Environmental factors affecting the balance of autotrophs versus heterotrophs in the microbial food web of temporary ponds

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• 作者：Núria Àvila ; Rocio López-Flores ; Dani Boix ; Stéphanie Gascón…
• 关键词：Phytoplankton ; Bacterioplankton ; Shallow lakes ; Temporary waters ; Dissolved organic carbon ; Compositional data analysis
• 刊名：Hydrobiologia
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：782
• 期：1
• 页码：127-143
• 全文大小：1,405 KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Life Sciences
  Hydrobiology
  Ecology
  
• 出版者：Springer Netherlands
• ISSN：1573-5117
• 卷排序：782

文摘

The relative abundance of autotrophic (A) and heterotrophic (H) organisms in the microbial food web of temporary ponds and its relationship to environmental variables were analysed. Four localities (43 temporary ponds) were selected for study. They were located in unaltered, protected basins without intensive agriculture or strong human pressure. Because the supply of allochthonous organic matter is expected to be higher than inorganic nutrient inputs in temporary ponds, we hypothesized that the microbial food web in these unaltered basins was dominated by heterotrophic organisms. Our results showed that the log A:H biomass ratio (A/H) was always negative, indicating strong dominance by heterotrophic organisms in these ponds. Moreover, A/H was negatively related to DOC concentrations, but this relationship was weaker in the locality with the highest DOC concentration. No significant relationships were found between A/H and the other environmental variables analysed, namely inorganic nutrients, fulvic acids, chlorophyll-a concentrations, macrophyte biomass or total zooplankton biomass. However, when the different groups of zooplankton were considered separately, A/H correlated negatively with cladoreran biomass and positively with harpacticoid biomass. Thus, temporary ponds differ from deeper ecosystems, in which the greater importance of autochthonous energy inputs leads to microbial food web that is more dominated by autotrophs.