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Liu, X.

Publications and source records attributed to Liu, X..

At least 127 records · Page 7Linked to original sources

Lineage recording reveals hijacked hepatic progenitor states as a common origin of HCC and ICC

HighlightsCERAMIC enables continuous and high-capacity lineage tracing of liver tumor initiation Fatty liver-associated hepatocytes acquire regenerative and premalignant cell states before malignant transformation Lineage reconstruction identifies Hep_Bi-zonal cells as the cellular origin of liver tumor initiation Transcriptional and regulatory programs distinguish tumor-fated hepatocytes from failed-to-transform lineages Peroxisomal metabolism is required for progenitor-state formation and liver tumor initiation Spatial remodeling identifies a macrophage niche associated with tumor-fated hepatocytes Dual ontogenies and functional specialization of lipid-associated macrophages shape the tumor-fated hepatocyte niche Fatty liver disease predisposes to primary liver cancer, yet the lineage routes and niche mechanisms that select rare tumor-fated hepatocytes remain unclear. Here we developed CERAMIC, a high-capacity CRISPR-Cas9 lineage recorder that co-recovers editing scars and transcriptomes from single cells, and applied it to an AKT/NRAS-driven model of MASLD-associated liver tumor initiation. Longitudinal lineage, single-cell and spatial analyses revealed a hierarchical trajectory in which bipotential bi-zonal hepatocytes (Hep_Bi-zonal), rather than pericentral-like hepatocytes (Hep_CVlike), generated regenerative and neoplastic hepatocyte progenitor states that progressed toward both hepatocellular carcinoma and intrahepatic cholangiocarcinoma lineages. Tumor-fated cells preferentially expanded along a remodeled midlobular-periportal axis and depended on ACOX1-mediated peroxisomal beta-oxidation to withstand lipotoxic and oxidative stress. Spatial and lineage analyses further identified a sequential lipid-associated macrophage niche, in which monocyte-derived LAMs engaged tumor-fated hepatocytes through an LGALS9-P4HB axis, and P4HB inhibition suppressed tumor expansion. These findings define liver tumor initiation as a lineage-restricted process licensed by peroxisomal metabolic adaptation and macrophage-derived niche signals.

cancer biology↗

Bone Mechanosensing Dictates Hematopoietic Stem Cell Fate and Immune Homeostasis

The vertebrate water-to-land transition was accompanied by a six-fold increase in gravitational force, followed by the migration of hematopoietic stem cells (HSCs) from kidney or liver to the bone marrow, and the acquisition of enhanced immune functions to cope with novel environmental pressures. Bone senses mechanical loading and provides a microenvironment for HSC development, yet whether bone mechanosensation affects immune cell development and immune homeostasis remains unclear. Here, we unveil bone as a mechanosensory organ that translates mechanical force into hematopoietic instructions. Mechanical loading of bone directs HSCs toward lymphoid lineages in mice and non-human primates, whereas unloading favors myeloid commitment. This process requires osteocyte mechanosensor Piezo1, which induces loading-responsive bone-derived factors such as IL1R2, SERPINC1 and INMT, thereby restraining inflammatory signaling and guiding HSC differentiation. Osteocyte Piezo1 deficiency recapitulates the hematopoietic and immune alterations observed during unloading. Functionally, this pathway enhances acute infection resistance and suppresses immunosenescence in mice and in aged long-tailed macaques. Notably, skeletal mechanoregulation of immune homeostasis is conserved across vertebrate species. Our research defines the mechano-bone-immune axis (mechano-osteoimmunology), offering a novel evolutionary perspective on the interconnected development of the skeletal and immune systems and presenting a promising non-pharmacological target to address immune dysfunction.

immunology↗

Kidney medulla macrophages maintain a free flow of urine by sensing force

Blockade by sedimentary particles, such as mineral crystals, is a continuous risk the kidney tubule faces. To prevent that, kidney resident macrophages form transepithelial protrusions and remove intratubular sedimentary particles, a behavior particularly prevailing in the medulla over the cortex. However, the molecular mechanisms underlying this characteristic behavior of medulla macrophages are incompletely understood. In this study, we identified that the medulla had higher mechanical stiffness than the cortex in steady state, which was further elevated when kidney stone formed. Increased tissue rigidity was sensed by medulla macrophages via mechanoreceptor Piezo1, which promoted macrophage protrusion formation and their ability to clean the tubules. Loss of Piezo1 expression in kidney macrophages predisposed mice to intratubular accumulation of mineral crystal in steady state and accelerated kidney stone formation during oxalate intake challenge. Signaling via Piezo1 mobilized molecules involved in cell adhesion and protrusion assembly, including Talin2 and focal adhesion kinase (FAK). Finally, we developed a first-of-its-kind cell-based therapy for the treatment of experimental nephrolithiasis by exploiting macrophage Piezo1 activity, and this strategy shows great promise for future translational research.

physiology↗

PLANCK: super-multiplex optical imaging without labeling

Molecular information is vital for imaging technology. Optical imaging acquires molecular specificity almost exclusively via labeling strategy, which is fundamentally constrained by limited multiplexing capacity, high running costs, and experimental complexity. Conversely, label-free optical imaging offers substantial technical simplicity but is believed to have little true molecular specificity. Contrary to common belief, here we introduce super-multiplex optical imaging without labeling. By systematically studying paired vibrational spectroscopic imaging and mass spectrometry imaging, we discovered a surprisingly strong (more than 0.9) correlation between their latent space representations, supported by both experiments and theory. This insight prompts us to build supervised learning models to successfully predict spatial distribution of 100 molecular species directly from label-free vibrational images across diverse tissue systems. We developed this technology, named Prediction through Learning with AdvaNced Chemical Kaleidoscope (PLANCK), and demonstrated it with both infrared-based vibrational imaging of organ-scale tissues and Raman-based vibrational imaging of live tissues. Powered by AI, PLANCK decodes the exquisitely rich but otherwise hidden vibrational information into a surprisingly large number of ( [≥] 100) specific molecular species, providing a cost-effective and scalable solution for basic research and translation, including applications in live imaging.

biophysics↗

Targeting folate-dependent purine synthesis sensitizes melanoma cells to immune attack through suppressing glycolysis

Cytotoxic T lymphocytes (CTLs) play a central role in antitumor immunity; however, metabolic reprogramming within the tumor microenvironment often compromises their effector function, making metabolic targeting crucial for the improvement of T cell function. Folate-dependent purine synthesis, a core pathway sustaining the nucleotide pool, is highly activated in tumors, yet its role in regulating tumor immune sensitivity remains unclear. Here, by establishing a co-culture system of melanoma cells and human T Cell Receptor (TCR)-engineered T cells, we systematically evaluated the effects of folate-dependent purine synthesis inhibitors on tumor cell response to CD8+ T cell cytotoxicity. We found that inhibition of key enzymes such as methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) and glycinamide ribonucleotide transformylase (GART) markedly enhanced tumor cell sensitivity to T cell killing, an effect also observed with exogenous nucleoside supplementation. Mechanistically, inhibition of folate-dependent purine synthesis suppresses glycolysis by downregulating critical glycolytic enzymes, thereby reducing lactate production. Reduction in lactate further weakens lactylation and stability of the immune checkpoint protein PD-L1. In parallel, impaired purine synthesis disrupts uridine metabolism, blocks ribose salvage, and distally influences glycolysis. Collectively, our study identified the folate-dependent purine synthesis - glycolysis axis as key regulator of tumor immune response and highlights metabolic targeting as a promising strategy to improve cancer immunotherapy.

cancer biology↗

A vascular chip for disease-relevant flow shear stress topology

Vascular chips have advanced endothelial mechanobiology by enabling controlled responses to hemodynamic cues, yet disease-relevant wall shear stress (WSS) modeling remains limited. Simplified one-dimensional flow shear systems, designed mainly for physiological mechanobiology, miss the topological organization of pathological flow, whereas patient-specific vascular models capture complex hemodynamics but sacrifice generality and imaging compatibility. Here we develop a programmable vascular chip that converts disease-associated WSS topology into a physiologically parameterized experimental input. The device reconstructs a representative pathological shear-topology field on endothelial layer, supports stationary and physiologically paced oscillatory flow modes, and integrates matched unidirectional-shear references within the same chip. Using this system, we show that oscillatory WSS topology destabilizes endothelial monolayers, drives asymmetric collective emergent behaviors, impairs actin-nuclear mechanotransduction, accompanied by nuclear softening and enhanced perinuclear nanoparticle uptake. Integrated live-cell imaging, fluorescence analysis, Brillouin microscopy, and transport assays enable multimodal phenotyping across collective, subcellular mechanical and functional scales. By making disease-relevant WSS topology experimentally controllable, this vascular-chip framework bridges computational hemodynamics and experimental mechanomedicine, supporting standardized vascular disease modeling and functional screening.

bioengineering↗

Multi-layered regulatory networks driving human dopaminergic neuron differentiation

Neuronal differentiation requires coordinated regulation across chromatin organization, gene expression, protein abundance, and post-translational modifications. Using the LUHMES human dopaminergic neuronal differentiation model, we integrated proteome and phosphoproteome profiling with previously generated enhancer-promoter interaction maps from NET-CAGE and HiCap and transcriptomic analysis across three consecutive differentiation stages. Differentiation was accompanied by increased abundance and phosphorylation of proteins involved in axon guidance, cytoskeletal organization, and synaptic signaling, alongside repression of the cell cycle, DNA replication, and chromatin-associated programs. Phosphoproteome analysis further revealed extensive remodeling of signaling networks associated with neuronal maturation. Enhancer-promoter interaction analysis revealed substantially greater rewiring at enhancers than promoters and identified master and relay transcription factors regulated across multiple molecular layers. siRNA-mediated knockdown showed that transcription factors MYT1, ISL2, and NHLH2 are crucial for proper neuronal maturation, whereas LCOR acts as a negative regulator of differentiation. Integrative network reconstruction further nominated MEOX2 as a candidate enhancer-associated regulator of late dopaminergic maturation. Together, these findings provide a multi-layered view of regulatory networks governing human neuronal differentiation.

systems biology↗

Abbapolin inhibitors of the PLK1 PBD as Prostate Cancer Therapeutics, in vivo activity and synergy with androgen therapy

Polo-like kinase 1 (PLK1) is an established therapeutic target in cancer; however, ATP-competitive kinase inhibitors have shown limited clinical success because of toxicity, acquired resistance, and incomplete inhibition of non-catalytic PLK1 functions. Targeting the Polo-box domain (PBD), which regulates PLK1 localization and substrate recognition, represents an alternative therapeutic strategy but has been hindered by the lack of selective, cell-active small molecules. Here, the optimization and biological characterization of abbapolins, a series of non-peptidic PLK1 PBD inhibitors developed using the REPLACE strategy are described. Structure-guided optimization and screening across the NCI-60 cancer cell panel identified compounds with preferential activity against prostate cancer cells. Proteomic analyses demonstrated that cellular sensitivity correlated with PLK1 protein abundance, supporting an on-target mechanism of action. Abbapolins directly engaged PLK1 in cells, induced selective degradation of endogenous PLK1, and suppressed long-term clonogenic growth. Lead compounds demonstrated favorable pharmacokinetic properties and significantly inhibited prostate tumor growth in xenograft models without detectable systemic toxicity. PLK1 abundance was significantly reduced in treated tumors and correlated with tumor response, identifying PLK1 degradation as a potential pharmacodynamic biomarker. Abbapolins also synergized with enzalutamide in castration- resistant prostate cancer cells, supporting their potential as combination therapies for advanced disease. Collectively, these studies establish selective inhibition of the PLK1 Polo-box domain as a viable therapeutic strategy, provide in vivo proof-of-concept for the REPLACE approach, and identify abbapolins as promising leads for advanced prostate cancer.

cancer biology↗

Genomic impact of the second plague pandemic on three human populations

The second plague pandemic (early 14th-early 19th centuries), which was caused by Yersinia pestis, had a profound demographic, socio-economic and cultural impact across Eurasia and North Africa. Many regions in Europe and the Middle East are estimated to have lost 40-60% of their human populations, with some areas suffering even higher mortality. Whether exposure to Y. pestis drove strong positive selection on protective genetic variants in the human genome, and how it shaped migration patterns, remains debated, despite several recent studies based on ancient DNA. Here, we analyse a markedly larger, higher coverage, and geographically diverse dataset based on shotgun sequencing of genomes from 529 ancient individuals to a mean depth 8.8x dating to either before or after the arrival of the pandemic at three sites in northern Europe: Trondheim (Norway), Lund (Sweden) and Vilnius (Lithuania). Genome-wide scans for signatures of selection provide no evidence for strong positive selection acting on specific genetic variants driven by Y. pestis exposure: we neither replicate selection signatures reported by previous studies nor identify new genome-wide significant candidates. However, for all three sites, we observe evidence for a reduction in long-range immigration, indicated by a drop in the diversity of ancestry that followed the arrival of Y. pestis and broadly coincided with the end of the Viking Age, Christianisation and the onset of the Little Ice Age. Our results shed important light on the demographic impact of major sociohistorical changes that occurred during the late Medieval period in Scandinavia and the Baltic region and link Christianisation to increased diversity in ancestry before the pandemic.

genomics↗

An open-access CT-based 3D anatomical dataset of extant sharks across all major lineages

0Sharks exhibit extraordinary morphological diversity across a wide range of ecological niches, yet large-scale, high-resolution digital datasets of their internal anatomy remain limited. Here we present an open-access 3D shark anatomical repository derived from published X-ray computed tomography (CT) data, featuring manually segmented and systematically annotated models of the chondrocranium, visceral arches, axial skeleton, musculature, and viscera in standard STL format. The dataset comprises 117 individuals, representing 72 species across 25 families and all nine extant shark orders, with 115 full-body reconstructions and two head-only models. This open-access dataset offers a comprehensive resource for comparative anatomy, biomechanical simulations, evolutionary developmental biology and biomimetics research of extant sharks.

evolutionary biology↗

Rapid vegetation reorganization in Hengduan Mountains driven by high climatic oscillations

The accelerating global climate change has been triggering large-scale vegetation reorganizations, yet our understanding of how mountain ecosystems respond to rapid climatic oscillations is critically constrained. Here, we present a high-resolution palynological record from Erhai Lake, southwestern China, revealing eight episodes of rapid vegetation reorganizations in the Hengduan Mountains (HMs) over the past 35,200 years. These reorganizations closely tracked the rhythms of rapid climate oscillations, particularly during the Last Glacial Maximum and the Last Deglacial Period. We find that while the timing of rapid vegetation reorganizations were synchronous with Atlantic Meridional Overturning Circulation (AMOC) anomalies that modulated global climate variability, the magnitude of these reorganizations did not exhibit a linear correlation with AMOC strength; instead, they were governed by local heat and moisture availability mediated through teleconnections. This demonstrates a strong natural regulatory capacity of mountain vegetation in HMs, enabling resilience to intense climatic fluctuations. However, when using the Erhai record as a benchmark, we project that rapid reorganizations under the high-emission pathway (SSP585) will likely surpass the intensities observed during historical events. These findings reveal the high climatic sensitivity and strong natural regulatory capacity of mountain ecosystems, highlighting the critical necessity of climate mitigation actions and nature-based solutions to safeguard subalpine and alpine biodiversity against unprecedented future climate change.

ecology↗

Multi-Omics Study of Ancestry in Adults with Intracranial Cancers Glioma (MOSAIC)

BackgroundMost genomic studies of adult-type diffuse gliomas have focused on predominantly European ancestry populations, limiting the generalizability of molecular classifications and precision medicine approaches. We assembled a multi-institutional glioma cohort of diverse patients to investigate how germline ancestry, molecular subtypes, and mutational processes shape tumor biology and clinical outcomes. MethodsWe analyzed 1,102 adults with WHO 2021-classified diffuse gliomas (IDH-mutant, 1p/19q-codeleted oligodendroglioma; IDH-mutant astrocytoma; IDH-wildtype glioma) from seven U.S. institutions. Whole-exome sequencing (WES) of FFPE tumors identified somatic alterations and COSMIC SBS v3.2 mutational signatures. Genetic ancestry was estimated from WES using 1000 Genomes reference populations. Overall survival was assessed using Kaplan-Meier and multivariable models. ResultsThe cohort included 66.9% European (EUR), 21.1% Admixed American/Hispanic (AMR), 10.3% Admixed African (AFR), and 1.6% Asian (AS) ancestry. Survival followed expected molecular hierarchy (median overall survival: oligodendroglioma 15.7 years, astrocytoma 10.6 years, IDH-wildtype glioma 1.9 years). Within oligodendroglioma, AMR patients showed improved survival versus EUR (HR 0.67, 95% CI 0.48-0.94; p=0.011), with similar trends across subtypes. Somatic profiling confirmed canonical subtype-defining alterations and revealed higher ATRX alterations in AFR and AMR IDH-wildtype tumors compared with EUR. ATRX alterations were associated with improved survival only in AFR (p=0.003). Mutational signature analysis identified subtype-specific signatures, including therapy-associated signatures. Chemotherapy-related signatures were more frequent in EUR and AMR than in AFR. ConclusionsThis ancestrally diverse glioma cohort confirms established molecular classifications and identifies ancestry-associated differences in survival, somatic alterations, and mutational processes, indicating the critical need for broad representation to inform precision neuro-oncology. Key PointsO_LIA multi-institutional glioma cohort validates subtype and survival patterns across ancestries. C_LIO_LITherapy-associated mutational signatures differ by ancestry, suggesting distinct treatment-related mutational processes. C_LIO_LIAdmixed American patients show improved survival, particularly in oligodendroglioma. C_LI Importance of the StudyMost genomic studies of adult-type diffuse glioma have focused on populations of predominantly European ancestry which limits the ability to examine variation in tumor biology and clinical outcomes across populations. In this study, we assembled one of the largest ancestrally diverse cohorts of molecularly characterized adult diffuse gliomas, integrating germline ancestry inference with tumor whole-exome sequencing and mutational signature analysis. We confirm that established molecular classifications and survival hierarchies remain robust across ancestry groups. However, we also identified ancestry-associated differences in survival within specific tumor subtypes, higher ATRX alteration frequencies in African American and admixed American patients with IDH-wildtype tumors, and variation in therapy-associated mutational signatures across ancestry groups. These findings highlight the importance of incorporating population differences into genomic studies of glioma and provide a resource for future multi-ancestry investigations of glioma risk, tumor evolution, and treatment response, ultimately supporting more inclusive precision neuro-oncology.

bioinformatics↗

Generative Modeling of Mouse Embryogenesis for Fate and Disease Prediction

Embryonic development is orchestrated by complex gene regulatory networks, and learning regulatory dynamics from developmental data could allow us to understand, predict, and ultimately engineer cell fates. Here we introduce Navigo (https://github.com/aristoteleo/Navigo-release), a biologically grounded generative modeling framework that learns a developmental vector field by integrating flow matching at the population level with RNA kinetics modeling at the molecular level. Navigo accurately maps developmental trajectories across lineages on a mouse embryogenesis scRNA-seq atlas spanning 43 time points and comprising 12.4 million cells. Applied to cardiac development, Navigo enables disease modeling by mechanistically resolving regulatory networks that distinguish congenital heart disease subtypes. Navigo also predicts perturbation effects in a zero-shot manner, as validated on independent in vivo data from six knockout genotypes without perturbation-specific training, uncovering lineage-specific gene-compensation mechanisms. Moreover, Navigo guides rational cell-fate engineering, exemplified by fibroblast reprogramming analyses, including identifying pro-fibrotic barriers to cardiac fates and evaluating hundreds of pairwise transcription factor combinations for neuronal fate, each consisting of one bHLH factor and one POU factor. Overall, Navigo provides a generalizable AI platform for perturbation-effect prediction, disease modeling, and rational cell-fate engineering, advancing toward AI-based virtual embryos for developmental biology and regenerative medicine.

bioinformatics↗

Ciz1 safeguards Drosophila wing development by suppressing oxidative stress

Cell proliferation and fate specification are fundamental processes that ensure the generation of organs with proper size and patterning. Oxidative stress caused by accumulation of reactive oxygen species (ROS) can lead to cell cycle arrest, senescence, cell death and cell fate misspecification, thereby impairing normal development and contributing to many pathological processes. In this study, we identify Drosophila Ciz1 as a critical factor that safeguards epithelial homeostasis and development by preventing oxidative stress. Knockdown of Ciz1 in the Drosophila wing imaginal disc, an epithelial tissue that serves as the larval precursor of the adult wing, results in a small wing phenotype accompanied by thickened and ectopic veins. We further demonstrate that reduced Ciz1 expression leads to accumulation of donut-shaped mitochondria and elevated ROS levels. The increased oxidative stress subsequently suppresses proliferation via activation of JNK and promotes excessive vein formation by upregulating Rhomboid, a positive regulator of EGFR signaling. Interestingly, although Ciz1 is a zinc finger protein that predominantly localizes to the nucleus, neither its zinc finger motifs nor its nuclear localization is required for suppression of oxidative stress. Instead, the prion-like domain in its N-terminal part is essential for this activity. Our work identifies Ciz1 as an important factor in preventing oxidative stress and maintaining epithelial homeostasis.

Developmental Biology↗

Chitin oligomers induce atypical NLRP3 inflammasome activation and innate immune training

Chitin is a highly abundant poly- N-acetyl-glucosamine (GlcNAc) and linked to immune recognition of fungal infections and asthma in humans. Ubiquitous in fungi and insects, in mammals and plants chitin represents a microbe-associated molecular pattern (MAMP) and whereas highly polymeric chitin is insoluble and immunologically inert, soluble chitin oligomers of 6 to 15 GlcNAc activate immediate pro-inflammatory cytokine release via TLR2 in human immune cells. However, TLR2 ligands do not the most typical activators of the NLRP3 inflammasome pathway or innate immune training, a phenomenon of long-term immunological remodeling. Here we show that especially 16-20 GlcNAc long chitin oligomers activate NLRP3-dependent IL-1{beta} and IL-18 release in human myeloid immune cells in an atypical, phagocytosis-dependent manner. Moreover, phagocytosis and methyl transferase activity were essential for innate immune training, by which the same chito-oligomer-training enhanced TNF release in primary murine and human immune cells. Collectively, this suggests that oligomer length impacts on the immune features of chitin which can be customized using glycan assembly.

immunology↗

Persistent Post-Inflammatory Matrix Stiffening Defines a Premalignant Mechanical Niche in Ulcerative Colitis-Associated Neoplasia

Patients with long-standing ulcerative colitis (UC) remain at risk for colorectal neoplasia even after overt inflammatory activity improves, suggesting that repaired mucosa may retain residual tissue-level abnormalities. Whether extracellular matrix remodeling leaves a persistent mechanical cue that contributes to early neoplastic remodeling is unknown. Here we identify post-inflammatory matrix stiffening as a premalignant mechanical niche in UC-associated neoplasia. In human colonic biopsies, collagen remodeling and atomic-force-microscopy-based mucosal stiffness increased from non-UC controls to UC and UC-associated dysplasia. A stiffness-associated transcriptional program was also enriched in histologically non-dysplastic mucosa from patients with UC-associated neoplasia. In mouse models, colonic stiffness increased along the colitis-to-tumorigenesis axis and remained elevated during apparent recovery, when epithelial permeability, junctional protein loss, crypt proliferation and nuclear {beta}-catenin accumulation persisted despite reduced disease activity. Stiffness-controlled intestinal epithelial cultures showed that stiff substrates were sufficient to disrupt ZO-1 organization and enhance {beta}-catenin redistribution, particularly under TNF- stimulation. Pharmacological matrix normalization with {beta}-aminopropionitrile partially restored barrier organization and attenuated early epithelial remodeling in vivo. Single-cell profiling identified a stiffness-associated MMP7-positive/YAP-active epithelial state that was enriched in collagen-rich regions and reduced after matrix softening. Inhibition of YAP or MMP7 attenuated stiffness-associated junctional disruption and {beta}-catenin redistribution. These findings suggest that inflammatory recovery and mechanical recovery can be uncoupled, and that persistent mucosal stiffening provides a tissue-level mechanism by which chronically injured UC mucosa may remain biologically vulnerable to premalignant epithelial remodeling.

Cancer Biology↗

Multitrophic interaction networks mediate biodiversity effects on ecosystem multifunctionality

Biodiversity loss threatens the multifunctionality of ecosystems on which human well-being ultimately depends. Changes in multitrophic species interactions may be key to explaining the ecological consequences of biodiversity loss, but research explicitly linking species interactions and ecosystem multifunctionality remains rare. To assess interaction-mediated biodiversity effects and underlying mechanisms, characterizing the structure of species interaction networks is invaluable. Using comprehensive species interaction and ecosystem functioning data from a large-scale tree biodiversity experiment, we find consistent effects of the structure of species interaction networks on ecosystem multifunctionality across multiple types of antagonistic and mutualistic interactions. While positive effects of network size align with expected positive effects of multitrophic species diversity, positive effects of niche overlap among interacting species and negative effects of highly connected species (i.e. high linkage density) reveal additional, interaction-mediated drivers of multifunctionality. Specifically, the effects of niche overlap suggest benefits of functionally similar species, and the effects of linkage density underscore the importance of specialized interactions in promoting ecosystem multifunctionality. These findings emphasize that to effectively safeguard ecosystem service provisioning, ecosystem management and biodiversity conservation not only need to account for biodiversity changes at multiple trophic levels, but also explicitly for how species interact among each other.

ecology↗

Stratigraphic Paleobiology of Carbonate Systems

Stratigraphic paleobiology is a newly established interdisciplinary approach, which has demonstrated that the fossil record is a joint expression of biotic and stratigraphic change, and all inferences from it must be grounded in a solid understanding of the stratigraphic context. Fossiliferous strata can be found in all depositional systems (e.g., marine, terrestrial, or lacustrine; siliciclastics or carbonates), each having a unique characteristic timescale and set of external controls, which govern the accumulation of sedimentary particles, including fossils. Consequently, the same biotic changes are preserved differently across depositional systems. While carbonate systems form a large portion of the fossil record, most studies in stratigraphic paleobiology have focused on siliciclastic systems and are not easily generalizable. As they are predominantly formed by living organisms, carbonates are both fossils and record, opening the opportunity to study the co-dependency of life and its environment. Here, we explore the stratigraphic paleobiology of carbonate systems by combining simulations of carbonate platform and ramp geometries with synthetic fossil records. We explore the preservation of extinction patterns and rates spatially and across geometries. By examining stratigraphic biases in isolation (unconformity and condensation, ecology, and abundance biases), we find characteristic differences between ramp and platform geometries due to their differential response to sea level change, spatial variability, and differences in ecological clines. Differences in the structure of the fossil record between platform geometries are traceable to the contribution and properties of the carbonate producing organisms (carbonate factories), showing that preservation of earth system data in carbonate systems will vary both latitudinally and temporally or as a result of major perturbations of the biogeosphere. Our results show that while general rules on the structure of the fossil record can be derived for entire depositional systems, accounting for the geological and ecological dynamics of a particular sedimentary basin can hugely refine interpretations of the fossil record. That is particularly true for biogenic and biologically-mediated sediments.

paleontology↗