The production, biomass and structure of phytoplankton in large rivers
The production, biomass and structure of phytoplankton in large rivers
复制标题
DOI：
10.1127/lr/10/1996/161
复制
发表时间：
1996-09
期刊：
影响因子：
--
通讯作者：
C. Reynolds;J. Descy
中科院分区：
文献类型：
--
作者：
C. Reynolds;J. Descy
大多数温带河流达到第四级或更高的携带一个独特的，往往是定义良好的浮游植物，定期和可预测的波动的丰度和组成。本文试图将河流浮游生物的维持、生产生态和物种选择与所谓的单向流动、急剧波动的排放和剧烈的湍流所带来的直观困难相协调。它检查了几个早期的理论，关于维护木板在河流沃茨，其中许多是接受含蓄，即使他们几乎没有受到挑战或验证。我们认为一系列的相邻和相互作用的栖息地，包括侧臂和底栖生物，作为避难所和河流浮游生物的来源。河流浮游生物包括相对较少的湖泊属，即使在那些情况下，它是受中间湖泊和水库。物理因素支配这些选择性状。在适当的流量、透明度和温度条件下，浮游植物可以维持高水平的光合生产，对中游河流的碳代谢做出积极贡献。而在下游的高级河流中，浊度可能会降低初级生产力，导致浮游植物减少，河流生态系统越来越受外来碳的驱动。河道内浮游生物的生长补充能力受站位特征和水文水位的强烈制约。人口增长往往是精细平衡的呼吸损失，但有时，可能会有明显的下游招募人口。这一过程显然不是通过增强增长，而是通过扩大机会来帮助的，这应该得到河流水力储存的支持，并在一定程度上，作为通道形态（截面，梯度，sinuosity）的函数。营养物和放牧很少被证明对浮游生物动态产生关键的控制，除非在持续和严重的物理限制得到缓解。在河流中的浮游植物的Perennation的支持faci lity为周栖或底栖生存和一个可检验的假设是先进的能力meropriotity是河流phytoplankton的一个基本属性。审查以个案研究为例证，并尽可能特别强调在多瑙河上进行的研究。
Most temperate rivers achieving fourth order or greater carry a distinctive and often wel l-defined phytoplankton with regular and predictable fluctuations in abundance and composition. This paper attempts to reconcile the maintenance, production ecology and species selection of river plankton with the intuitive difficulties posed by supposedly unidirectional flow, sharply fluctuating discharges and vigourous turbulence. It examines several of the early theories about the maintenance of plank ton in river waters, many of which are accepted implicitly even though they have been scarcely challenged or verified. We consider a range of adjacent and interacting habitats, including side-arms and the benthos, as refuges and sources of river plankton. River plankton comprises relatively few of the l imnetic genera, even in those instances where it is influenced by intermediate lakes and reser voirs. Physical factors dominate these selective traits. Under appropriate conditions of flow, clarity and temperature, phytoplankton may sustain high levels of photosynthetic production, contributing positively to the carbon metabolism of middle-order rivers . In lower reaches of higher order, howev er, turbidity may so lower primary productivity that the phytoplankton diminishes and the river eco system is driven increasingly by allochthonous carbon . In tum, the capacity for in-channel recruit ment of plankton by growth is strongly conditioned by characters of station and hydrological stage. Population increase is often finely balanced against respirational loss, yet, at times, there may be evident a prodigious downstream recruitment to populations. The process is apparently assisted not by enhanced growth but by extended opportunities, which are supposed to be supported by fluvial hydraulic storage and, to an extent, as a function of channel morphology (section, gradient, sinuosi ty). Nutrients and grazing have rarely been shown to exert critical control over plankton dynamics, except where the continuous and severe physical constraints are alleviated . Perennation of phyto plankton in rivers has to be supported by a faci lity for periphytic or benthic survival and a testable hypothesis is advanced that a capacity for meroplankty is an essential property of fluvial phytoplank ton . The review is i l lustrated by case studies and, wherever possible, with special emphasis on those carried out on the Danube.