EGU2020-2337
https://doi.org/10.5194/egusphere-egu2020-2337
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Effects of intermittency and land use on the in-stream phosphorus and organic carbon uptake

Gabriele Weigelhofer and Matthias Pucher
Gabriele Weigelhofer and Matthias Pucher
  • University of Natural Resources and Life Sciences Vienna, Institute of Hydrobiology and Aquatic Ecosystem Management, Water, Atmosphere and Environment, Vienna, Austria (gabriele.weigelhofer@wcl.ac.at)

Understanding the consequences of the interplay between land use and climate change is among the most pressing challenges of the 21st century for river managers. Over the past decades, agricultural land use has altered nutrient concentrations and stoichiometric ratios in stream ecosystems, thereby affecting aquatic biogeochemical cycles and the coupling among carbon, phosphorus, and nitrogen. In addition, the frequency and duration of droughts has increased dramatically across Europe, causing perennial streams to shift to intermittency and changing the capacity of sediments for the uptake and storage of macronutrients.

Our study aims to understand the effects of drying and re-wetting on the uptake, storage, and release of phosphorus and organic carbon from the benthic and the hyporheic zone of headwater streams under the additional stressor of agricultural land use. In specific, we are interested in the potential coupling and decoupling of phosphorus and dissolved organic carbon cycling in autotrophic and heterotrophic benthic biofilms. We sampled headwater streams before, during, and after the dry period in 2018 and 2019 and performed laboratory experiments with artificial drying and re-wetting and additions of dissolved organic carbon. We measured nutrient uptake and release, microbial biomass, respiration, and the activity of extra-cellular enzymes. The first results show an increased phosphorus release from the sediments immediately after re-wetting, foolowed by a reduced uptake capacity. The uptake of DOC was correlated with phosphorus in autotrophic biofilms, but not in heterotrophic ones.

How to cite: Weigelhofer, G. and Pucher, M.: Effects of intermittency and land use on the in-stream phosphorus and organic carbon uptake, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-2337, https://doi.org/10.5194/egusphere-egu2020-2337, 2020

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