Mechanistic origins of variability in phytoplankton dynamics: Part I: niche formation revealed by a size-based model

作者：Wirtz Kai W^*

来源：Marine Biology, 2013, 160(9): 2319-2335.

DOI：10.1007/s00227-012-2163-7

This paper aims to unravel the complexity of how cell size determines major ecological and physiological functions in unicellular algae. It assembles recent mechanistic descriptions for size dependencies of respiration and maximal resource uptake rates. New dependencies are derived for mortality due to sinking and grazing. The model also describes how internal nutrient quota varies within an autotrophic community due to the allometry of nutrient uptake. Net production, grazing, and sedimentation can be shown to be uni- or multi-modal functions of cell size, in accordance with literature data. Grazing mortality attains maxima at distinct prey sizes, which result from overlaying major zooplankton feeding spectra. Sedimentation vanishes for small cells due to Stokes' law, but also for huge diatoms as long as they are vital. Their greater degree of vacuolation possibly promotes the capacity of buoyancy regulation. After synthesizing the physiological, morphological, and ecological relationships, intricate and eventually multi-modal growth-size dependencies arise. This niche building may explain part of the great diversity in phytoplankton. Multi-modal allometries can also induce paradoxical community shifts or enlarge the variety of community responses to external changes.

• 出版日期2013-9