The Limits to Copepod Growth: Resolving the Malthusian Dilemma

浮游动物是碳向更高营养层、更深的水和沉积物转移的主要途径。对浮游动物产量的估计对于了解初级产量的短期和长期变化如何影响这些碳转移速率至关重要。Drs。兰德里、亨特利和洛佩斯假设，单从栖息地温度就能以一级精度预测桡足动物的生长。如果这种关系被证明是可靠的，我们将有一个强大的工具来估计浮游动物的产量。然而，这种显而易见的简单关系引发了关于浮游生物动力学的重大问题，因为它否定了浮游动物食物有限的通常假设。这些来自加利福尼亚大学和夏威夷大学的研究人员将调查这一论点，即在种群水平上，桡足类的食物限制主要通过死亡率的变化来实现。他们认为，在鱼类种群中有强有力的证据表明，密度依赖于早期生命阶段的死亡率。因此，对于海洋种群来说，马尔萨斯困境的一般解决方案是早死而不是晚饿死。他们将通过以下方式解决这些关键问题：-(1)直接测量各种温水桡足动物物种的繁殖时间，以填补数据库中的关键空白；-(2)实验验证了特定尺寸的捕食压力可以通过提高种群水平上的表观发育速度来补偿食物限制生长速度的影响。

Zooplankton are the major pathway for carbon transfer to higher trophic levels, and to deeper water and the sediments. Estimates of zooplankton production are critical in understanding how short and long term variations in primary production affect these rates of carbon transfer. Drs. Landry, Huntley and Lopez have hypothesized that copepod growth is predictable with first-orderprecision from habitat temperature alone. If this relationship proves to be robust, we will have a powerful tool for estimating zooplankton production. However, the apparent simplicity of this relation raises major issues about plankton dynamics since it denies the usual assumption that zooplankton are food-limited. These investigators from the Universities of California and Hawaii will investigate the thesis that, at the population level, food limitation of copepods operates mainly through changes in mortality rate. They suggest that there is strong evidence for this in fish populations where density dependence operates on the mortality of the early life stages. Thus, the general solution of the Malthusian dilemma for marine populations is to die young rather than starve later. They will address these key questions in the following ways: - (1) Direct measurements of the generation times of a variety of warm-water copepod species, to fill a critical gap in the database; - (2) Experimental testing of the hypothesis that size-specific predation pressure can compensate for the effects of food-limited growth rate by increasing apparent development rate at the population level.