Tidal pumping facilitates dissimilatory nitrate reduction in intertidal marshes
Yanling Zheng1,2, Lijun Hou1, Min Liu2
1State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China.
Scientific Reports
|February 18, 2016
Summary
Tides significantly boost dissimilatory nitrate reduction in intertidal marshes. This tidal pumping enhances nitrogen cycling microorganisms and their activities, crucial for marsh biogeochemistry.
Area of Science:
- Environmental Microbiology
- Biogeochemistry
- Coastal Ecology
Background:
- Intertidal marshes experience regular submersion and exposure from tides, influencing ecosystem processes.
- Intertidal sediments host nitrogen cycling microorganisms crucial for dissimilatory nitrate reduction.
- The impact of tidal cycles on these nitrate reduction pathways remains largely unstudied.
Purpose of the Study:
- To investigate the effect of tidal cycles on dissimilatory nitrate reduction pathways in intertidal marsh sediments.
- To determine how tidal fluctuations influence the abundance of bacteria involved in nitrogen cycling.
- To elucidate the role of tidal pumping in sustaining microbial nitrogen cycling.
Main Methods:
- Simultaneous application of isotope-tracing and molecular techniques.
- Analysis of nutrient profiles and nitrogen component fluctuations across tidal cycles.
- Conducting tidal simulation experiments in laboratory settings.
Main Results:
- Nitrate-reduction activities and functional bacterial abundances were elevated at the sediment-tidal water interface and in the tide-induced groundwater fluctuating layer.
- Tidal pumping was identified as a key mechanism sustaining dissimilatory nitrate reduction.
- Nutrient dynamics and nitrogen transformations showed significant variations correlating with tidal cycles.
Conclusions:
- Tides play a critical role in regulating the rates and pathways of dissimilatory nitrate reduction in intertidal marshes.
- Tidal pumping enhances microbial nitrogen cycling, impacting overall marsh biogeochemistry.
- This research provides novel insights into the nitrogen cycle within these dynamic coastal ecosystems.
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