About this Research Topic
To mitigate Greenhouse Gas (GHG) emissions and limit global warming to 1.5°C above pre-industrial levels (COP21 Paris Agreement), more research is needed to assess spatio-temporal variabilities in the major processes and drivers controlling GHG emissions from terrestrial freshwater ecosystems, which are key environments for C and N cycling. The variability in, and complexity of, hydrological and biogeochemical processes render assessments of GHG emissions from freshwater systems particularly challenging. Understanding of C and N cycling and transfer in and between surface and subsurface freshwaters is currently limited and impedes the accuracy and robustness of global GHG estimations from freshwater ecosystems. Further, the scarcity of continuous, long-term data together with detailed background information of different climatic, hydrological, and geological conditions as well as land use types and management in the catchments means that our knowledge of global GHG fluxes remain unconstrained and patchy.
To gain an improved process-based knowledge of spatial and temporal variabilities of GHG emissions and their drivers, there is a need to establish interdisciplinary GHG observatories, combining new methodologies with traditional approaches (e.g. combining concentration and stable isotope measurements and modeling). Remote sensing (RS) together with unmanned aerial vehicles (UAV) and satellites could also yield valuable new input for large-scale GHG emissions from freshwater systems. Such observation networks could be used to identify hotspots of groundwater influx in gaining streams with often elevated concentrations of CO2, CH4 and N2O.
This Research Topic invites review papers, research papers and technological notes with the main aims to:
1) identify small- and large-scale GHG emission hotspots together with contemporary and projected drivers;
2) present new on-site measurement and remote sensing methods in case studies or summary papers;
3) perform and improve process-based measuring and modeling approaches;
4) support the compilation and evaluation of global GHG databases and define standard variables for improved global datasets for a range of parameters including dissolved oxygen (DO), inorganic and organic nitrogen (DIN, DON) and carbon (DIC, DOC);
5) develop improved GHG upscaling methodologies and possible mitigation strategies regarding GHG source and sink strengths of terrestrial freshwater ecosystems.
Experimental field studies and results from inadequately investigated regions in Asia, Africa and South America and freshwater ecosystems under high anthropogenic or climate pressures are highly welcome.
Keywords: Freshwater, Ecosystem, Greenhouse gas, Carbon, Nitrogen, CO2, CH4, N2O, Global warming, Remote sensing, Modeling, Land use, Measurement, Methods, Nutrients, Data, Indicators
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