Department Biologie II, Ludwig-Maximilians-Universität München, Grosshaderner Strasse 2, Planegg-Martinsried, Germany.
Am Nat. 2010 Apr;175(4):E91-E104. doi: 10.1086/650728.
Most phytoplankters face opposing vertical gradients in light versus nutrient supplies but have limited capacities for vertical habitat choice. We therefore explored a dynamical model of negatively buoyant algae inhabiting a one-dimensional water column to ask how water column depth and turbulence constrain total (areal) phytoplankton biomass. We show that the population persistence boundaries in water column depth-turbulence space are set by sinking losses and light limitation but that nutrients are most limiting to total biomass in water columns that are neither too shallow or too weakly mixed (where sinking losses prevail) nor too deep and turbulent (where light limitation prevails). In shallow waters, the most strongly limiting process is nutrient influx to the bottom of the water column (e.g., from sediments). In deep waters, the most strongly limiting process is turbulent upward transport of nutrients to the photic zone. Consequently, the highest total biomasses are attained in turbulent waters at intermediate water column depths and in deep waters at intermediate turbulences. These patterns are insensitive to the assumption of fixed versus flexible algal carbon-to-nutrient stoichiometry, and they arise irrespective of whether the water column is a surface layer above a deep water compartment or has direct contact with sediments.
大多数浮游植物都面临着光照与养分供应的垂直梯度相反的情况，但它们在垂直栖息地选择方面的能力有限。因此，我们探索了一种居住在一维水柱中的负浮力藻类的动力模型，以探讨水柱深度和湍流如何限制总（面积）浮游植物生物量。我们表明，水柱深度-湍流空间中的种群持续边界是由下沉损失和光照限制设定的，但在既不太浅也不太弱混合（下沉损失占主导地位）或太深且湍流（光照限制占主导地位）的水柱中，养分对总生物量的限制最大。在浅水中，最具限制作用的过程是水柱底部的营养物质流入（例如，来自沉积物）。在深水中，最具限制作用的过程是营养物质向上的湍流输送到光区。因此，在中等深度的湍流水域和中等湍流的深水中，总生物量最高。这些模式对固定与灵活藻类碳-养分化学计量比的假设不敏感，并且无论水柱是深水区上方的表层还是与沉积物直接接触，都会出现这些模式。
