Succession of phytoplankton functional groups regulated by monsoonal hydrology in a large canyon-shaped reservoir

Li Juan Xiao, Tian Wang, Ren Hu, Bo Ping Han, Sheng Wang, Xin Qian, Judit Padisák

Research output: Contribution to journalArticle

85 Citations (Scopus)

Abstract

Liuxihe reservoir is a deep, monomictic, oligo-mesotrophic canyon-reservoir in the subtropical monsoon climate region of southern China. Phytoplankton functional groups in the reservoir were investigated and a comparison made between the succession observed in 2008, an exceptionally wet year, and 2009, an average year. The reservoir shows strong annual fluctuations in water level caused by monsoon rains and artificial drawdown. Altogether 28 functional groups of phytoplankton were identified, including 79 genera. Twelve of the groups were analyzed in detail using redundancy analysis. Because of the oligo-mesotrophic and P-limited condition of the reservoir, the dominant functional groups were those tolerant of nutrient (phosphorus) deficiency. The predominant functional groups in the succession process were Groups A (Cyclotella with greatest axial linear dimension < 10 μm), B (Cyclotella with greatest axial linear dimension >10 μm), LO (Peridinium), LM (Ceratium and Microcystis), E (Dinobryon and Mallomonas), F (Botryococcus), X1 (Ankistrodesmus, Ankyra, Chlorella and Monoraphidium) and X2 (Chlamydomonas and Chroomonas). The development of groups A, B and LO was remarkably seasonal. Group A was dominant during stratification, when characteristic small size and high surface/volume ratio morphology conferred an advantage. Group LO was dominant during dry stratification, when motility was advantageous. Group B plankton exhibited a high relative biomass during periods of reduced euphotic depth and isothermy. Groups LM, E, F, X1 and X2 occasionally exhibited high relative biomasses attributable to specific environmental events (e.g. drawdown, changes in zooplankton community). A greater diversity of phytoplankton functional groups was apparent during isothermy. This study underscores the usefulness of functional algal groups in studying succession in subtropical impoundments, in which phytoplankton succession can be significantly affected by external factors such as monsoonal hydrology and artificial drawdown, which alter variables such as retention time, mixing regime and thermal structure and influence light and nutrient availability.

Original languageEnglish
Pages (from-to)5099-5109
Number of pages11
JournalWater Research
Volume45
Issue number16
DOIs
Publication statusPublished - Oct 15 2011

Keywords

  • Algal morphology
  • Diversity
  • Driving factors
  • Functional groups
  • Monsoonal rains
  • Reservoir drawdown

ASJC Scopus subject areas

  • Ecological Modelling
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution

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