Moeller Holly V, Archibald Kevin M, Leles Suzana G, Pfab Ferdinand
Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA 93106-9620, USA.
Department of Marine and Environmental Biology, University of Southern California, Los Angeles, CA 90089-0378, USA.
Sci Adv. 2024 Dec 13;10(50):eadr0664. doi: 10.1126/sciadv.adr0664.
Mixotrophic protists combine photosynthesis with the ingestion of prey to thrive in resource-limited conditions in the ocean. Yet, how they fine-tune resource investments between their two different metabolic strategies remains unclear. Here, we present a modeling framework (Mixotroph Optimal Contributions to Heterotrophy and Autotrophy) that predicts the optimal (growth-maximizing) investments of carbon and nitrogen as a function of environmental conditions. Our model captures a full spectrum of trophic modes, in which the optimal investments reflect zero-waste solutions (i.e., growth is colimited by carbon and nitrogen) and accurately reproduces experimental results. By fitting the model to data for , we were able to predict metabolic strategies at a global scale. We find that high phagotrophic investment is the dominant strategy across different oceanic biomes, used primarily for nitrogen acquisition. Our results therefore support empirical observations of the importance of mixotrophic grazers to upper ocean bacterivory.
混合营养型原生生物将光合作用与捕食猎物相结合，从而在海洋资源有限的条件下茁壮成长。然而，它们如何在两种不同的代谢策略之间微调资源分配仍不清楚。在此，我们提出了一个建模框架（混合营养对异养和自养的最优贡献），该框架可预测碳和氮的最优（使生长最大化的）分配，此分配是环境条件的函数。我们的模型涵盖了全范围的营养模式，其中最优分配反映了零浪费解决方案（即生长受碳和氮的共同限制），并能准确再现实验结果。通过将模型与……的数据拟合，我们能够在全球尺度上预测代谢策略。我们发现，高吞噬营养投资是不同海洋生物群落中的主导策略，主要用于获取氮。因此，我们的结果支持了关于混合营养型食草动物对上层海洋噬菌作用重要性的实证观察。
