Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2019
Forfattere
Junbin ZhaoSammendrag
Det er ikke registrert sammendrag
Forfattere
James Fourqurean Sparkle Malone Edward Castaneda Sean Charles Carl Fitz Daniel Gann David Ho John Kominoski Christian Lopes Steven. F. Oberbauer Gregory Starr Christina Staudhammer Tiffany Troxler Bryce Van Dam Junbin ZhaoSammendrag
Det er ikke registrert sammendrag
Forfattere
Junbin ZhaoSammendrag
As the main drivers of climate change, greenhouse gas (e.g., CO2 and CH4) emissions have been monitored intensively across the globe. The static chamber is one of the most commonly used approaches for measuring greenhouse gas fluxes from ecosystems (e.g., stem/soil respiration, CH4 emission, etc.) because of its easy implementation, high accuracy and low cost (Pumpanen et al., 2004). To perform the measurements, a gas analyzer is usually used to measure the changes of greenhouse gas concentrations within a closed chamber that covers an area of interest (e.g., soil surface) over a certain period of time (usually several minutes). The flux rates (F) are then calculated from the recorded gas concentrations assuming that the changing rate is linear: F = vol/(R · T a · area) · dG/dt where vol is the volume of the chamber (l), R is the universal gas constant (l atm K-1 mol-1), Ta is the ambient temperature (K), area is the area of the chamber base (m2 ), and dG/dt is the rate of the measured gas concentration change over time t (ppm s-1) (i.e., the slope of the linear regression).
Forfattere
Sparkle Malone Abad Chabbi Gregory Starr Teng Hu Nicolas Puche Steven. F. Oberbauer Paulo Olivas Jessica Schedlbauer Junbin Zhao Christina Staudhammer Sean Charles Zhuoran YuSammendrag
Det er ikke registrert sammendrag
Forfattere
Junbin Zhao Sparkle L. Malone Steven. F. Oberbauer Paulo C. Olivas Jessica L. Schedlbauer Christina L. Staudhammer Gregory StarrSammendrag
Climate change has altered global precipitation patterns and has led to greater variation in hydrological conditions. Wetlands are important globally for their soil carbon storage. Given that wetland carbon processes are primarily driven by hydrology, a comprehensive understanding of the effect of inundation is needed. In this study, we evaluated the effect of water level (WL) and inundation duration (ID) on carbon dioxide (CO2) fluxes by analysing a 10‐year (2008–2017) eddy covariance dataset from a seasonally inundated freshwater marl prairie in the Everglades National Park. Both gross primary production (GPP) and ecosystem respiration (ER) rates showed declines under inundation. While GPP rates decreased almost linearly as WL and ID increased, ER rates were less responsive to WL increase beyond 30 cm and extended inundation periods. The unequal responses between GPP and ER caused a weaker net ecosystem CO2 sink strength as inundation intensity increased. Eventually, the ecosystem tended to become a net CO2 source on a daily basis when either WL exceeded 46 cm or inundation lasted longer than 7 months. Particularly, with an extended period of high‐WLs in 2016 (i.e., WL remained >40 cm for >9 months), the ecosystem became a CO2 source, as opposed to being a sink or neutral for CO2 in other years. Furthermore, the extreme inundation in 2016 was followed by a 4‐month postinundation period with lower net ecosystem CO2 uptake compared to other years. Given that inundation plays a key role in controlling ecosystem CO2 balance, we suggest that a future with more intensive inundation caused by climate change or water management activities can weaken the CO2 sink strength of the Everglades freshwater marl prairies and similar wetlands globally, creating a positive feedback to climate change.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Recent studies on using soil enhancer material, such as biochar, provide varying results from a soil hydrological and chemical perspective. Therefore, research focusing on soil-biochar-plant interactions is still necessary to enhance our knowledge on complex effects of biochar on soil characteristics. The present study investigated the changes in soil water content (SWC) and soil respiration (belowground CO2 production) over time during the growth of Capsicum annuum (pepper) in pot experiments. Concurrently, we investigated the influence of grain husk biochar with the amount of 0, 0.5%, 2.5%, and 5.0% (by weight) added to silt loam soil. Pepper plants were grown under natural environmental conditions to better represent field conditions, and additional irrigation was applied. SWC among treatments showed minor changes to precipitation during the beginning of the study while plants were in the growing phase. The highest water holding throughout the experiment was observed in the case of BC5.0. CO2 production increased in biochar amended soils during the first few days of the experiments; while the overall cumulative CO2 production was the highest in control and the lowest in BC2.5 treatments. We used the HYDRUS 1D soil hydrological model to simulate changes in SWC, using the control treatment without biochar as a reference data source for model calibration. The simulated SWC dynamics fitted well the measured ones in all treatments. Therefore, the HYDRUS 1D can be an exceptionally valuable tool to predict the hydrological response of different amount of biochar addition to silt loam soil including plant growth.
Sammendrag
The Balaton lake is the focal area of implementing the WFD in Hungary. At present, nutrient loads are primary threat to surface and subsurface water quality in the Balaton watershed. With increasing anthropogenic pressure and increased occurrence of extreme precipitation events in the future the nitrate loads might increase. The goal of this study was to evaluate the combined effect of climate, land use and soil management changes on nitrogen loads in Tetves Creek, which is the tributary of the Balaton lake. We applied the INCA-N (INtegrated CAtchment Model) water quality model to simulate the hydrological processes and nitrate transport for two periods: the current situation (baseline, 2006 to 2015) and for a future period (2046-2055). We calibrated the model against measured discharge and nitrate concentration data. The inorganic nitrogen sub-model was further validated using data of an independent period. The modelling chain was able to reproduce 59% of the variability of average nitrate concentrations in the Tetves Creek for the validation period. After validation, we examined several climate change, land use and nitrogen supply scenarios and their combined effects on runoff and nitrogen loads. Our main conclusions are summarised below.
Forfattere
Csilla FarkasSammendrag
Det er ikke registrert sammendrag
Forfattere
Csilla FarkasSammendrag
Soil moisture is an important but often undervalued element of the water cycle. Compared to other components, the volume of soil moisture is small; nonetheless, it is of fundamental importance to many hydrological, biological and biogeochemical processes. Through processes like evaporation and plant transpiration, soil moisture is a key variable in controlling the water and energy exchange between the land surface and the atmosphere, hence, it plays an important role in the development of weather patterns and the precipitation formation. It also strongly effects surface and subsurface runoff, soil erosion, food production, greenhouse gas emission, the buffer capacity of the soil, the soil biota and many other processes and sectors. It is deducable today that short-sighted mismanagement of soil or soil water strongly contributed to the collapse of large, powerful historic civilazations. Soil degradation is a global problem that is of strong concern for European countries as well. Yet, while much focus is given to open surface water recources - the EU Water Framework Directive is in place since 2000 - the Soil Framework Directive is still to be adopted. It is important to improve the global understanding of the importance of soil as a natural resource, and its hydraulic functioning, including its global change context. The presentation aims at taking a deeper insight into the “butterfly effect” of soil status and moisture dynamics by highlighting how small-scale management decisions and processes might influences large-scale processes and our life.