Jiangsu Key Laboratory for Biodiversity and Biotechnology, School of Biological Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China.
Institute of Integrative Biology, Biosciences Building, University of Liverpool, Liverpool L69 7ZB, U.K.
Environ Sci Technol. 2020 Apr 7;54(7):4495-4503. doi: 10.1021/acs.est.0c00104. Epub 2020 Mar 10.
Solar ultraviolet-B (UVB) radiation reaching the earth's surface is increasing due to stratospheric ozone depletion. How the elevated UVB affects the trophic interactions is critical for predicting the ecosystem functioning under this global-scale stressor. Usually, inducible defenses in phytoplankton stabilize community dynamics within aquatic environments. To assess the effects of elevated UVB on induced defense, we examined the changes in antigrazer colony formation in under environmentally relevant UVB. exposed to infochemicals consistently formed multicelled colonies, traits confirmed to be adaptive under predation risk. However, the suppressed photochemical activity and the metabolic cost from colony formation resulted in the severer reductions in algal growth by UVB under predation risk. The transcriptions of key enzyme-encoding genes, regulating the precursor synthesis during polysaccharide production, were also inhibited by UVB. Combination of the reduced production of daughter cells and the ability of daughter cells to remain attached, the antigrazing colony formation was interrupted, leading to the dominant morphs of algal population shifting from larger-sized colonies to smaller ones at raised UVB. The present study revealed that elevated UVB will not only reduce the phytoplankton growth but also increase their vulnerability to predation, probably leading to potential shifts in plankton food webs.
由于平流层臭氧消耗，到达地球表面的太阳紫外线-B（UVB）辐射正在增加。升高的 UVB 如何影响营养相互作用对于预测在这种全球范围内的胁迫下的生态系统功能至关重要。通常，浮游植物中的诱导防御可稳定水生环境中的群落动态。为了评估升高的 UVB 对诱导防御的影响，我们研究了在环境相关的 UVB 下 中抗食草动物群体形成的变化。 暴露于 信息素会一致形成多细胞群体，这些特征被证实是在捕食风险下具有适应性的。然而，由于群体形成而导致的光化学活性抑制和代谢成本，使藻类在受到捕食风险时，UVB 对藻类生长的抑制作用更为严重。调节多糖产生过程中前体合成的关键酶编码基因的转录也被 UVB 抑制。由于子细胞的产生减少和子细胞保持附着的能力，抗食草动物群体的形成被中断，导致藻类种群的优势形态从较大的群体转变为在升高的 UVB 下较小的群体。本研究表明，升高的 UVB 不仅会降低浮游植物的生长，还会增加它们受到捕食的脆弱性，可能导致浮游动物食物网发生潜在变化。
