Thermodynamic models predict that marine metal availability has changed over geological time, particularly in the Archean Eon (4.0 – 2.5 billion years ago), when seawater was anoxic and Fe²⁺-rich. Since metals are essential micronutrients required to build metalloproteins, changes in metal availability in seawater would have influenced evolving microbial ecosystems. Recent work on Archean rocks has highlighted the role of greenalite as an abundant, primary precipitate in Archean seawater, and its potential as a faithful geochemical archive. Greenalite can be exceptionally well preserved in early diagenetic chert, providing protection from diagenesis and metamorphic alteration. Furthermore, experimental work has demonstrated that several key metals enter the greenalite precursor phase during precipitation, and the associated partition coefficients are consistent under a range of conditions. Furthermore, most metals are retained in the structure during heating and crystallisation, suggesting that greenalite could represent a robust archive of the metal content of early oceans. Here, we present mineral-specific laser ablation ICP-MS data for natural greenalite from the ~2.5 Ga Transvaal Supergroup, South Africa. Petrographic relationships and rare earth element patterns suggest this greenalite precipitated from seawater in a shelf environment. We place metal abundance into a quantitative framework to predict metal availability in Archean seawater. Our calculations suggest that V and Zn were depleted, Ni was similar, Co was enriched, and Mn was super-enriched in this setting compared to modern marine environments. These results are consistent with predictions based on marine chemistry and proteomics, as well as some bulk geochemical records.

How to cite: Tostevin, R., Nke, A. Y., Tsikos, H., Mhlanga, X., and Mason, P. R. D.: Greenalite provides a snapshot of metal availability in an Archean shelf environment., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4614, https://doi.org/10.5194/egusphere-egu24-4614, 2024.

Evidence for the co-evolution of Earth and life is abundantly preserved in the minerals, which are the oldest objects you can hold in your hand. Each information-rich specimen is a time capsule waiting to be opened and to tell the stories of Earth and other worlds. The emerging field of “mineral evolution” considers changes in the diversity and distribution of minerals through billions of years of planetary history [1-5], and reveals dramatic episodes of the co-evolution of minerals and life, including stages of life's origins, microbial biomineralization, influences of global oxygenation, and the rise of the terrestrial biosphere. 

Traditional approaches to classifying minerals ignore this history. The International Mineralogical Association (IMA) has catalogued >6000 mineral species, each with a unique combination of idealized chemical composition and crystal structure. This essential scheme allows the confident identification of different condensed crystalline building blocks of planets and moons. However, lacking perspectives of time and process, this system is limited in its ability to address the evolution of planets, much less the co-evolution of the geosphere and biosphere.

We have introduced, and are now completing, a new complementary approach to mineral classification called the “evolutionary system of mineralogy.” Our system differs from IMA's in three ways. First, it splits IMA species that form in more than one way; for example, pyrite forms by both abiotic and microbial processes. Second, it lumps IMA species that form continuous solid solutions through the same process; i.e., we lump many different species of the tourmaline group into a single kind. Third, we include varied amorphous or poorly crystalline solids, such as obsidian, kerogen, and limonite, which are important in crustal processes and were included in mineral inventories before the application of x-ray diffraction.

The resulting evolutionary system of mineralogy is being released in 12 parts, 8 of which are now published or in press [6-13]. These works underscore the close connections between mineral and biological evolution. We find that while minerals played key roles in life’s origins and evolution, life changed near-surface environments in ways that led to the formation of approximately half of all known mineral species, most of which are only known to form through biological mediation.

References: 1. Hazen R.M. et al. (2008) Am.Min., 93, 1693-1720; 2. Hazen R. & Morrison S. (2022) Am.Min., 107, 1262-1287; 3. Hazen, R. et al. (2023) In: Bindi and Cruciani [Eds.], Celebrating the International Year of Mineralogy. NY: Springer, pp.15-37; 4. Hazen R. et al. (2023) JGR Planets, 128, e2023JE007865; 5. Hazen R. et al. (2022) Am.Min., 107, 1288-1301; 6. Hazen R. (2019) Am.Min., 104, 468-470; 7. Hazen R. & Morrison S. (2020) Min., 105, 627-651; 8. Morrison S. & Hazen R. (2020) Am.Min., 105, 1508-1535; 9. Hazen R. et al. (2021) Am.Min., 106, 325-350; 10. Morrison S. & Hazen R. (2021) Am.Min., 106, 730-761; 11. Hazen R. & Morrison S. (2021) Am.Min., 106, 1388-1419; 12. Morison S. et al. (2023) Am.Min., 108, 42-58; 13. Hazen R. et al. (2023) Am.Min., 108, 1620-1641; 14. Morrison et al. (2024) Am.Min., 109, in press.

How to cite: Hazen, R.: Documenting the Co-Evolution of Earth and Life: A Mineral Evolution Approach , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4723, https://doi.org/10.5194/egusphere-egu24-4723, 2024.

Primary producers convert light energy from the sun into chemical energy in the form of sugars, a fundamental process that has enabled life on Earth. Once ancestral cyanobacteria evolved, they played a crucial role in Earth's history by facilitating the rise of atmospheric oxygen, paving the way for the development of complex life forms. Despite its significance, the origins of photosynthesis are still not fully understood. During the talk, I will highlight key evolutionary events in the history of Cyanobacteria: 1) the Archean origin of PSII,  photochemical reaction centre that catalyses the light-driven oxidation of water to molecular oxygen; 2) the emergence of the crown group of Cyanobacteria; 3) the appearance of filamentous forms around the Great Oxidation Event at 2.32 Ga; and 4) the late emergence of marine planktonic groups between 800-600 Mya. Molecular evolution analyses reveal a significant time gap between the Archean origin of oxygenic photosynthesis and the appearance of planktonic forms at the end of the Precambrian era. By studying the 'genomic record,' we can now unravel how oxygenic phototrophs co-evolved with the Earth's biosphere, contributing to the habitability of our planet.

How to cite: Sanchez-Baracaldo, P.: Primary producers during the early Earth , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9713, https://doi.org/10.5194/egusphere-egu24-9713, 2024.

The maintenance of Earth’s habitability over geologic timescales is largely driven by the metabolisms and ecologies of bacteria and archaea. In this context, the role that microorganisms have played throughout major environmental transitions during the Archean and Proterozoic Eons are especially noteworthy. The “genomic record” represents the accumulated adaptations to planetary change maintained within the collective genetic pool of life. In this presentation, we will describe how the genomic record can be used to improve our understanding of microbial natural history and present six broadly applicable principles to aid in the investigation these complex questions. This framework will then be used to guide a a meta-analysis of microbial genomes derived from collections large metagenomic databases across diverse environments to illustrate how specific environmental variables drive the microbial diversity patterns we see today.

How to cite: Magnabosco, C., Rodriguez, P., Husain, F., Paoletti, M., Parsons, C., Payette, J., Swartz, S., Tamre, E., and Fournier, G.: Uncovering life and planetary co-evolution through the genomic record, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17160, https://doi.org/10.5194/egusphere-egu24-17160, 2024.

There is considerable potential to apply traits-based approaches to the subfossil remains of shell-forming micro-organisms which preserve well in sediments and whose short generation times make it possible to achieve high-temporal resolution in palaeoecological studies.  In this paper we review progress in applying traits-based approaches to freshwater testate amoebae (Arcellinida), a diverse group of protists which are abundant in lakes and are valuable palaeoecological indicators.  Drawing on published studies from the last ~10 years, we describe the methodologies which have been applied to delimit testate amoeba (TA) traits and review the challenges associated with their measurement and interpretation.  We also showcase the results of ongoing work in seven lakes (UK, Canada) which aims to (i) examine the character and causes of trait-based variability in palaeolimnological settings; (ii) apply novel biometric approaches to aid in trait delimitation; and (iii) explore the potential for combining phylogenetic with advanced morphometric approaches to better understand the ecological and evolutionary significance of TA traits.

            We applied geometric morphometric analysis to define test size and shape indices and summarise testate amoeba community dynamics along a temporal gradient of eutrophication in a large shallow lake in Scotland, UK.  Cluster analysis of test size and shape indices yielded three assemblages, each dominated by a single shape: elongate, spherical and ovoid. When plotted stratigraphically, we observed increases in spherical tests, decreases in elongate tests and shrinking of test size coeval with eutrophication. Decreases in the elongate cluster may reflect benthic conditions with reduced oxygen levels, while increases in the spherical cluster are likely associated with an expanding macrophyte community that promoted pelagic and epibiotic life habits.  Shrinking of test size may be a stress response to eutrophication and/or warming temperatures. Tracking community dynamics using test size and shape indices was found to be as effective as using traditional species-based approaches to summarize key palaeolimnological changes, with the added benefit of being free of taxonomic bias.  The approach thus shows significant potential for future studies of aquatic community change in nutrient-impacted lakes.

            To further investigate the functional significance of the Arcellinida shape groups, we examined the phylogenetic signal of morphological traits in elongate Difflugia species which occur in eutrophic and mesotrophic lakes.  Previous phylogenetic work has shown that whilst overall test morphology (e.g., spherical or elongate) is generally conserved in Arcellinida lineages, the taxonomic significance of other traits (e.g., size, ornamentation, mixotrophy/heterotrophy metabolism type) is not well understood.  Our analyses revealed two clades which could be reliably separated by test size and the presence/absence of mixotrophy.  This suggests that test size may reflect trophic level, with smaller taxa occupying lower trophic levels.  In addition to having larger tests, elongate mixotrophic Difflugia are characterised by wide, flat bases and inflation of the lower part of the test.  These morphological traits may provide additional space for endosymbionts and/or increased surface area to aid light transmission.  Continued research into the ecological and evolutionary significance of morphological traits will serve to strengthen palaeoecological inferences, increasing the importance of lacustrine testate Arcellinida as environmental proxies.

How to cite: Roe, H., Macumber, A., Prentice, S., Patterson, T., Sayer, C., and Emson, D.: Exploring the Links between Testate Amoeba Traits and Eutrophication in Lakes, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18509, https://doi.org/10.5194/egusphere-egu24-18509, 2024.

Ecosystem engineers are keystone taxa whose behaviours alter the habitability of their environments for themselves and other organisms by directly influencing the availability of resources in their ecosystems. From a deep time perspective, ecosystem engineers are hypothesized to have played a major role in the co-evolution of life and the Earth systems, as many major ecosystem engineering activities directly modulate the cycling of key nutrients. Moreover, ecosystem engineers are thought to have impacted diversity by increasing environmental heterogeneity, and so their evolution may drive some of the biodiversity dynamics observed in the fossil record. Here, we investigate the impact of two groups of marine ecosystem engineers – bioturbators and reef-builders – on biodiversity through the Phanerozoic. Using fossil occurrence data from the Paleobiology Database, we calculate the effect size of bioturbating and reef-building ecosystem engineers on various biodiversity metrics for each stage through the Phanerozoic. Most broadly, we find that ecosystem engineers had a positive impact on biodiversity within the environments where they live during the Phanerozoic. We also find clear taxonomic differences between environments with and without ecosystem engineers, suggesting ecosystem engineers create a unique set of environmental characteristics to which taxa of specific ecological characteristics become adapted. These results emphasize the important role of ecosystem engineers in influencing key aspects of the Earth systems on a variety of scales that manifest in changes in biodiversity.

How to cite: Cribb, A., Darroch, S., and Ezard, T.: Ecosystem engineers impact marine biodiversity during the Phanerozoic, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13629, https://doi.org/10.5194/egusphere-egu24-13629, 2024.

A major discovery in the last 5 years has been the recognition that the geomagnetic field was at ultralow field strengths, some ten times weaker than the present-day, during the Ediacaran Period. These ultralow values were first reported from single crystal paleointensity analyses of 565 Ma rocks of the Sept Îles Mafic Intrusion Suite (Bono et al., Nature Geosci., 2019), and were later confirmed by studies of dikes and lavas from other sites in Ukraine and Canada (e.g., Thallner et al., EPSL, 2021). The ultralow values are followed by a rapid increase in field strength in the early Cambrian (Zhou et al., Nature Commun., 2022) and together these signals are consistent with initial nucleation of Earth’s inner core, as predicted by thermal models and geodynamo simulations (Davies et al., GJI, 2022). An updated timeline incorporating new paleointensity data from several localities in North America, South America and Africa highlights a striking temporal correspondence between the ultralow field, the Ediacaran diversification of macroscopic animals, and some geochemical indicators for the rise of oxygenation. The onset of inner core growth and unusual state of the geomagnetic field should not correspond with animal evolution or oxygenation unless changes in the Ediacaran magnetosphere attendant with the ultralow field somehow affected the atmosphere, oceans and/or biosphere. We will consider these possibilities. 

How to cite: Cottrell, R., Tarduno, J., Huang, W., Xiao, S., Blackman, E., Zhou, T., Schneider, J., Bono, R., and Ibañez-Mejia, M.: Ediacaran ultra-weak geomagnetic field, oxygen rise, and the diversification of macroscopic animals, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12706, https://doi.org/10.5194/egusphere-egu24-12706, 2024.

It is commonplace to claim that the geo-, atmo-, and bio- spheres of the Earth are coupled, or that biodiversity depends on their interplays, but the implicit hypothesis on the time and space scales at which coupling holds are seldom envisioned. For instance, "deep time" is a convenient shortcut that loosely conveys the ideas of steady state and large spatial scales, but what are the limits? Observations often fall short because the geological record is fragmentary, but also because it is uncommon to access crucial informations such as rates of speciation, extinction, or migration. Recent advances in numerical landscape evolution models permit to explore the dynamic equilibrium between the spheres of the Earth. Based on a few examples at different time and space scales, we will browse settings where steady state holds (where biodiversity depends on the instantaneous states of the geology and climate, as for instance set by the Wilson cycle), where transient state prevails (where considering the time derivative of their states is needed, as for instance when the pace of landscape reshaping promotes biodiversification), and where dynamic equilibrium breaks down in some sort of metastable situations (as in the press-pulse theory that well applies to the mass extinction events). 

How to cite: Husson, L., Lorcery, M., and Salles, T.: On the time and space scales of geological, climatic, and biological changes, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10608, https://doi.org/10.5194/egusphere-egu24-10608, 2024.

Changes in the physical environment, whether geological or climatic, are known to be major drivers of biodiversity. At the interface between the solid Earth and the climate lies the physiography, and landscape complexity and variety may control biodiversity mechanisms at a finer scale that the large scale patterns of plate tectonics and global climate. To test whether variation of physiography through time and space can explain the current richness pattern of biodiversity and understand the impact of landscape complexity evolution on specific mechanistic processes, we simulated the diversification of terrestrial mammals at global scale, over 125 Ma of geological and climatic changes, using a spatially explicit eco-evolutionary simulation model (genesis). We designed four evolutionary scenarios in which evolution was only dependent on climate and plate tectonics (M0), and scenarios where physiographic diversity was implemented in speciation (M1), dispersion (M2) and niche ecology (M3). To assess whether model predictions are consistent with the empirical distribution of terrestrial mammals, we statistically identify general emergent patterns of biodiversity within and across spatial and temporal scales. 

How to cite: Lorcery, M., Husson, L., Salles, T., Hagen, O., Skeels, A., and Lavergne, S.: 125 Ma of physiographic changes and mammal macroevolution, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17379, https://doi.org/10.5194/egusphere-egu24-17379, 2024.

Identifying the geological drivers of long-term climate change is key to improve our understanding of the interactions between the deep Earth and the Earth’s surface. Long-term Cenozoic climate cooling has been largely attributed to an increase in atmospheric carbon consumption by enhanced silicate weathering linked to the uplift of the Tethyan orogenic belt. Alternatively, this cooling trend has been explained by decreasing magmatic CO₂ outgassing during the progressive closure of Neo-Tethys Ocean. However, the outgassing rates associated with Neo-Tethyan magmatism remain poorly constrained, making it difficult to assess its contribution to Cenozoic climate change. Here, we present the first results of numerical geodynamic experiments aimed at obtaining improved quantitative estimates of the magmatic CO₂ outflux along the Neo-Tethyan margins. To this end, we use 2D numerical petrological-thermomechanical models of oceanic subduction and continental collision that account for partial melting and slab decarbonation. Calibrating these numerical experiments on available geological constraints from the Neo-Tethyan margin, we estimate the Neo-Tethyan magma production volumes through the Early Cenozoic. We discuss how these results are sensitive to changes in model setup and input parameters such as convergence rates, rheology, and crustal composition. To quantify the time-dependent magmatic CO₂ emissions, we combine the magma production histories with both modelling- and observation-based quantifications of the volatile contents of pre- and post-eruptive igneous rocks. Finally, we discuss the potential Neo-Tethyan magmatic forcing of Early Cenozoic climate change in light of our new results and its implications for the global carbon cycle and surface-deep Earth feedbacks.

How to cite: Vaes, B., Sternai, P., Ostorero, L., Castrogiovanni, L., Gonzalez, C., and Donnadieu, Y.: Numerical modelling of magmatic CO2 emissions from the Neo-Tethyan margin during the Early Cenozoic, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-620, https://doi.org/10.5194/egusphere-egu24-620, 2024.

Dinosaurs were dominant members of terrestrial ecosystems throughout the Mesozoic, yet only recently are studies beginning to illuminate the key role of global climate variation in controlling dinosaur biodiversity, global distribution, and macroevolution. Our work uses statistical, biogeographic, and phylogenetic comparative approaches with comprehensive fossil occurrence data and paleoclimate data from general circulation models to quantitatively examine key hypotheses connecting patterns of dinosaur diversity and evolution with climatic conditions. We examined the impact of climate change in driving early dinosaur evolution across the end-Triassic mass extinction (ETME). Our results demonstrate that the geographic distribution of early sauropodomorphs was constrained by climate and following the ETME, the expansion of climate zones facilitated the geographic expansion of sauropodomorphs and other dinosaurs. Evolutionary model-fitting analyses provide evidence for an important evolutionary shift from cooler to warmer climatic niches during the origin of Sauropoda. This same approach is also revealing the relationship between climatic conditions and dinosaur diversity in the Jurassic to Cretaceous, with implications for our understanding of the origins of sauropod gigantism and the evolution of herbivory. Our results suggest that primary productivity was a key climatic factor in driving sauropod evolution and promoting the evolution of larger body sizes, supporting the hypothesis that gigantism was facilitated by the increasing availability of high quality vegetation. Analyses of dinosaur paleoclimatic niche space show evidence of niche partitioning between herbivorous theropods and ‘traditional’ herbivorous dinosaurs (e.g. sauropods), indicating that climatic changes may have influenced evolutionary innovations related to dinosaur diet. Further work examining the relationship between dinosaur diversity and changes in vegetation using state-of-the-art vegetation models will illuminate the key role played by environmental change in controlling dinosaur diversity and evolution throughout the Mesozoic.

How to cite: Dunne, E., Schnetz, L., Farnsworth, A., Lautenschlager, S., Godoy, P., Tasimov, E., Butler, R., and Greene, S.: Climatic controls on dinosaur evolution, diversity and biogeography, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15098, https://doi.org/10.5194/egusphere-egu24-15098, 2024.

The Permian section of the Paraná-Etendeka basin is represented by the Palermo and Irati formations, comprising a shallow sea that occupied ca. 5 million km² of southern Gondwana before completely drying out around 277 million years ago (Irati-Whitehill ocean). This is broadly coincident with the uprising of the Cape Fold Belt of southern Africa and the San Rafael orogeny of the paleo-Pacific margin of South America, leading to the interpretation that basin restriction and the major ecosystem changes that followed were ultimately caused by uprising of mountainous domains surrounding the shallow sea. We combine new iron speciation, organic carbon isotope and trace element data with previous biomarker, organic carbon and nitrogen isotope data to unravel the biogeochemical and redox changes during this transition from an open marine realm to a restricted setting, and to test the hypothesis of external controls on the biogeochemical cycles of southern Gondwana. Mudstones and shales of the Palermo Formation yielded Fe_HR/Fe_T around or below 0.2, suggesting oxic bottom water conditions, reinforced by muted redox-sensitive element (RSE) concentrations and overall low Total Organic Carbon (TOC) contents, with δ¹³C_org around -25‰. Black shales of the overlying Irati Formation, on the other hand, record an abrupt shift to anoxic conditions, with Fe_HR/Fe_T between 0.3 and 0.9, representing mostly ferruginous conditions with sporadic euxinic incursions (Fe_Py/Fe_HR > 0.8), higher concentrations of RSE such as Mo, higher TOC contents and d¹³C_org rapidly oscillating from ca. -29 up to ca. -19‰. The euxinic intervals are associated with the Assistência Member, containing tephra layers dated at 277 Ma and thus coeval to the Cape and San Rafael orogenies. Our results reinforce the hypothesis of mountain belt formation as the main external driver of biogeochemical changes, leading to toxic conditions for complex life forms in the Permian internal basins and to the accumulation of important organic-rich source rocks in the shallow seas of southern Gondwana.

How to cite: Caxito, F., Sperling, E., Bastos, L., and Pereira, E.: Anoxia in the Permian Irati-Whitehill Ocean of southern Gondwana: A possible link with uprising of the Cape and San Rafael mountain belts, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1345, https://doi.org/10.5194/egusphere-egu24-1345, 2024.

Large and fast collisional systems such as the Eastern Tibetan-Himalayan orogenic system can have distinct corner structures. Away from the corners, plate convergence is accommodated primarily by convergence-parallel processes such as (continental) subduction, crustal thickening and buckling. Around the corners, oblique and convergence-perpendicular processes become more important, such as strike-slip, transpressional and transtensional faults. The strike of the subduction front itself can also vary in space, as tomographic images show for the case of the Indian slab beneath Tibet and Burma. At the corners themselves, a peculiar syntaxis structure may form which is characterised by effective strain localisation and high rates of exhumation and erosion. However, our understanding of the temporal evolution of orogenic syntaxis formation is still elusive. 

Here, we use high-resolution, three-dimensional thermomechanical models to investigate principal stress orientations, strain rate patterns and upper versus lower crustal flow patterns within a continental corner collision setting loosely resembling the Eastern Tibetan-Himalayan orogenic system. We use a 1000 x 200 x 1000 (x * y * z) model domain with a permeable lower boundary and a 2 km grid resolution in each dimension. Each grid cell has 8 markers. The models are carried out using I3ELVIS (Gerya and Yuen, 2007) coupled to the surface process model FDSPM (Munch et al., 2022). Our numerical experiments highlight that i) significant lateral variability occurs despite prescribing orthogonal kinematic boundary conditions; ii) a high variability of stress states and deformation styles occur within the modelled orogen and plateau; iii) Lower crust beneath the plateau escapes later than upper crust, but around 3-4 times faster. Lastly, we examine the sensitivity of the model evolution to different degrees of strain weakening, intracrustal layering, and the diffusion coefficient of the surface process model.

Gerya, T. V., & Yuen, D. A. (2007). Robust characteristics method for modelling multiphase visco-elasto-plastic thermo-mechanical problems. Physics of the Earth and Planetary Interiors, 163(1), 83–105. https://doi.org/10.1016/j.pepi.2007.04.015

Munch, J., Ueda, K., Schnydrig, S., May, D. A., & Gerya, T. V. (2022). Contrasting influence of sediments vs surface processes on retreating subduction zones dynamics. Tectonophysics, 836, 229410. https://doi.org/10.1016/j.tecto.2022.229410

How to cite: van Agtmaal, L., Balazs, A., May, D., and Gerya, T.: Stress, strain and crustal flow patterns in a corner collision: insights from coupled 3D numerical models, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15917, https://doi.org/10.5194/egusphere-egu24-15917, 2024.

Narrow Orogenic Arcs (NOA) on Earth are oftenly biodiversity hotspots, where biogeographic evolution is influenced by tectonic forcing. However, the relationships between tectonic mechanisms intrinsic to NOA, landscape evolution and speciation forming biodiversity hotspots have not been dwelt with. Different mechanisms inherent to NOA, such as slab roll back, slab tearing, edge delamination, mantle upwelling and flow around subducted slabs, basin and archipelago migration and volcanic arc growth drive a dynamic landscape evolution that fosters processes of dispersal and allopatric-speciation. Here, we show this with examples from the Western Mediterranean and Caribbean. Slab tearing drives migrating waves of tectonic uplift and subsidence at the edges of orogenic arcs, coupled with crustal thickening followed by heterogeneous extension, forming endorheic basins and marine gateways among high-elevation ranges. Furthermore, vicariant events by isolation in high-elevation mountain ranges, internal drainage basins, stranded back-arc and volcanic arc archipelagos- seem to have driven the distribution and diversification of many taxa. Dispersal events would have been promoted by- drifting forearc archipelagos, changes of river courses (captures) and land bridges between continents, where ancient lineage dispersal followed by allopatric speciation-multiple diversification resulted in the current complex biological assemblages. The characteristic time and space migration of NOA, fosters recurrent processes of dispersal and vicariance, including in situ diversification through time. In this setting, long-time emerged parts of both drifting-forearc or stranded-backarc archipelagos represent both refuge and diversification centers where insular fauna may relate to distant, previously- attached land masses or islands. This is the case of drifting islands like the late Miocene Alboran archipelago in the Gibraltar arc or the Present Margarita island in the Caribbean, bearing biota with most common recent ancestors in the Balearic islands or the Central Coastal Range of Venezuela, respectively. Insular lineages may disperse by the closure of marine gateways between the mainland continents and drifting archipelagos, a process that may also drive the isolation of confined seaways, like the Mediterranean during the Messinian Salinity Crisis. Topographic uplift closing marine gateways or restricting seaways may occur by lithospheric rejuvenation, following delamination or detachment of subducted subcontinental mantle slabs and also by the growth of a volcanic arc. The emergence of new land and islands in the forearc domain, results in speciation and less species-rich communities in the direction of slab retreat. 

How to cite: Booth Rea, G., Mas Peinado, P., Galve, J. P., Jiménez Robles, O., and Azañón, J. M.: Biogeodynamics of narrow orogenic arcs and their biodiversity hotspots, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8733, https://doi.org/10.5194/egusphere-egu24-8733, 2024.

Mountain regions harbor disproportionally high biodiversity levels on Earth, which can hardly be explained solely by contemporary climate and heterogeneity. The complex interactions between the geological and climate dynamics in the mountain system could provide a unique substrate for species to diversify, leading both to higher diversity and higher endemism in the mountains. The Hengduan Mountains region is a unique biodiversity hotspot outside of the tropics. It is characterized by complex geological and climate histories associated with the Indian-Eurasia plate collision and monsoon intensification shaping intense geomorphic processes. These unique and complex histories are expected to have shaped landscapes across millions of years, fostering the emergence of lineages. Using the clade level of phylogenies and species range maps, we generated the spatial pattern of diversification rate for 33 highly diversified clades in the Hengduan Mountains. These spatial clade diversification rate patterns are spatially associated with active deformation history in the past 15 Ma. In this talk, I will present hotspots of diversification rate and potential linkage to geological and climate processes. I will demonstrate that the diversification rate hotspots are concentrated in the Three Rivers Region, Dadu River, and Shangri-La Plateau in the Hengduan Mountains. Then I will show the elevational gradient of the diversification rate within these hotspots and link them to specific geological processes. Specifically, long-term erosion from low-temperature thermochronology indicates the deformation process in the recent 15 Ma associated with new habitat and high diversification speciation process in the Three Rivers region and Dadu River in the Hengduan Mountains. Moreover, the landscape transience characterized by divides migration and low relief surface formation may create habitat disruption and range fragmentation to increase allopatric speciation. Taken together, the high plant diversity of Hengduan Mountain may be caused by intense focalized geological processes generating new species from habitat disruption.

How to cite: Chang, Y., Ding, W., He, J., Willett, S., Gelwick, K., Zimmermann, N., and Pellissier, L.: Plant diversification is associated with habitat disruption in the transient Hengduan Mountains, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1446, https://doi.org/10.5194/egusphere-egu24-1446, 2024.

Northern South America, particularly the geologically dynamic Colombian Andes, stands as a region of highest plant biodiversity. While the influence of mountain uplift in the tropical Andes on biodiversity patterns is well-recognized, the repercussions of these landscape changes on the evolutionary dynamics of the local flora have been understudied. Here, we aim to fill this gap by investigating the role of uplift history and landscape evolution in driving the assembly and maintenance of plant biodiversity in the Colombian Andes. We integrate a comprehensive reconstruction of individual geological blocks with plant phylogenies, distribution patterns, and the resulting biogeographic structuring of the endemic flora. Our comparative analysis reveals a substantial agreement between the geological blocks and biogeographic realms instead of climate, indicating the fundamental role of regional tectonics shapes the observed pattern of biodiversity. Notably, the northern segments of the Western and Central Cordillera and Eastern Cordillera, representing the two most-recent fast uplift blocks, exhibit a higher prevalence of endemic species and a significant accumulation of in situ speciation events over the last 10 million years. Our findings provide a detailed perspective on how landscape changes have driven the diversification of flora in the Colombian Andes and contribute to a broader understanding of the intricate interplay between geological processes and plant evolution, emphasizing the importance of considering regional tectonic dynamics in unraveling the heterogeneous biodiversity patterns on Earth.

How to cite: Liu, Y., Ott, R., Pellissier, L., and Zimmermann, N.: Regional tectonics shaped plant biodiversity in Colombian Andes, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21627, https://doi.org/10.5194/egusphere-egu24-21627, 2024.

Madagascar, as a biodiversity hotspot on Earth, exhibits a high level of endemism as observed from the prevalent vicariant speciation of terrestrial mammals, amphibians, and flora. Species richness of the island is uneven, with the highest species richness and endemism found on the steep great escarpment of the eastern margin. The unevenness is further observed within the escarpment region in that phylogenic turnover shows both latitudinal and altitudinal variations. Madagascar has remained almost tectonically inactive since the last rifting with Seychelles-India in the late Cretaceous. The high diversity and endemism of Madagascar challenge the conventional notion of uplift-driven speciation, which argues that speciation is driven by the formation of diverse habitat types from tectonic uplift.

Although the fundamental topographic framework of Madagascar has been in place since the late Cretaceous, it is modified in the Cenozoic by multiple processes including island-wide mantle-driven dynamic uplift, erosion-driven landward retreat of the escarpment at the eastern margin, localized volcanic and faulting activities. Our topographic reconstruction reveals that the dominant correlation is between the escarpment and species richness. To investigate the causal mechanisms of the diversity at the eastern escarpment, we constructed landscape evolution models, tracing the dynamics of habitable land surface patches throughout model simulations.

We investigated two distinct landscape scenarios: an escarpment retreat model simulating river incision into a pre-existing plateau with negligible tectonic uplift, and a tectonic uplift model featuring spatially and temporally constant uplift with river incision into the resulting mountain range. The steady-state topographic height of the tectonic uplift model is calibrated to match the plateau elevation of the escarpment model to ensure the same number of habitat types between models. The landscape of a great escarpment is highly dynamic and the heterogenous retreat of the escarpment and the water divide makes the geographically isolated drainage basins expand landward at different rates during the retreat process. Within the escarpment region, habitat patches dynamically appear, disappear, fragment, or merge at a frequency that scales with the retreat rate. In contrast, the tectonic uplift model only exhibits similar dynamic landscape change during the transient phase with habitat patches stabilizing spatially and temporally once a steady state topography was achieved.

The models predict that escarpment retreat fosters habitat patch dynamics such that patches isolate, or reconnect with a frequency on the order of a million years, appropriate for allopatric speciation. The habitat patch dynamics are a consequence of processes of catchment expansion, river captures, isolation of highland remnants, and formation of topographic barriers during the retreat. We conclude that the spatially heterogeneous but temporally steady retreat of the Madagascar escarpment since rifting has sustained allopatric speciation over evolutionary timescales resulting in the observed high diversity and its spatial pattern of eastern Madagascar.

How to cite: Wang, Y., Willett, S., Liu, Y., Pellissier, L., and Zimmerman, N.: Escarpment Retreat Drives Diversification of Eastern Madagascar through Allopatric Speciation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10412, https://doi.org/10.5194/egusphere-egu24-10412, 2024.

Plants have been a key interface in the global carbon and water cycles for nearly 475 million years. The magnitude of vegetational effects has waxed and waned dynamically because plant abundance and community composition have changed over time. Unravelling how plant communities have shaped, and been shaped by, global biogeochemical cycles relies upon reconstructing the paleoecology and paleoecophysiology of plants, and this process can be challenging in deep time, when plant communities contained organisms with traits that are rare in—or absent from—present-day ecosystems. Fortunately, the archive of how plants have shaped and responded to environmental change is preserved in the fossil record, because the traits and properties of extinct plants can be interpreted from fossilized anatomy in a qualitative, semi-quantitative, and quantitative way. Traits related to water transport in plants. including drought resistance and hydraulic supply to leaves, are particularly useful and important because these traits link individual plant performance to the water and carbon cycles.

The collapse of tropical everwet rainforests end of the Carboniferous Period (~300 Ma) provides an illustration of how plant water transport traits influenced, and were shaped by, the water and carbon cycles. These traits are quantified by combining mathematical models of stem hydraulic conductivity and drought resistance with anatomical measurements from scanning electron and light microscopy images of fossilized plant water transport cells, called xylem. Analysis of stem hydraulic traits in five lineages of extinct Carboniferous plants—arborescent lycophytes, stem group seed plants, stem group tree ferns, coniferophytes, and sphenophytes—reveals differential hydraulic capacity and drought resistance among these plants, despite their simultaneous presence in tropical everwet ecosystems. Significant differences in these two traits are not only present between these five lineages, but can also be observed within several of these plant groups: for example, key parameters may vary by more than an order of magnitude in related plants. High hydraulic capacity and low drought resistance traits were associated with a decline in relative abundance toward the close of the Carboniferous Period, whereas plants with lower hydraulic capacity and higher drought resistance traits increased in relative abundance and survived this floral transition. This change in relative abundance within these communities shaped the hydrologic and carbon cycles which, in turn, amplified environmental stress that, consequently, further altered plant community composition. Implementing this analysis in trait-aware paleoecosystem models illustrates the effect of plant traits on global environments, and vice versa, yielding insight into plant performance during extreme environmental change that is analogous to anthropogenic impacts predicted for the late 21^st century and beyond.

How to cite: Wilson, J.: Plant paleoecophysiology traits in deep time: hydraulic conductivity and drought resistance in late Carboniferous Period plants, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6891, https://doi.org/10.5194/egusphere-egu24-6891, 2024.

During the Permian-Triassic Mass Extinction (PTME) ~252Ma, diverse lowland forests were replaced by low diversity pioneer herbaceous lycopod communities that proceeded to dominate the Early and Middle Triassic landscape. The flourishing of Early-Middle Triassic herbaceous lycopods was coincident with data that suggests lethally warm surface temperatures (>40ºC) occurred across large regions of the planet. To explore how these plants were able to thrive during this interval of enhanced climatic stress, we collected data from over 400 fossil plant specimens from South China, supplemented by additional data from literature reviews from other regions and geological ages. Our studies on their morphology indicate that among all Phanerozoic lycopods the transitional Permian-Triassic genus Tomiostrobus (=Annalepis) has the closest morphological relationship with the recent lycopod Isoetes.

Extant Isoetes are renowned for their flexibility with regard to the photosynthetic pathway they use and their capacity to absorb CO₂ through their roots. To evaluate whether this photosynthetic flexibility was linked to their Early-Middle Triassic ecosystem dominance, we undertook carbon isotope and sedimentary facies analysis including plant taphonomy to test for the presence of the Crassulacean Acid Metabolism (CAM) photosynthetic pathway. Plants capable of CAM pathway growing in stressful environment typically have heavier isotopic signatures while show typical C3 plant signatures in hospitable environment. Our carbon isotope data shows that Permian Triassic Transition Tomiostrobus isotopic signature is on average ~2‰ less negative when compared to contemporary non lycophyte vegetation. Furthermore, the carbon isotope of the Middle Triassic lycopods ~1.07‰ heavier than the other plants, while Late Permian Lepidodendron exhibits a similar δ¹³C value with other contemporary plants. These findings suggest that CAM photosynthesis may have played a role in the dominance of the Triassic herbaceous lycopods. The dominance of CAM plants following the PTME has implications from an Earth Systems standpoint due to their diminished productivity and a lower capacity for biotic weathering, features that likely suppressed negative feedback loops important in driving climate stabilization during the ~5Ma PTME recovery phase.

How to cite: Xu, Z., Yu, J., Hilton, J., Lomax, B. H., Wignall, P. B., and Mills, B.: How did the Permian-Triassic hot house climate shape the vegetation landscape and how did the land plant fight back?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18738, https://doi.org/10.5194/egusphere-egu24-18738, 2024.

Functional traits were originally defined as any characteristic of an organism that contributes to fitness. From this autecological perspective, trait-based research has considerably expanded into approaches of ecosystem analysis that also have high potential for palaeoecological research. In the ecosystem context, the meaning of “trait” has become much broader, encompassing all sorts of measurable quantities carrying ecological information that are themselves categorized into different “trait classes”. For instance, “response traits” are organismal traits responding to environmental parameters whereas “effect traits” act upon the environment.

As primary producers, plants represent a crucial part of ecosystem functioning. Basic ecophysiological processes of plants, particularly gas exchange and photosynthesis, are key elements in the carbon and water cycle and can thereby be understood as “effect traits”. Fossil anatomical traits, such as from fossil leaves, allow for deriving basic ecophysiological parameters from physical laws (such as calculating leaf gas conductance from the diffusion equation). Biochemical parameters, however, are not provided by fossil material and require therefore estimation based on extant plants (such as kinetic properties of the enzyme apparatus of photosynthesis) which adds a certain error margin to the results. Nevertheless, these “mixed” approaches to fossil plant ecophysiology allow for obtaining crucial benchmark data on various ecosystem characteristics, such as primary productivity or evapotranspiration.

            Another branch of trait-based ecosystem research is the study of functional diversity which can be roughly described as the richness and distribution of functions expressed by organisms coexisting within a habitat. Functional diversity is less frequently considered for fossil vegetation compared to the study of autecological effect traits. One reason may be that various approaches for studying extant functional diversity are difficult or even impossible to apply to fossil plants, requiring the development of novel methods suitable for fossil remains.

As a recent example, the Shannon Diversity of leaf architecture based on functional leaf traits identifiable from fossil leaf material was shown to be related to environmental parameters for extant as well as fossil angiosperms.  Devising trait-based approaches to functional diversity suitable for fossil organisms can offer additional fruitful research perspectives for studying environments of the past.

How to cite: Roth-Nebelsick, A. and Traiser, C.: Functional traits and trait diversity of leaves: palaeoecological perspectives, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7442, https://doi.org/10.5194/egusphere-egu24-7442, 2024.