Variation in the abundance of pico, nano, and microplankton in Lake Michigan: Historic and basin-wide comparisons
Variation in the abundance of pico, nano, and microplankton in Lake Michigan: Historic and basin-wide comparisons
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DOI：
10.1016/j.jglr.2015.09.009
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发表时间：
2015-01-01
影响因子：
2.2
通讯作者：
Vanderploeg, Henry A.
中科院分区：
文献类型：
--
作者：
Carrick, Hunter J.;Butts, Emon;Vanderploeg, Henry A.
密歇根湖的生态系统经历了许多系统性的变化(营养减少、气候变化、贻贝入侵)，这些变化改变了食物网的部分，因此似乎改变了湖泊的营养状态。尽管如此，人们对微生物食物网的组成(MFW、异养和光养微微浮游生物、纳米浮游生物和微型浮游生物)知之甚少，我们假设，鉴于最近大型浮游植物(主要是硅藻)生物量的下降，这些微生物食物网作为甲壳类浮游动物的食物来源已经得到补偿。因此，我们在密歇根湖北部和南部以及苏必利尔湖的一个地点使用补充显微镜技术、流式细胞术和大小分级的叶绿素浓度测量了整个MFW的丰度；后者作为寡营养条件的基准。此外，还对南密歇根湖遗址在1987年和2013年的历史进行了比较。与20世纪80年代相比，2013年的Ppico数量(即微蓝细菌)有所减少；但总叶绿素的50%的贡献率。小型有色金藻和隐藻的丰度在1987年和2013年之间没有显著差异，而PMicro的丰度却有所下降；这种向Ppico和PNano优势的转变可能与最近密歇根湖的寡营养有关。与1987年相比，2013年纤毛虫(HMicro大小类)的丰度下降了3倍，而Hpico(真细菌，范围为0.24-1.36×10(6)cell mL(-1))和HNano(主要是无色金藻；范围为0.11-6.4 x 10(3)cell mL(-1))的丰度保持稳定，反映了细菌-鞭毛虫营养联系的弹性。(C)2015年国际五大湖研究协会。爱思唯尔出版，版权所有。
The Lake Michigan ecosystem has undergone numerous, systemic changes (reduced nutrient, changing climate, invasive mussels) that have altered portions of the food web and thus, appear to have changed the lake's trophic state. That said, little is known about the components of the microbial food web (MFW, heterotrophic and phototrophic pico, nano, and micro-plankton), which we hypothesized have compensated as a food source for crustacean zooplankton given the recent declines in the biomass of large phytoplankton (mainly diatoms). Therefore, we measured the abundance of the entire MFW using complementary microscopic techniques, flow cytometry, and size fractionated chlorophyll concentrations at sites in northern and southern Lake Michigan, and one site in Lake Superior; the latter site served as a benchmark for oligotrophic conditions. In addition, a historic comparison was made between 1987 and 2013 for the southern Lake Michigan site. Ppico numbers (i.e., picocyanobacteria) in 2013 were lower compared with those in the 1980s; however, the percent contribution of the 50% of total chlorophyll). The abundance of small, pigmented chrysomonads and cryptomonads (Pnano size category) was not significantly different between 1987 and 2013 at the same time Pmicro did decline; this shift towards Ppico and Pnano dominance may be related to the recent oligotrophication of Lake Michigan. The abundance of ciliated protists (Hmicro size class) was 3-fold lower in 2013 compared with levels in 1987, while the abundance of both Hpico (eubacteria, range 0.24-1.36 x 10(6) cells mL(-1)) and Hnano (mainly colorless chrysomonads; range 0.11-6.4 x 10(3) cells mL(-1)) remained stable and reflected the resilience of bacteria-flagellate trophic linkage. (C) 2015 International Association for Great Lakes Research. Published by Elsevier B.V. All rights reserved.