Plate tectonics and mantle plumes are two of the most fundamental solid-Earth processes that operated through much of the Earth’s history. For the past 300 million years, mantle plumes are known to derive mostly from two large low shear velocity provinces (LLSVPs) above the core-mantle boundary, referred to as the African and Pacific superplumes. Whether such LLSVPs and their plume products are stationary through Earth history, or dynamically linked to global plates motions and subduction geometry, remains a first-order question for the geoscience community. Here, we demonstrate that transition elements (Ni, Cr and Fe/Mn) in basaltic rocks can be used as a tool to trace plume-related magmatism through Earth history. An analysis of the global petro-chemical database indicates the presence of a direct relationship between the intensity of plume magmatism and the supercontinent cycle. Such results favour the presence of a dynamic supercontinent-superplume coupling over the fixed-LLSVP geodynamic model. In addition, our analysis shows a consistent sudden drop in MgO, Ni and Cr at ~3.2–3.0 billion years ago, possibly indicating an abrupt change in mantle temperature at the start of global plate tectonics.

A catchment in southern England, UK, included a substantial area of bare ground within the surrounding heathland and woodland. Runoff from this area has, in the past, contributed large volumes of sediment to a large lake; although this input is now significantly reduced as a result of previous and on-going management works that are reported on in this paper. Historic realignment and re-sectioning of the main watercourse, has also resulted in the overdeepening, vertical and lateral erosion of the stream channel resulting in downstream transport of sediment to the lake. In addition to sediment erosion, the associated limited connectivity with the floodplain and focus of sediment transport in the fluvial channel has been a key factor in the shallowing and deterioration in the condition of the lake. Over the last 15 years a wide range of investigative, monitoring and management work has been undertaken within the catchment by a partnership between UK Government organisations, a local authority and a charity, with continuous involment by the author throughout this period. This work has evaluated the causes and effects associated with this erosion and transportation, tested and defined viable practical solutions (the delivery of natural sediment and flood management solutions and habitat restoration) and delivered a series of sustainable management interventions to reduce erosion, promote sediment deposition and to reconnect the stage zero and larger fluvial pathways to the floodplain – supporting the restoration of the lake. These works have resulted in the reduction in erosion at source and increased deposition through the catchment system, ultimately contributing to the improvement in condition of the lake and associated wetland habitats. Works in the headwaters of the catchment focused on defining the existing distribution, status and significance of areas of sediment generation, transport and deposition to the stream and lake, facilitating sustainable sediment management within this area. Works in the lower reaches focused on slowing flow velocities and diverting higher velocity sediment rich flows into new channels to reconnect with the floodplain and promote deposition. Management measures included the use of small diversion channels through woodland with the creation of glades to increase understory recovery and sediment deposition; use of geotextile cells filled with sand, gravel or stone to increase the flow path, reduce velocity and promote out of channel flooding and deposition of sediment; use of scrub and woody material to form leaky dams and increase channel roughness promoting out of bank flooding and deposition; use of online ponds, backwaters and embayments; blanking off channels to promote overland flow through woodland to reduce flow depth and velocity and promote deposition; use of leaky dams to promote higher flows transporting sediment into new sinuous channels and allowing out of bank flooding to promote sediment deposition.

In studying problems like plant-soil-microbe interactions in environmental biogeochemistry and ecology, one usually has to quantify and model how substrates control the growth of, and interaction among, biological organisms. To address these substrate-consumer relationships, many substrate kinetics and growth rules have been developed, including the famous Monod kinetics for single substrate-based growth, Liebig’s law of the minimum for multiple-nutrient co-limited growth, etc. However, the mechanistic basis that leads to these various concepts and mathematical formulations and the implications of their parameters are often quite uncertain. Here we show that an analogy based on Ohm’s law in electric circuit theory is able to unify many of these different concepts and mathematical formulations. In this Ohm’s law analogy, a resistor is defined by a combination of consumers’ and substrates’kinetic traits. In particular, the resistance is equal to the mean first passage time that has been used by renewal theory to derive the Michaelis-Menten kinetics under substrate replete conditions for a single substrate as well as the predation rate of individual organisms. We further show that this analogy leads to important insights on various biogeochemical problems, such as (1) multiple-nutrient co-limited biological growth, (2) denitrification, (3) fermentation under aerobic conditions, (4) metabolic temperature sensitivity, and (5) the accuracy of Monod kinetics for describing bacterial growth. We expect our approach will help both modelers and non-modelers to better understand and formulate hypotheses when studying certain aspects of environmental biogeochemistry and ecology.

The excess of radiogenic lead (Pb) isotopes in the silicate Earth, which is referred to as “the first terrestrial Pb paradox” has remained a confusion for a long time. A large-scale U/Pb fractionation with an increase of μ value (238U/204Pb) compared with CI chondrite is proposed to be the main culprit. The volatile e.g., Pb diffuses into space from the planetesimal-scale collisional melting, which plays a critical role in Pb loss on the accreting proto-Earth. The N-body simulation describes the collisional history of terrestrial planets in the first 200 million years of the Solar System. The collisional information provides the degree of silicate melting and further obtains the volatile loss fraction. Within the early 20% accretion of proto-Earth, the cumulative fraction of Pb loss can reach 80%-90%. Meanwhile, the μ value could rise to 1.5-4 setting the initial value to be 0.2-0.6. Besides, the silicate melting with higher temperature and lower oxygen fugacity (relatively reduced condition) can bring about more Pb loss. Further increase of μ to 9.26 possibly caused by a late large-scale U/Pb fractionation can effectively explain the excess of radiogenic Pb isotopes in the bulk silicate Earth. The two-stage model with the planetesimal-scale evaporation predicts a young age of 240 million years of the last large-scale fractionation event. The last fractionation is more consistent with the “Hadean matte” event than a late Moon-forming giant impact.

Underground fluid monitoring is a common method for earthquake prediction. However, the correlations depending on statistic between the results of various underground fluids and earthquakes are usually not significant. In this study, based on a set of experimental instruments to monitor the hydrogen concentration escaping from the observation wells at Eryuan station, it was found that the hydrogen concentration changed dramatically before most earthquakes occurred in the surrounding area. Based on this finding, a detailed analysis of the changes in the hydrogen concentration in the wells is conducted to extract the changes that are related to earthquakes and to derive the related anomaly indicators. Then, the concept of the impact factor is proposed, and correlation analysis is performed with the impact factor and the integral value of hydrogen concentration at Eryuan. The results show that there is a significant correlation between the sudden changes of the hydrogen concentration at Eryuan and the neighboring earthquakes.

The continental lithospheric mantle plays an essential role in stabilizing continents over long geological time scales. Quantifying spatial variations in compositional and thermochemical properties of the mantle lithosphere is crucial to understanding its formation and its impact on continental stability; however, our understanding of these variations remains limited. Here we apply the Whole-rock Interpretive Seismic Toolbox For Ultramafic Lithologies (WISTFUL) to estimate thermal, compositional, and density variations in the continental mantle beneath the contiguous United States from MITPS_20, a joint body and surface wave tomographic inversion for Vp and Vs with high resolution in the shallow mantle (60‒100 km). Our analysis shows lateral variations in temperature beneath the continental United States of up to 800–900°C at 60, 80, and 100 km depth. East of the Rocky Mountains, the mantle lithosphere is generally cold (350–850°C at 60 km), with higher temperatures (up to 1000°C at 60 km) along the Atlantic coastal margin. By contrast, the mantle lithosphere west of the Rocky Mountains is hot (typically >1000°C at 60 km, >1200°C at 80–100 km), with the highest temperatures beneath Holocene volcanoes. In agreement with previous work, we find that the predicted chemical depletion does not fully offset the density difference due to temperature. Extending our results using Rayleigh-Taylor instability analysis, implies the lithosphere below the United States could be undergoing oscillatory convection, in which cooling, densification, and sinking of a chemically buoyant layer alternates with reheating and rising of that layer.

Subduction zones are the interface between Earth’s interior (crust and mantle) and exterior (atmosphere and oceans), where carbon and other volatiles are actively cycled between Earth reservoirs by plate tectonics. Helium is highly sensitive to mantle inputs and can be used to deconvolute mantle and crustal volatile pathways in arcs. We report He isotope and abundance data for 18 deeply-sourced gas seep samples in the Central Volcanic Zone (CVZ) of Argentina and the Southern Volcanic Zone (SVZ) of Chile. We use 4He/20Ne values to assess the extent of air contributions, as well as He concentrations. Air-corrected He isotopes from the CVZ range from 0.21 to 2.58 RA (n=7), with the highest value in the Puna and the lowest in the Sub-Andean foreland fold-and-thrust belt. 4He/20Ne values range from 1.7 to 546 and He contents range from 1.0 to 31 x 106 cm3STP/cm3. Air-corrected He isotopes from the SVZ range from 1.27 to 5.03 RA (n=7), 4He/20Ne values range from 0.3 to 69 and He contents range from 0.5 to 175 x 106 cm3STP/cm3). Taken together, these data reveal a clear southeastward increase in 3He/4He, with the highest values (in the SVZ) plotting below the nominal range of values associated with pure upper mantle He (8 ± 1 RA1), but approaching the mean He isotope value for arc gases of ~5.4 RA2. Notably, the lowest values are found in the CVZ, suggesting more significant crustal contributions to the He budget. The crustal thickness in the CVZ is up to 70 km, significantly more than in the SVZ, where it is just 35-45 km3. It thus appears that crustal thickness exerts a primary control on the extent of fluid-crust interaction, as helium and other volatiles rise through the upper plate in the Andean Convergent Margin. These data agree well with the findings of several previous studies4-14 conducted on the volatile geochemistry along the Andean Convergent Margin, which suggest a much smaller mantle influence, presumably associated with thicker crust masking the signal in the CVZ. [1] Graham, 2002 [2] Hilton et al., 2002 [3] Tassara and Echaurren, 2012 [4] Hilton et al., 1993 [5] Varekamp et al., 2006 [6] Ray et al., 2009 [7] Aguilera et al., 2012 [8] Tardani et al., 2016 [9] Tassi et al., 2016 [10] Tassi et al., 2017 [11] Peralta-Arnold et al., 2017 [12] Chiodi et al., 2019 [13] Inostroza et al., 2020 [14] Robidoux et al., 2020

We examined liquidus phase relations in Fe-O+/-H at ~40 and ~150 GPa, and subsolidus phase equilibria in Fe-FeH. While it has been speculated that Fe and FeH form continuous solid solution to core pressures, our experiments show the coexistence of the H-poor hcp and H-rich fcc phases in the Fe-FeH system. Considering higher melting temperature of stoichiometric FeH than that of Fe-FeH, it indicates eutectic melting between Fe and FeH. It is consistent with the liquidus phase diagram in Fe-O-H, which implies the Fe-FeH binary eutectic liquid composition of FeH0.42 at ~40 GPa. We estimated the outer core liquid composition to be Fe + 2.9-5.2% O + 0.03-0.32% H + 0-3.4% Si + 1.7% S by weight, based on the liquidus phase relations, solid-liquid partitioning, and outer/inner core densities and velocities, indicating that O and either H or Si are important core light elements.

Preservation of organic carbon (OC) in marine and terrestrial deposits is enhanced by bonding with reactive iron (FeR) phases. The association of OC with FeR (OC-FeR) provides physical protection and hinders microbiological degradation. Roughly 20% of all OC stored in unconsolidated marine sediments and 40% of all OC present in Quaternary terrestrial deposits is preserved as OC-FeR, but this value varies from 10 to 80% across depositional environments. In this work, we provide a new assessment of global OC-FeR burial rates in both marine and terrestrial environments, using published estimates of the fraction of OC associated with FeR, carbon burial, and probabilistic modelling. We estimate the marine OC-FeR sink at between 31 – 70 Mt C yr-1 (mean 52 Mt C yr-1), and the terrestrial OC-FeR sink at between 171 - 946 Mt C yr-1 (mean 472 Mt C yr-1). In marine environments, continental shelves (mean 17 Mt C yr-1) and deltaic/estuarine environments (mean 11 Mg C yr-1) are the primary locations of OC-FeR burial. On land, croplands (279 Mt C yr-1) and grasslands (121 Mt C yr-1) dominate the OC-FeR burial budget. Changes in the Earth system through geological time likely alter the OC-FeR pools, particularly in marine locations. For example, periods of intense explosive volcanism may lead to increased net OC-FeR burial in marine sediments. Our work highlights the importance of OC-FeR in marine carbon burial and demonstrates how OC-FeR burial rates may be an order of magnitude greater in terrestrial environments, those potentially most sensitive to anthropogenic impacts.

Naturally-occurring colloids, particles of diameter < 10μm, are ubiquitous in geo-environments and can potentially facilitate transport of numerous contaminants in soil including heavy metals, pesticides, pathogens etc. via Colloid-Facilitated Transport (CFT). The CFT of contaminants to groundwater is still an underrepresented transport domain and may lead to significant environmental and health problems related to groundwater contamination. Colloid mobilization, transport and CFT in various geomedia are highly sensitive to physico-chemical perturbations. This study investigated colloid transport and colloid-facilitated heavy metal transport in saturated porous media with a series of column experiments using soil colloids extracted from two areas affected by Chronic Kidney Disease of Unknown Etiology (CKDu) in North Central Province of Sri Lanka. Colloid breakthrough curves were obtained from the column studies to observe the colloid transport under different flow rates (0.5±0.05, 1.65±0.05, 4.10±0.05 cm3/s) and ionic strengths (NaCl - 0.01 M, 0.05 M, 0.1 M). The CFT was studied using Cadmium (Cd(II)) as a model contaminant together with colloidal suspension under selected scenarios for high colloid deposition. Elevated colloid concentrations were observed in high CKDu affected area compared to the low endemic area. The experimental results were numerically simulated on an advection-diffusion/dispersion modelling framework coupled with first-order attachment, detachment and straining parameters inversely estimated using HYDRUS 1D software. Experimental and simulated colloid breakthrough curves showed a good agreement, and recognized colloid attachment as the key mechanism for colloid immobilization in selected soil. Both colloids and CFT of Cd(II) showed pronounced deposition under low flow rate and high ionic strength.

This mass balance study was intended to provide up-to-date information about the water quality of the headwater streams draining to the Mohican and Walhonding rivers. This data will be used to define target locations for conservation practices, including agricultural and stormwater management practices. During the study, 124 sites were sampled twice in 2021: during spring high-flow conditions (May) and fall low-flow conditions (August).

Wetlands are the most important natural source of methane (CH4) to the atmosphere. When present, plant efflux is often the dominant pathway for methane emissions from the anoxic wetland sediments, however, they are rarely considered in chamber measurement campaigns of CH4 flux in wetlands. While studies have focused on the mechanisms that govern transport through plant structures, none have addressed how CH4 emissions relate with carbon uptake or how this relationship may vary among plants. Understanding this relationship has important implications for linking carbon flux at the ecosystem level to wetland CH4 emission predictions, and ultimately, to help improve current carbon budget and greenhouse gas models of wetlands. This study presents simultaneous measurements of CH4 and CO2 fluxes in three macrophyte species of different cosmopolitan genera: Typha (emergent), Nelumbo, and Nymphaea (floating attached). These measurements were conducted using the Picarro GasScouter G4301 fitted with custom-designed leaf chambers. Chamber measurements were performed three times during a day (morning, noon and afternoon), in three separate months. Results indicate significant negative correlations between CH4 flux and carbon uptake in Nelumbo and Nymphaea species and a non-significant positive correlation in Typha sp. We term the rate of CH4 flux per unit CO2 uptake – CH4 flux efficiency. We found that in Nymphaea CH4 flux efficiency is almost double that of Nelumbo. These results suggest the dependence of CH4 efflux in stomatal conductance in the floating attached macrophytes, while in the Typha CH4 flux is primarily through other pores, probably aerenchyma, not regulated by stomata. Our results emphasize the importance of species-specific knowledge and considering the growth type of different wetland macrophytes (e.g. emergent vs floating attached) in scaling of bottom-up observations and ecosystem models.

Recently, the continually increasing availability of seismic data has allowed high-resolution imaging of lithospheric structure beneath the African cratons. In this study, S-wave seismic tomography are combined with high resolution satellite gravity data in an integrated approach to investigate the structure of the cratonic lithosphere of Africa. A new model for the Moho depth and data on the crustal density structure are employed along with global dynamic models to calculate residual topography and mantle gravity residuals. Corrections for thermal effects of an initially juvenile mantle are estimated based on S-wave tomography and mineral physics. Joint inversion of the residuals yields necessary compositional adjustments that allow to recalculate the thermal effects. After several iterations, we obtain a consistent model of upper mantle temperature, thermal and compositional density variations, and Mg# as a measure of depletion, as well as an improved crustal density model. Our results show that thick and cold depleted lithosphere underlies West African, northern to central eastern Congo, and Zimbabwe Cratons. However, for most of these regions, the areal extent of their depleted lithosphere differs from the respective exposed Archean shields. Meanwhile, the lithosphere of Uganda, Tanzania, most of eastern and southern Congo, and the Kaapvaal Craton is thinner, warmer, and shows little or no depletion. Furthermore, the results allow to infer that the lithosphere of the exposed Archean shields of Congo and West African cratons was depleted before the single blocks were merged into their respective cratons.

The tectonic history of Southern Africa includes Archean formation of cratons, multiple episodes of subduction and rifting and some of the world’s most significant magmatic events. These processes left behind a compositional trail that can be observed in xenoliths and measured by geophysical methods. The abundance of kimberlites in southern Africa makes it an ideal place to test and calibrate mantle geophysical interpretations that can then be applied to less well-constrained regions. Magnetotellurics (MT) is a particularly useful tool for understanding tectonic history because electrical conductivity is sensitive to temperature, bulk composition, accessory minerals and rock fabric. We produced three-dimensional MT models of the southern African mantle taken from the SAMTEX MT dataset, mapped the properties of $\sim36000$ garnet xenocrysts from Group I kimberlites, and compared the results. We found that depleted regions of the mantle are uniformly associated with high electrical resistivities. The conductivity of fertile regions is more complex and depends on the specific tectonic and metasomatic history of the region, including the compositions of metasomatic fluids or melts and the emplacement of metasomatic minerals. The mantle beneath the $\sim 2.05$ Ga Bushveld Complex is highly conductive, probably caused by magmas flowing along a lithospheric weakness zone and precipitating interconnected, conductive accessory minerals such as graphite and sulfides. Kimberlites tend to be emplaced near the edges of the cratons where the mantle below 100 km depth is not highly resistive. Kimberlites avoid strong mantle conductors, suggesting a systematic relationship between their emplacement and mantle composition.

Dissolved oxygen (DO) sustains aquatic life and is an essential water quality measure. Our capabilities of forecasting DO levels, however, remain elusive. Unlike the increasingly intensive earth surface and hydroclimatic data, water quality data often have large temporal gaps and sparse areal coverage. Here we ask the question: can a Long Short-Term Memory (LSTM) deep learning model learn the spatio-temporal dynamics of stream DO from intensive hydroclimatic and sparse DO observations at the continental scale? That is, can the model harvest the power of big hydroclimatic data and use them for water quality forecasting? Here we used data from CAMELS-chem, a new dataset that includes sparse DO concentrations from 236 minimally-disturbed watersheds. The trained model can generally learn the theory of DO solubility under specific temperature, pressure, and salinity conditions. It captures the bulk variability and seasonality of DO and exhibits the potential of forecasting water quality in ungauged basins without training data. It however often misses concentration peaks and troughs where DO level depends on complex biogeochemical processes. The model surprisingly does not perform better where data are more intensive. It performs better in basins with low streamflow variations, low DO variability, high runoff-ratio (> 0.45), and precipitation peaks in winter. This work suggests that more frequent data collection in anticipated DO peak and trough conditions are essential to help overcome the issue of sparse data, an outstanding challenge in the water quality community.

For quantitative understanding of thermal features of fossil fluid activity derived from the Philippine Sea slab, we applied fluid-inclusion and thermochronometric analyses to hydrothermal veins and their host rocks outcropping in the Hongu area in southwestern Japan. Although hydrothermal events at ~150{degree sign}C and ~200{degree sign}C were identified by fluid-inclusion analyses of quartz veins, no thermal anomaly was found associated with the veins’ host rocks. Cooling ages showed no variation as a function of distance from the veins. Using zircon, we determined U-Pb ages of 77.3-66.9 Ma in the youngest population, fission-track pooled ages of 34.1-24.0 Ma, and (U-Th)/He single-grain ages of 23.6-8.7 Ma. Apatite yielded pooled fission-track ages of 12.0-9.0 Ma. All these ages can be explained by fluid flow that occurred either (1) before ~10 Ma at a depth where ambient temperature is higher than closure temperature of the apatite fission-track system (90{degree sign}C-120{degree sign}C, equivalent to ~3-km depth) or (2) after ~10 Ma but of such duration that is too short to have annealed fission tracks in apatite, which process requires ~10 yr at ~150{degree sign}C or as short as a few months at ~200{degree sign}C. Apatite fission-track ages of ~10 Ma might reflect regional mountain uplift and exhumation related to rapid subduction of the Philippine Sea slab and associated with clockwise rotation of the Southwest Japan Arc.

The Amazon River has the largest volume on earth, making up 15–20% of the annual fluvial discharge into oceans. The neighboring Pará River mixes with the Amazon River waters in the Amazon Estuary before forming a plume that extends into the Atlantic. Despite the global importance of these rivers, dissolved trace metal fluxes from this estuary remain unknown. Here we present data for dissolved (<0.2 µm) trace metals (Al, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb and U) in the Amazon Estuary during the high discharge season (April–May 2018). We observed distinct trace metal signatures for the Amazon and Pará Rivers, reflecting different catchment areas. Concentrations of the particle-reactive elements (Mn, Fe and Pb) decreased rapidly at low-salinity (S≤2), resulting in the highest estuarine removal (86–94% in the Amazon; 61–70% for the Pará). Co, Ni and Cu removal was comparatively low in both river transects (6–39%), while Cd was the only element with a consistent net input. Chemical fluxes were estimated using (a) endmember concentrations and estuarine removal and (b) combining trace element concentrations with 228Ra fluxes. Relative to global total river fluxes, the Amazon and Pará Rivers combined contribute 21% of dissolved Cu and 18% of dissolved Ni during the high discharge season, but account for comparatively low fractions of Mn, Fe, Co and Zn. These data quantify, for the first time, the trace metal output from the world’s largest and 5th largest river into the Atlantic Ocean, filling a critical gap in knowledge of this globally-important region.

Volcanism is the dominant natural source of mercury (Hg) to the atmosphere, biosphere, ocean and sediments. In recent years, sedimentary Hg contents have emerged as a tool to reconstruct volcanic activity, and particularly activity of (subaerially emplaced) large igneous provinces (LIP) in geological deep time. More specifically, Hg has shown potential as a useful proxy to illuminate the previously elusive impact of such large-scale volcanism on marine and terrestrial paleo-environments. While Hg is now widely applied as volcanism tracer, non-volcanic factors controlling sedimentary Hg content are generally not well constrained. Part of this uncertainty stems from our inability to directly observe a natural unperturbed “steady-state” environment as a baseline, as the modern Hg cycle is heavily influenced by anthropogenic activity. Here we focus on the effects of ambient redox conditions in the water column and shallow sediments (early diagenesis), quantify their influence on the geological Hg record and thereby constrain their potential impact on the use of Hg as a proxy for deep-time volcanic activity. Constraining these factors is of critical importance for the application of Hg as a proxy. Many periods in the geological past for which records have been generated, such as the Mesozoic Oceanic Anoxic Events, are marked by a variety of high-amplitude environmental perturbations, including widespread deoxygenation and deposition of organic-rich sediments. We estimate the impact of redox changes and early diagenesis on the geological Hg record using a suite of (sub)recent–Pleistocene and Upper Cretaceous sediments representing oxic to euxinic marine conditions. Our sample set includes a transect through an oxygen minimum zone and cores that record transient shifts in oxygenation state, as well as post-depositional effects – all unrelated to volcanism, to the best of our knowledge. We find substantial alterations to the Hg record and the records of organic carbon and total sulfur, which are typically assumed to be the most common carrier phases of Hg in marine sediments. Moreover, these biases can lead to signal-alterations on a par with those interpreted to result from volcanic activity. Geochemical modifications are ubiquitous and their potential magnitude implies that the factors leading to biases in the geological record warrant careful consideration before interpretation. Factors of particular concern to proxy application are (1) the disproportionate loss of organic carbon and sulfur compounds relative to Hg during oxidation that strongly modulates normalized Hg records, (2) the evasion of Hg in anoxic and mildly euxinic sediments and (3) sharp focusing of Hg during post-depositional oxidation of organic matter.

The local temperarture cannot explain the inter-annual variation in δ18Oprecip in the coastal Antarctic in past few decades. To understand this enigmatic variation, we have used long-term modern δ18Oprecip value of three coastal Antarctic sites. Using the δ18O-d-excess relationship and modelled δ18O value of vapor at source, we have shown that δ18Oprecip inherits the signature of moisture source parameters (MSPs). Furthermore, the wavelet analysis suggests that the variation in the MSPs impacts the seasonal cycle of δ18Oprecip which lead to disparity in the seasonal isotope-temperature relationship. The Southern Ocean surface stratification, due to increase in the freshwater flux by glacier melting, led to alignment of MSPs in such a manner that altogether significantly lowered the isotopic composition of initially formed vapor, which is reflected in δ18Oprecip at inter-annual scale. Our observations suggest that the palaeothermometry will underestimate the Antarctic temperature change for the periods characterized by warming and high glacier-melt.