Park Gihong, Batoh Christina, Dam Hans G
Department of Marine Sciences, University of Connecticut, 1080 Shennecossett Road, Groton, CT 06340, USA.
Toxins (Basel). 2025 Jun 7;17(6):290. doi: 10.3390/toxins17060290.
The non-consumptive effects of past predator exposure on phytoplankton have gained recognition, but how these effects are modulated by resource availability requires further study. We examined the simultaneous effects of past predator exposure (direct, indirect, and no exposure) and nutrient regime (combinations of N- and P-repletion and limitation) on the paralytic shellfish toxin retention and cell growth rate of a toxic dinoflagellate, (strain BF-5), under a laboratory-simulated bloom condition (exponential, stationary, and declining phases). Within a past predator exposure treatment, cell toxin retention was generally higher under N-replete than N-limited conditions. The cells of past direct predator exposure treatment retained or produced more toxin than those in the indirect-exposure or no-exposure treatments regardless of nutrient regime in the exponential and stationary phase. By contrast, cells directly exposed to predators showed lower growth rates than the other two treatments, and also showed a tradeoff between toxin retention rate and growth rate. Separate experiments also showed that the effect of past predator exposure on reducing cell growth is stronger under N repletion than N limitation. These results imply that the interactions of past predator exposure and resource availability impact bloom dynamics and toxin transfer in the food web.
过去捕食者暴露对浮游植物的非消费性影响已得到认可，但这些影响如何受资源可用性调节仍需进一步研究。我们在实验室模拟的水华条件（指数期、稳定期和衰退期）下，研究了过去捕食者暴露（直接暴露、间接暴露和无暴露）和营养状况（氮和磷充足与限制的组合）对有毒甲藻（BF - 5株）麻痹性贝类毒素保留和细胞生长速率的同时影响。在过去捕食者暴露处理中，氮充足条件下细胞毒素保留通常高于氮限制条件。在指数期和稳定期，无论营养状况如何，过去直接捕食者暴露处理的细胞比间接暴露或无暴露处理的细胞保留或产生更多毒素。相比之下，直接暴露于捕食者的细胞生长速率低于其他两种处理，并且在毒素保留率和生长速率之间也存在权衡。单独的实验还表明，过去捕食者暴露对细胞生长的抑制作用在氮充足条件下比氮限制条件下更强。这些结果表明，过去捕食者暴露与资源可用性之间的相互作用会影响食物网中的水华动态和毒素转移。
