Particulate organic matter (POM) forms the base of the pelagic food web, but is a complex category of material that undergoes substantial changes in quantity and quality across different time scales. As the primary consumers of POM, zooplankton are influenced by these fluctuations, resulting in shifts in the food web pathways that contribute to the production of higher trophic levels. We measured POM fatty acids, which are critical nutritional components in marine food webs, along with a suite of associated biotic and abiotic environmental conditions at a temperate coastal site over four years. Using these data, we investigated the co-occurring patterns of prey quality, quantity, and size, to develop a holistic understanding of how the prey field for zooplankton varies over the seasonal cycle and inter-annually. The seasonal pattern of POM fatty acids corresponded to the succession of phytoplankton taxa, but displayed stronger relationships to size-fractionated Chl a than taxonomic observations. Times with high micro-Chl biomass (spring and fall blooms) had the greatest concentrations of high quality food, but fatty acid levels remained high throughout the summer when Chl a concentrations dropped and the size distribution shifted towards pico-Chl. The 18-carbon polyunsaturated fatty acids 18:3ω3 (α-linolenic acid) and 18:4ω3 (stearidonic acid) increased during this time and were correlated with pico-Chl. In addition, the important nutritional factor for zooplankton and fish, the fatty acid ratio DHA:EPA (22:6ω3/20:5ω3), peaked during the middle of summer separately from the peak in Chl a. These seasonal patterns resulted in tradeoffs among the abundance, size, and nutritional quality of prey for zooplankton. We validated the basal sources of several fatty acids used as trophic markers within food web studies and in particular note their power for resolving size-based trophic connections. Interannual variability, e.g., the occurrence of fall diatom blooms and the timing of community shifts, is also discussed. This work lays the foundation for future studies of the zooplankton community at this location and the incorporation of realistic prey conditions into zooplankton studies.

颗粒有机物 (POM) 构成了远洋食物网的基础，但它是一种复杂的物质类别，在不同的时间尺度上会发生数量和质量的重大变化。作为 POM 的主要消费者，浮游动物受到这些波动的影响，导致食物网路径发生变化，从而有助于产生更高的营养水平。我们测量了 POM 脂肪酸，它是海洋食物网中的关键营养成分，以及四年来温带沿海地区的一系列相关生物和非生物环境条件。利用这些数据，我们调查了猎物质量、数量和大小的共同发生模式，以全面了解浮游动物的猎物场如何在季节周期和年际变化。a比分类观察。微量叶绿素生物量高的时期（春季和秋季开花）具有最高浓度的优质食物，但在整个夏季，当叶绿素a浓度下降并且尺寸分布向 pico-Chl 转变时，脂肪酸水平仍然很高。18 碳多不饱和脂肪酸 18:3ω3（α-亚麻酸）和 18:4ω3（硬脂酸）在此期间增加，并与 pico-Chl 相关。此外，浮游动物和鱼类的重要营养因子DHA:EPA（22:6ω3/20:5ω3）的脂肪酸比例在仲夏达到峰值，与叶绿素a的峰值不同。. 这些季节性模式导致浮游动物猎物的数量、大小和营养质量之间的权衡。我们验证了在食物网研究中用作营养标记的几种脂肪酸的基础来源，并特别指出了它们在解决基于大小的营养联系方面的能力。还讨论了年际变化，例如秋季硅藻水华的发生和群落变化的时间。这项工作为未来对该地区浮游动物群落的研究以及将现实的猎物条件纳入浮游动物研究奠定了基础。