Instituto Argentino de Oceanografía (IADO-CONICET), Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina.
Instituto Antártico Argentino (IAA), Buenos Aires, San Martín, Argentina.
PLoS One. 2020 May 14;15(5):e0232614. doi: 10.1371/journal.pone.0232614. eCollection 2020.
The rapid increase in atmospheric temperature detected in the last decades in the Western Antarctic Peninsula was accompanied by a strong glacier retreat and an increase in production of melting water, as well as changes in the sea-ice dynamic. The objective of this study was to analyze the succession of micro- and mesozooplankton during a warm annual cycle (December 2010-December 2011) in an Antarctic coastal environment (Potter Cove). The biomass of zooplankton body size classes was used to predict predator-prey size relationships (i.e., to test bottom-up/top-down control effects) using a Multiple Linear Regression Analysis. The micro- and mesozooplanktonic successions were graphically analyzed to detect the influence of environmental periods (defined by the degree of glacial melting, sea-ice freezing and sea-ice melting) on coupling/uncoupling planktonic biomass curves associated to possible predator-prey size relationship scenarios. At the beginning of the glacial melting, medium and large mesozooplankton (calanoid copepods, Euphausia superba, and Salpa thompsoni) exert a top-down control on Chl-a and microzooplankton. Stratification of the water column benefitted the availability of adequate food-size (Chl-a <20) for large microzooplankton (tintinnids) development observed during fall. High abundance of omnivores mesozooplankton (Oithona similis and furcilia of E. superba) during sea-ice freezing periods would be due to the presence of available heterotrophic food under or within the sea ice. Finally, the increase in microzooplankton abundance in the middle of spring, when sea-ice melting starts, corresponded to small and medium dinoflagellates and ciliates species, which were possibly part of the biota of sea ice. If glacier retreat continues and the duration and thickness of the sea ice layer fluctuates as predicted by climate models, our results predict a future scenario regarding the zooplankton succession in Antarctic coastal environments.
过去几十年在西南极半岛探测到的大气温度的快速上升伴随着冰川的大量消退和融水的增加，以及海冰动态的变化。本研究的目的是分析在南极沿海环境（波特湾）的一个温暖年周期（2010 年 12 月至 2011 年 12 月）中微型和中型浮游动物的演替。使用多元线性回归分析，根据浮游动物生物量的大小类来预测捕食者-猎物的大小关系（即测试自上而下/自下而上的控制效果）。对微和中型浮游动物的演替进行了图形分析，以检测环境时期（由冰川融化、海冰冻结和海冰融化的程度定义）对浮游生物生物量曲线的耦合/解耦的影响，这些曲线与可能的捕食者-猎物大小关系情景有关。在冰川融化开始时，中型和大型浮游动物（哲水蚤、磷虾和萨氏索马）对叶绿素 a 和微型浮游动物施加自上而下的控制。水柱的分层有利于在秋季观察到的大型微型浮游动物（纤毛类）的发展所需的足够食物大小（Chl-a<20）的可用性。在海冰冻结期间，兼性食者浮游动物（Oithona similis 和磷虾的 furcilia）的大量存在是由于海冰下或海冰内存在可用的异养食物。最后，在春季中期，当海冰开始融化时，微型浮游动物的数量增加，对应于小型和中型甲藻和纤毛虫，它们可能是海冰生物群的一部分。如果冰川继续消退，并且海冰层的持续时间和厚度如气候模型所预测的那样波动，我们的结果将预测南极沿海环境中浮游动物演替的未来情景。
