Mat Material Research Articles

The Preservation and Spectral Detection of Historic Museum Specimen Microbial Mat Biosignatures Within Martian Dust: Lessons Learned for Mars Exploration and Sample Return.

The key building blocks for life on Mars could be preserved within potentially habitable paleo-depositional settings with their detection possible by utilizing mid-infrared spectroscopy; however, a definite identification and confirmation of organic or even biological origin will require the samples to be returned to Earth. In the present study, Fourier-transform infrared (FTIR) spectroscopic techniques were used to characterize both mineralogical and organic materials within Mars dust simulant JSC Mars-1 and ancient Antarctic cyanobacterial microbial mats from 1901 to 1904 Discovery Expedition. When FTIR spectroscopy is applied to cyanobacterial microbial mat communities, the resulting spectra will reflect the average biochemical composition of the mats rather than taxa-specific spectral patterns of the individual organisms and can thus be considered as a total chemical analysis of the mat colony. This study also highlights the potential difficulties in the detection of these communities on Mars and which spectral biosignatures will be most detectable within geological substrates. Through the creation and analysis of a suite of dried microbial mat material and Martian dust simulant mixtures, the spectral signatures and wavenumber positions of CHx aliphatic hydrocarbons and the C-O and O-H bands of polysaccharides remained detectable and may be detectable within sample mixtures obtained through Mars Sample Return activities.

Environmental Factors Impacting the Development of Toxic Cyanobacterial Proliferations in a Central Texas Reservoir.

Cyanobacterial harmful algal proliferations (cyanoHAPs) are increasingly associated with dog and livestock deaths when benthic mats break free of their substrate and float to the surface. Fatalities have been linked to neurotoxicosis from anatoxins, potent alkaloids produced by certain genera of filamentous cyanobacteria. After numerous reports of dog illnesses and deaths at a popular recreation site on Lady Bird Lake, Austin, Texas in late summer 2019, water and floating mat samples were collected from several sites along the reservoir. Water quality parameters were measured and mat samples were maintained for algal isolation and DNA identification. Samples were also analyzed for cyanobacterial toxins using LC-MS. Dihydroanatoxin-a was detected in mat materials from two of the four sites (0.6-133 ng/g wet weight) while water samples remained toxin-free over the course of the sampling period; no other cyanobacterial toxins were detected. DNA sequencing analysis of cyanobacterial isolates yielded a total of 11 genera, including Geitlerinema, Tyconema, Pseudanabaena, and Phormidium/Microcoleus, taxa known to produce anatoxins, including dihydroanatoxin, among other cyanotoxins. Analyses indicate that low daily upriver dam discharge, higher TP and NO3 concentrations, and day of the year were the main parameters associated with the presence of toxic floating cyanobacterial mats.

Crane Mat Layout Optimization Based on Agent-Based Greedy and Reinforcement-Learning Approach

The growing prevalence of modular construction, while it offers benefits in terms of productivity and sustainability, has led to increased use of heavy mobile cranes and related resources on construction sites. One significant resource associated with crane use is the crane mat, which offers practical mobile crane ground support against poor soil-bearing capacity. Due to increased use of crane mats, crane mat layout plans/drawings have become increasingly significant in today’s construction industry. The present work describes an automated crane mat optimization framework for preparing crane mat layout plans/drawings built on an agent-based greedy algorithm and reinforcement learning. The proposed framework employs these approaches to achieve the maximum area with the minimum number of crane mats. The proposed framework is found to decrease the time required for preparing a crane mat layout plan/drawing (approximately 97% time saving) with more uniform and efficient crane mat planning outcomes (approximately 63% crane mat material reduction).

Investigation of the impact of environmental conditions on the vibration mitigation performance of typical commercial under ballast mat materials

The performance of under ballast mats (UBMs) in mitigating vibrations caused by regular rail traffic has been the subject of numerous studies. However, most of these studies have focused on the impact of design and material properties on the vibration attenuation characteristics of UBMs, with little attention paid to the influence of environmental factors such as temperature, freeze/thaw cycling, and weathering. In this paper, we present the results of an investigation into the effect of environmental conditions on the vibration mitigation performance of typical commercial UBM materials including rubber and closed cell polyurethane elastomer. We conducted controlled laboratory experiments in which we exposed UBM samples to a range of simulated environmental conditions. The results of these experiments were compared to the results of tests conducted under standard laboratory conditions to evaluate the impact of the environmental conditions on the vibration attenuation performance of the UBMs. The results of this investigation have important implications for the design and selection of UBMs for use in railway systems, particularly in regions with extreme environmental conditions.

Interface Characterization of Consolidated PPGF Tapes on PPGF Mat Material.

Laminated composites with thermoset matrices are already well established in major engineering fields like automotive and aviation. The primary drawbacks of such thermoset-based composites are the high cycle times required during manufacturing and their limited potential for recycling. Providing an alternative to thermoset-based composites, thermoplastic matrix materials gained more and more momentum by addressing these previously mentioned drawbacks. The preferred manufacturing technique for these materials employs fiber-reinforced thermoplastic tapes consolidated and formed together with a compatible substrate. The most critical aspect for all these applications is the stress or load transfer between the thermoplastic tapes and the substrate. If the interface is too weak and fails prior to the substrate or tape, a high amount of theoretical mechanical performance is lost. The presented research investigates the influence of variations in manufacturing parameters, within the industrially relevant process window, on the interface strength of the final composite. The investigated composite material consists of PPGF UD tapes consolidated on a PPGF mat substrate. In particular, the influence of the consolidation parameters of pressure, temperature, and time are of special interest. The results of this work reveal a 400% increase in the measured mean strain energy release rate upon increasing the consolidation time from 60 s to 120 s at a consolidation temperature of 230 °C and a pressure of one bar. In contrast to this, an increase in the consolidation pressure, at constant temperature and time, leads to a minor improvement in the GC value of 20%. For testing and characterizing the corresponding interface properties, a mandrel peel testing setup was employed.

REVIEW: STUDI ETNOBOTANI FARMAKOLOGI DAN FITOKIMIA PANDANUS TECTORIUS DI INDONESIA

The purpose of the review of Pandanus tectorius (P. tectorius) is to provide information on the ethnobotany, pharmacological and phytochemical activities of sea pandanus (P. tectorius) included in the pandanaceae tribe, Pandanus odoratissimus is a synonym of P. tectorius. Pandanus fasicularis Lam is also a synonym of P. tectorius, P. odoratissimus. Sea pandanus (P. tectorius) is a shrub plant that is still not widely utilized. P. tectorius is also one type of plant from the pandan family that grows wildly on the coast. Sea pandanus is widely found in South Asia, tropical Australia. This plant in Indonesia grows wild along the north coast of Java, Kepulauan Seribu, Sumatra and other islands. This review of P. tectorius aims to provide information on the ethnobotany, pharmacological and phytochemical activities of P. tectorius, using the literature study method from several studies on the ethnobotany, pharmacological and phytochemical activities of P. tectorius, sea pandanus leaves have the potential as a woven mat material, the fruit has the potential for antioxidant, cytotoxic, antibacterial, analgesic, antihyperlipidemia, antihyperglycemic, antimicrobial and anti-inflammatory activities.

Experimental Study on Anti-Scour Property and Erosion Resistance of 3D Mat Materials for Slope Protection in Waterway Engineering

3D mats are environmentally friendly and ecological materials for protecting river and waterway banks. The anti-scour properties of the materials and the erosion resistance of the soil under them can be studied to provide decision support for the selection of slope protection materials and their applicable areas. In this paper, an indoor prototypical scouring experiment with a flume is carried out to study the anti-scour properties of three types of 3D mat materials (vegetation grass mats, Enkamat and reinforced Mike mat) and the erosion resistance of the underlying soil under typical combined conditions of flow rate and water stage. It is concluded that the 3D mats increase the resistance coefficient of the bed surface, and that with the same incoming flow, the average flow velocity is inversely related to the resistance coefficient. There are three scouring modes for 3D mats under the action of water flow: material failure caused by mechanical damage, performance failure caused by serious erosion of the soil mass and non-failure. Of the three mat materials, the reinforced Mike mats are more resistant to scouring than the other two unreinforced materials, and the erosion volume ratios of reinforced Mike mats, vegetation grass mats and Enkamat are 59.24%, 61.81% and 62.17%, respectively, under the same small flow rate and high water stage. The results show that the reinforced Mike mats have the best anti-scour property and soil conservation performance, followed by Enkamat and the vegetation grass mats. In addition, reinforced materials outperform non-reinforced ones in their anti-scour performance and their protection for the underlying soil on the bank slope.

Effect of different cow floor mat on the pressure in anterior knees of Holstein dry cows determined using pressure measurement sheet.

To analyze limb pain in tethered dairy cows, we compared three cow floor mat materials (pasture mat® [PM], KKM rubber mat® [RM], and woodchip [WC]) with soil ground considering the pressure applied to the anterior knee of Holstein cows. Three Holstein dry cows (791.3 ± 44.6kg, 3.8 ± 1.1years old) moored at the Education and Research Center of Alpine Field Science of the Faculty of Agriculture, Shinshu University, were tested. Pressure applied to the anterior knee of the cow by four different floor mat materials was compared using a commercially available pressure measurement sheet. The sustained pressures applied to the anterior knee of the test cow were 7.2 ± 1. 5, 29.3 ± 5.1, 17.0 ± 1.4, and 27.7 ± 2.5MPa in the control, RM, PM, and WC, respectively, showing significant lower values (P < 0.05) than in the control. Sustained pressure was significantly lower in the PM than in the other treatments (P < 0.05). The RM was 41.7% cheaper than the PM. The pressure applied to the anterior knee of cow is lower on PM than on RM and WC. PM was more costly than RM but the sustained pressure was much lower on PM.

Study on Ultrasonic Monitoring of Resin Impregnation into Fiber Bundles and Acceleration of Resin Impregnation by Ultrasonic Vibration

The quality of RTM products is highly dependent on the state of resin impregnation into fiber preform during the mold-filling stage, and it is required to avoid creation of molding defects such as dry spots and voids. In our previous studies, it has been reported that ultrasonic testing can be used to evaluate the state of resin impregnation in RTM. However, fiber preform is limited to glass fiber chopped strand mats. In this study, we investigated the applicability of our method to glass cloth preform. It was found that the latter stage of resin impregnation process of glass cloth can be monitored by ultrasonic testing as in the case of the mat materials. The effect of ultrasonic vibration on resin impregnation was also investigated. Although sufficient effect on resin impregnation was not confirmed within the scope of this experiment, it was possible to apply ultrasonic monitoring under ultrasonic vibration.

Mechanistic Understanding of Nitrogen Behaviour in Floating Treatment Wetlands: Abatement of Ammonia Flux

Nitrogen behaviour in domestic wastewater was investigated to develop a mechanistic understanding of ammonia dynamics in Floating Treatment Wetlands (FTWs) and to improve design and operation. A critical FTW design (full coverage of the floating mat and maximum plant density) was evaluated to optimize treatment performance of a pilot-scale system in removing ammonia under different operational volumes. A system dynamics approach as a framework was employed for robust understanding of the treatment mechanisms and system performance in removing ammonia. The results revealed that ammonia removal was enhanced in FTWs and the magnitude of removal was controlled by the design examined. Findings suggest that a design code of full coverage of water surface with mat material, high plant density, and low water volume can be considered as a critical design for FTW system to remove ammonia from domestic wastewater. This design promoted nitrification as principal ammonia removal process even when plants were present. The contribution of nitrification to overall ammonia removal was estimated to be between 81 and 85%. Plant uptake contributed to 14-19% of the total N loss. Ammonia loss via volatilization was determined to be negligible in examined system. Kinetics parameters for ammonia removal were between 0.14-0.22 day-1 in FTWs compared to 0.01-0.02 day-1 in controls. Understanding the contribution of removal processes of N could be useful to improve treatment system design, and enhance treatment performance.

The Role of Microbial Biofilm in Removing Ammonia in Floating Treatment Wetlands

Abstract Laboratory experiments were conducted under controlled conditions to quantify the potential of microbial transformation associated with floating matrix of floating treatment wetland (FTW) in ammonia removal and nitrification kinetics. The effect of different design parameters on ammonia removal from synthetic medium was investigated to optimize system performance. Effects of surface area of mat material, range of ammonia concentrations, and aeration on ammonia removal kinetics were studied using microcosm systems. A simple dynamics model of mineral nitrogen transformation was used as a framework for interpreting the experimental results. The results revealed that ammonia removal was enhanced in FTWs, and the magnitude of removal was controlled by the design factors examined. Removal by nitrification was directly proportional to mat surface area. The higher ammonia removal efficiency was caused by a larger surface area, which could support the growth of more microbes. Removal rate constants for treatments were 0.011, 0.015, 0.026, 0.035, and 0.033 day–1 for T1, T2, T3, T4, and T5, respectively. There was also a clear inhibitory effect of NH3 on second-stage nitrification manifested as low production of NO3–. Quantitative index of optimized knit/calibrated knit indicated high inhibition effects of NH3 at high concentration of total ammonia (60 mg N L–1). There was no major effect of oxygen saturation on NHx removal using aerated and nonaerated conditions. Better mechanistic understanding of the fundamental processes operating in FTWs should provide the basis for improving FTW design and efficacy.

Mass Occurrence of Anatoxin-a- and Dihydroanatoxin-a-Producing Tychonema sp. in Mesotrophic Reservoir Mandichosee (River Lech, Germany) as a Cause of Neurotoxicosis in Dogs.

In August 2019, three dogs died after bathing in or drinking from Mandichosee, a mesotrophic reservoir of the River Lech (Germany). The dogs showed symptoms of neurotoxic poisoning and intoxication with cyanotoxins was considered. Surface blooms were not visible at the time of the incidents. Benthic Tychonema sp., a potential anatoxin-a (ATX)-producing cyanobacterium, was detected in mats growing on the banks, as biofilm on macrophytes and later as aggregations floating on the lake surface. The dogs’ pathological examinations showed lung and liver lesions. ATX and dihydroanatoxin-a (dhATX) were detected by LC-MS/MS in the stomachs of two dogs and reached concentrations of 563 and 1207 µg/L, respectively. Anatoxins (sum of ATX and dhATX, ATXs) concentrations in field samples from Mandichosee ranged from 0.1 µg/L in the open water to 68,000 µg/L in samples containing a large amount of mat material. Other (neuro)toxic substances were not found. A molecular approach was used to detect toxin genes by PCR and to reveal the cyanobacterial community composition by sequencing. Upstream of Mandichosee, random samples were taken from other Lech reservoirs, uncovering Tychonema and ATXs at several sampling sites. Similar recent findings emphasize the importance of focusing on the investigation of benthic toxic cyanobacteria and applying appropriate monitoring strategies in the future.

Energy models and the process of fluid-magnetic separation for recovering cobalt micro-particles from vacuum reduction products of spent lithium ion batteries

Improper treatment of spent lithium ion batteries will cause great damages to environment. Vacuum reduction was advised as a green recovery technology of nickel and cobalt from spent lithium ion batteries. However, the separation of magnetic particles from the vacuum-reduced products of spent lithium-ion batteries has not been studied. After reduction, the particle size was so small that the formation of agglomerates would affect the separation efficiency which was a common problem in fine magnetic particle sorting. In this paper, a fluid-magnetic separation method was developed for micro-separation of cobalt from the vacuum reduction product of electrode materials of spent lithium ion batteries. This method had a high level of clean production and sustainable development at the same time as high separation rate. An energy model was established to analyze the mechanism of breaking agglomerates, and the experimental parameters affecting recovery efficiency were studied according to the energy model. In simulation experiments, under the optimal parameter conditions of 35 °C, solid-liquid ratio of 500 mL/g and collection mat material of plastic, the recovery rate and purity of cobalt micro-particles were both above 99%. After applying the vacuum reduction product to fluid-magnetic separation, the recovery rate of magnetic fine particles was 98.26%, which fully verified the effectiveness. Further, it provides a new idea for separating micro magnetic particles from micro-sized mixed particles and promoted the process of recycling spent lithium ion batteries.

Lead Content on Fried Foods Against Seller Sanitation and Fried Frequency in the Area of Semarang City

Introduction: Fried food is a snacks that is widely consumed and become a favorite food of Indonesian society, the food is usually consumed more than once in a single meal. However fried foods are also foods that are easily contaminated physically, microbiological and chemical. Preliminary study results indicate the presence of unqualified lead levels in fried foods. In the meantime, it has a toxic effect on the body that is mutagen, teratogen and carcinogen. This research aims to analyze the sanitation condition of sellers with a lead content on fried food in the subdistrict of Pedurungan Semarang. Method: This research was an analytical observational research with a cross sectional design study. Determination of the sample by the total sampling method of 38 fried food merchants and Bakwan fried samples. Data analysis was performed using a correlation test Rank Spearman. This research had been worthy of ethics through the commission of Ethics of Health Research Faculty of Public Health of Diponegoro University with number 285/EA/KEPK-FKM/2019. Result and Discussion: The lead rate of the average fried meal was 0.184 mg/kg and the fried frequency was 24 times in a moment. The results of a correlation analysis of Rank Spearman showed no significant link between the serving Mat material (p value = 0.008), the sanitary condition of snacks facilities (p value = 0.011) and the fried frequency (p value = 0.001) with a lead content in fried foods. Conclusion: The sanitation factor of the seller's facilities related to the lead content in the Sub-district of Pedurungan is the presentation base material, sanitary conditions and fried frequency.

Эффективность ионизации кислорода в макете свинцово-кислотного аккумулятора с использованием сепаратора из абсорбтивно-стеклянной матрицы и нетканого волокнистого материала на основе поливинилиденфторида и полистирола

Эффективность ионизации кислорода в макете свинцово-кислотного аккумулятора с использованием сепаратора из абсорбтивно-стеклянной матрицы и нетканого волокнистого материала на основе поливинилиденфторида и полистирола

REVIEW OF THE MODERN BALLASTED RAILWAY TRACKS’ SUBSTRUCTURE AND FURTHER INVESTIGATIONS

Purpose. The authors’ aim is to summarize the results of relevant international publications and, based on these, to give a comprehensive review about the modern ballasted tracks’ substructure. Methodology. This article is a start of a PhD research, which means it was proceeded by a secondary research. At first, the substructure and its protection layers were summarized, after that the geosynthetic cementious composite mat materials, especially the Concrete Canvas are discussed. Findings. The experiences of the geosynthetics’ and other protection layers’ functions, show that a possible using of the GCCM (geosynthetic cementious composite mat) under the ballast can be a good solution for renewing short sections in the railway tracks. Originality. One of the authors – namely Balázs Eller – is a PhD student at Szechenyi Istvan University in Gyor (Hungary). His research topic is the reinforcement possibilities of railway substructure with the usage of special (mainly cement-bonded) layers. This article was written to collect and summarize the up to date knowledge related to modern ballasted railway tracks’ substructure to be able to determine the following research ways and possibilities at this topic. The research plan will be sentenced in the near future, as well as the required laboratory and field tests will be prepared. Practical value. As expectation, after having executed the related research, the advantages and disadvantages of GCCM layers in the railway substructure will be able to defined, as well as factual deterioration process can be determined related to the ballasted tracks and their geometrical stability.

Decimeter-scale mapping of carbonate-controlled trace element distribution in Neoarchean cuspate stromatolites

Ancient stromatolites can provide key insights into the early evolution of life on Earth. Neoarchean fenestrate stromatolites from the ∼2520 Ma Upper Nauga Formation (Transvaal Supergroup, South Africa) preserve cuspate morphologies. They possess clearly delineated support and drape structures interpreted as dolomitized microbial mat material. Petrographic observations show that the biogenic structures are composed of planar-s to non-planar ferroan dolomite, encased in ferroan calcite, including herringbone calcite textures. The cuspate stromatolites were analyzed using Synchrotron Rapid Scanning X-Ray Fluorescence (SRS-XRF) and more conventional techniques to determine: (i) whether element distributions could be distinguished in ancient stromatolites at both cm to dm scales, (ii) whether element distributions show variation between biogenic and abiogenic textures, and (iii) the sample’s paragenesis. The distributions of Ca, Fe, Mn, Pb, Cu, As, Br, Al, Si, P, and S directly correspond to dolomitized stromatolitic structures and show trace element distributions are principally controlled by calcite and dolomite occurrence. Dolomite formation was mainly driven by seawater-derived fluids given the high concentrations of Fe and retention of marine shale-normalized rare earth element and yttrium (REY SN ) patterns, however the spatial association of dolomite to stromatolite structures may reflect microbially-influenced mineral nucleation. Given the complexity of this sample’s paragenetic evolution, trace metal distributions cannot be conclusively tied to specific metabolic pathways, bioaccumulation or passive binding, however, the results show SRS-XRF can be used for quantifiable, spatial, in-situ investigation of ancient microbialites.

Nanoparticle Embedded Nanofiber Synthesis and Evaluation of Usability on Biomedical Applications

ABSTRACTWhen nanoparticles and nanofibers combined at the nanoscale, they could create new features in the material and therefore new areas of use. In this study, polyvinylpyrrolidone (PVP) nanofibers containing carbon nanoparticles produced by dense medium plasma technology have been fabricated via electrospinning technique for the first time, a new class of nanocomposite mat material has been prepared and evaluated for medical devices. A dense medium plasma technique is used for nanoparticles synthesis, which is novel, cost-efficient, and fast technology when is compared with other common nanoparticles synthesis techniques. Carbon based nanoparticles are synthesized from an arc sustained in benzene (purity, 99.5%) between iron electrodes by the lab-made dense medium plasma system. The study first mentions the production of nanoparticles by a pressure of 8 bar argon gas for glow discharge in a period of 9 seconds using a 0.5 cm electrode distance in a liquid environment (volume of benzene: 30 ml). Then, separated carbon nanoparticles are integrated with the PVP nanofibers produced by the electrospinning method. Processing parameters of PVP nanofibers containing carbon nanoparticle (nanocomposites) are optimized with various conditions such as polymer concentration: 7.8-8.0 %w/v, ratio of nanoparticle to polymer solution: 1-3.9 mg /ml, distance of electrode: 10-25 cm, processing time: 5-30 min. All samples are characterized by contact angle measurements, scanning electron microscopy and transmission electron microscopy. At the same time, electrical conductivity of nanocomposite mats are tested for foreseeing usage in biomedical application. Results showed that carbon nanoparticles have diameters in 25 ± 5.4 nm. New nanocomposite material production is proven by transmission electron microscopy. It is a super hydrophilic mat material (static contact angle is lower than 10°). According to the optimization of processing parameters, the diameters of nanocomposite fibers reach down to 150 ±75 nm., Nanocomposite mat resistance is found to be dramatically higher than that for the bare PVP nanofiber mat resistance. According to these results, usage in biomedical application of new material was discussed. It has a great potential to use as biocompatible, light, insulator new material.

Microbial mats as shelter microhabitat for amphipods in an intermittent karstic spring

Microbial mats represent complex communities where cyanobacteria and diatoms as key organisms provide shelter for diverse assemblages of aquatic invertebrates, like the small stygophilous amphipodSynurella ambulans. Studies addressing such communities in the karst springs have rarely examined springheads, and have ignored intermittent springs. During high flow conditions the stygophilic crustaceans are flushed to the surface of a temporary stream Krčić where microbial mats prevent their drift and enables their successful retreat into underground in the periods of drought. The objective of this study was to characterize the microbial mat community of the Krčić Spring as a shelter forS.ambulansduring strong current and high water level. Representative samples for diatom and cyanobacterial species identification and composition, as well as the fresh mat material for potential animal activity and cyanobacterial phylogenetic analysis were collected. The most dominant diatom wasAchnanthidiumminutissimum, whilstFragilariacapucina,Meridioncirculare,NaviculacryptocephalaandNitzschiapaleahad abundance greater than 0.5%. Morphological observations of cyanobacteria revealed thatPhormidiumfavosumwas the most dominant, withHydrocoleummuscicolaas a subdominant. Cyanobacterial phylogenetic relationship revealed two distinct clusters: (i) "Phormidiumcluster", confirming morphological observations in both winter and spring samples, and (ii) "Wilmottiacluster", a first report for Croatia and found exclusively in the winter sample. Laboratory observations revealed a small stygophilic amphipodS.ambulans, hiding and feeding inside the pockets of fresh microbial mat. The intermittent Krčić Spring as a predator-free and competitor-free ecosystem provides a spatiotemporal conformity between microbial mat and stygophilous amphipod.

Stable isotope evidence for the biogeochemical transformation of ancient organic matter beneath Suess Glacier, Antarctica

ABSTRACT Glaciers overrun organic matter (OM) during periods of advance, making this overrun OM available as a metabolic substrate for subglacial microbes. The biogeochemical fate of this overrun OM remains poorly understood, ultimately limiting our understanding of subglacial biogeochemical cycling, particularly for cold-based glaciers. This study presents evidence for the biogeochemical transformation of algal mat material that was overrun by a cold-based glacier (Suess Glacier, Taylor Valley, Antarctica) during its advance 4840–3570 years BP. We use a suite of stable isotope analyses to show that active nitrogen cycling has depleted N-isotope values to amongst the lowest reported in Taylor Valley (-15.59 ‰) from an initial value of ~-1.88 ‰, while potentially depleting C-isotope values by 2.46 ‰. While this study examines biogeochemical conditions beneath a single glacier, all glaciers export meltwater during the melt season that may host algae and other OM in proglacial streams and lakes that may be overridden during glacier advance. As such, subglacial nitrogen cycling detected here may represent processes that occur in cold zones beneath glaciers generally.