Phytoplankton growth, microzooplankton grazing, and carbon cycling in marine systems
Phytoplankton growth, microzooplankton grazing, and carbon cycling in marine systems
复制标题
DOI：
10.4319/lo.2004.49.1.0051
复制
发表时间：
2004-01-01
影响因子：
4.5
通讯作者：
Landry, MR
中科院分区：
文献类型：
--
作者：
Calbet, A;Landry, MR
我们分析了微型浮游食草动物对海洋浮游植物的全球影响及其对微生物群落中再矿化过程的影响。这些数据是通过广泛的文献搜索获得的，从稀释实验中获得了788对自养生长(Mu)和微型浮游动物放牧(M)的配对率估计。从浮游植物现存量以碳当量衡量的研究中，我们表明，稀释实验的产量估计值是用标准C-14方法确定的产量的合理替代(r=0.89)。微型食草动物消耗初级生产量(PP)的比例m：Mu表明，微型浮游动物的消耗是海洋浮游植物死亡的主要来源，占整个数据集浮游植物日增长的67%。这一比率在不同的海洋生境和区域之间略有不同，数据平均值从沿海和河口环境的60%到公海的70%，从温带-亚极地和极地系统的类似到59%，到热带-亚热带地区的75%。根据对微型食草动物新陈代谢需求的估计，并假设它们消耗大部分细菌生产，区域平均估计的原生生物呼吸对于第一级消费者是每日PP的35-43%，对于三种营养转移是PP的49-59%。据估计，微生物食草动物对群落总呼吸的贡献与细菌呼吸的贡献相同。因此，对于仅从细菌参数来预测微生物群落在碳循环中的作用的生物地球化学模型来说，微型食草动物活动或营养结构的潜在生态系统差异是一个很大的不确定性。
We present an analysis of the global impact of microplanktonic grazers on marine phytoplankton and its implications for remineralization processes in the microbial community. The data were obtained by an extensive literature search that yielded 788 paired rate estimates of autotrophic growth (mu) and microzooplankton grazing (m) from dilution experiments. From studies in which phytoplankton standing stock was measured in terms of carbon equivalents, we show that the production estimate from dilution experiments is a reasonable proxy (r = 0.89) for production determined by the standard C-14 method. The ratio m: mu, the proportion of primary production (PP) consumed by micrograzers, shows that microzooplankton consumption is the main source of phytoplankton mortality in the oceans, accounting for 67% of phytoplankton daily growth for the full data set. This ratio varies modestly among various marine habitats and regions, with data averages ranging from 60% for coastal and estuarine environments to 70% for the open oceans, and from similar to59% for temperate-subpolar and polar systems to 75% for tropical-subtropical regions. Given estimates for the metabolic requirements of micrograzers and assuming they consume most bacterial production, regionally averaged estimates of the protistan respiration are 35-43% of daily PP for the first level of consumer or 49-59% of PP for three trophic transfers. The estimated contributions of microbial grazers to total community respiration are of the same magnitude as bacterial respiration. Consequently, potential ecosystem differences in micrograzer activity or trophic structure are a large uncertainty for biogeochemical models that seek to predict the microbial community role in carbon cycling from bacterial parameters alone.