Ongoing and amplified climate change in the Arctic is leading to glacier retreat and to the exposure of an ever\uffe2\uff80\uff90larger portion of non\uffe2\uff80\uff90glaciated permafrost\uffe2\uff80\uff90dominated landscapes. Warming will also cause more precipitation to fall as rain, further enhancing the thaw of previously frozen ground. Yet, the impact of those perturbations on the geochemistry of Arctic rivers remains a subject of debate. Here, we determined the geochemical composition of waters from various contrasting non\uffe2\uff80\uff90glacial permafrost catchments and investigated their impact on a glacially dominated river, the Zackenberg River (Northeast Greenland), during late summer (August 2019). We also studied the effect of rainfall on the geochemistry of the Zackenberg River, its non\uffe2\uff80\uff90glacial tributaries, and a nearby independent non\uffe2\uff80\uff90glacial headwater stream Gr\uffc3\uffa6nse. We analyzed water properties, quantified and characterized dissolved organic matter (DOM) using absorbance and fluorescence spectroscopy and radiocarbon isotopes, and set this alongside analyses of the major cations (Ca, Mg, Na, and K), dissolved silicon (Si), and germanium/silicon ratios (Ge/Si). The glacier\uffe2\uff80\uff90fed Zackenberg River contained low concentrations of major cations, dissolved Si and dissolved organic carbon (DOC), and a Ge/Si ratio typical of bulk rock. Glacial DOM was enriched in protein\uffe2\uff80\uff90like fluorescent DOM and displayed relatively depleted radiocarbon values (i.e., old DOM). Non\uffe2\uff80\uff90glacial streams (i.e., tributaries and Gr\uffc3\uffa6nse) had higher concentrations of major cations and DOC and DOM enriched in aromatic compounds. They showed a wide range of values for radiocarbon, Si and Ge/Si ratios associated with variable contributions of surface runoff relative to deep active layer leaching. Before the rain event, Zackenberg tributaries did not contribute notably to the solute export of the Zackenberg River, and supra\uffe2\uff80\uff90permafrost ground waters governed the supply of solutes in Zackenberg tributaries and Gr\uffc3\uffa6nse stream. After the rain event, surface runoff modified the composition of Gr\uffc3\uffa6nse stream, and non\uffe2\uff80\uff90glacial tributaries strongly increased their contribution to the Zackenberg River solute export. Our results show that summer rainfall events provide an additional source of DOM and Si\uffe2\uff80\uff90rich waters from permafrost\uffe2\uff80\uff90underlain catchments to the discharge of glacially dominated rivers. This suggests that the magnitude and composition of solute exports from Arctic rivers are modulated by permafrost thaw and summer rain events. This event\uffe2\uff80\uff90driven solute supply will likely impact the carbon cycle in rivers, estuaries, and oceans and should be included into future predictions of carbon balance in these vulnerable Arctic systems. It is possible to control the source of recombination in the same sample of porous silicon by applying a cyclic sequence of hydrogenation\u2013oxidation\u2013hydrogenation processes and, consequently, switching on-demand between Shockley\u2013Read\u2013Hall and Auger recombinations.
Our understanding of plant-microbe interactions in soil is limited by the difficulty of observing processes at the microscopic scale throughout plants\uffe2\uff80\uff99 large volume of influence. Here, we present the development of 3D live microscopy for resolving plant-microbe interactions across the environment of an entire seedling growing in a transparent soil in tailor-made mesocosms, maintaining physical conditions for the culture of both plants and microorganisms. A tailor made dual-illumination light-sheet system acquired scattering signals from the plant whilst fluorescence signals were captured from transparent soil particles and labelled microorganisms, allowing the generation of quantitative data on samples approximately 3600 mm3in size with as good as 5 \uffce\uffbcm resolution at a rate of up to one scan every 30 minutes. The system tracked the movement ofBacillus subtilispopulations in the rhizosphere of lettuce plants in real time, revealing previously unseen patterns of activity. Motile bacteria favoured small pore spaces over the surface of soil particles, colonising the root in a pulsatile manner. Migrations appeared to be directed towards the root cap, the point \uffe2\uff80\uff9cfirst contact\uffe2\uff80\uff9d, before subsequent colonisation of mature epidermis cells. Our findings show that microscopes dedicated to live environmental studies present an invaluable tool to understand plant-microbe interactions.
", "keywords": ["0301 basic medicine", "570", "Microscopy", "Silicon", "0303 health sciences", "Temperature", "root-microbe interactions", "Equipment Design", "Biological Sciences", "Environment", "15. Life on land", "Plant Roots", "630", "Fluorescence", "Soil", "03 medical and health sciences", "Seedlings", "Calibration", "Rhizosphere", "Image Processing", " Computer-Assisted", "environmental imaging", "rhizosphere", "Soil Microbiology", "Bacillus subtilis", "Lactuca"]}, "links": [{"href": "https://eprints.whiterose.ac.uk/178939/18/e2109176118.full.pdf"}, {"href": "https://pnas.org/doi/pdf/10.1073/pnas.2109176118"}, {"href": "https://doi.org/10.1073/pnas.2109176118"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Proceedings%20of%20the%20National%20Academy%20of%20Sciences", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1073/pnas.2109176118", "name": "item", "description": "10.1073/pnas.2109176118", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1073/pnas.2109176118"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-02-13T00:00:00Z"}}, {"id": "10.1029/2024GB008367", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-05-29T16:17:43Z", "type": "Journal Article", "created": "2025-04-05", "title": "Insect Herbivory Releases More Nutrients in Warmer and Drier Forests", "description": "AbstractClimate, forest successional stage, and soil substrate age can alter herbivore communities and their effects on biogeochemical cycling, but the size and spatial variability of these effects are poorly quantified. To address this knowledge gap, we established a globally distributed network of 50 broadleaved old\uffe2\uff80\uff90growth forests across six continents, encompassing well\uffe2\uff80\uff90constrained local\uffe2\uff80\uff90scale gradients in mean annual temperature (MAT), mean annual precipitation (MAP), succession, and soil substrate age. We used this network to investigate how these variables impact insect foliar herbivory and the associated carbon, nitrogen, phosphorus, and silica fluxes in forest ecosystems. Over 1 to 2\uffc2\uffa0years, we measured stand\uffe2\uff80\uff90level foliar biomass production, leaf\uffe2\uff80\uff90level herbivory, and foliar element concentrations. At the global scale, insect herbivores liberated higher amounts of elements from the canopies of warmer and drier sites than those of cooler and wetter sites with patterns for phosphorus being most pronounced. MAT exerted a stronger influence over insect\uffe2\uff80\uff90mediated element fluxes than MAP. Foliar biomass production and leaf\uffe2\uff80\uff90level herbivory responses to MAT and MAP were mainly responsible for the observed changes in insect\uffe2\uff80\uff90mediated element fluxes; we also observed minor effects of foliar phosphorus concentration on phosphorus fluxes. Local\uffe2\uff80\uff90scale trends were mixed and successional stage or soil substrate age did not appear to influence insect herbivore\uffe2\uff80\uff90mediated element fluxes. These results demonstrate that climate effects on plant\uffe2\uff80\uff90herbivore interactions are stronger at large than small scales, at which herbivory rates and nutrient fluxes appear to be more strongly affected by a diversity of non\uffe2\uff80\uff90climate factors.Climate, forest successional stage, and soil substrate age can alter herbivore communities and their effects on biogeochemical cycling, but the size and spatial variability of these effects are poorly quantified. To address this knowledge gap, we established a globally distributed network of 50 broadleaved old\uffe2\uff80\uff90growth forests across six continents, encompassing well\uffe2\uff80\uff90constrained local\uffe2\uff80\uff90scale gradients in mean annual temperature (MAT), mean annual precipitation (MAP), succession, and soil substrate age. We used this network to investigate how these variables impact insect foliar herbivory and the associated carbon, nitrogen, phosphorus, and silica fluxes in forest ecosystems. Over 1 to 2\uffc2\uffa0years, we measured stand\uffe2\uff80\uff90level foliar biomass production, leaf\uffe2\uff80\uff90level herbivory, and foliar element concentrations. At the global scale, insect herbivores liberated higher amounts of elements from the canopies of warmer and drier sites than those of cooler and wetter sites with patterns for phosphorus being most pronounced. MAT exerted a stronger influence over insect\uffe2\uff80\uff90mediated element fluxes than MAP. Foliar biomass production and leaf\uffe2\uff80\uff90level herbivory responses to MAT and MAP were mainly responsible for the observed changes in insect\uffe2\uff80\uff90mediated element fluxes; we also observed minor effects of foliar phosphorus concentration on phosphorus fluxes. Local\uffe2\uff80\uff90scale trends were mixed and successional stage or soil substrate age did not appear to influence insect herbivore\uffe2\uff80\uff90mediated element fluxes. These results demonstrate that climate effects on plant\uffe2\uff80\uff90herbivore interactions are stronger at large than small scales, at which herbivory rates and nutrient fluxes appear to be more strongly affected by a diversity of non\uffe2\uff80\uff90climate factors.The permafrost active layer is a key supplier of soil organic carbon and mineral nutrients to Arctic rivers. In the active layer, sites of soil-water exchange are locations for organic carbon and nutrient mobilization. Previously these sites were considered as connected during summer months and isolated during winter months. Whether soil pore waters in active layer soils are connected during shoulder seasons is poorly understood. In this study, exceptionally heavy silicon isotope compositions in soil pore waters show that during late winter, there is no connection between isolated pockets of soil pore water in soils with a shallow active layer. However, lighter silicon isotope compositions in soil pore waters reveal that soils are biogeochemically connected for longer than previously considered in soils with a deeper active layer. We show that an additional 21% of the 0\uffe2\uff80\uff931\uffe2\uff80\uff89m soil organic carbon stock is exposed to soil - water exchange. This marks a hot moment during a dormant season, and an engine for organic carbon transport from active layer soils. Our findings mark the starting point to locate earlier pathways for biogeochemical connectivity, which need to be urgently monitored to quantify the seasonal flux of organic carbon released from permafrost soils. Glacial environments play an important role in high-latitude marine nutrient cycling, potentially contributing significant fluxes of silicon (Si) to the polar oceans, either as dissolved silicon (DSi) or as dissolvable amorphous silica (ASi). Silicon is a key nutrient in promoting marine primary productivity, contributing to atmospheric CO 2 removal. We present the current understanding of Si cycling in glacial systems, focusing on the Si isotope (\uffce\uffb4 30 Si) composition of glacial meltwaters. We combine existing glacial \uffce\uffb4 30 Si data with new measurements from 20 sub-Arctic glaciers, showing that glacial meltwaters consistently export isotopically light DSi compared with non-glacial rivers (+0.16\uffe2\uff80\uffb0 versus +1.38\uffe2\uff80\uffb0). Glacial \uffce\uffb4 30 Si ASi composition ranges from \uffe2\uff88\uff920.05\uffe2\uff80\uffb0 to \uffe2\uff88\uff920.86\uffe2\uff80\uffb0 but exhibits low seasonal variability. Silicon fluxes and \uffce\uffb4 30 Si composition from glacial systems are not commonly included in global Si budgets and isotopic mass balance calculations at present. We discuss outstanding questions, including the formation mechanism of ASi and the export of glacial nutrients from fjords. Finally, we provide a contextual framework for the recent advances in our understanding of subglacial Si cycling and highlight critical research avenues for assessing potential future changes in these environments. Our understanding of plant-microbe interactions in soil is limited by the difficulty of observing processes at the microscopic scale throughout plants\uffe2\uff80\uff99 large volume of influence. Here, we present the development of 3D live microscopy for resolving plant-microbe interactions across the environment of an entire seedling growing in a transparent soil in tailor-made mesocosms, maintaining physical conditions for the culture of both plants and microorganisms. A tailor made dual-illumination light-sheet system acquired scattering signals from the plant whilst fluorescence signals were captured from transparent soil particles and labelled microorganisms, allowing the generation of quantitative data on samples approximately 3600 mm3in size with as good as 5 \uffce\uffbcm resolution at a rate of up to one scan every 30 minutes. The system tracked the movement ofBacillus subtilispopulations in the rhizosphere of lettuce plants in real time, revealing previously unseen patterns of activity. Motile bacteria favoured small pore spaces over the surface of soil particles, colonising the root in a pulsatile manner. Migrations appeared to be directed towards the root cap, the point \uffe2\uff80\uff9cfirst contact\uffe2\uff80\uff9d, before subsequent colonisation of mature epidermis cells. Our findings show that microscopes dedicated to live environmental studies present an invaluable tool to understand plant-microbe interactions.Maize (Zea mays L.) production in the smallholder farming areas of Zimbabwe is based on both organic and mineral nutrient sources. A study was conducted to determine the effect of composted cattle manure, mineral N fertilizer, and their combinations on NO3 concentrations in leachate leaving the root zone and to establish N fertilization rates that minimize leaching. Maize was grown for three seasons (1996\uffe2\uff80\uff931997, 1997\uffe2\uff80\uff931998, and 1998\uffe2\uff80\uff931999) in field lysimeters repacked with a coarse\uffe2\uff80\uff90grained sandy soil (Typic Kandiustalf). Leachate volumes ranged from 480 to 509 mm yr\uffe2\uff88\uff921 (1395 mm rainfall) in 1996\uffe2\uff80\uff931997, 296 to 335 mm yr\uffe2\uff88\uff921 (840 mm rainfall) in 1997\uffe2\uff80\uff931998, and 606 to 635 mm yr\uffe2\uff88\uff921 (1387 mm rainfall) in 1998\uffe2\uff80\uff931999. Mineral N fertilizer, especially the high rate (120 kg N ha\uffe2\uff88\uff921), and manure plus mineral N fertilizer combinations resulted in high NO3 leachate concentrations (up to 34 mg N L\uffe2\uff88\uff921) and NO3 losses (up to 56 kg N ha\uffe2\uff88\uff921 yr\uffe2\uff88\uff921) in 1996\uffe2\uff80\uff931997, which represent both environmental and economic concerns. Although the leaching losses were relatively small in the other seasons, they are still of great significance in African smallholder farming where fertilizer is unaffordable for most farmers. Nitrate leaching from sole manure treatments was relatively low (average of less than 20 kg N ha\uffe2\uff88\uff921 yr\uffe2\uff88\uff921), whereas the crop uptake efficiency of mineral N fertilizer was enhanced by up to 26% when manure and mineral N fertilizer were applied in combination. The low manure (12.5 Mg ha\uffe2\uff88\uff921) plus 60 kg N ha\uffe2\uff88\uff921 fertilizer treatment was best in terms of maintaining dry matter yield and minimizing N leaching losses.
", "keywords": ["2. Zero hunger", "Tropical Climate", "Nitrates", "Rain", "rainfall", "cattle manure", "04 agricultural and veterinary sciences", "15. Life on land", "Silicon Dioxide", "Plant Roots", "losses", "6. Clean water", "Manure", "corn", "nitrogen-fertilizer", "Soil Pollutants", "0401 agriculture", " forestry", " and fisheries", "Water Pollutants", "lysimeters", "Fertilizers", "zimbabwe", "time", "Environmental Monitoring"]}, "links": [{"href": "https://doi.org/10.2134/jeq2003.5990"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Journal%20of%20Environmental%20Quality", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.2134/jeq2003.5990", "name": "item", "description": "10.2134/jeq2003.5990", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.2134/jeq2003.5990"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2003-01-01T00:00:00Z"}}, {"id": "10.2134/jeq2005.0047", "type": "Feature", "geometry": null, "properties": {"license": "Closed Access", "updated": "2026-05-29T16:20:17Z", "type": "Journal Article", "created": "2005-11-08", "title": "In Situ Measurements Of Nitrate Leaching Implicate Poor Nitrogen And Irrigation Management On Sandy Soils", "description": "ABSTRACTMinimizing the risk of nitrate contamination along the waterways of the U.S. Great Plains is essential to continued irrigated corn production and quality water supplies. The objectives of this study were to quantify nitrate (NO3) leaching for irrigated sandy soils (Pratt loamy fine sand [sandy, mixed, mesic Lamellic Haplustalfs]) and to evaluate the effects of N fertilizer and irrigation management strategies on NO3 leaching in irrigated corn. Two irrigation schedules (1.0\uffc3\uff97 and 1.25\uffc3\uff97 optimum) were combined with six N fertilizer treatments broadcast as NH4NO3 (kg N ha\uffe2\uff88\uff921): 300 and 250 applied pre\uffe2\uff80\uff90plant; 250 applied pre\uffe2\uff80\uff90plant and sidedress; 185 applied pre\uffe2\uff80\uff90plant and sidedress; 125 applied pre\uffe2\uff80\uff90plant and sidedress; and 0. Porous\uffe2\uff80\uff90cup tensiometers and solution samplers were installed in each of the four highest N treatments. Soil solution samples were collected during the 2001 and 2002 growing seasons. Maximum corn grain yield was achieved with 125 or 185 kg N ha\uffe2\uff88\uff921, regardless of the irrigation schedule (IS). The 1.25\uffc3\uff97 IS exacerbated the amount of NO3 leached below the 152\uffe2\uff80\uff90cm depth in the preplant N treatments, with a mean of 146 kg N ha\uffe2\uff88\uff921 for the 250 and 300 kg N preplant applications compared with 12 kg N ha\uffe2\uff88\uff921 for the same N treatments and 1.0\uffc3\uff97 IS. With 185 kg N ha\uffe2\uff88\uff921, the 1.25\uffc3\uff97 IS treatment resulted in 74 kg N ha\uffe2\uff88\uff921 leached compared with 10 kg N ha\uffe2\uff88\uff921 for the 1.0\uffc3\uff97 IS. Appropriate irrigation scheduling and N fertilizer rates are essential to improving N management practices on these sandy soils.
", "keywords": ["2. Zero hunger", "Nitrates", "Nitrogen", "Agriculture", "04 agricultural and veterinary sciences", "Kansas", "15. Life on land", "Silicon Dioxide", "Plant Roots", "Zea mays", "01 natural sciences", "6. Clean water", "Random Allocation", "Soil", "0401 agriculture", " forestry", " and fisheries", "Fertilizers", "0105 earth and related environmental sciences"], "contacts": [{"organization": "Gary A. Clark, John P. Schmidt, Loyd R. Stone, Alan J. Schlegel, Ronald J. Gehl,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.2134/jeq2005.0047"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Journal%20of%20Environmental%20Quality", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.2134/jeq2005.0047", "name": "item", "description": "10.2134/jeq2005.0047", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.2134/jeq2005.0047"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2005-11-01T00:00:00Z"}}, {"id": "10.3389/feart.2020.00229", "type": "Feature", "geometry": null, "properties": {"updated": "2026-05-29T16:20:51Z", "type": "Journal Article", "created": "2020-06-26", "title": "Silicon Isotopes Reveal a Non-glacial Source of Silicon to Crescent Stream, McMurdo Dry Valleys, Antarctica", "description": "In high latitude environments, silicon is supplied to river waters by both glacial and non-glacial chemical weathering. The signal of these two end-members is often obscured by biological uptake and/or groundwater input in the river catchment. McMurdo Dry Valleys streams in Antarctica have no deep groundwater input, no connectivity between streams and no surface vegetation cover, and thus provide a simplified system for us to constrain the supply of dissolved silicon (DSi) to rivers from chemical weathering in a glacial environment. Here we report dissolved Si concentrations, germanium/silicon ratios (Ge/Si) and silicon isotope compositions (\u03b430SiDSi) in Crescent Stream, McMurdo Dry Valleys for samples collected between December and February in the 2014\u22122015, 2015\u22122016, and 2016\u22122017 austral seasons. The \u03b430SiDSi compositions and DSi concentrations are higher than values reported in wet-based glacial meltwaters, and form a narrow cluster within the range of values reported for permafrost dominated Arctic Rivers. High \u03b430SiDSi compositions, ranging from +0.90\u2030 to +1.39\u2030, are attributed to (i) the precipitation of amorphous silica during freezing of waters in isolated pockets of the hyporheic zone in the winter and the release of Si from unfrozen pockets during meltwater-hyporheic zone exchange in the austral summer, and (ii) additional Si isotope fractionation via long-term Si uptake in clay minerals and seasonal Si uptake into diatoms superimposed on this winter-derived isotope signal. There is no relationship between \u03b430SiDSi compositions and DSi concentrations with seasonal and daily discharge, showing that stream waters contain DSi that is in equilibrium with the formation of secondary Si minerals in the hyporheic zone. We show that \u03b430SiDSi compositions can be used as tracers of silicate weathering in the hyporheic zone and possible tracers of freeze-thaw conditions in the hyporheic zone. This is important in the context of the ongoing warming in McMurdo Dry Valleys and the supply of more meltwaters to the hyporheic zone of McMurdo Dry Valley streams.", "keywords": ["550", "Science", "Q", "silicon", "Antartica", "15. Life on land", "551", "01 natural sciences", "hyporheic zone", "silicon isotopes", "13. Climate action", "weathering", "Antarctica", "isotopes", "permafrost", "0105 earth and related environmental sciences"]}, "links": [{"href": "https://doi.org/10.3389/feart.2020.00229"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Frontiers%20in%20Earth%20Science", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.3389/feart.2020.00229", "name": "item", "description": "10.3389/feart.2020.00229", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.3389/feart.2020.00229"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2020-06-26T00:00:00Z"}}, {"id": "10.3389/feart.2020.00286", "type": "Feature", "geometry": null, "properties": {"updated": "2026-05-29T16:20:51Z", "type": "Journal Article", "created": "2020-07-14", "title": "Silicon Isotopic Composition of Dry and Wet-Based Glaciers in Antarctica", "description": "Glaciers and ice sheets export significant amounts of silicon (Si) to downstream ecosystems, impacting local and potentially global biogeochemical cycles. Recent studies have shown Si in Arctic glacial meltwaters to have an isotopically distinct signature when compared to non-glacial rivers. This is likely linked to subglacial weathering processes and mechanochemical reactions. However, there are currently no silicon isotope (\u03b430Si) data available from meltwater streams in Antarctica, limiting the current inferences on global glacial silicon isotopic composition and its drivers. To address this gap, we present dissolved silicon (DSi), \u03b430SiDSi and major ion data from meltwater streams draining a polythermal glacier in the region of the West Antarctic peninsula (King George Island) and a cold-based glacier in East Antarctica (Commonwealth Stream, McMurdo Dry Valleys). These data, alongside other global datasets, improve our understanding of how contrasting glacier thermal regime can impact upon Si cycling and therefore the \u03b430SiDSi composition. ud We find a similar \u03b430SiDSi composition between the two sites, with the streams on King George Island varying between -0.23 and +1.23\u2030 and the Commonwealth stream varying from -0.40 to +1.14\u2030. However, meltwater streams in King George Island have higher DSi concentrations, and the two glacial systems exhibit opposite DSi - \u03b430SiDSi trends. These contrasts likely result from differences in weathering processes, specifically the role of subglacial processes (King George Island) and, supraglacial processes followed by in-stream weathering in hyporheic zones (Commonwealth Stream). These findings are important when considering likely changes in nutrient fluxes from Antarctic glaciers under climatic warming scenarios and consequent shifts in glacial thermal regimes.", "keywords": ["silicon isotope geochemistry", "550", "Stream Weathering", "Science", "Q", "500", "Antartica", "subglacial weathering", "15. Life on land", "01 natural sciences", "silicon cycle", "13. Climate action", "stream weathering", "solicon isotope", "Silicon Cycle", "Antarctica", "Subglacial Weathering", "Silicon Isotope Geochemistry", "geochemistry", "0105 earth and related environmental sciences"]}, "links": [{"href": "https://orca.cardiff.ac.uk/id/eprint/133147/2/feart-08-00286.pdf"}, {"href": "https://doi.org/10.3389/feart.2020.00286"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Frontiers%20in%20Earth%20Science", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.3389/feart.2020.00286", "name": "item", "description": "10.3389/feart.2020.00286", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.3389/feart.2020.00286"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2020-07-14T00:00:00Z"}}, {"id": "10.3390/bios14070326", "type": "Feature", "geometry": null, "properties": {"updated": "2026-05-29T16:21:04Z", "type": "Journal Article", "created": "2024-07-01", "title": "Biosensors for Cancer Biomarkers Based on Mesoporous Silica Nanoparticles", "description": "Mesoporous silica nanoparticles (MSNs) exhibit highly beneficial characteristics for devising efficient biosensors for different analytes. Their unique properties, such as capabilities for stable covalent binding to recognition groups (e.g., antibodies or aptamers) and sensing surfaces, open a plethora of opportunities for biosensor construction. In addition, their structured porosity offers capabilities for entrapping signaling molecules (dyes or electroactive species), which could be released efficiently in response to a desired analyte for effective optical or electrochemical detection. This work offers an overview of recent research studies (in the last five years) that contain MSNs in their optical and electrochemical sensing platforms for the detection of cancer biomarkers, classified by cancer type. In addition, this study provides an overview of cancer biomarkers, as well as electrochemical and optical detection methods in general.
It is possible to control the source of recombination in the same sample of porous silicon by applying a cyclic sequence of hydrogenation\u2013oxidation\u2013hydrogenation processes and, consequently, switching on-demand between Shockley\u2013Read\u2013Hall and Auger recombinations.
Glacial environments play an important role in high-latitude marine nutrient cycling, potentially contributing significant fluxes of silicon (Si) to the polar oceans, either as dissolved silicon (DSi) or as dissolvable amorphous silica (ASi). Silicon is a key nutrient in promoting marine primary productivity, contributing to atmospheric CO 2 removal. We present the current understanding of Si cycling in glacial systems, focusing on the Si isotope (\uffce\uffb4 30 Si) composition of glacial meltwaters. We combine existing glacial \uffce\uffb4 30 Si data with new measurements from 20 sub-Arctic glaciers, showing that glacial meltwaters consistently export isotopically light DSi compared with non-glacial rivers (+0.16\uffe2\uff80\uffb0 versus +1.38\uffe2\uff80\uffb0). Glacial \uffce\uffb4 30 Si ASi composition ranges from \uffe2\uff88\uff920.05\uffe2\uff80\uffb0 to \uffe2\uff88\uff920.86\uffe2\uff80\uffb0 but exhibits low seasonal variability. Silicon fluxes and \uffce\uffb4 30 Si composition from glacial systems are not commonly included in global Si budgets and isotopic mass balance calculations at present. We discuss outstanding questions, including the formation mechanism of ASi and the export of glacial nutrients from fjords. Finally, we provide a contextual framework for the recent advances in our understanding of subglacial Si cycling and highlight critical research avenues for assessing potential future changes in these environments. Ongoing and amplified climate change in the Arctic is leading to glacier retreat and to the exposure of an ever\uffe2\uff80\uff90larger portion of non\uffe2\uff80\uff90glaciated permafrost\uffe2\uff80\uff90dominated landscapes. Warming will also cause more precipitation to fall as rain, further enhancing the thaw of previously frozen ground. Yet, the impact of those perturbations on the geochemistry of Arctic rivers remains a subject of debate. Here, we determined the geochemical composition of waters from various contrasting non\uffe2\uff80\uff90glacial permafrost catchments and investigated their impact on a glacially dominated river, the Zackenberg River (Northeast Greenland), during late summer (August 2019). We also studied the effect of rainfall on the geochemistry of the Zackenberg River, its non\uffe2\uff80\uff90glacial tributaries, and a nearby independent non\uffe2\uff80\uff90glacial headwater stream Gr\uffc3\uffa6nse. We analyzed water properties, quantified and characterized dissolved organic matter (DOM) using absorbance and fluorescence spectroscopy and radiocarbon isotopes, and set this alongside analyses of the major cations (Ca, Mg, Na, and K), dissolved silicon (Si), and germanium/silicon ratios (Ge/Si). The glacier\uffe2\uff80\uff90fed Zackenberg River contained low concentrations of major cations, dissolved Si and dissolved organic carbon (DOC), and a Ge/Si ratio typical of bulk rock. Glacial DOM was enriched in protein\uffe2\uff80\uff90like fluorescent DOM and displayed relatively depleted radiocarbon values (i.e., old DOM). Non\uffe2\uff80\uff90glacial streams (i.e., tributaries and Gr\uffc3\uffa6nse) had higher concentrations of major cations and DOC and DOM enriched in aromatic compounds. They showed a wide range of values for radiocarbon, Si and Ge/Si ratios associated with variable contributions of surface runoff relative to deep active layer leaching. Before the rain event, Zackenberg tributaries did not contribute notably to the solute export of the Zackenberg River, and supra\uffe2\uff80\uff90permafrost ground waters governed the supply of solutes in Zackenberg tributaries and Gr\uffc3\uffa6nse stream. After the rain event, surface runoff modified the composition of Gr\uffc3\uffa6nse stream, and non\uffe2\uff80\uff90glacial tributaries strongly increased their contribution to the Zackenberg River solute export. Our results show that summer rainfall events provide an additional source of DOM and Si\uffe2\uff80\uff90rich waters from permafrost\uffe2\uff80\uff90underlain catchments to the discharge of glacially dominated rivers. This suggests that the magnitude and composition of solute exports from Arctic rivers are modulated by permafrost thaw and summer rain events. This event\uffe2\uff80\uff90driven solute supply will likely impact the carbon cycle in rivers, estuaries, and oceans and should be included into future predictions of carbon balance in these vulnerable Arctic systems.In active volcanic regions, high\uffe2\uff80\uff90temperature chemical reactions in the hydrothermal system consume CO2 sourced from magma or from the deep crust, whereas reactions with silicates at shallow depths mainly consume atmospheric CO2. Numerous studies have quantified the load of dissolved solids in rivers that drain volcanic regions to determine chemical weathering rates and atmospheric CO2 consumption rates. However, the balance between thermal and non\uffe2\uff80\uff90thermal components to riverine fluxes in these areas remains poorly constrained, hindering accurate estimates of atmospheric CO2 consumption rates. Here we use the Ge/Si ratio and the stable silicon isotopes (\uffce\uffb430Si) as tracers for quantifying non\uffe2\uff80\uff90thermal silicon contributions in rivers draining the Yellowstone Plateau Volcanic Field, USA. The Ge/Si ratio (\uffc2\uffb5mol.mol\uffe2\uff88\uff921) was determined for seven thermal water samples (183\uffc2\uffa0\uffc2\uffb1\uffc2\uffa022), eight rivers (35\uffc2\uffa0\uffc2\uffb1\uffc2\uffa023) and six creeks flowing into Yellowstone Lake (5\uffc2\uffa0\uffc2\uffb1\uffc2\uffa03) during base flow and during peak water discharge following snowmelt. The \uffce\uffb430Si value (\uffe2\uff80\uffb0) was determined for thermal waters (\uffe2\uff88\uff920.09\uffc2\uffa0\uffc2\uffb1\uffc2\uffa00.04), Yellowstone River at Yellowstone Lake outlet (1.91\uffc2\uffa0\uffc2\uffb1\uffc2\uffa00.23) and creek samples (0.82\uffc2\uffa0\uffc2\uffb1\uffc2\uffa00.29). The calculated atmospheric CO2 consumption associated with non\uffe2\uff80\uff90thermal waters flowing through Yellowstone's rivers during peak discharge is \uffe2\uff88\uffbc3.03 ton.km\uffe2\uff88\uff922.yr\uffe2\uff88\uff921, which is \uffe2\uff88\uffbc2% of the annual mean atmospheric CO2 consumption in other volcanic regions. This study highlights the significance of quantifying seasonal variations in chemical weathering rates for improving estimates of atmospheric CO2 consumption rates in active volcanic regions.The permafrost active layer is a key supplier of soil organic carbon and mineral nutrients to Arctic rivers. In the active layer, sites of soil-water exchange are locations for organic carbon and nutrient mobilization. Previously these sites were considered as connected during summer months and isolated during winter months. Whether soil pore waters in active layer soils are connected during shoulder seasons is poorly understood. In this study, exceptionally heavy silicon isotope compositions in soil pore waters show that during late winter, there is no connection between isolated pockets of soil pore water in soils with a shallow active layer. However, lighter silicon isotope compositions in soil pore waters reveal that soils are biogeochemically connected for longer than previously considered in soils with a deeper active layer. We show that an additional 21% of the 0\uffe2\uff80\uff931\uffe2\uff80\uff89m soil organic carbon stock is exposed to soil - water exchange. This marks a hot moment during a dormant season, and an engine for organic carbon transport from active layer soils. Our findings mark the starting point to locate earlier pathways for biogeochemical connectivity, which need to be urgently monitored to quantify the seasonal flux of organic carbon released from permafrost soils.Our understanding of plant-microbe interactions in soil is limited by the difficulty of observing processes at the microscopic scale throughout plants\uffe2\uff80\uff99 large volume of influence. Here, we present the development of 3D live microscopy for resolving plant-microbe interactions across the environment of an entire seedling growing in a transparent soil in tailor-made mesocosms, maintaining physical conditions for the culture of both plants and microorganisms. A tailor made dual-illumination light-sheet system acquired scattering signals from the plant whilst fluorescence signals were captured from transparent soil particles and labelled microorganisms, allowing the generation of quantitative data on samples approximately 3600 mm3in size with as good as 5 \uffce\uffbcm resolution at a rate of up to one scan every 30 minutes. The system tracked the movement ofBacillus subtilispopulations in the rhizosphere of lettuce plants in real time, revealing previously unseen patterns of activity. Motile bacteria favoured small pore spaces over the surface of soil particles, colonising the root in a pulsatile manner. Migrations appeared to be directed towards the root cap, the point \uffe2\uff80\uff9cfirst contact\uffe2\uff80\uff9d, before subsequent colonisation of mature epidermis cells. Our findings show that microscopes dedicated to live environmental studies present an invaluable tool to understand plant-microbe interactions. Mesoporous silica nanoparticles (MSNs) exhibit highly beneficial characteristics for devising efficient biosensors for different analytes. Their unique properties, such as capabilities for stable covalent binding to recognition groups (e.g., antibodies or aptamers) and sensing surfaces, open a plethora of opportunities for biosensor construction. In addition, their structured porosity offers capabilities for entrapping signaling molecules (dyes or electroactive species), which could be released efficiently in response to a desired analyte for effective optical or electrochemical detection. This work offers an overview of recent research studies (in the last five years) that contain MSNs in their optical and electrochemical sensing platforms for the detection of cancer biomarkers, classified by cancer type. In addition, this study provides an overview of cancer biomarkers, as well as electrochemical and optical detection methods in general.
Our understanding of plant-microbe interactions in soil is limited by the difficulty of observing processes at the microscopic scale throughout plants\uffe2\uff80\uff99 large volume of influence. Here, we present the development of 3D live microscopy for resolving plant-microbe interactions across the environment of an entire seedling growing in a transparent soil in tailor-made mesocosms, maintaining physical conditions for the culture of both plants and microorganisms. A tailor made dual-illumination light-sheet system acquired scattering signals from the plant whilst fluorescence signals were captured from transparent soil particles and labelled microorganisms, allowing the generation of quantitative data on samples approximately 3600 mm3in size with as good as 5 \uffce\uffbcm resolution at a rate of up to one scan every 30 minutes. The system tracked the movement ofBacillus subtilispopulations in the rhizosphere of lettuce plants in real time, revealing previously unseen patterns of activity. Motile bacteria favoured small pore spaces over the surface of soil particles, colonising the root in a pulsatile manner. Migrations appeared to be directed towards the root cap, the point \uffe2\uff80\uff9cfirst contact\uffe2\uff80\uff9d, before subsequent colonisation of mature epidermis cells. Our findings show that microscopes dedicated to live environmental studies present an invaluable tool to understand plant-microbe interactions.