Purpose
Humanity has been modifying the planet in a measurable way for thousands of years. Recently, this influence has been such that some feel we are in a new geological epoch, the Anthropocene. ...This review will describe how soil erosion and sediment dynamics have (i) been used to assess the impact of humans on the planet and (ii) affected the global climate and influenced water security. Emphasis is placed on changes since the middle of the twentieth century, as this coincides with what many suggest is the start of the Anthropocene Epoch.
Results and discussion
The use of sediment archives has been instrumental in our understanding of how environmental systems have developed over time, both naturally and in response to anthropogenic activities. Additional information has come from measurement and monitoring programs, and tracing and fingerprinting studies. In turn, models have been developed that enable forecasting. Some of the main global impacts of enhanced soil erosion and changes in sediment dynamics and sediment composition include: changes in radiative energy balances and impacts on the cryosphere; the global carbon cycle; and greenhouse gas emissions. Impacts on water security include: effects on freshwater biota, including wild salmon populations; fluxes of contaminants, including microplastics; and reservoir and river channel sedimentation, including flooding. Sediment archives and monitoring programs have also been used to document the effect of mitigation measures and environmental policies.
Conclusion
Sediment archives enable us to assemble information over a variety of timescales (i.e., 10
0
to 10
5
years and longer) and a range of spatial scales (from sub-watershed to continental), in addition to environments ranging from arid to tropical to polar. Often the temporal resolution is better than other paleoenvironmental reconstruction approaches. As such, sedimentary records, when combined with measurement and monitoring approaches and other sources of information, have enabled us to determine changes in atmospheric, terrestrial, and aquatic systems, especially over the last 100 years. While soil erosion and sediment dynamics have provided a wealth of information and greatly enhanced our understanding of the role of humanity in modifying the planet, suggestions are given for further research.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Purpose
Given the rapid growth of people living in urban and peri-urban areas, this study examined the downstream trends in concentrations and determined the total storage of potentially toxic ...elements (PTEs) and phosphorus (P) associated with fine-grained sediment (0.45 to 63 µm) stored in the channel bed of an urban river.
Materials and methods
Samples were collected from seven sites along McMillan Creek (watershed area = 55 km
2
) in the city of Prince George, British Columbia, Canada, between 2010 and 2016 using a resuspension approach. Grabs samples were also collected from two key tributaries and a large culvert.
Results and discussion
Some elements (e.g., As, Mn and P) decreased in a downstream direction due to inputs from agricultural sources in the headwaters, while others (e.g., Cr, Cu, Pb and Zn) increased downstream reflecting inputs from urban sources in the lower part of the watershed. Several PTEs increased significantly due to a large culvert which supplied road-deposited sediment (RDS) and other urban materials. In some cases (e.g., As, Mn, Zn) PTE concentrations exceeded Canadian sediment quality guidelines (SQGs) for the protection of aquatic organisms. While concentrations were similar for most years, they were elevated in 2016 which may reflect higher rainfall prior to sample collection. The average total storage of fine-grained sediment in the channel bed of McMillan Creek was 155 t (4198 g m
−2
), while for PTEs this ranged from 0.01 kg (0.0002 g m
−2
) for Hg to 1130 kg (30.7 g m
−2
) for Mn.
Conclusions
The channel bed of an urban river stored large amounts of fine sediment, PTEs and P, with concentrations that exceeded SQGs for some elements. Given the expected increase of people living in urban and peri-urban areas, more studies are required to assess the impacts of this growth on the amount and quality of fine-grained sediment stored in urban rivers.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Glaciers in most parts of the world are retreating, releasing water and sediments to downstream rivers. Studies have found elevated levels of fallout radionuclides (FRNs) and other contaminants in ...glacial sediments, especially cryoconite, in European glaciers and Greenland. However, there are no equivalent studies for glaciers in North America. We report concentrations of FRNs (i.e.
Cs,
Pb
and
Am) and other contaminants (i.e. metal(loids), phosphorus) in cryoconite and proglacial sediments from a glacier in British Columbia, Canada, and compare values to suspended sediments from the downstream river. The mean concentrations of
Cs,
Pb
and
Am in cryoconite were 2,123 ± 74, 7,535 ± 224 and 11.5 ± 3.0 Bq kg
, respectively, which are an order of magnitude greater than those for most soils and surficial materials. FRNs were much lower in suspended sediments and decreased with distance away from the glacier. Geochemical elements were enriched in cryoconite relative to local clastic materials and upper continental crust. Concentrations of FRNs in cryoconite were correlated with organic matter, which suggests this is important in controlling the scavenging of hydrophobic contaminants in glacial meltwater. Low concentrations of FRNs and contaminants in suspended sediments suggest that glacial meltwater and the delivery of cryoconite have limited impact on downstream aquatic ecosystems.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
SARS-CoV-2 remains a global threat to human health particularly as escape mutants emerge. There is an unmet need for effective treatments against COVID-19 for which neutralizing single domain ...antibodies (nanobodies) have significant potential. Their small size and stability mean that nanobodies are compatible with respiratory administration. We report four nanobodies (C5, H3, C1, F2) engineered as homotrimers with pmolar affinity for the receptor binding domain (RBD) of the SARS-CoV-2 spike protein. Crystal structures show C5 and H3 overlap the ACE2 epitope, whilst C1 and F2 bind to a different epitope. Cryo Electron Microscopy shows C5 binding results in an all down arrangement of the Spike protein. C1, H3 and C5 all neutralize the Victoria strain, and the highly transmissible Alpha (B.1.1.7 first identified in Kent, UK) strain and C1 also neutralizes the Beta (B.1.35, first identified in South Africa). Administration of C5-trimer via the respiratory route showed potent therapeutic efficacy in the Syrian hamster model of COVID-19 and separately, effective prophylaxis. The molecule was similarly potent by intraperitoneal injection.
The SARS-CoV-2 virus is more transmissible than previous coronaviruses and causes a more serious illness than influenza. The SARS-CoV-2 receptor binding domain (RBD) of the spike protein binds to the ...human angiotensin-converting enzyme 2 (ACE2) receptor as a prelude to viral entry into the cell. Using a naive llama single-domain antibody library and PCR-based maturation, we have produced two closely related nanobodies, H11-D4 and H11-H4, that bind RBD (K
of 39 and 12 nM, respectively) and block its interaction with ACE2. Single-particle cryo-EM revealed that both nanobodies bind to all three RBDs in the spike trimer. Crystal structures of each nanobody-RBD complex revealed how both nanobodies recognize the same epitope, which partly overlaps with the ACE2 binding surface, explaining the blocking of the RBD-ACE2 interaction. Nanobody-Fc fusions showed neutralizing activity against SARS-CoV-2 (4-6 nM for H11-H4, 18 nM for H11-D4) and additive neutralization with the SARS-CoV-1/2 antibody CR3022.
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FZAB, GEOZS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Tracing sediments back to their catchment sources using biogeochemical and physical fingerprints involves multiple assumptions. One of the most fundamental assumptions is that these fingerprints are ...consistent during sediment generation, transportation, and deposition processes. Accordingly, the biogeochemical fingerprints used to trace sediment must remain constant, during detachment and redistribution, or they must vary in a predictable and measurable way. One key challenge to this assumption is the sorting effect of particles by size during detachment, mobilization, transportation and deposition processes. Owing to the notable effect of particle size on sediment fingerprints, we believe it is important to review the main approaches used to address the effects of changes in particle size composition on sediment fingerprints. The two main approaches to addressing particle size impacts on fingerprint properties are: fractionation of source and sediment material to a narrow particle size range (e.g. isolation of <10μm or <63μm fractions), and concentration corrections (e.g. normalizing concentrations by parameters such as specific surface area). These approaches are often used in combination. The utility of fractionation and corrections to address particle size effects has received increasing attention and the relative merits of these procedures have been subject to debate. Accordingly, alternative techniques to address particle size effects in sediment fingerprinting studies are being adopted. For example, a tributary tracing technique or edge-of-field samplers may minimize particle size effects on sediment source fingerprints. The interrelationships between particle size and biogeochemical tracer properties suggest that particle size may also contribute to the formation of contrasts in sediment fingerprints between sources. Indeed, there may be a significant opportunity to derive further sediment source information through comprehensively investigating and unravelling the complexity of particle size–biogeochemical interactions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
This book reviews the major achievements recently made in soil erosion and sediment redistribution research and management, and identifies future requirements. The book presents work from key players ...in river basin soil erosion and sediment redistribution from sources to sinks, field to riverbank, from academia to policy and industry. It examines the developments made in three themes - measurement, modelling and management - and covers a variety of scales (in both time and space) and geographical locations.
Mountain geomorphology Owens, Philip N; Slaymaker, Olav
2004., 2004, 20140204, 2014, 2014-02-04
eBook
Mountains represent one of the most inspiring and attractive natural features on the surface of the earth. Visually, they dominate the landscape. However, the increasing realization of the fragility ...of mountain areas because of changes in land use, management and climate, combined with an understanding of their importance for water and other natural resources, has resulted in a growing interest in mountain environments in recent years. Hence, Mountain Geomorphology represents a timely and unique contribution to the literature. Written by a team of international experts, this book is divided into three sections, which consider historical, functional and applied mountain geomorphology from both global and local perspectives. Historical mountain geomorphology focuses on the evolution of landforms. Functional mountain geomorphology emphasises the interaction between processes and landforms, while applied mountain geomorphology concerns the interrelationships between geomorphological processes and society. Mountain Geomorphology is a valuable source of information for students studying mountain geomorphology, and also for academics and research scientists interested in mountain environments.
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