Shucheng Xie

China University of Geosciences · Department of Earth Science

Long-term carbon sequestration by the ocean's recalcitrant dissolved organic carbon (RDOC) pool regulates global climate. Algae and bacteria interactively underpin RDOC formation. However, on the long-term scales, the influence of their persistent interactions close to in situ state on ocean RDOC dynamics and accumulation remains unclear, limiting...

Methane (CH4) is a potent greenhouse gas but also an important carbon and energy substrate for some lake food webs. Understanding how CH4 incorporates into food webs is, therefore, crucial for unraveling CH4 cycling and its impacts on climate and ecosystems. However, CH4-fueled lake food webs from pre-Holocene intervals, particularly during greenho...

Hydroxylated isoprenoid GDGTs (OH‐GDGTs) have emerged as a novel tool for reconstructing sea surface temperatures. However, when using marine OH‐GDGT calibration in lacustrine settings, it leads to a significant overestimation of temperatures, emphasizing the necessity for a thorough examination of OH‐GDGTs in lakes. Here, we investigated OH‐GDGT d...

The ocean has been a regulator of climate change throughout the history of Earth. One key mechanism is the mediation of the carbon reservoir by refractory dissolved organic carbon (RDOC), which can either be stored in the water column for centuries or released back into the atmosphere as CO2 depending on the conditions. The RDOC is produced through...

Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial membrane lipids that have been widely used as tools for the quantitative reconstruction of past terrestrial temperatures in lakes. Two approaches, i.e., regional/global and site-specific calibrations, have been previously employed in the reconstruction. However, their strengths...

Aims Coastal salt marshes are productive ecosystems that are highly efficient carbon sinks, but there is uncertainty regarding the interactions among climate warming, plant species, and tidal restriction on C cycling. Methods Open-top chambers (OTCs) were deployed at two coastal wetlands in Yancheng, China, where native Phragmites australis (Phrag...

The patterns and mechanisms of Holocene temperature variability in China remain highly controversial, possibly due to the lack of sufficient high-resolution records and few systematic compilations and reviews of published records. Here, we used branched glycerol dialkyl glycerol tetraethers (brGDGTs) to generate a Holocene mean annual air temperatu...

Gram-negative bacterial 3-hydroxy fatty acids (3-OH-FAs) have received recent attention for their potential as palaeoclimate proxies. A novel temperature proxy, the ratio of anteiso to normal C13 3-OH-FA (RAN13), has been proposed for sea surface temperature (SST) reconstruction in the North Pacific Ocean. However, whether this newly proposed tempe...

Modern precipitation variability over East China is known to be characterized by meridional tripole and dipole structures, linked to atmosphere and ocean dynamics. As the instrumental data may be influenced by anthropogenic global warming, it is unclear whether the physical mechanism underlying the tripole and dipole pattern have remained constant...

Microbial glycerol dialkyl glycerol tetraethers (GDGTs) in lacustrine sediments are widely used to reconstruct terrestrial paleoenvironments. However, lipids of diverse origin in lakes make it difficult to decipher environmental information, appealing for the necessity to evaluate the impact of terrigenous input on the distribution of GDGTs through...

The goal of achieving carbon neutrality in the next 30-40 years is approaching worldwide consensus and requires coordinated efforts to combat the increasing threat of climate change. Two main sets of actions have been proposed to address this grand goal. One is to reduce anthropogenic CO2 emissions to the atmosphere, and the other is to increase ca...

The Permian–Triassic mass extinction is characterized by a massive injection of carbon dioxide associated with Siberian Traps volcanism, pronounced global warming and ocean acidification. However, in the absence of high-resolution records of atmospheric CO2 (pCO2), detailed changes in the carbon cycle and their relationship to biosphere perturbatio...

Anthropogenic peatland degradation is a global threat. As peatlands store large amounts of carbon (C) their potential for mitigation of climate change has been emphasized recently. Global C cycling is linked to silicon (Si) fluxes from the continents into the oceans. These fluxes in turn are driven by biosilicification, the incorporation of inorgan...

Peatlands, one of the largest biosphere carbon reservoirs, are facing climate change induced water-table drawdown and carbon loss. To provide insights into peatland protection and carbon-water cycle under the background of global change, the detailed relationship between peatland ecology and water table depth (WTD) should be considered. In this stu...

The mineral protection of microbial necromass is critical for soil carbon stabilization. The water impact on the interactions between minerals and microbial necromass, however, remains unclear due to a lack of proper methods to quantify the mineral-protected microbial necromass. Here, we used offline hydrous pyrolysis to release the archaeal necrom...

The BNA15 biomarker proxy, which reflects the relative abundance of the branched over the normal C15 alkan-1-ols, was recently proposed as a novel terrestrial paleothermometer and applied to ancient peat deposits to reconstruct past temperature variations across the Holocene. However, to date, a peat-specific calibration for this novel temperature...

Droughts and floods caused by extreme hydroclimatic events in East Asian monsoon area often have serious effects on human society. The Poyang Lake region has always been one of the most severe floods and droughts in East China. In order to explore the relationship between monsoon climate change and occurrence of drought/flood, this study rebuilt a...

The Holocene hydroclimate evolution and underlying mechanisms modulating the East Asian summer monsoon (EASM) remains controversial, especially in south eastern China. Here we present a multiproxy peat record of monsoon evolution from southeastern China covering the last 14 ka. Our new records show a relatively weaker EASM but wetter hydroclimate d...

Char and polycyclic aromatic hydrocarbons (PAHs), which can serve as proxies for wildfire frequency and/or intensity, are widely present in Permian-Triassic boundary (PTB) strata, providing information on volcanism or on climatic control of fuel availability (linked to vegetation type and density) or combustibility (linked to aridity). Here, we pre...

Methane-derived carbonates (MDCs) are common along modern and ancient continental margins, and the majority of such formations are associated with seafloor cold seeps. Here, we document petrographic, rare earth element + yttrium (REE+Y), carbonate clumped isotope temperature (TΔ47), and carbon-isotopic evidence from a shale succession in southern T...

Loess deposits are important records of the evolution of the soil environment and pedogenic weathering. Changes in pedogenic weathering conditions through space and time, as well as discrimination/sourcing of loess-derived soils, are important scientific issues in the soil (paleosol) community. Here, 502 soil samples from four loess chronosequences...

Direct evidence of intense chemical weathering induced by volcanism is rare in sedimentary successions. Here, we undertake a multiproxy analysis (including organic carbon isotopes, mercury (Hg) concentrations and isotopes, chemical index of alteration (CIA), and clay minerals) of two well-dated Triassic-Jurassic (T-J) boundary sections representing...

Wetlands play a crucial role in the carbon cycle as they are the largest natural source of methane, a potent greenhouse gas. Changes in wetland hydrology can alter the rate of greenhouse gas release from wetlands and have the potential to alter Earth’s carbon budget. However, the microbial dynamics underpinning these observations are poorly constra...

Biotic carbon pumps in marine systems discussed here mainly include the well-known biological pump (BP) and microbial carbon pump (MCP). Through these carbon pumps, microorganisms have made a great contribution to rising atmospheric oxygen levels, the sequestration of atmospheric carbon and the decrease of air temperature in Earth history, which fi...

The policy and practice of ecological restoration and conservation in China obtained some remarkable results. For example, Sphagnum moss growing on abandoned farmland, which was peatland before agricultural use, has rapidly expanded the wetland area in SW China. Microorganisms such as testate amoebae are sensitive to environmental change and thus h...

Bacterial 3-hydroxy fatty acids (3-OH-FAs) show potential for terrestrial paleoclimate reconstruction; however, the possibility of using 3-OH-FAs as proxies in lacustrine environments remains to be investigated. We analysed the composition and distribution of 3-OH-FAs in surface sediments from 20 Chinese alkaline lakes and investigated the developm...

Recent time-series from sediment traps show abnormally high chlorophyll-a concentrations and primary productivity in the oligotrophic central South China Sea (SCS), especially during wintertime. Here we present new insights from compound-specific hydrogen isotopic analysis of leaf wax n-alkanes and Sr-Nd isotope compositions extracted from four bas...

Enhanced regional subduction-related volcanism in the South China craton concurrent with Siberian Traps large igneous province magmatism was a likely contributor to major biotic and environmental stresses associated with the Permian-Triassic boundary (ca. 252 Ma) mass extinction. However, the timing, intensity, and duration of this regional volcani...

Glycerol dialkyl glycerol tetraethers (GDGTs) are widespread but unique membrane-spanning lipids of many Archaea and some Bacteria. However, their specific biological sources and the associated environmental controls on their distribution remain unclear, especially in lacustrine settings, hindering our understanding of these compounds and their app...

Testate amoebae (TA) are a common and diverse group of protists and are especially abundant in peatlands. The structure of peatland TA communities is well correlated to surface moisture and water table depth (WTD). For that reason, TA are widely used as proxy indicators in ecological and palaeoecological studies. Peatlands are abundant across Asia,...

Considerable uncertainty remains over the nature and causes(s) of East Asian monsoon evolution since the Late Miocene, a significantly warmer period characterized by substantially weaker meridional and zonal Pacific sea surface temperature (SST) gradients than today and therefore regarded as a potential analog for current and future global warming....

Combustion-derived polycyclic aromatic hydrocarbons (PAHs) are frequently used as molecular proxies for wildfire in recent and ancient sediments. Here, we document the abundances of four hydrocarbon compounds, i.e., phenanthrene (Phe), benzo[e]pyrene (BeP), benzo[ghi]perylene (Bpery), and coronene (Cor), across the Permian–Triassic boundary (PTB) i...

3-Hydroxy fatty acids (3-OH-FAs), derived from Gram-negative bacterial outer membranes, have received recent attention for their potential as new terrestrial pH and temperature proxies for palaeoclimate studies. Initial studies from altitudinal transects of contemporary soils - correlating bacterial 3-OH-FA compositions to air temperature and pH -...

Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial membrane lipids that have been extensively used as tools for paleoclimate reconstruction. Temperature and pH were thought to be two major factors affecting the distributions of brGDGTs; however, the effects of other factors on the distribution of brGDGTs and related temperature...

Here we present multiproxy inorganic geochemical records from a peat core (ZK5) from the Dajiuhu Basin in central China to investigate peatland deposition processes and atmospheric metal pollution and to explore their relationships with East Asian monsoon change and human activities in the Middle Yangtze Valley since 20,000 cal yr BP. The peat phys...

Late Devonian marine systems were characterized by major environmental perturbations and associated biotic community changes linked to climate change and widespread oceanic anoxia. Here, we provide high-resolution lipid biomarker chemostratigraphic records from the Upper Devonian Chattanooga Shale (Tennessee, USA) to investigate algal-microbial com...

Significance Massive Paleozoic and Precambrian dolostone successions have long puzzled geologists in light of the kinetic barriers that inhibit low-temperature dolomite nucleation and precipitation (i.e., the “dolomite problem”). Significantly, the widely accepted hypothesis that such massive dolomites are the product of burial–hydrothermal dolomit...

Peatland ecosystem processes are strongly influenced by hydrology linked to climate change. However, how transpiration, as major water loss pathway in closed peatland, responds to climate change and then regulates ecosystem water balance that remains poorly understood. Here, we reported an 18,000-year fossil phytolith record from an herbaceous comm...

The Long-chain Diol Index (LDI) is a palaeotemperature proxy applied to marine sediments up to Miocene in age. Recent studies have revealed that the LDI-inferred temperature yields significant errors in waters > 27 °C. This necessitates further assessment of the performance of the LDI proxy in high-temperature marine regimes. For this purpose, we c...

Many peatlands have been damaged by human activities like Sphagnum harvesting and draining reflected in reduced peatland areas and ecosystem functioning. Peatlands generally play an important role in global silicon (Si) cycling and maintain huge numbers of testate amoebae (TA). However, there is a lack of knowledge on (i) the quantity of protozoic...

3-Hydroxy fatty acids (3-OH-FAs), derived from Gram-negative bacterial outer membranes, have received recent attention for their potential as new terrestrial pH and temperature proxies for palaeoclimate studies. However, it is not known whether 3-OH-FA based proxies can be developed and applied to the marine environment. Here we analyze 3-OH-FAs fr...

Hydrogen isotope compositions of leaf wax long-chain n-alkanes (δDalk) buried in soils have the potential to provide records of continental paleoclimatic and paleohydrological changes. However, different factors and processes influence the δDalk signature, making interpretation of the soil isotope record complicated. The relative humidity/aridity a...

The end-Devonian mass extinction (~359 Ma) substantially impacted marine ecosystems and shaped the roots of modern vertebrate biodiversity. Although multiple hypotheses have been proposed, no consensus has been reached about the mechanism inducing this extinction event. In this study, I/Ca ratio of carbonate was used to unravel the changes in local...

Understanding how terrestrial carbon storage feeds back on warm climate states is critical for improving global warming projections. Soils may act as a positive feedback on climate if warming increases soil carbon decomposition rates. Conversely, if increases in net primary production (NPP) exceed increases in decomposition, the climate feedback wi...

C4-grasslands are known to have first expanded globally in the Late Miocene, and recent research has hinted at a second expansion phase during the Early Pliocene; however, the geographic extent of this second event and its driving force are debated. In this study, we present organic carbon-isotopic evidence from a high-resolution drillcore in North...

Arbuscular mycorrhizal fungi (AMF) is presumably to be associated with carbon sequestration and nutrient acquisition through mineral weathering in wetland ecosystems. However, information on AMF‐carbon‐weathering interactions is limited. Grain size, concentrations of nutrients, and the major components of 304 surface sediment samples and glomalin‐r...

The Siberian Traps large igneous province (STLIP) was the likely trigger for the ca. 252 Ma latest Permian mass extinction (LPME), but direct evidence for global volcanic effects on land remains rare. Here, we used mercury (Hg) enrichments, a proxy for ancient volcanic activity, to assess volcanic inputs to two terrestrial Permian-Triassic boundary...

Studies of acid mine drainage (AMD), a typically extremely acidic environment, can provide opportunities to determine how microorganisms adapt to low-pH environments by regulating membrane lipid compositions. In this study, to gain an understanding of microbial pH adaptation mechanisms, we investigated the distribution of lipid biomarkers, primaril...

Quantitative reconstructions of the depth to water table (DWT) of ombrotrophic (rain-fed) peatlands are important for understanding the palaeohydrological responses of peatlands to past climate changes. This understanding can provide insights into projecting peatlands future variability and evolution. However, the postglacial DWT reconstruction of...

Molecular fossils (biomarkers)are abundant in organic rich natural archives such as peats and lignites (fossilized peat), where their distribution is governed by their biological source, environmental factors, such as temperature and pH, and diagenetic reactions. As a result, biomarkers in peat have become an important tool to study past variations...

Bacterial branched and archaeal isoprenoid glycerol dialkyl glycerol tetraethers (brGDGTs and isoGDGTs, respectively) have become important tools for the paleoclimate reconstruction of lacustrine systems. However, it is still unclear how geochemical proxies based on GDGTs, particularly in lake surface sediments, respond to seasonal environmental ch...