npj Clean Water ( IF 11.4 ) Pub Date : 2022-05-23 , DOI: 10.1038/s41545-022-00161-6 Chengxiang Zhang , Hongcui Pei , Cai Lu , Peizhong Liu , Cunqi Liu , Guangchun Lei
Homeostasis for phosphorus (HP) in submerged macrophytes may influence the susceptibility of lakes to regime shifts; however, the mechanisms linking submerged macrophyte HP to regime shifts remain unclear. We conducted an in situ mesocosm experiment to compare the dynamic responses of a high-HP species, Potamogeton maackianus, and a low-HP species, Hydrilla verticillata, to different phosphorus (P) level gradients, as well as their effects on phytoplankton inhibition. The biomass of P. maackianus under mesotrophic P (MP; P concentration 0.05 mg L−1) and eutrophic P (EP; P concentration 0.10 mg L−1) conditions was either non-significantly different from, or lower than that under oligotrophic P conditions (OP; P concentration under detection limit of 0.01 mg L−1). Conversely, H. verticillata biomass under EP was significantly higher than that under MP on day 90, whereas it died under OP. This variable response of submerged macrophyte species to P level gradients increased the relative growth advantage of H. verticillata compared to P. maackianus during eutrophication. The inhibition ratio of phytoplankton (IRP) for P. maackianus was ~15 times higher than that for H. verticillata under EP. Our study demonstrated a trend that submerged macrophyte assemblage IRP increased along with its assemblage HP. Thus, the changes in submerged macrophyte assemblages from high-HP species-dominance to low-HP species-dominance would erode its phytoplankton inhibition capacity, and further promote the regime shift from a clear-water state to a turbid state. Our results advance the regime shift theory from an ecological stoichiometry perspective and highlight the importance of high-HP submerged macrophyte species in the restoration of eutrophic lakes.
中文翻译:
富营养化通过基于化学计量稳态的沉水大型植物组合的变化来驱动政权转变
沉水植物中磷 (HP) 的稳态可能会影响湖泊对状态变化的敏感性;然而,将淹没的大型植物 HP 与政权转变联系起来的机制仍不清楚。我们进行了原位中宇宙实验,以比较高 HP 物种Potamogeton maackianus和低 HP 物种Hydrilla verticillata对不同磷 (P) 水平梯度的动态响应,以及它们对浮游植物抑制的影响。P. maackianus在中营养磷(MP;P 浓度 0.05 mg L -1)和富营养 P(EP;P 浓度 0.10 mg L -1 )下的生物量) 条件与贫营养 P 条件(OP;P 浓度低于 0.01 mg L -1检测限)下的条件没有显着差异或低于该条件。相反, EP 下的H. verticillata生物量在第 90 天显着高于 MP 下的生物量,而它在 OP 下死亡。与P. maackianus相比,沉水植物物种对 P 水平梯度的这种可变响应增加了H. verticillata在富营养化期间的相对生长优势。P. maackianus对浮游植物 (IRP) 的抑制率比H. verticillata高约 15 倍根据 EP。我们的研究表明,沉水植物组合 IRP 随组合 HP 增加而增加。因此,沉水植物组合从高HP物种优势到低HP物种优势的变化将削弱其对浮游植物的抑制能力,并进一步促进水体状态从清水状态转变为浑浊状态。我们的研究结果从生态化学计量学的角度推进了政权转变理论,并强调了高 HP 淹没大型植物物种在富营养化湖泊恢复中的重要性。