Centre for Ocean Life , Technical University of Denmark , 2800 Kongens Lyngby , Denmark.
Marine Science Institute , University of Texas at Austin , Port Aransas , Texas 78373 , United States.
Environ Sci Technol. 2018 May 15;52(10):5718-5724. doi: 10.1021/acs.est.8b00335. Epub 2018 Apr 25.
After oil spills and dispersant applications the formation of red tides or harmful algal blooms (HABs) has been observed, which can cause additional negative impacts in areas affected by oil spills. However, the link between oil spills and HABs is still unknown. Here, we present experimental evidence that demonstrates a connection between oil spills and HABs. We determined the effects of oil, dispersant-treated oil, and dispersant alone on the structure of natural plankton assemblages in the Northern Gulf of Mexico. In coastal waters, large tintinnids and oligotrich ciliates, major grazers of phytoplankton, were negatively affected by the exposure to oil and dispersant, whereas bloom-forming dinoflagellates ( Prorocentrum texanum, P. triestinum, and Scrippsiella trochoidea) notably increased their concentration. The removal of key grazers due to oil and dispersant disrupts the predator-prey controls ("top-down controls") that normally function in plankton food webs. This disruption of grazing pressure opens a "loophole" that allows certain dinoflagellates with higher tolerance to oil and dispersants than their grazers to grow and form blooms when there are no growth limiting factors (e.g., nutrients). Therefore, oil spills and dispersants can act as disrupters of predator-prey controls in plankton food webs and as indirect inducers of potentially harmful dinoflagellate blooms.
溢油和分散剂的应用后，已观察到赤潮或有害藻华（HAB）的形成，这可能会对溢油影响的地区造成额外的负面影响。然而，溢油和 HAB 之间的联系仍然未知。在这里，我们提供了实验证据，证明了溢油和 HAB 之间存在联系。我们确定了石油、经分散剂处理的石油和单独的分散剂对墨西哥湾北部自然浮游生物组合结构的影响。在沿海水域，大型纤毛虫和寡毛类纤毛虫（浮游植物的主要捕食者）因暴露于石油和分散剂而受到负面影响，而形成赤潮的甲藻（Prorocentrum texanum、P. triestinum 和 Scrippsiella trochoidea）的浓度明显增加。由于石油和分散剂的存在，关键捕食者的消失破坏了浮游生物食物网中通常起作用的捕食者-被捕食者控制（“自上而下的控制”）。这种摄食压力的破坏为某些甲藻开辟了一个“漏洞”，使它们在没有生长限制因素（例如营养物质）时能够生长并形成赤潮，而这些甲藻对石油和分散剂的耐受性高于其捕食者。因此，溢油和分散剂可以作为浮游生物食物网中捕食者-被捕食者控制的破坏者，并作为潜在有害甲藻赤潮的间接诱导剂。
