0 - 1.6 d(-1)), constrained by contemporaneous measurements of silicate uptake, implied a relatively small biomass (10 - 45 nmol C L-1) with high rates of turnover and recycling.