Highly Unsaturated Fatty Acids: The Missing Link in Aquatic Food Webs?

在水生食物网中，通过植物-食草动物界面的能量流动是高度可变的，而控制浮游植物转化为浮游动物生物量效率的因素却知之甚少。本研究的目的是提高对调节能量转移效率、二次生产和营养级联强度的过程的理解。中心假设是，高不饱和脂肪酸（HUFA）含量的松子强烈影响这些过程。HUFA的生物学意义在动物细胞膜生理学、激素合成、人体健康与营养、水产养殖等诸多领域都是一个有前景且发展迅速的研究领域。HUFA之所以重要，主要有两个原因：首先，它们对动物细胞膜流动性有很大影响，是类二十烷（包括前列腺素、白三烯和其他动物激素）的前体；其次，它们只由植物产生。与许多脂质不同，HUFA不用于能量储存。这些事实导致了具体的预测，在以高HUFA含量的浮游植物为主的季节，耦合紧密，能量传递高效，而在低HUFA含量的季节，耦合较弱。在湖泊类型的比较中已经观察到这种模式，在以hufa -贫蓝藻为主的湖泊中耦合非常弱，而在以富含hufa的硅藻和隐生植物为主的湖泊中耦合紧密。在本研究中，将通过一系列实验来检验这些模式的控制，以研究浮游动物生长和生长效率与海藻元素和生化组成之间的关系。

9615888 Goldman In aquatic food webs, the flow of energy across the plant-herbivore interface is highly variable and the factors controlling the efficiency at which phytoplankton is converted to zooplankton biomass are poorly understood. The objective of this research is to improve understanding of processes that regulate efficiency of energy transfer, secondary production and strength of trophic cascades. The central hypothesis is that the highly unsaturated fatty acid (HUFA) content of seston strongly influences these processes. The biological significance of HUFA is a promising and rapidly developing area of research in a very wide variety of fields including animal cell membrane physiology, hormonal synthesis, human health and nutrition, and aquaculture. HUFA are important for two principal reasons: first, they have a large impact on animal cell membrane fluidity and are precursors for eicosanoids (which includes prostaglandins, luekotrienes and other animal hormones), and second, they are only produced by plants. Unlike many lipids, HUFA are not used for energy storage. These facts lead to the specific prediction that during periods when the seston is dominated by phytoplankton with high HUFA content, coupling will be tight and energy transfer will be efficient, while during periods with low-HUFA seston, coupling will be weak. This pattern has already been observed in comparisons among lake types, with very weak coupling in lakes dominated by HUFA-poor cyanobacteria and tight coupling in lakes dominated by HUFA-rich diatoms and cryptophytes. In this research, controls on these patterns will be tested in a series of experiments to examine the relationship between seston elemental and biochemical composition and zooplankton growth and growth efficiency.