Department of Marine Sciences, University of Gothenburg, Box 461, SE-450 30 Göteborg, Sweden.
Sven Loven Center Kristineberg, University of Gothenburg, Fiskebäckskil, Sweden.
Sci Adv. 2019 Feb 20;5(2):eaat5096. doi: 10.1126/sciadv.aat5096. eCollection 2019 Feb.
Fear of predation may influence food webs more than actual predation. However, the mechanisms and magnitude of nonconsumptive predator effects are largely unknown in unicellular-dominated food webs such as marine plankton. We report a general mechanism of chemically induced predator effects in marine plankton. Copepods, the most abundant zooplankton in the oceans, imprint seawater with unique polar lipids-copepodamides-which trigger toxin production and bioluminescence in harmful dinoflagellates. We show that copepodamides also elicit defensive traits in other phytoplankton, inducing the harmful algal bloom-forming diatom to produce 10 times more toxins, and colony-forming diatoms to decrease colony size by half. A 1-year study in the northeast Atlantic revealed that natural copepodamide concentrations are high enough to induce harmful algal toxins and size reduction in dominant primary producers when copepods are abundant. We conclude that copepodamides will structure marine plankton toward smaller, more defended life forms on basin-wide scales.
对捕食的恐惧可能比实际捕食对食物网的影响更大。然而，在以单细胞为主的食物网中，如海洋浮游生物，非消耗性捕食者的作用机制和程度在很大程度上是未知的。我们报告了海洋浮游生物中一种普遍的化学诱导捕食者效应的机制。桡足类是海洋中最丰富的浮游动物，它们在海水中留下独特的极性脂质——桡足酰胺，这会引发有毒甲藻产生毒素和生物发光。我们表明，桡足酰胺也会在其他浮游植物中引发防御特征，促使形成有害藻华的硅藻产生的毒素增加 10 倍，并使形成群体的硅藻的群体大小减半。在东北大西洋进行的为期一年的研究表明，当桡足类丰富时，自然桡足酰胺浓度足以在优势初级生产者中诱导有害藻类毒素和体积减小。我们的结论是，桡足酰胺将使海洋浮游生物朝着更小、更具防御性的生命形式发展，这种影响在整个盆地范围内都存在。
