Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2022
Forfattere
P.L. Sullivan S.A. Billings D. Hirmas L. Li X. Zhang S. Ziegler K. Murenbeeld H. Ajami A. Guthrie K. Singha D. Giménez A. Duro V. Moreno A. Flores A. Cueva A.N. Koop E.L. Aronson H.R. Barnard S.A. Banwart R.M. Keen Attila Nemes N.P. Nikolaidis J.B. Nippert D. Richter D.A. Robinson K. Sadayappan Souza de Souza M. Unruh H. WenSammendrag
Soils form the skin of the Earth’s surface, regulating water and biogeochemical cycles and generating production of food, timber, and textiles around the world. Changes in soil and its ability to perform a range of processes have important implications for Earth system function, especially in the critical zone (CZ)—the area that extends from the top of the canopy to the bottom of groundwater and that harbors most of Earth’s biosphere. A key aspect of the way soil functions results from its structure, defined as the size, shape, and arrangement of soil particles and pores. The network of pores provides storage space for at least a quarter of Earth’s biodiversity, while the abundance, size and connectivity of the pore space regulates fluxes of heat, water, nutrients and gases that define the physical and chemical environment. Here we review the nature of soil structure, focusing on its co-evolution with the plants and microbes that live within the soil, and the degree to which these processes have been incorporated into flow and transport models. Though it is well known that soil structure can change with wetting and drying events, often oscillating seasonally, the dynamic nature of soil structure that we discuss is a systematic shift that results in changes in its hydro-bio-geochemical function over decades to centuries, timescales over which major changes in carbon and nutrient cycles have been observed in the Anthropocene. We argue that the variable nature of soil structure, and its dynamics, need to be better understood and captured by land surface and ecosystem models, which currently describe soil structure as static. We further argue that modelers and empiricists both are well-poised to quantify and incorporate these dynamics into their studies. From these efforts, four fundamental questions emerge: 1) How do rates of soil aggregate formation and collapse, and their overall arrangements, interact in the Anthropocene to regulate CZ functioning from soil particle to continental scales? 2) How do alterations in rooting-depth distributions in the Anthropocene influence pore structure to control hydrological partitioning, biogeochemical transformations and fluxes, exchanges of energy and carbon with the atmosphere and climate, regolith weathering, and thus regulation of CZ functioning? 3) How does changing microbial functioning in a high CO2, warmer world with shifting precipitation patterns influence soil organic carbon dynamics and void-aggregate profile dynamics? 4) How deeply does human influence in the Anthropocene propagate into the subsurface, how does this depth relate to profile structure, and how does this alter the rate at which the CZ develops? The United Nations has recently recognized that 33% of the Earth's soils are already degraded and over 90% could become degraded by 2050. This recognition highlights the importance of addressing these proposed questions, which will promote a predictive understanding of soil structure.
Forfattere
David A. Robinson Attila Nemes Sabine Reinsch Alan Radbourne Laura Bentley Aidan M. KeithSammendrag
Global land use change has resulted in more pasture and cropland, largely at the expense of woodlands, over the last 300 years. How this change affects soil hydraulic function with regard to feedbacks to the hydrological cycle is unclear for earth system modelling (ESM). Pedotransfer functions (PTFs) used to predict soil hydraulic conductivity (K) take no account of land use. Here, we synthesize >800 measurements from around the globe from sites that measured near-saturated soil hydraulic conductivity, or infiltration, at the soil surface, on the same soil type at each location, but with differing land use, woodland (W), grassland (G) and cropland (C). We found that texture based PTFs predict K reasonably well for cropland giving unbiased results, but increasingly underestimate K in grassland and woodland. In native woodland and grassland differences in K can usually be accounted for by differences in bulk density. However, heavy grazing K responses can be much lower indicating compaction likely reduces connectivity. We show that the K response ratios (RR) between land uses vary with cropland (C/W = 0.45 [W/C = 2.2]) and grassland (G/W = 0.63 [W/G = 1.6]) having about half the K of woodland.
Forfattere
Alice BudaiSammendrag
No abstract has been registered
Forfattere
Nils-Otto Kitterød Jens Kværner Per Aagaard Jurga Arustiene Jānis Bikše Atle Dagestad Pål Gundersen Birgitte Hansen Árni Hjartarson Enn Karro Maris Klavins Andres Marandi Rasa Radiene Inga Retike Pekka M. Rossi Lærke ThorlingSammendrag
No abstract has been registered
Sammendrag
Data compilation of groundwater chemistry and freshwater abstraction documents the importance of groundwater as an economical resource in the Nordic Region. Management of groundwater require chemical monitoring to minimize risks for contamination, and mitigation is needed to identify anthropogenic and geogenic hazards related to groundwater quality (Kitterød et al, 2022). The interaction between groundwater and surface water is crucial for important ecological systems in the Nordic Region, and the impacts of climate change is a big challenge for hydrological and environmental research. The increased net global energy influx has impact on average temperature, seasonality, precipitation, and runoff, but issues related to water quality and groundwater have received less attention. The interaction between surface water and groundwater chemistry is embraced in the term hydrogeochemistry. In this context the geological framework plays a cardinal role in combination with residence time of water in the subsurface. Extensive sampling of hydrogeochemical variables have been undertaken in the Nordic Region and results are made available in public databases. Such data deserve more attention from the research community, and a pertinent challenge is to include geochemical variables in water balance studies and regional hydrological modeling. Reference: Kitterød, N-O, Kværner, J., Aagaard, P, Arustienė, J, de Beer, H, Bikše, J, Dagestad, A, Gundersen, P, Hansen, B, Hjartarson, Á, Karro, E, Klavins, M, Marandi, A, Putys, P, Radienė, R, Retiķe, I, Rossi, P M, and Thorling, L: Hydrogeology and Groundwater Quality in the Nordic Region. Submitted to Hydrology Research, 2022. Keywords: Hydrogeochemsitry; groundwater quality; surface water quality.
Forfattere
Cornelya KlutschSammendrag
No abstract has been registered
Forfattere
Michelle Wainstein Louisa B. Harding Sandra M. O'Neill Daryle T. Boyd Fred Koontz Bobbi Miller Cornelya Klutsch Philippe J. Thomas Gina M. YlitaloSammendrag
River otters (Lontra canadensis) are apex predators that bioaccumulate contaminants via their diet, potentially serving as biomonitors of watershed health. They reside throughout the Green-Duwamish River, WA (USA), a watershed encompassing an extreme urbanization gradient, including a US Superfund site slated for a 17-year remediation. The objectives of this study were to document baseline contaminant levels in river otters, assess otters’ utility as top trophic-level biomonitors of contaminant exposure, and evaluate the potential for health impacts on this species. We measured a suite of contaminants of concern, lipid content, nitrogen stable isotopes (δ15N), and microsatellite DNA markers in 69 otter scat samples collected from twelve sites. Landcover characteristics were used to group sampling sites into industrial (Superfund site), suburban, and rural development zones. Concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ether flame-retardants (PBDEs), dichlorodiphenyl-trichloroethane and its metabolites (DDTs), and polycyclic aromatic hydrocarbons (PAHs) increased significantly with increasing urbanization, and were best predicted by models that included development zone, suggesting that river otters are effective biomonitors, as defined in this study. Diet also played an important role, with lipid content, δ15N or both included in all best models. We recommend river otter scat be included in evaluating restoration efforts in this Superfund site, and as a potentially useful monitoring tool wherever otters are found. We also report ΣPCB and ΣPAH exposures among the highest published for wild river otters, with almost 70% of samples in the Superfund site exceeding established levels of concern.
Forfattere
Cornelya KlutschSammendrag
No abstract has been registered
Forfattere
Cornelya KlutschSammendrag
No abstract has been registered
Forfattere
Cornelya KlutschSammendrag
No abstract has been registered