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Evolution of the Cambrian and Ordovician Biodiversification Onset Over Space and Time – ECO-BOOST

Evolution of the Cambrian-Ordovician Biodiversification Onset Over Space and Time

The ECO-BOOST project aims to compare the diversity of modeled species with empirical data based on fossils, then to project them onto new paleogeographic reconstructions, in order to propose the first reconstruction, through time and space, of the Early Paleozoic biodiversification.

Main objectives of ECO-BOOST

The Early Paleozoic is characterized by the establishment of the first complex marine ecosystems and by two major episodes of diversification: the «Cambrian Explosion« and the «Great Ordovician Biodiversification Event« (GOBE). However, in recent years, the distinction between these two «events« has become significantly blurred. Thus, critical analysis of the «global« biodiversity databases generally used in the literature, the PaleoBiology DataBase (PBDB) and the GeoBiodiversity DataBase (GBDB), suggests that the so-called «Furongian gap«, which separates the Explosion Cambrian of the GOBE, results in part from biases inherent in the databases. In addition, the recent discovery of several sites with exceptional preservation (Lagerstätten) showed that organisms typical of the Cambrian Explosion were still present in the Ordovician. This project aims to test the existence of two distinct “explosions” of biodiversity in the Lower Paleozoic. Our main objective is to transfer data from paleontological archives onto paleogeographic maps, then to compare them with data from climatic/geographic and macro-ecological models. This comparison between data and models will make it possible to reconstruct, for the first time, the spatio-temporal evolution of marine ecosystems during the Cambro-Ordovician. We aim to identify latitudinal diversity gradients (LDGs) and their evolution over time and, potentially, locate marine diversity “hotspots” in the Lower Paleozoic. The modeling will produce testable palaeo-climatic, -ecological and -biogeographic predictions, providing spatio-temporal patterns of biodiversity for the Cambrian and Ordovician. Our project therefore proposes to combine empirical and modeling approaches, with new tools that have never before been applied to Lower Paleozoic marine ecosystems.

The analysis of the spatio-temporal distribution of Cambro-Ordovician echinoderms (WP2-WP3) has made good progress in Lyon thanks to the recruitment of Pauline Guenser (contractual CNRS researcher) who co-supervised two interns, Léa Trémeau (Master 2, Dijon ) and Mellie Lauze (L3, Lyon) on this issue; a lot of compilation and verification work was carried out, in order to generate a new database (EBDB, Echinoderm Biodiversity Data Base), as complete as possible for Cambrian and Ordovician echinoderms. The first latitudinal distribution maps of Cambrian echinoderms were completed at the end of June 2024 and those of Ordovician forms are in progress. This work was the subject of communications at international congresses; at least two publications are currently being written. The analysis of the different biases (historical, sampling, preservation) affecting the paleontological databases (EBDB, GBDB, PBDB) has also been the subject of various analyses; the bias linked to taphonomy and the impact of exceptional preservation was highlighted in the context of the description of the Lagerstätte of Cabrières (Saleh et al. 2024; lejournal.cnrs.fr/videos/sur -the-trail-of-rare-fossils).

We began to analyze the past distribution of conodonts (WP3) using ecological niche models. However, the use of these models in this context has many limitations. Indeed, fossil data are incomplete, and it is possible that the ecological niche is not correctly modeled. An engineering student from IMT Atlantique is working on improving the NPPEN model by proposing a mixed iterative model NPPEN/Convex envelope, in order to create pseudo-presences to complete the group of observations used for the calibration of the model.

Concerning the coupled climate-biodiversity modeling of WP4 and WP5, the project planned to start work in 2025. We nevertheless took advantage of the opportunities presented to us to launch certain areas of research earlier than planned. Alexis Balembois was hired by the UMR LOG (1/01/2023-12/05/2023) then the UMR Biogéosciences (15/05/2023-29/09/2023) as a research engineer, before to continue his work as part of a doctoral thesis at UMR LOG (thesis co-supervised by the partners LOG, Lyon and Biogéosciences). His results are the subject of a manuscript currently being prepared. Two articles have already been published, focusing on the joint evolution of climate and biodiversity on the Phanerozoic scale (Ontiveros et al., 2023; Pohl et al., 2023b). Two other articles focused on the evolution of environmental conditions during key periods in the evolution of Paleozoic biodiversity (He et al., 2024; Pohl et al., 2023a). These organizational changes generated additional results for the ANR without calling into question the work planned in the project. There are in fact 10.5 full-time equivalent months of funding remaining at the UMR Biogéosciences to hire a post-doc in the coming years to carry out the work initially proposed.

Together, our first results from coupled climate-biodiversity modeling (Ontiveros et al., 2023; Pohl et al., 2023b) explain both the high extinction rates and the strong increase in biodiversity documented during the Cambrian and from the Ordovician. They therefore shed new light on the very particular dynamics of the marine biosphere at this time, and on its coupling with the climate (ocean temperature) and ocean biogeochemistry (water oxygenation).

An article currently being prepared confirms the results published by Ontiveros et al (2023) based on other paleoclimatic simulations. In this article, the impact of Ordovician cooling on the GOBE is found by adding the possibility of allopatric speciation to the model. At the Phanerozoic scale, we show that the niche-environment interaction is a fundamental interaction which makes it possible to explain the patterns of variability of biodiversity and its changes in time and space, as well as the temporal evolution of global biodiversity in the marine environment of continental shelves, or close to continents. The explicit consideration of the niche-environment interaction in the models resulting from the METAL theory (Macro Ecological Theory for the Arrangement of Life) also makes it possible to take into consideration the influence of climate, climatic regime, position and rate. fragmentation of continents, the available area around continents and its influence on environmental heterogeneity which conditions the number of niches but also the number of species created per niche by allopatric speciation.

The discovery of a new Lagerstätte in the Lower Ordovician of France («Cabrières Biota«; Saleh et al., 2024) confirms the persistence of numerous «Cambrian type« forms until at least the end of the Floian and, therefore, the existence of an evolutionary continuum between Cambrian Explosion and GOBE. In addition, the extremely high diversity observed at this site, although located near the South Pole, reinforces the hypothesis of a very warm climate (greenhouse) at the end of the Cambrian / beginning of the Ordovician, compatible with a migration of biodiversity hotspots towards higher latitudes.

From a scientific perspective, the ANR project ECO-BOOST will lead to a paradigm shift in how palaeontological studies are conducted. As expected from our preliminary results published in Zacaï et al. (2021), the project outcomes will rapidly demonstrate the strength of coupling spatially-informed data collection / compilation with numerical models of global climate and marine ecology, to gain a mechanistic understanding of the evolution of biodiversity through geological ages. Due to its inherent pluri-disciplinarity and in the longer term, this methodological (re)volution will cascade down from palaeontology to other fields of geosciences such as sedimentology and geochemistry, which are routinely associated with palaeontology in integrative (inter)national projects. By identifying future sampling targets, necessarily outside the intensively sampled North America and Europe, the ECO-BOOST project will also have economic consequences in fostering international collaborations with developing countries, and societal impacts by actively contributing to decolonizing the scientific (geoscientific) database (Raja et al. 2022). Finally, our project will have major repercussions in the cultural domain, by imposing a step change in our vision of the co-evolution of Life and the physical environment in the geological past. Put simply, our results will put an end to previous dogmas related to the appearance of complex forms of Life, first in the scientific community and, and the medium term, in the public domain (once schoolbooks updated). Beyond the direct academic and public exploitation of the results, numerical code developments (WP4, WP5 and WP6 in particular) will be made publicly available on GitHub, which will foster further research on the co-evolution of Life and the Environment, with far-reaching implications for the development of the next generation of coupled climate-biodiversity models used for the prediction of ongoing climate change, and ultimately for decisions by policy-makers.

Beaugrand, G., 2023. Towards an understanding of large-scale biodiversity patterns on land and in the sea. Biology 12, 339. doi.org/10.3390/biology12030339
Dupichaud, C., Lefebvre, B., Milne, C.H., Mooi, R., Nohejlová, M., Roch, R., Saleh, F. & Zamora, S., 2023. Solutan echinoderms from the Fezouata Shale Lagerstätte (Lower Ordovician, Morocco): diversity, exceptional preservation, and palaeoecological implications. Frontiers in Ecology and Evolution 11, 1290063. doi.org/10.3389/fevo.2023.1290063
Guenser, P., Nohejlová, M., Nardin, E. & Lefebvre, B., 2023. A methodological scheme to analyse the early Palaeozoic biodiversification with the example of echinoderms. Estonian Journal of Earth Sciences 72, 130. doi.org/10.3176/earth.2023.32
He, R., Pohl, A., Prow, A., Jiang, G., Huan, C.C., Saltzman, M.R. & Lu, Z., 2024. The dynamic ocean redox evolution during the late Cambrian SPICE: Evidence from the I/Ca proxy. Global and Planetary Change 233, 104354. doi.org/10.1016/j.gloplacha.2024.104354
Lefebvre, B. & Servais, T., 2023. Filling knowledge gaps in the Ordovician radiations. Geobios 81, 1–5. doi.org/10.1016/j.geobios.2023.10.001
Ontiveros, D.E., Beaugrand, G., Lefebvre, B., Marcilly, C.M., Servais, T., Pohl, A., 2023. Impact of global climate cooling on Ordovician marine biodiversity. Nature Communications 14, 6098. doi.org/10.1038/s41467-023-41685-w
Pohl, A., Nardin, E., Vandenbroucke, T.R.A. & Donnadieu, Y., 2023a. The Ordovician ocean circulation: a modern synthesis based on data and models. Geological Society of London, Special Publications 532, 157–169. doi.org/10.1144/SP532-2022-1
Pohl, A., Stockey, R.G., Dai, X., Yohler, R., Le Hir, G., Hülse, D., Brayard, A., Finnegan, S. & Ridgwell, A., 2023b. Why the Early Paleozoic was intrinsically prone to marine extinction. Science Advances 9, adg7679. doi.org/10.1126/sciadv.adg7679
Saleh, F., Lustri, L., Gueriau, P., Potin, G.J.M., Pérez-Peris, F., Laibl, L., Jamart, V., Vite, A., Antcliffe, J.B., Daley, A.C., Nohejlová, M., Dupichaud, C., Schöder, S., Bérard, E., Lynch, S., Drage, H.B., Vaucher, R., Vidal, M., Monceret, E., Monceret, S. & Lefebvre B., 2024. The Cabrières Biota (France) provides insights into Ordovician polar ecosystems. Nature Ecology & Evolution 8, 651-662. doi.org/10.1038/s41559-024-02331-w
Servais, T., Cascales-Miñana, B., Harper, D.A.T., Lefebvre, B., Munnecke, A., Wang, W.H. & Zhang, Y.D., 2023. No (Cambrian) explosion and no (Ordovician) event: A single long-term radiation in the early Palaeozoic. Palaeogeography, Palaeoclimatology, Palaeoecology 623, 111592 doi.org/10.1016/j.palaeo.2023.111592
Servais, T., Harper, D.A.T. & Wang, W.H., 2023. Editorial Preface to Special issue: The radiations within the Great Ordovician Biodiversification Event. Palaeogeography, Palaeoclimatology, Palaeoecology 632, 111838. doi.org/10.1016/j.palaeo.2023.111838

The early Palaeozoic biodiversification is the most significant radiation of marine ecosystems of Earth’s History, with two major pulses documented from diversity datasets: the 'Cambrian Explosion’ and the 'Great Ordovician Biodiversification Event’. However, in recent years, it became obvious that these two ‘events’ were more intensively studied in a few locations, creating a gap of data, and thus a bias, in biodiversity databases. Moreover, recent investigations documented that exceptionally preserved fossils typical of the 'Cambrian Explosion’ were still present in the Ordovician. We hypothesize that global ‘explosions’ of diversity never occurred. Our main objective is to plot all data of the marine fossil record on new palaeogeographical maps in combination with climatological/geographical and macro-ecological modelling to allow data/model comparisons and biodiversity reconstructions. We will document that very complex, long-term evolutionary processes took place over space and time, starting in the late Precambrian and lasting throughout most of the early Palaeozoic. This will allow us to obtain, for the first time, spatial and temporal views illustrating the biodiversity changes in the earliest marine ecosystems, including the identification and location of diversity ‘hotspots.’ It will also allow us to determine the timing of establishment of the first Latitudinal Diversity Gradient (LDG) and its evolution through time. The modelling approach will produce testable palaeoclimatological, palaeoecological and biogeographical predictions, providing spatio-temporal models of biodiversity patterns for the Cambrian and Ordovician. Our project thus proposes to combine empirical and modelling approaches, with new tools that have never been applied to early Palaeozoic marine ecosystems.

Project coordination

Bertrand LEFEBVRE (Centre national de la recherche scientifique)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.


Université de Lille
LGL-TPE Centre national de la recherche scientifique
Université Littoral-Côte d'Opale
BGS Université Bourgogne

Help of the ANR 473,447 euros
Beginning and duration of the scientific project: December 2022 - 48 Months

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