Dalsgaard Johanne, St John Michael, Kattner Gerhard, Müller-Navarra Dörthe, Hagen Wilhelm
University of Copenhagen, Danish Institute for Fisheries Research, Charlottenlund Castle, DK-2920 Charlottenlund, Denmark.
Adv Mar Biol. 2003;46:225-340. doi: 10.1016/s0065-2881(03)46005-7.
Fatty acids have been used as qualitative markers to trace or confirm predator-prey relationships in the marine environment for more than thirty years. More recently, they have also been used to identify key processes impacting the dynamics of some of the world's major ecosystems. The fatty acid trophic marker (FATM) concept is based on the observation that marine primary producers lay down certain fatty acid patterns that may be transferred conservatively to, and hence can be recognized in, primary consumers. To identify these fatty acid patterns the literature was surveyed and a partial least squares (PLS) regression analysis of the data was performed, validating the specificity of particular microalgal FATM. Microalgal group specific FATM have been traced in various primary consumers, particularly in herbivorous calanoid copepods, which accumulate large lipid reserves, and which dominate the zooplankton biomass in high latitude ecosystems. At higher trophic levels these markers of herbivory are obscured as the degree of carnivory increases, and as the fatty acids originate from a variety of dietary sources. Such differences are highlighted in a PLS regression analysis of fatty acid and fatty alcohol compositional data (the components of wax esters accumulated by many marine organisms) of key Arctic and Antarctic herbivorous, omnivorous and carnivorous copepod species. The analysis emphasizes how calanoid copepods separate from other copepods not only by their content of microalgal group specific FATM, but also by their large content of long-chain monounsaturated fatty acids and alcohols. These monounsaturates have been used to trace and resolve food web relationships in, for example, hyperiid amphipods, euphausiids and fish, which may consume large numbers of calanoid copepods. Results like these are extremely valuable for enabling the discrimination of specific prey species utilized by higher trophic level omnivores and carnivores without the employment of invasive techniques, and thereby for identifying the sources of energetic reserves. A conceptual model of the spatial and temporal dominance of group-specific primary producers, and hence the basic fatty acid patterns available to higher trophic levels is presented. The model is based on stratification, which acts on phytoplankton group dominance through the availability of light and nutrients. It predicts the seasonal and ecosystem specific contribution of diatom and flagellate/microbial loop FATM to food webs as a function of water column stability. Future prospects for the application of FATM in resolving dynamic ecosystem processes are assessed.
三十多年来，脂肪酸一直被用作定性标记物，以追踪或确认海洋环境中的捕食者 - 猎物关系。最近，它们还被用于识别影响世界一些主要生态系统动态的关键过程。脂肪酸营养标记（FATM）概念基于这样的观察结果：海洋初级生产者形成特定的脂肪酸模式，这些模式可能保守地传递给初级消费者，因此可以在初级消费者中识别出来。为了识别这些脂肪酸模式，我们对文献进行了调研，并对数据进行了偏最小二乘（PLS）回归分析，验证了特定微藻FATM的特异性。微藻群体特异性FATM已在各种初级消费者中得到追踪，特别是在食草性哲水蚤中，它们积累了大量脂质储备，并且在高纬度生态系统中占浮游动物生物量的主导地位。在较高营养级，随着肉食程度的增加以及脂肪酸来源的多样化，这些食草标记会变得模糊。北极和南极关键的食草性、杂食性和肉食性哲水蚤物种的脂肪酸和脂肪醇组成数据（许多海洋生物积累的蜡酯成分）的PLS回归分析突出了这些差异。该分析强调了哲水蚤不仅通过其微藻群体特异性FATM的含量，而且通过其大量的长链单不饱和脂肪酸和醇与其他哲水蚤区分开来。这些单不饱和脂肪酸已被用于追踪和解析例如掠食性端足类动物、磷虾和鱼类等食物网关系，这些动物可能会消耗大量的哲水蚤。这样的结果对于在不采用侵入性技术的情况下区分较高营养级杂食动物和肉食动物所利用的特定猎物物种，从而识别能量储备来源极为有价值。本文提出了一个关于特定群体初级生产者的时空优势以及因此可供较高营养级利用的基本脂肪酸模式的概念模型。该模型基于分层现象，分层通过光和营养物质的可利用性对浮游植物群体优势产生作用。它预测了硅藻和鞭毛藻/微生物环FATM作为水柱稳定性函数对食物网的季节性和生态系统特定贡献。评估了FATM在解析动态生态系统过程中的应用前景。
