Responses of Phytoplankton Communities to Internal Waves in Oligotrophic Oceans

作者：Lingqi Ma, Xiaolin Bai, Edward A. Laws, Wupeng Xiao, Cui Guo, Xin Liu, Kuo‐Ping Chiang, Kunshan Gao, Bangqin Huang · 发表于：Journal of Geophysical Research Oceans · 年份：2023 · DOI：10.1029/2023jc020201 · 被引用次数：14 · 研究领域：Marine and coastal ecosystems、Oceanographic and Atmospheric Processes、Marine Biology and Ecology Research

Abstract Understanding the potential impacts of internal waves on phytoplankton communities in oligotrophic oceans remains an important research challenge. In this study, we elucidated the impact of internal waves on phytoplankton communities through a comprehensive 154‐hr time‐series of observations in the South China Sea (SCS). We identified distinctive variations in phytoplankton pigment biomass and composition across the upper, middle, and lower layers of the euphotic zone, which we attributed to the perturbations triggered by internal waves. Phytoplankton other than Prochlorococcus in the lower, nutrient‐replete layer likely benefitted from allochthonous nutrients introduced by internal waves, but their growth rates were constrained by light limitation, and their pigment biomass was held in check by microzooplankton grazing. In contrast, in the upper, nutrient‐depleted layer, the relative abundance of Prochlorococcus increased, likely because of the ammonium regenerated by zooplankton. The middle layer, characterized as the deep chlorophyll maximum layer, exhibited a dynamic equilibrium characterized by nutrient and light co‐limitation. This equilibrium resulted in high nitrate assimilation and growth by phytoplankton. The balancing of those rates by significant grazing losses maintained total chlorophyll a concentrations at a high level. Based on these findings, we proposed a three‐layer euphotic zone structure characterized by distinct physiological conditions, nutrien...