Phytoplankton productivity and growth measurements: past, present and future
Phytoplankton productivity and growth measurements: past, present and future
复制标题
浮游植物生产力和生长测量：过去、现在和未来
DOI：
10.1093/plankt/6.2.219
复制
发表时间：
1984
影响因子：
2.1
通讯作者：
G. Harris
中科院分区：
文献类型：
--
作者：
G. Harris
首先，有必要界定生产力和增长的含义。产量是“在一段时间内形成的新有机物质的重量，加上在此期间的任何损失”（ML-3 T-1），（Wetzel，1975）。死亡、下沉和放牧造成生产损失（图1）。毛生产力是指观察到的（净）生物量变化率加上所有损失。传统上，浮游植物生产力的总速率是从观察到的净生产力加上呼吸损失中获得的。生物体被认为是光合自养的，生产力通常以光合碳固定或氧释放来衡量（Harris，1978）。在培养瓶实验中，细胞死亡、下沉和放牧在孵化过程中往往被大大忽视。忽视放牧和养分再生对产量估计的影响可能是相当大的。生产率通常用叶绿素或碳来表示，存在标准因子来从一个转换到另一个。磷、氮和硫也被用来衡量生产力和估计生物量。种群增长也可以通过细胞数量的变化，颗粒碳或其他元素的变化，或叶绿素的变化来测量。根据这些生物量计量方法估计的增长率可能会因使用的生物量计量方法而有所不同。在几乎所有情况下，观察到的生物量变化都代表着类似于净生产力的东西，因为死亡率造成的损失无法估计（图1）。由于用瓶中碳或氧流量衡量的净生产力通常不包括死亡率造成的损失，因此由此得出的估计数与从种群计数或生物量变化得出的估计数之间可能存在相当大的差异。在这里，净生产力和毛生产力是通过元素流动测量的速率，而生长是通过细胞计数或生物量的其他变化测量的生物量的增加。相对增长率表示为最大增长率的分数。许多工人将生产率测量转换为特定的增长率或周转时间。有必要区分再生生产和“新”生产（Eppley和Peterson，1979年），在“新”生产只是再生生产的一小部分的情况下，生产率的估计可能与增长率的估计有很大差异。在“新”产品的沃茨-
At the outset it is necessary to define what we mean by productivity and growth. Production is' the weight of new organic material formed over a period of time, plus any losses during that period'(ML-3 T-1),(Wetzel, 1975). Losses of production occur as a result of death, sinking and grazing (Figure 1). Gross productivity refers to the observed (net), rate of change in biomass plus all losses. Traditionally the gross rate of phytoplankton productivity has been obtained from the observed net productivity plus respiratory losses. The organisms are assumed to be photoautotrophic, and productivity is usually measured as photosynthetic carbon fixation or oxygen release (Harris, 1978). In bottle experiments, cell death, sinking and grazing during the incubation have often been largely neglected. The effects on production estimates of the neglect of grazing and nutrient regeneration may be considerable. Rates of productivity are commonly expressed in terms of chlorophyll or carbon and standard factors exist to convert from one to another. Phosphorus, nitrogen and sulphur have also been used to measure productivity and to estimate biomass. Population growth may also be measured by changes in cell number, changes in paniculate carbon or other elements, or changes in chlorophyll. The growth rate, as estimated by these measures of biomass, may show differences depending on which measure of biomass is used. In almost all cases the observed changes in biomass represent something akin to net productivity as losses due to mortality (Figure 1) cannot be estimated. Because the net productivity measured by carbon or oxygen flux in a bottle does not usually include losses due to mortality, there may be a considerable discrepancy between the estimates so obtained and those obtained from population counts or biomass changes. Here net and gross productivity are the rates measured by the flux of elements, and growth is the increase in biomass as measured by cell counts or other changes in biomass. Relative growth rate is expressed as a fraction of the maximum growth rate. Many workers convert productivity measurements to specific growth rates or turnover times. It has become necessary to distinguish between regenerated production and'new'production (Eppley and Peterson, 1979) and, in cases where'new'production is only a small fraction of the regenerated production, estimates of productivity may differ greatly from estimates of growth. In waters where'new'produc-