Short-period hydrological regimes outperform physicochemical variables in shaping stream diatom traits and biofilm community functions

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  • Kun Guo
  • Naicheng Wu, Xi’an Jiaotong-Liverpool University
  • ,
  • Paraskevi Manolaki
  • Annette Baattrup-Pedersen, WATEC Aarhus University Centre for Water Technology , Aarhus University , Aarhus 8000C , Denmark., Denmark
  • Tenna Riis
Despite increasing interests on hydrological effects on riverine ecosystems, few studies have documented the effects of hydrology on biofilm community functions and typically the studies have focused on annual based hydrological indices. In this study, we investigated the impact of hydrological conditions on diatom community structure and biofilm community functions. During one year we sampled five lowland streams in Denmark with different flow regimes. Instead of the commonly used hydrological indices, we calculated short-period hydrological indices i.e., hydrological regimes in 14 and ~ 28 days. We then explored how hydrological and physicochemical variables affected diatom community composition and biofilm community functions (metabolism and nutrient uptake rates). Our results showed that short-period hydrological indices (10.10±7.18%) contributed more to species distribution than physicochemical variables (5.90±3.83%), indicating the dominant role of hydrology on structuring diatom community. Specifically, we found different structural response patterns for different guilds and size classes to hydrological and physicochemical variables, demonstrating that species that can tolerate high disturbance (e.g., low profile and small species) may be more appropriate as indicators for environmental disturbances than those that cannot. We also found significant effects of short-period hydrological conditions on biofilm community functions, i.e., high flow events were the most important factors reducing metabolism and nutrient uptake rates. In conclusion, our study highlights the importance of including short-period hydrological conditions in studies on environmental control of shaping benthic algae community. Considering that hydrological disturbance is expected to become even more intense in the future due to climate changes, and that stream ecosystems usually are exposed to multiple stressors, effects of short-period hydrology within the context of multiple stressors on biofilm composition and function are warranted.
Original languageEnglish
JournalScience of the Total Environment
ISSN0048-9697
Publication statusSubmitted - 2020

    Research areas

  • hydrological regimes, diatom traits, biofilm community functions, metabolism, nutrient uptake rates

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