Pulkit Singh

All Publications

• Macroevolutionary coupling of marine biomass and biodiversity across the Phanerozoic. Current biology : CB Singh, P., Ferré, J., Thrasher, B., Monarrez, P. M., Al-Ramadan, K., Cantrell, D. L., Lehrmann, D. J., Morsilli, M., Payne, J. L. 2025

  Abstract

  Ecosystem function and its evolution depend on the number of taxa and the amount of biomass. For the oceans, spatial and temporal trends in diversity are well known, and spatial variation in biomass within the modern ocean is increasingly documented. Temporal variation in biomass, by contrast, remains undocumented, leaving a crucial gap in our understanding of how the marine biosphere evolved over geologic time. Here, we compiled compositional data from 7,749 marine limestone samples spanning the past 541 million years that document the proportion of sediment comprising the shells of animals, algae, and protists. The data capture temporal variation in skeletal content that is consistent across geologic settings, water depths, and latitudes. The variation largely parallels long-term trends in taxonomic diversity during intervals of diversification and across the three major mass extinctions with high-resolution compositional data, pointing toward a macroevolutionary coupling between marine biodiversity and biomass.

  View details for DOI 10.1016/j.cub.2025.06.006

  View details for PubMedID 40570849

• Calcium isotopes support spatial redox gradients on the Tethys European margin across the Triassic-Jurassic boundary CHEMICAL GEOLOGY Prow-Fleischer, A. N., Lu, Z., Blattler, C. L., He, T., Singh, P., Kemeny, P., Todes, J. P., Pohl, A., Bhattacharya, T., van de Schootbrugge, B., Wignall, P. B., Todaro, S., Payne, J. L. 2025; 673

  View details for DOI 10.1016/j.chemgeo.2024.122530

  View details for Web of Science ID 001389439500001

• Selectivity of mass extinctions: Patterns, processes, and future directions. Cambridge prisms. Extinction Payne, J. L., Al Aswad, J. A., Deutsch, C., Monarrez, P. M., Penn, J. L., Singh, P. 2023; 1: e12

  Abstract

  A central question in the study of mass extinction is whether these events simply intensify background extinction processes and patterns versus change the driving mechanisms and associated patterns of selectivity. Over the past two decades, aided by the development of new fossil occurrence databases, selectivity patterns associated with mass extinction have become increasingly well quantified and their differences from background patterns established. In general, differences in geographic range matter less during mass extinction than during background intervals, while differences in respiratory and circulatory anatomy that may correlate with tolerance to rapid change in oxygen availability, temperature, and pH show greater evidence of selectivity during mass extinction. The recent expansion of physiological experiments on living representatives of diverse clades and the development of simple, quantitative theories linking temperature and oxygen availability to the extent of viable habitat in the oceans have enabled the use of Earth system models to link geochemical proxy constraints on environmental change with quantitative predictions of the amount and biogeography of habitat loss. Early indications are that the interaction between physiological traits and environmental change can explain substantial proportions of observed extinction selectivity for at least some mass extinction events. A remaining challenge is quantifying the effects of primary extinction resulting from the limits of physiological tolerance versus secondary extinction resulting from the loss of taxa on which a given species depended ecologically. The calibration of physiology-based models to past extinction events will enhance their value in prediction and mitigation efforts related to the current biodiversity crisis.

  View details for DOI 10.1017/ext.2023.10

  View details for PubMedID 40078672

  View details for PubMedCentralID PMC11895734

• Reduction in animal abundance and oxygen availability during and after the end-Triassic mass extinction. Geobiology Singh, P., Lu, W., Lu, Z., Jost, A. B., Lau, K., Bachan, A., van de Schootbrugge, B., Payne, J. L. 2022

  Abstract

  The end-Triassic biodiversity crisis was one of the most severe mass extinctions in the history of animal life. However, the extent to which the loss of taxonomic diversity was coupled with a reduction in organismal abundance remains to be quantified. Further, the temporal relationship between organismal abundance and local marine redox conditions is lacking in carbonate sections. To address these questions, we measured skeletal grain abundance in shallow-marine limestones by point counting 293 thin sections from four stratigraphic sections across the Triassic/Jurassic boundary in the Lombardy Basin and Apennine Platform of western Tethys. Skeletal abundance decreased abruptly across the Triassic/Jurassic boundary in all stratigraphic sections. The abundance of skeletal organisms remained low throughout the lower-middle Hettangian strata and began to rebound during the late Hettangian and early Sinemurian. A two-way ANOVA indicates that sample age (p < .01, η2  = 0.30) explains more of the variation in skeletal abundance than the depositional environment or paleobathymetry (p < .01, η2  = 0.15). Measured I/Ca ratios, a proxy for local shallow-marine redox conditions, show this same pattern with the lowest I/Ca ratios occurring in the early Hettangian. The close correspondence between oceanic water column oxygen levels and skeletal abundance indicates a connection between redox conditions and benthic organismal abundance across the Triassic/Jurassic boundary. These findings indicate that the end-Triassic mass extinction reduced not only the biodiversity but also the carrying capacity for skeletal organisms in early Hettangian ecosystems, adding to evidence that mass extinction of species generally leads to mass rarity among survivors.

  View details for DOI 10.1111/gbi.12533

  View details for PubMedID 36329603

• Proliferation of Chondrodonta as a proxy of environmental instability at the onset of OAE1a: Insights from shallow-water limestones of the Apulia Carbonate Platform SEDIMENTOLOGY Del Viscio, G., Frijia, G., Posenato, R., Singh, P., Lehrmann, D. J., Payne, J. L., Al-Ramadan, K., Struck, U., Jochum, K. P., Morsilli, M. 2021

  View details for DOI 10.1111/sed.12887

  View details for Web of Science ID 000664228000001

• A GENERAL MODEL FOR GROWTH TRAJECTORIES OF LINEAR CARBONATE PLATFORMS JOURNAL OF SEDIMENTARY RESEARCH Goudemand, N., Singh, P., Payne, J. L. 2020; 90 (9): 1139–55

  View details for DOI 10.2110/jsr.2020.55

  View details for Web of Science ID 000595068100008