SSP4.3 | Ecological and climate inferences from paleo-archives: implications for near-future dynamics
EDI
Ecological and climate inferences from paleo-archives: implications for near-future dynamics
Convener: Isabella LeonhardECSECS | Co-conveners: Niels de WinterECSECS, Daniele Scarponi, Jens Zinke, Eleanor JohnECSECS, Johan Vellekoop, Shirin N. RahmanECSECS
Orals
| Thu, 18 Apr, 10:45–12:30 (CEST), 14:00–15:35 (CEST)
 
Room -2.33
Posters on site
| Attendance Wed, 17 Apr, 16:15–18:00 (CEST) | Display Wed, 17 Apr, 14:00–18:00
 
Hall X3
Posters virtual
| Attendance Wed, 17 Apr, 14:00–15:45 (CEST) | Display Wed, 17 Apr, 08:30–18:00
 
vHall X3
Orals |
Thu, 10:45
Wed, 16:15
Wed, 14:00
Marine and terrestrial ecosystems and species are drastically affected by today's changing climate and other anthropogenic stressors. Understanding how climate change drives changes in seasonality and weather variability on the human timescale (hours to decades) requires detailed records of variability at this resolution throughout (geological) history. However, monitoring the ecological consequences of climate and environmental impacts on biodiversity is difficult. By covering only recent decades, scientific surveys, climate records and monitoring are limited in time and space and, therefore, insufficient to fully assess the long-term human impacts and ecosystem status.

This session will explore how interdisciplinary approaches to the geological record can enhance the interpretation of past ecosystems and short-term climate dynamics, and thus provide context and guidance for the future of modern ecosystems. We will showcase geohistorical records through case studies at various spatial and temporal scales, including high-resolution records of environmental and climate variability that bridge the gap between the (palaeo)weather and climate using a wide range of tools and analytical approaches from palaeontology, geochemistry, geology and historical ecology.

We hope to foster discussion of the (dis)advantages of certain techniques, archives and statistical methods and provide a breeding ground for collaborations between researchers working in different sub-domains whose research goals are aligned.

Orals: Thu, 18 Apr | Room -2.33

Chairpersons: Niels de Winter, Johan Vellekoop
10:45–10:50
10:50–11:00
|
EGU24-15713
|
ECS
|
Highlight
|
On-site presentation
Jorit F. Kniest, Amelia J. Davies, David Evans, Jens Fiebig, Axel Gerdes, Wolfgang Müller, Jonathan A. Todd, Julia D. Sigwart, Johan Vellekoop, Silke Voigt, and Jacek Raddatz

Understanding past Earth system processes is an essential component of placing current climate changes in context and testing climate model output. In this context, reconstructing patterns in marine or terrestrial temperatures is as important as understanding the mode of the hydrological cycle. However, there is only limited research on past hydrological systems, as the interplay between evapotranspiration, precipitation and runoff makes comprehensive reconstructions challenging. To overcome this issue, the spatiotemporal distribution of precipitation and riverine runoff can be estimated by reconstructing the dynamics of enhanced fresh water input into marginal sea.

Here, we focus on the hydrological conditions of shallow marine areas around the southern paleo-North Sea during the Eocene, including the Paris, Hampshire and Belgium Basins.  We utilised fossil bivalve shells (Venericor planicosta and Crassatella ponderosa) as archives as they can be used to reconstruct both long-term climate changes due to their widespread abundance and temporal continuity in the geological record as well as short-term variability via the time-distinct (sub-seasonal) layering of their shells. We reconstruct fresh water flux to these basins at different spatiotemporal resolutions, ranging from regional differences across millions of years to (sub-)seasonally resolved local variations. Depending on the targeted spatiotemporal resolution, different proxy systems were used. For the reconstruction of large scale changes in the input of terrigenous material by riverine runoff, Ba/Ca and 87Sr/86Sr are employed. In addition, δ18O and Δ4748 measurementswere conductedto detect sub-annual changes in the isotopic composition of the sea water by isotopically lighter fresh-water influx.

Result exhibit regionally specific Ba/Ca and 87Sr/86Sr values for each of the examined basins, generally reflecting the hinterland geology. However, these values show time dependent variations throughout the Eocene, suggesting variable degrees of terrigenous input by varying riverine runoff. The detected changes in riverine runoff are generally congruent to the depositional evolution of the basins, as derived from the sedimentary record, revealing less terrigenous input signal with increasing open marine conditions and vice versa.  A specimen of V. planicosta from the Paris Basin, showing a distinct riverine signal in Ba/Ca and 87Sr/86Sr, was used for combined δ18O and Δ4748 measurements to identify seasonal variations in the oxygen isotopic composition of the sea water (δ18OSW). The resulting δ18OSW values show a minimum seasonal variability of 0.9‰ and an enhanced fresh water input during the summer.

These results shed new light on the hydrological conditions in Western Europe during the Eocene and show how different proxy systems can be interlinked to reconstruct basin hydrology on different spatiotemporal scales.

How to cite: Kniest, J. F., Davies, A. J., Evans, D., Fiebig, J., Gerdes, A., Müller, W., Todd, J. A., Sigwart, J. D., Vellekoop, J., Voigt, S., and Raddatz, J.: Reconstructing regional to local scale patterns of fresh water input into the Eocene North Sea Basin, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15713, https://doi.org/10.5194/egusphere-egu24-15713, 2024.

11:00–11:05
11:05–11:15
|
EGU24-21421
|
ECS
|
On-site presentation
Jun Geng, Hong Yan, Chengcheng Liu, Tao Han, Shan Liu, Nanyu Zhao, Hanfeng Wen, Haotian Yang, Pengchao Zhou, Guozhen Wang, and John Dodson

El Niño-Southern Oscillation (ENSO) is the strongest signal of global interannual climate anomaly and reconstructing past ENSO variations using high-resolution paleoclimate archives can improve our understanding of ENSO variability, as well as improve our ability to predict future climate changes. Here, a daily resolution standardized growth index (SGI) was established using a giant clam (Tridacna spp.) shell specimen MD2 (life span: AD 1994-2013), collected from the Yongshu Reef, southern South China Sea (SCS). The cross-spectral and correlation analysis indicated that the SGI variation of MD2 was strongly influenced by ENSO variability on an interannual timescale. Tridacna spp. is in symbiosis with zooxanthellae, and its growth index is usually modulated by the photosynthetic efficiency of zooxanthellae. During the El Niño (La Niña) period, the convective anomalies stimulated in western Pacific would increase (decrease) the effective solar radiation on Yongshu Reef, and in turn influence the photosynthesis rate of zooxanthellae and enzyme activity for the calcification site and thus the SGI of giant clam MD2. The SGI can explain 54.7% of ENSO variance, demonstrating the potential for Tridacna SGI in ENSO reconstruction. Compared with conventional ENSO reconstruction using high-resolution geochemical proxies, the method of giant clam SGI is rapid and economical.

How to cite: Geng, J., Yan, H., Liu, C., Han, T., Liu, S., Zhao, N., Wen, H., Yang, H., Zhou, P., Wang, G., and Dodson, J.: Reconstruction of ENSO variability using the standardized growth index of a Tridacna shell from Yongshu Reef, South China Sea, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21421, https://doi.org/10.5194/egusphere-egu24-21421, 2024.

Q&A
11:15–11:25
|
EGU24-6241
|
ECS
|
On-site presentation
Walid Naciri, Arnoud Boom, Takaaki K. Watanabe, Deiter Garbe-Schönberg, Edmund Hathorne, Nicola Browne, Noreen J. Evans, Ramasamy Nagarajan, and Jens Zinke

The El Niño Southern Oscillation (ENSO) is a worldwide climate phenomenon impacting temperatures and precipitation regimes in Australia, Southeast Asia, and America. Previous studies have shown this climate phenomenon and the Indo–Australian monsoon to have a strong influence on Malaysian Borneo’s hydroclimate. In a context of climate change and increasingly strong extreme ENSO events, understanding the influence of ENSO on this region, as well as its evolution through time, is essential to better constrain the possible future impacts it will have on the Maritime Continent’s hydroclimate. To compensate for the limited availability of dependable instrumental data in the first half of the 20th century, we used coupled δ18O and Sr/Ca records from massive corals’ carbonate calcium skeletons to build a proxy for past hydroclimate: δ18Oseawater18Osw). We first assessed our two 90 and 60-year-long δ18Osw records’ quality as proxies for hydroclimate by correlating them with different instrumental datasets before performing moving windowed correlations with the NINO3.4 index, an indicator of ENSO state. Results show variable agreement with local instrumental data depending on the distance from the river mouth, monsoon season, and instrumental dataset used. When correlated against the NINO3.4 index, our δ18Osw records showed a nonstationary increasing influence of ENSO from the 1980s and onwards on the local hydroclimate with correlation coefficients r > 0.8 using month groups towards the end of the year. Our findings highlight the differences in results depending on the chosen dataset, time scale, or period of the year, as well as the usefulness of these geochemical archives to better understand the impacts of climate phenomena across periods predating reliable instrumental data.

How to cite: Naciri, W., Boom, A., Watanabe, T. K., Garbe-Schönberg, D., Hathorne, E., Browne, N., Evans, N. J., Nagarajan, R., and Zinke, J.: Paired coral Sr/Ca and δ18O records reveal increasing ENSO influence on Malaysian Borneo’s hydroclimate, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6241, https://doi.org/10.5194/egusphere-egu24-6241, 2024.

Q&A
11:25–11:35
|
EGU24-8312
|
ECS
|
On-site presentation
Qian Zhang, Hong Yan, Jibao Dong, Guozhen Wang, Yana Jia, and Xiangzhong Li

Weather-scale precipitation have a significant impact on ecosystems and human activities. Reconstructing weather-scale precipitation events is critical to improving our understanding of precipitation event mechanisms. Currently, the snail shells ultra-high resolution δ18O records obtained by secondary ion mass spectroscopy (SIMS) is the main methods of reconstruction the terrestrial weather-scale precipitation events. However, research in this field is limited due to the rarity and costliness of SIMS instrumentation, as well as the complexity of sample preparation. In this study, we collected three modern land snails (Cathaica fasciola) from the Shizuishan area in Northwest China in June, September, and December 2021. The shells of these snails were sampled continuously with a spatial resolution of ~700μm and tested using gas-source mass spectrometry (GSMS) to obtain high-resolution δ18O records. The results showed that the δ18O of snails shell (δ18Oshell) of different snails grown at the same time period were well reproducible. We obtained the growth rate of Cathaica fasciola is 546μm/day from June to September. This growth rate is obviously faster than Xingyang (181μm/day from June to September) and Xi'an (56μm/day from April to September). The observed disparity in growth rates may be attributed to the snail survival strategy changes, which appear to be more efficient in water usage in the monsoon margin zone. More importantly, the δ18Oshell exhibited sensitivity to precipitation, as evidenced by three negative fluctuations in δ18Oshell record that corresponded to three precipitation events during the period. These findings indicate that δ18Oshell records obtained by GSMS could effectively capture weather-scale precipitation information in the monsoon margin region. GSMS is widely used, less costly for testing, and relatively simple for sample preparation. This greatly improves the feasibility and applicability in reconstruct weather-scale precipitation events under different climatic conditions using δ18Oshell record, and deepens our understanding of the mechanisms such events. Meanwhile, this finding holds significance in unraveling the intricate nature of weather-scale precipitation events. 

How to cite: Zhang, Q., Yan, H., Dong, J., Wang, G., Jia, Y., and Li, X.: Daily-weekly scale precipitation events in the monsoon marginal zone recorded by high-resolution δ18O of land snail shells, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8312, https://doi.org/10.5194/egusphere-egu24-8312, 2024.

Q&A
11:35–11:45
|
EGU24-1862
|
ECS
|
On-site presentation
Christoph J. Gey, Laurent Pfister, Guilhem Türk, Frankie Thielen, Loic Leonard, and Bernd R. Schöne

Stream water oxygen isotopes are a powerful natural tracer of watershed functions (e.g., water collection, storage, mixing, and release). However, instrumental δ18Owater records have limited spatial coverage and rarely span over more than a decade. Long-lived (> 200 years) freshwater pearl mussels (Margaritifera margaritifera) are a promising natural archive for complementing these δ18O chronicles because their shells faithfully capture the isotope composition of the water in which the mussel lived. The reconstruction of reliable shell-based δ18Owater chronologies relies on several steps: (i) identifying which layer of the shell biomineralizes in thermodynamic equilibrium with the ambient water, (ii) determining the seasonal timing and rate of shell growth to assign each isotope sample to a precise calendar date, and (iii) employing a temperature record or temperature reconstruction to resolve the thermodynamic relationship between δ18Oshell and δ18Owater. First, we assessed the oxygen isotope fractionation between the ambient water and both sublayers of the outer shell layer, i.e., the outer prismatic and inner nacreous portion. We found that reconstructions based on δ18Oshell of the prismatic sublayer provided excellent δ18Owater data, whereas the nacreous portions showed evidence of growth rate-induced (kinetic) effects. Second, we carried out tank experiments to quantify temperature controls on biomineralization rates, constrain the seasonal timing and rate of shell formation, and construct a monthly resolved seasonal growth model. Third, we assessed the temperature sensitivity of shell ultrastructural properties and observed a poor relationship between water temperature and the nacre table thickness, strongly masked by pH fluctuations in stream water. Based on these findings, we have reconstructed sub-seasonal δ18Owater records of streams in Luxembourg, Germany and Sweden extending back to the early 19th century. These unprecedented reconstructions of stream water δ18O chronicles will open new vistas on multidecadal to centennial dynamics in the continental water cycle (e.g., for the assessment of watershed sensitivity to global change).

How to cite: Gey, C. J., Pfister, L., Türk, G., Thielen, F., Leonard, L., and Schöne, B. R.: Reconstructing stream water oxygen isotopes using freshwater pearl mussels (Margaritifera margaritifera): Toward an exploration of sub-seasonal watershed dynamics over the past 200 years, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1862, https://doi.org/10.5194/egusphere-egu24-1862, 2024.

Q&A
11:45–11:55
|
EGU24-3059
|
ECS
|
On-site presentation
Monika Doubrawa, Peter Stassen, Marci M. Robinson, Robert P. Speijer, and Johan Vellekoop

The Mg/Ca ratio of foraminiferal tests is widely used to reconstruct seawater temperature in past climates. With traditional methods (i.e. Inductively Coupled Plasma Optical Emission Spectrometry or ICP-OES), multiple tests have to be clustered together to attain enough material for analysis. The need for high amounts of carbonate can be problematic for shelf sediments if suitable foraminifera are scarce. As a consequence, grouping of different taxa into one bulk value or ‘sample grouping’ is applied, losing information on interspecific and intra-specimen geochemical variability. Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) solves this problem by targeting extremely small surfaces, e.g., single foraminifer tests or even single chambers.

Nevertheless, understanding LA-ICP-MS-generated foraminiferal Mg/Ca records requires in-depth knowledge on the growth and reproductive cycle of extinct foraminiferal taxa, such as Cibicidoides sp. and Anomalinoides acutus from the Paleocene-Eocene transition and early Eocene. These species are commonly used for environmental reconstruction because they are thought to have incorporated the ocean water chemistry in equilibrium with their tests, yet not much is known about their life or precipitation cycle.

The reproductive cycle of modern benthic foraminifera ranges from a few weeks to a year, depending on species and size, requiring about a single day to precipitate a new chamber. This implies a potential change in geochemistry from chamber to chamber. Hence, LA-ICP-MS hypothetically allows for an extremely high-resolution, in situ Mg/Ca record across a year, or a precipitation season, if sufficient snapshots of chamber calcification moments are incorporated. As a result, a comparison of cyclic temperature changes on both annual (seasonal variations across individual specimens of a sample) and sub-millennial (variations across closely spaced samples) scale could be feasible. However, the complex growth of the foraminiferal test (e.g. layering due to overgrowth of older chambers) likely also results in geochemical variability within chambers.

Here we investigate the inter- and intra-chamber variability in Mg/Ca composition of extinct benthic foraminifera using LA-ICP-MS. We evaluate the resulting potential and risks stemming from inhomogeneous trace-element distribution in the tests. We utilize foraminiferal tests from shelves from the western North Atlantic and the North Sea Basin, covering a paleodepth transect (<150 m) during the early Eocene. The foraminiferal tests record not only the long-term global warming trend of the early Paleogene but also short temperature spikes during hyperthermals such as the Paleocene-Eocene Thermal Maximum.

How to cite: Doubrawa, M., Stassen, P., Robinson, M. M., Speijer, R. P., and Vellekoop, J.: Inter- and intra-chamber variability of trace elements in benthic foraminifera – potential and risks of LA-ICP-MS analyses, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3059, https://doi.org/10.5194/egusphere-egu24-3059, 2024.

Q&A
11:55–12:05
|
EGU24-5846
|
On-site presentation
Steffen Hetzinger, Jochen Halfar, and Alexandra Tsay

Greenland is particularly vulnerable to ongoing anthropogenic climate change and observational data document recent rapid mass loss of many of the Greenland Ice Sheet (GIS) glaciers. Mass loss of the GIS represents a major contributor to global sea level rise, but uncertainties in future projections are large. A recent acceleration in mass loss has been observed, with 2012 and 2018/19 record years documented by direct observations. However, estimates of melt variability and glacier runoff remain uncertain before the satellite era and the influence on surface ocean waters is unclear. In general, available observational records from high latitudes are sparse and short. Models require high-resolution data of past variability to resolve how fast the GIS reacts to warming.

Past climate can be reconstructed from natural proxy archives. In high latitudes, however, most proxy time series utilised to date come from indirect land-based proxies. Calcified coralline algae are important shallow-marine calcifiers that grow attached to the seafloor and have emerged as subannual-resolution climate recorders for the extratropics. By analyzing long-lived coralline algae from Disko Bay, West-Greenland, in close proximity to Jakobshavn Glacier, we address this data gap. Jakobshavn Glacier is one of the largest glaciers in Greenland and the single largest source of mass loss from the GIS over the last 20 years. Sclerochronological analysis and ultra-high-resolution laser ablation ICP-MS data from calcified coralline algae (Clathromorphum compactum) provide seasonally-resolved records that capture the impact of surface temperature warming and glacier runoff on coastal Arctic environments. Algal Ba/Ca ratios track past glacier-derived meltwater input to the ocean surface layer and we report an unprecedented nonlinear increase in Jakobshavn glacier runoff into Disko Bay in the last 20 years. Our chronology from southern Disko Bay sites shows a distinct increasing trend from the early 2000s, recording the acceleration of GIS glacier mass loss and matching recent years of record amounts of ice loss in satellite data. The rate of increase in Ba/Ca (a runoff proxy) is unprecedented over at least the last 100 years, highlighting the rising influence of global warming on Arctic coastal ecosystems. The new algal chronology provides a long-term perspective on high-resolution variability in Jakobshavn Glacier runoff into Disko Bay, extending before observations, and confirming model data.

How to cite: Hetzinger, S., Halfar, J., and Tsay, A.: Nonlinear 21st century increase of Greenland Ice Sheet runoff into Disko Bay surface water recorded by long-lived coralline algae, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5846, https://doi.org/10.5194/egusphere-egu24-5846, 2024.

Q&A
12:05–12:15
|
EGU24-6200
|
ECS
|
On-site presentation
Manlin Zhang, Jens Zinke, Arnoud Boom, Dieter Garbe-Schönberg, Takaaki Watanabe, and Daniel Frick

Over the past century, the Indian Ocean stands out as the fastest warming ocean in the world. Yet, the southwestern Indian Ocean (SWIO) faces challenges in acquiring in-situ observational data, both spatially and temporally. The limited availability of long term continuous high-resolution instrumental data in the SWIO hinders a comprehensive understanding of sea surface temperature (SST) variability and its intricate relationship with large-scale atmospheric and oceanic modes. This scarcity further hinders efforts to disentangle natural variability from anthropogenic influences. To address these limitations, we present a 335 yr continuous coral record of monthly SST reconstruction in the Indian Ocean based on proxy Sr/Ca, obtained from Ambodivahibe Bay, northeast of Madagascar.

Sampled from a strategic region under the control of the NW monsoon during austral summer and trade winds for the rest of the year, this unique long record provides insights into coral resilience in a coastal upwelling zone amidst the rapid pace of ocean warming, as well as long-term trade wind variability, which significantly impacts the temperature signature of the South Equatorial Current and the downstream Northeast Madagascar current (NEMC), subsequently influencing moisture delivery to the East African and Asian Monsoon regions.Our SST reconstruction uncovers annual to multidecadal variations in the tropical SWIO spanning from 1672 to 2007, highlighting the dynamic interplay between local and remote climate processes, each dominating at different time scales. Furthermore, this new record extends the existing coral Sr/Ca-SST monthly reconstructions in the SWIO back to the 17th century and underscores the enhanced capacity to reconstruct regional climate variability using proxy records from multiple sites. Particularly noteworthy is its ability to capture SST variations under the alternating influence of monsoon and trade winds. This new coral Sr/Ca record provides valuable initial SST reconstruction along the route of the NEMC, serving as an indicator of the long-term NEMC strength variability.

How to cite: Zhang, M., Zinke, J., Boom, A., Garbe-Schönberg, D., Watanabe, T., and Frick, D.: A 335-year Coral-Based Reconstruction of Sea Surface Temperature along the Route of the Northeast Madagascar Current in the Tropical Southwestern Indian Ocean, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6200, https://doi.org/10.5194/egusphere-egu24-6200, 2024.

12:15–12:30
Break
Lunch break
Chairpersons: Isabella Leonhard, Shirin N. Rahman, Daniele Scarponi
14:00–14:05
14:05–14:15
|
EGU24-11373
|
ECS
|
solicited
|
Highlight
|
On-site presentation
Simone Moretti, Alexandra Auderset, Curtis Deutsch, Ronja Schmitz, Lukas Gerber, Ellen Thomas, Valeria Luciani, Maria Rose Petrizzo, Ralf Schiebel, Aradhna Tripati, Philip Sexton, Richard Norris, Roberta d'Onofrio, James Zachos, Daniel Sigman, Gerald Haug, and Alfredo Martínez-García

Ocean’s oxygen (O2) is essential to most marine life forms and represent a fundamental component of the biogeochemical cycling of nitrogen and carbon. Its inventory is declining in response to global warming. Contrasting predictions about the future of the tropical oxygen deficient zones (ODZs) in numerical simulations and palaeoceanographic evidence for contracted ODZs during Cenozoic’s warmest periods, make long-term predictions about the future of ocean O2 challenging. We present new evidence for tropical ocean oxygenation during the Paleocene-Eocene Thermal Maximum (PETM), a rapid warming event that serves as a geologic analogue to ongoing warming. Foraminifera-bound nitrogen isotopes indicate that the tropical North Pacific ODZ contracted during the PETM, implying higher O2. Metabolic modelling of aquatic ectotherms shows that a concomitant increase in planktic foraminifera size implies that seawater oxygen partial pressure (pO2) rose in the shallow subsurface throughout the tropical North Pacific, beyond the spatial extent of the ODZs. These findings call for an oceanographic mechanism capable of both enhancing subsurface oxygenation and operating beyond the regional scale of the North Pacific ODZs, on millennial timescales. These divergent changes are consistent with Ocean General Circulation Models under SSP5-8.5 scenario for 2300, in which a decline in biological productivity allows tropical subsurface oxygen to rise even as global ocean oxygen declines. The tropical upper ocean oxygen increase may have relieved physiological stress, helping to avoid a mass extinction in planktic organisms during the PETM, in spite of the largest benthic extinction of the Cenozoic.

How to cite: Moretti, S., Auderset, A., Deutsch, C., Schmitz, R., Gerber, L., Thomas, E., Luciani, V., Petrizzo, M. R., Schiebel, R., Tripati, A., Sexton, P., Norris, R., d'Onofrio, R., Zachos, J., Sigman, D., Haug, G., and Martínez-García, A.: Foraminifera nitrogen isotopes and body size reveal an oxygen rise in the tropical upper ocean during the Paleocene-Eocene Thermal Maximum (PETM), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11373, https://doi.org/10.5194/egusphere-egu24-11373, 2024.

14:15–14:20
14:20–14:30
|
EGU24-413
|
ECS
|
On-site presentation
Eileen Straube, Manuel Steinbauer, Seth Finnegan, and Gregor Mathes

Climate change is one of the main drivers for the wave of species extinctions predicted for this century. IPCC extinction risk assessments are based in part on predicted climate-driven reductions in the geographic ranges of focal species (range loss). This builds on the well-established IUCN (2022) Red List criterion, in which a species is considered critically endangered (>50% extinction risk) if it loses ≥80% of its geographic range. However, while there is clear evidence that extinction risk is related to the absolute geographic range of a species, the empirical relationship between range loss and extinction risk is not well understood. Using fossil evidence of true extinctions over the past 23 million years, with 2600 range change observations of 1215 marine genera, this study implements a Bayesian hierarchical weighted generalized additive model to investigate how extinction risk changes with the percentage decrease in geographic range of a genus. Results clearly indicate how extinction risk increases non-linearly with range loss. Taxon dependent differences in the relationship between extinction risk and range loss indicate great potential for adapting its application in extinction risk predictions and the IUCN criteria.

How to cite: Straube, E., Steinbauer, M., Finnegan, S., and Mathes, G.: Predicting extinction risk by range loss: Evidence from the fossil record, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-413, https://doi.org/10.5194/egusphere-egu24-413, 2024.

Q&A
14:30–14:40
|
EGU24-13312
|
On-site presentation
Adam Tomašových, Michał Kowalewski, Rafał Nawrot, Daniele Scarponi, and Martin Zuschin

Species diversity increases with time averaging according to the species-timespan relation. This scaling effect can exaggerate geographic or temporal variability in diversity because the time averaging of fossil assemblages can vary by several orders of magnitude owing to variability in sedimentation, mixing and/or disintegration, and thus can affect analyses focusing on the detection of baseline and novel community states in the Holocene stratigraphic record or in live-dead comparisons. However, the relation between abundance and sample size-independent diversity can be used to detect the fingerprints of time averaging. A decrease in sediment accumulation rate should lead to higher abundance and diversity, and the relation is thus expected to be positive. Consistently with this hypothesis, we find that sedimentation rates in the Holocene record of the northern Adriatic correlate negatively with abundance and diversity. Moreover, as sedimentation rates decrease, correlation between abundance and diversity becomes increasingly positive. This scaling-induced relation differs from a negative abundance-diversity relationship observed in living (non-averaged) communities. We suggest that the positive abundance-diversity relation will be a diagnostic of scenarios where variability in fossil abundance and diversity is determined by temporal scaling controlled by variability in sediment accumulation rate rather than by variability in natural or anthropogenic processes.

How to cite: Tomašových, A., Kowalewski, M., Nawrot, R., Scarponi, D., and Zuschin, M.: Assessing abundance-diversity relationship in the context of time-averaging: implications for evaluating baseline and novel states in conservation paleobiology, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13312, https://doi.org/10.5194/egusphere-egu24-13312, 2024.

Q&A
14:40–14:50
|
EGU24-14914
|
On-site presentation
Martin Zuschin, Rafał Nawrot, Markus Dengg, Ivo Gallmetzer, Alexandra Haselmair, Michal Kowalewski, Daniele Scarponi, Sandra Wurzer, and Adam Tomašových

Predation can play an important role in shaping marine ecosystems, but we often lack long-term baseline data that would allow for tracking how predator-prey interactions have responded to increasing anthropogenic impact. Here, we assess temporal changes in benthic community composition and interactions between drilling predatory gastropods and their molluscan prey using the Holocene fossil record of the northern Adriatic Sea (NAS), a shallow shelf characterized by a long history of human transformation of coastal and deltaic ecosystems. Molluscan assemblages differ between the Isonzo and Po prodeltas but both regions show consistent temporal trends in the abundance of dominant species. Samples of mollusc prey collected at high stratigraphic resolution indicate that drilling frequencies have drastically declined in the prodelta of the Po River since the mid-20th century, while a weaker trend in more condensed sediments of the Isonzo delta is not statistically significant. The decrease in drilling predation intensity and the community turnover is related to the loss of predatory gastropods, decreased abundance of preferred and increased abundance of less-preferred prey organisms, and a rapidly progressing infaunalization observed in the northern Adriatic basin during the most recent decades. Our results align with data showing the substantial depletion of marine resources at higher trophic levels in the NAS and indicate that the strong simplification of the food web since the late 19th century accelerated since the mid-20th century.

How to cite: Zuschin, M., Nawrot, R., Dengg, M., Gallmetzer, I., Haselmair, A., Kowalewski, M., Scarponi, D., Wurzer, S., and Tomašových, A.: Anthropocene breakdown of predator-prey interactions in the northern Adriatic Sea, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14914, https://doi.org/10.5194/egusphere-egu24-14914, 2024.

Q&A
14:50–15:00
|
EGU24-17776
|
ECS
|
Virtual presentation
Rafał Nawrot, Melita Peharda, Saskia Macharia, Hana Uvanović, Adam Tomašových, and Martin Zuschin

Changes in life history of marine species in response to harvesting and human-induced environmental changes are frequently observed in modern ecosystems, but the true magnitude of these shifts is difficult to evaluate without robust information on the pre-impact state of the affected populations. The edible bivalve Noah’s Ark shell (Arca noae L.) is commercially exploited in the eastern Adriatic Sea, where its fishery rapidly expanded during the first half of the 20th century until a mass mortality in the late 1940s caused a population collapse. In spite of partial recovery, the lack of data on growth parameters of this species prior to that event complicates establishing sustainable levels of harvesting. To provide a baseline for assessment of the current state of populations of A. noae we compared modern and fossil (middle to late Holocene) specimens from the northern Adriatic Sea using samples from benthic surveys and sediment cores. Estimates of growth and longevity were based on annual shell growth lines visible in acetate peel replicas of the umbo and outer prismatic shell layer. The maximum lifespan observed in our modern samples was 35 years – a full decade longer than previously documented for this species. However, this estimate was still much shorter than the lifespan of multiple fossil specimens, among which the ontogenetically oldest one reached the age at least 85 years. Our results indicate that modern individuals of A. noae grow faster and have shorter lifespan compared to their Holocene counterparts, suggesting that harvesting pressure combined with increasing water temperatures and eutrophication of the northern Adriatic Sea had a significant impact on the population dynamics of this species.

How to cite: Nawrot, R., Peharda, M., Macharia, S., Uvanović, H., Tomašových, A., and Zuschin, M.: Changes in growth and longevity of the exploited bivalve Arca noae in the northern Adriatic Sea: a conservation paleobiology perspective, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17776, https://doi.org/10.5194/egusphere-egu24-17776, 2024.

Q&A
15:00–15:10
|
EGU24-18785
|
On-site presentation
Daniela Basso, Roberta Dessi, Riccardo Racis, Sandro Demuro, Carla Buosi, Andrea Preda, and Valentina Alice Bracchi

Mollusks and benthic foraminifera are reliable tools to paleo-environmental reconstructions because they commonly occur in most marine habitats and are sensitive to major and short-lived changes of environmental drivers, induced by both natural and anthropogenic events. Their community structure provides useful information about the characteristics of their habitat and some species are sensitive to specific environmental controls. Features such as changes in species composition and community, or variation in test morphology provide evidence of fluctuation of several environmental factors. Therefore, both mollusks and benthic foraminifera can be used as an efficient method for identifying the history and ecological trajectory of marine ecosystems.

This study focuses on the macro- (mollusks) and micropaleontological (benthic foraminifera) study of a 3 m long sediment core collected in the former military arsenal of the La Maddalena harbor (N Sardinia, Italy), at a depth of 15 m. The core site is located on the S-E coast of La Maddalena island, that underwent a complex history of human occupation along with natural environmental evolution and human-derived pressures. We aimed to reconstruct the main environmental changes recorded in the fossil benthic communities along the core, and to propose the most likely factors that caused these changes. Both mollusks and benthic foraminifera have been picked from the core, identified at genus/species level and counted. Ecological indications for each species have been extracted from literature. Univariate and multivariate statistics have been applied to highlight the community dynamics.

More than 90 species of benthic foraminifera have been identified, and 101 mollusk species (846 specimens). The foraminifera diversity indices show a general reduction from the first 50 cm downcore. This slight decline is accompanied by changes in foraminiferal assemblages. The results concerning changes in foraminiferal species composition, their abundance and biodiversity, supported by statistical analyses (cluster analysis), allowed identification of three major foraminiferal associations corresponding to different marine coastal settings. The same results have been obtained by using mollusks and their ecological significance in the framework of benthic marine bionomics. Species are related to infralittoral vegetated bottom such as Posidonia meadows (HP) or photophilous algae through the core, but with variation in percentage of abundance, and HP species decreases from the bottom to the top, whereas species related to muddy bottom follow the opposite trend (coastal detritic mud, deep mud). This testifies that the area underwent a progressive reduction of Posidonia meadows and light-loving algae with a shift toward muddy bottoms, possibly related to the effect of the intensive renovation works of the harbor area. Moreover, radiocarbon dating obtained from Cerithium specimens indicated that the sedimentation rate increases in the upper portion of the core, according to the ecological signal reconstructed by the analysis of the mollusk assemblage.

How to cite: Basso, D., Dessi, R., Racis, R., Demuro, S., Buosi, C., Preda, A., and Bracchi, V. A.: Recent environmental changes in the area of La Maddalena Harbour (Sardinia, Italy): data from mollusks and benthic foraminifera, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18785, https://doi.org/10.5194/egusphere-egu24-18785, 2024.

Q&A
15:10–15:20
|
EGU24-13217
|
Highlight
|
On-site presentation
Aaron O'Dea, Brigida De Gracia, Kimberly García-Méndez, Jonathan Cybulski, Jessica Lueders-Dumont, and Erin Dillon

Predatory fishes are expected to regulate the abundances and body sizes of prey fishes on coral reefs, which may, in turn, have cascading effects across the food web. However, such top-down processes have been challenging to test, especially on Caribbean reefs where predator communities have been altered by centuries of selective harvesting, and therefore potentially function differently. To address this shifting baseline problem, we used Holocene fossil, archeological and modern fish remains (5758 otoliths and 807 shark denticles) to track changes in the relative abundances and body sizes of fishes of different functional and trophic modes on Caribbean reefs in Panama and the Dominican Republic over millennia. Piscivorous fish declined in relative abundance by 50-70% and became smaller since major human exploitation, which would have resulted in a decline in predation intensity since prehistoric times. In contrast, prey fishes like anchovy and damselfish became more abundant and larger over the same time period, consistent with a release from predation. Cryptobenthic fishes showed no change in body size or abundance over time, most likely because they are protected from predation and are controlled to a greater extent by habitat and food availability than predation. Our data support the hypothesis that predator loss has precipitated a release from predation for certain prey fish species, and yet despite this, some important facets of reef function have remained resilient over time.

How to cite: O'Dea, A., De Gracia, B., García-Méndez, K., Cybulski, J., Lueders-Dumont, J., and Dillon, E.: Fossil otoliths reveal changing predator-prey dynamics and partial resilience in reef fishes, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13217, https://doi.org/10.5194/egusphere-egu24-13217, 2024.

Q&A
15:20–15:30
|
EGU24-9773
|
ECS
|
On-site presentation
Hannah Sellers, Juan Carlos Berrio, Mark Williams, Richard Jones, Stefano De Sabbata, Angharad Evans, Andy Neilson, and Moya Burns

Woodlands in the British landscape have been reduced to fragments and continue to decline in species diversity. In the heavily human-modified landscape of the English Midlands, Ancient Semi-Natural Woodland sites have undergone various human disturbance, including extensive modification such as clear-felling in the 20th century. Through the integration of information from the fossil pollen record, place-name evidence of past vegetation cover, archaeological records and recent botanical surveys, we examine the patterns of past resilience of woodlands to environmental disturbances, to understand more about their current status and future concerns to ensure the persistence of these now rare, socially and ecologically important habitats. 
 
By adopting an interdisciplinary approach, we examine multiple sites across the English counties of Leicestershire and Rutland as case studies, integrating the different spatiotemporal datasets to provide new insights. The methodology aims to identify regions that have maintained long-term, stable woodland cover and to elucidate how ecosystems have changed and recovered after natural environmental or anthropogenic disturbances over the past 8,000 years and including more recent changes in the Anthropocene. Environmental change including deforestation and reforestation events have been identified with further details about the anthropogenic influence being provided by the historical (place-name evidence) and archaeological records. Our analysis is targeted at developing a replicable, spatiotemporal framework to identify future resilient woodland ecosystems in a time of Anthropocene environmental change, and to inform local policy and conservation efforts.

How to cite: Sellers, H., Berrio, J. C., Williams, M., Jones, R., De Sabbata, S., Evans, A., Neilson, A., and Burns, M.: An interdisciplinary approach to understanding British resilient woodlands in an Anthropocene landscape, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9773, https://doi.org/10.5194/egusphere-egu24-9773, 2024.

15:30–15:35

Posters on site: Wed, 17 Apr, 16:15–18:00 | Hall X3

Display time: Wed, 17 Apr 14:00–Wed, 17 Apr 18:00
Chairpersons: Isabella Leonhard, Niels de Winter, Shirin N. Rahman
X3.110
|
EGU24-2804
|
ECS
|
Highlight
Nanyu Zhao, Hong Yan, Fan Luo, Yuanjian Yang, Shan Liu, Pengchao Zhou, Chengcheng Liu, and John Dodson

Tropical cyclones (TC) are one of the most destructive weather phenomena on Earth. However, the short duration of instrumental weather records means that little is known of the frequency of TCs through geological time. Here we analyse a Tridacna squamosa shell with a life span about 6 years (from 12 May 2013 to 18 December 2018) from the northern South China Sea. Studies of daily growth rate variations (DGRV) were correlated with coeval environmental changes to develop a proxy for TC. Results reveal that the frequency and variation of extreme DGRV were conspicuously different between the typhoon-affected season (July to October) and the relatively stable growth season (March to June). During the typhoon-affected season, the frequency of sudden onset of decreased sea surface temperature, attenuated solar radiation and heavy precipitation can result in more days for extreme decreases of DGRV. On interannual timescale, the frequency of extreme DGRV was significantly correlated with TC influence days. Our findings indicate that the frequency of extreme DGRV profile in Tridacna squamosa shells has potential to be a novel recorder for past TC activity. We conclude that fossil shells in different geological eras offer the potential to extend modern instrumental datasets and provide opportunities for investigating TC activity in response to past and future global change.

How to cite: Zhao, N., Yan, H., Luo, F., Yang, Y., Liu, S., Zhou, P., Liu, C., and Dodson, J.: Daily growth rate variation in Tridacna shells as a record of tropical cyclones in the South China Sea: Palaeoecological implications, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2804, https://doi.org/10.5194/egusphere-egu24-2804, 2024.

X3.111
|
EGU24-2805
|
ECS
Chengcheng Liu, Hong Yan, Pengchao Zhou, Guozhen Wang, Nanyu Zhao, and Tao Han

The annual temperature cycle is an important component of the Earth’s climate system. Here, the multiple snapshots sea surface temperature (SST) seasonality during past ~1600 years of northern South China Sea were reconstructed using monthly resolved δ18O and Sr/Ca profiles of fossil Tridacna and  coral skeletons. The results showed SST seasonality in northern SCS was contrary to temperature of China mainland and West Pacific Warm Pool, with a large seasonality during cold period (Little Ice Age, Dark Ages Cold period) and a small seasonality during warm period (Medieval Climate Anomaly). During Little Ice Age and Dark Ages Cold periods, strong East Asia Winter Monsoon (EAWM) and La Niña-like state of tropical Pacific Ocean promote a cold winter, and thus induce a large SST seasonality of northern SCS. During the Medieval Climate Anomaly, weak East Asia Winter Monsoon (EAWM) and El Niño-like state of tropical Pacific Ocean promote a warm winter, and thus induce a small SST seasonality of northern SCS.

How to cite: Liu, C., Yan, H., Zhou, P., Wang, G., Zhao, N., and Han, T.: Seasonality in northern South China Sea during the late Holocene, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2805, https://doi.org/10.5194/egusphere-egu24-2805, 2024.

X3.112
|
EGU24-7323
|
ECS
Niels de Winter, Iris Arndt, Philippe Claeys, René Fraaije, Najat al Fudhaili, Steven Goderis, John Jagt, Matthias López Correa, Axel Munnecke, Jarosław Stolarski, Frank Vanhaecke, and Martin Ziegler

Earth’s climate history serves as a natural laboratory for testing the effect of (very) warm climates on the biosphere. The Cretaceous period featured prolonged intervals of greenhouse climates characterized by high atmospheric CO2 concentrations and mostly ice-free poles (O’Brien et al., 2017; Ladant and Donnadieu, 2016). In such a climate, shallow seas in low latitudes likely became very hot, especially during the summer (Jones et al., 2022; de Winter et al., 2021). At the same time, life seems to have thrived there in reef-like ecosystems built by rudists, an extinct group of bivalve mollusks (Gili and Götz, 2018). The summer temperatures documented for these ecosystems exceed the maximum tolerable temperatures of any marine mollusk alive today, which raises the question how these animals adapted to more extreme temperatures.

Studying the growth of these ancient organisms and the extreme climate conditions they faced can yield valuable insight into the resilience of marine ecosystems to climate change. To tackle this climate resilience conundrum, we present a detailed sclerochronological (incrementally sampled) dataset of daily to seasonal scale variability in shell chemistry from fossil mollusks from a Campanian (75-million-year-old) low-latitude shallow marine ecosystem. With it, we investigate the extreme climate conditions these animals lived through and how this affected their growth or even the paleo-weather patterns they experienced. The goal of this study is to demonstrate how high-resolution geochemical records through fossil mollusk shells can shed light on the variability in past warm ecosystems and open the discussion about the limits of life in the shallow marine realm during a greenhouse climate.

 

Gili, E. and Götz, S.: Treatise Online no. 103: Part N, Volume 2, Chapter 26B: Paleoecology of rudists, 1, https://doi.org/10.17161/to.v0i0.7183, 2018.

Jones, M. M., Petersen, S. V., and Curley, A. N.: A tropically hot mid-Cretaceous North American Western Interior Seaway, Geology, 50, 954–958, https://doi.org/10.1130/G49998.1, 2022.

Ladant, J.-B. and Donnadieu, Y.: Palaeogeographic regulation of glacial events during the Cretaceous supergreenhouse, Nat Commun, 7, 12771, https://doi.org/10.1038/ncomms12771, 2016.

O’Brien, C. L., Robinson, S. A., Pancost, R. D., Sinninghe Damsté, J. S., Schouten, S., Lunt, D. J., Alsenz, H., Bornemann, A., Bottini, C., Brassell, S. C., Farnsworth, A., Forster, A., Huber, B. T., Inglis, G. N., Jenkyns, H. C., Linnert, C., Littler, K., Markwick, P., McAnena, A., Mutterlose, J., Naafs, B. D. A., Püttmann, W., Sluijs, A., van Helmond, N. A. G. M., Vellekoop, J., Wagner, T., and Wrobel, N. E.: Cretaceous sea-surface temperature evolution: Constraints from TEX 86 and planktonic foraminiferal oxygen isotopes, Earth-Science Reviews, 172, 224–247, https://doi.org/10.1016/j.earscirev.2017.07.012, 2017.

de Winter, N. J., Müller, I. A., Kocken, I. J., Thibault, N., Ullmann, C. V., Farnsworth, A., Lunt, D. J., Claeys, P., and Ziegler, M.: Absolute seasonal temperature estimates from clumped isotopes in bivalve shells suggest warm and variable greenhouse climate, Commun Earth Environ, 2, 1–8, https://doi.org/10.1038/s43247-021-00193-9, 2021.

How to cite: de Winter, N., Arndt, I., Claeys, P., Fraaije, R., al Fudhaili, N., Goderis, S., Jagt, J., López Correa, M., Munnecke, A., Stolarski, J., Vanhaecke, F., and Ziegler, M.: Living on the edge: How did shallow-marine ecosystems thrive during hothouse climates?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7323, https://doi.org/10.5194/egusphere-egu24-7323, 2024.

X3.113
|
EGU24-7846
|
ECS
Anthea Willems, John W. M. Jagt, and Johan Vellekoop

Because our modern world is characterized by climate change, it is useful to study climate conditions of past greenhouse worlds in order to obtain a better understanding of what a similar world would entail. An example of such a past greenhouse climate is represented by the Late Maastrichtian Warming Event (LMWE), a global temperature increase of approximately 2.5-5°C that occurred 300-100 kyr prior to the Cretaceous-Paleogene boundary meteorite impact and the ensuing mass extinction. This warming event has traditionally been linked to a major pulse of Deccan Traps volcanism. Previous research has also recorded the LMWE in the Maastrichtian type region (SE Netherlands, NE Belgium), where this event is marked by characteristic blooms of the dinoflagellate Palynodinium grallator and a sudden appearance of hermatypic corals. A recent study using clumped-isotope analyses on fossil bivalves has shown that the LMWE was characterized by a 5 degrees warming in average annual sea water temperatures in this region (40° paleolatitude). However, little is known about changes in seasonality across this warming event, as high-resolution paleoseasonality reconstructions have not been previously attempted. Here, we present a seasonal, stable-isotope record through the LMWE for the Maastrichtian type area (SE Netherlands, NE Belgium), using stratigraphically well-constrained oyster specimens. This new record contributes to our understanding of the effects of a global warming event on seasonality in a mid-latitude shelf sea. Consistent with previous results, we have found a decreasing trend in δ18O values in the interval corresponding to the peak of the warming event, followed by an increase during the cooling-down period. Our results show that the LMWE also had profound effects on the seasonality in the Maastrichtian type area. The δ18O seasonality temporarily decreased at the onset of the event, suggesting that winter temperatures warmed disproportionately. Possibly, this could have allowed the previously recorded establishment of hermatypic corals in the region. Subsequently, seasonality increased again through the warming event, with the highest seasonality recorded in the later part of the event. Over the coming months, additional oyster specimens will be assessed for both stable and clumped isotopes to obtain a more complete record of seasonality throughout the LMWE.

How to cite: Willems, A., Jagt, J. W. M., and Vellekoop, J.: High-resolution paleoseasonality records across the Late Maastrichtian Warming Event (Late Cretaceous) as revealed by oyster shells from the Maastrichtian type area (SE Netherlands, NE Belgium), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7846, https://doi.org/10.5194/egusphere-egu24-7846, 2024.

X3.114
|
EGU24-8293
|
ECS
Beau Luiten, Emilia Jarochowska, Lonneke IJsseldijk, and Helen King

Whales are critical organisms in the ocean ecosystems, but direct and indirect human impact has decimated their populations. Because whales have long lifespans and migrate over large areas, there is no ecological baseline to evaluate their population dynamics. However, such information is available in fossil whale remains. Geoscientific expertise can aid conservation by interpreting proxy values from the most chemically stable tissue: their teeth. In this project we focus on North Atlantic toothed whales from the late Pleistocene on, with the aim to reconstruct their migrations and ecologies.

Whale teeth contain information about both the individual and its environmental conditions, depending on the proxy that is evaluated. An integrative methodology was developed to be applied on modern and fossil specimens. This includes oxygen isotope analysis to reconstruct migration and bathymetric niches, Sr/Ca and Ba/Ca ratios to assess trophic position and dietary patterns, and Raman spectroscopy for elemental composition and crystallography. Additionally, Scanning Electron Microscopy (SEM) enables growth analysis and measurements of chemical composition through EDX. However, fossil teeth in a marine environment might be altered by diagenesis, making their proxy values unrealistic and not comparable with modern values. By quantifying these changes we can identify and correct for altered proxy values: thus allowing reconstruction of ecologies.

In this initial phase of the project the modern teeth have been analysed using Raman spectroscopy and SEM. Notably, Raman has shown that both the enamel and cementum can be used to produce reliable spectra, while the dentine does not allow this. Chemical composition from the EDX can be assessed over growth layers and correlated with the Raman results. We provide an interdisciplinary framework to assess multiple proxies found in fossil and modern teeth, using geochemical methods to answer biological questions. In addition, we utilize physiological data obtained from stranded individuals whose teeth were sampled, along with historical records of whale populations. There is a large emphasis on anthropogenic impact, by evaluating specimens along a timeline for impact of fishing, whaling, climate change and pollution.

How to cite: Luiten, B., Jarochowska, E., IJsseldijk, L., and King, H.: Whale teeth as witnesses: assessing anthropogenic impact on whale ecology through a multi-proxy analysis, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8293, https://doi.org/10.5194/egusphere-egu24-8293, 2024.

X3.115
|
EGU24-8416
|
ECS
Jingjing Guo, Xiulan Zong, Wenru Yang, Jibao Dong, Niels de Winter, Hong Yan, Yougui Song, Youbin Sun, Francien Peterse, and Martin Ziegler

Quantitative reconstructions of past precipitation and temperature variations at the seasonal scale are essential for understanding East Asian Monsoon (EAM) dynamics. However, archives capable of capturing seasonal climate signals on land are limited. Here, we present high-resolution stable oxygen isotope (δ18Oshell) and carbonate clumped isotope (Δ47) data from modern and fossil land snail shells collected from the eastern (Lingbao, LB) and western (Yuanbao, YB) edge of the Chinese Loess Plateau (CLP).

The δ18Oshell of modern snails similarly reflect the seasonal variation in precipitation oxygen isotopic signals at both locations. The Δ47-derived temperatures for the same snails indicate that the seasonal temperature difference (summer vs. winter) is larger at YB than LB, aligning with modern observations from the western edge of the CLP, where a higher elevation results in a larger seasonality. The averaged whole shell Δ47-derived temperatures (T47) from modern Cathaica pulveritrix shells at LB and their related Cathaica richthofeni snails at YB resemble growing season temperatures. Interestingly, the T47 of shells of three smaller snail species, Pupilla muscorum, Kaliella lamprocystis, and Vallonia sp. are substantially (up to 10 ºC) lower than those of C. richthofeni from the same site. The temperature difference between snail species and among specimens suggests that optimal living conditions and micro-environments likely play a key role in the temperature signal recorded in the snail shells.

Fossil snails from LB show a larger variability in δ18Oshell  during the Last Glacial Maximum (LGM, 19–18 ka), with wet season values approximately 3‰ more depleted than modern shells. In contrast, the seasonal temperature difference in fossil snails is smaller than in their modern counterparts, and growing season temperatures are ~10 °C lower than the present at LB. Fossil shells from YB also have a more negative δ18Oshell during the last deglaciation (14‒13 ka) than their modern counterparts. Similar to LB snails, the whole shell T47 of fossil snail shells at YB indicates that growing season temperatures were ~10 °C lower than recorded by their modern counterparts, and the temperature variability on a seasonal scale is smaller than in modern snails. The relatively large variability, negative δ18Oshell values and low T47 values in fossil shells suggests weaker evaporation or longer water vapor transportation under glacial conditions. While snail shells can capture high-resolution climate signals, variations in living conditions and micro-environments among snail species and specimens should be considered in future Δ47-based temperature studies and their applications.

How to cite: Guo, J., Zong, X., Yang, W., Dong, J., de Winter, N., Yan, H., Song, Y., Sun, Y., Peterse, F., and Ziegler, M.: Seasonal scale records of hydroclimate and temperature derived from clumped isotopes of land snail shells from the Chinese Loess Plateau , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8416, https://doi.org/10.5194/egusphere-egu24-8416, 2024.

X3.116
|
EGU24-9658
Daniele Scarponi, Matilde Cervellieri, Gaia Crippa, Rafael La Perna, Angela Girone, Patrizia Maiorano, and Maria Marino

Conservation paleobiology (CP) is a relatively new, synthetic field of research that combines paleontology theories and analytical methods to address current issues related to conserving and managing biodiversity and understanding long-term present-day ecosystem dynamics.  

This research focuses on the latter aspect of CP and investigates how macrobenthic communities have responded to climate change in the past in the Pleistocene marine setting of Montalbano Jonico (Bradanic Trough, southern Italy). Specifically, being a SABS, the Montalbano Jonico Ideale Section presented a significant opportunity to explore past macrobenthic environmental dynamics of shelf marine environments in a data-rich and well-known environmental and stratigraphic framework.

We quantified responses of shelf macrobenthic assemblages to long-term climate changes using 29 samples (∼ 3,975 fossil remains) retrieved along the SABS, deposited between MIS 20 and MIS 18. Previously established paleo-bathymetric reconstructions indicate shelf environments during cold periods (glacials and stadials), which alternated with deeper settings (outer shelf/slope) during warmer phases (interstadials), reflecting the orbitally-driven climate shifts registered by stable oxygen isotopes.

Shelf macrobenthic assemblages naturally alternated between two states over observed long-term climate oscillations. Cold climate faunas were characterized by lower species richness and negligible abundance of species exclusive to the Mediterranean-to-Lusitanian regions compared to warm interstadial assemblages. The high similarity between cold climate assemblages and the distinct composition and abundances of interstadial faunas suggests that, over millennial timescales, shelf benthic assemblages have been primarily structured by environmental forcing, proving either remarkable resilience or persistence in the face of significant environmental and climatic perturbations.

In addition, being the interglacial MIS 19 a climate analog for future climate change, paleobiologic features (e.g., standardized richness or amount of most abundant taxa) might serve as an ecological baseline for the near future.

While biomonitoring, ecological data, and strategies are the main avenues for conservation and ecosystem management, conservation paleobiological approaches can provide unique insights from the recent past into biodiversity dynamics and ecosystem structure of present-day ecosystems that would have otherwise gone unnoticed.

How to cite: Scarponi, D., Cervellieri, M., Crippa, G., La Perna, R., Girone, A., Maiorano, P., and Marino, M.: Conservation paleobiology of the Montalbano Jonico succession (southern Italy): A Standard Auxiliary Boundary Stratotype (SABS) for the Middle Pleistocene of the Quaternary System, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9658, https://doi.org/10.5194/egusphere-egu24-9658, 2024.

X3.117
|
EGU24-9755
Johan Vellekoop, Daan Vanhove, Inge Jelu, Philippe Claeys, Linda C. Ivany, Niels J. de Winter, Robert P. Speijer, and Etienne Steurbaut

Stable isotope sclerochemistry of mollusks and otoliths is key in reconstructing temperature and seasonality in past greenhouse climates. It is therefore crucial to understand the paleoecology and –environment of these organisms, and how these factors influence intra-and inter-taxon isotope variability and variation. To gain more insights in these factors, we measured seasonal changes in δ18O and δ13C compositions in multiple specimens of two carditid bivalve species, a turritelline gastropod species, and two species of otoliths from demersal fish, from two successive early Eocene (latest Ypresian, 49.2 Ma) coquinas in the inner neritic Aalter Sand Formation, located in the Belgian part of the southern North Sea Basin (paleolatitude ~41°N). Results demonstrate variability among taxa in average, amplitude and shape of intra-annual δ18O and δ13C values. This intertaxon variability is at least partly caused by growth cessation during winters in turritellines and otoliths, leading to an incomplete representation of the seasonal cycle in their growth increments, compared to carditid bivalves. Other contributing factors to isotopic variability include sedimentary transport, mobility, and the lifespan of the specimens. Specifically, ophidiid fish otolith isotope records appear to reflect environmental conditions over a wider range of habitats and environments, due to sedimentary transport and postmortem transport by free-swimming predatory fish. Our study therefore highlights the variability between different taxa and environments in the shallow marine realm, which has implications for seasonality reconstructions. Studying multiple taxa and specimens in a death assemblage provides a more complete spectrum of isotope variation and variability.

How to cite: Vellekoop, J., Vanhove, D., Jelu, I., Claeys, P., Ivany, L. C., de Winter, N. J., Speijer, R. P., and Steurbaut, E.: A comparison of bivalve, gastropod and fish otolith stable isotope profiles from the Aalter Sands, early Eocene southern North Sea Basin, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9755, https://doi.org/10.5194/egusphere-egu24-9755, 2024.

X3.118
|
EGU24-11757
|
ECS
Bettina Bachmann, Rafał Nawrot, and Martin Zuschin

The consequences of prolonged human stressors on populations of marine benthic species are generally difficult to assess due to the paucity of long-term monitoring data. The youngest fossil record, preserved in sediment cores and grab samples, provides a rich historical archive that allows tracking ecological responses to natural environmental changes and reconstructing the state of populations prior to the onset of anthropogenic impacts. However, most studies using these paleoecological records focus on microfossil- or mollusc assemblages, and only limited knowledge is available on the responses of other key components of marine ecosystems, such as echinoids. This study presents a novel record of well-preserved tests of the infaunal clypeasteroid Echinocyamus pusillus from Holocene marine sediment cores, which provide new insights into the long-term population dynamics and ecological responses of the widely distributed echinoid. We investigated trends in test size and abundance of E. pusillus and relate them to sedimentological conditions during the last ~11,000 years in the shallow northern Adriatic Sea, where coastal marine habitats have been under prolonged anthropogenic pressure. We combined these data with radiocarbon dating of multiple specimens to extract ecological signals from time averaged assemblages. The sediment cores and grab samples collected from four stations, which cover different benthic habitats, document environmental changes during the post-glacial transgression and the Holocene-Anthropocene transition, as evidenced by shifts in molluscan assemblages and geochemical proxy records. The data suggest significant fluctuations in E. pusillus abundance, but remarkably stable test sizes over the past millennia and across sampling stations. Moreover, the age-dating results indicate a paucity of dead tests originating from the late 19th and 20th centuries in the surface mixed layer. This points to a strong decline in test production and thus population densities over the past ~200 years. This pattern can be linked to pronounced environmental changes during the onset of the Anthropocene, including siltation, eutrophication, and increased frequency of hypoxic events. Rapid decline of populations during that time combined with temporal mixing of fossil assemblages may thus explain the overall lack of body size shifts observed in sediment cores. Our results provide a fundamental baseline for evaluating temporal and spatial changes in body size and abundance of E. pusillus in the northern Adriatic Sea. They can be compared with recent monitoring and fossil data from other areas and serve to disentangle natural population variability from responses to recent intensification of human impacts.

How to cite: Bachmann, B., Nawrot, R., and Zuschin, M.: Impact of Holocene environmental change on northern Adriatic populations of Echinocyamus pusillus, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11757, https://doi.org/10.5194/egusphere-egu24-11757, 2024.

X3.119
|
EGU24-12809
Celia Martin-Puertas, Laura Boyall, Armand Hernandez, Antti Ojala, Ash Abrook, Emilia Kosonen, Paul Lincoln, and Didier Swingedouw

Global warming is leading to more persistent boreal summers in the Northern Hemisphere, characterised by a longer season with more extreme heat waves. These seasonal changes have already led to many ecological and socio-economic implications. Statistical significance between summer weather persistence and its potential drivers is weak due to the short instrumental period, in turn preventing skilful predictions. In this study, we develop a new proxy for seasonal weather persistence based on varve thickness measurements to extend observations further back in time. We used two lakes, Nautajärvi in Finland and Diss Mere in England, which provide i) a continuous, seasonally resolved varved records that cover most of the Holocene Epoch; ii) a detailed understanding of the annual depositional varve model supported by lake monitoring, demonstrating that the seasonal sedimentation responds to summer and winter-type weather conditions; and iii) a consistent varve structure over the entire study period, so data are comparable through time. In both lakes, the varve model is made of two seasonal layers, representing the limnological summer and winter. The thickness of the seasonal layers indicate either the length of the season (i.e. longer period of sedimentation) and/or occurrence of extreme events (e.g. intensification of the sedimentological process). This agrees with the definition of seasonal weather persistence, which refers to either stationarity or recurrence of characteristic surface weather or atmospheric circulation of a season. In order to estimate the relative persistence of the summer and winter season over a year, we calculate the percentage of the winter and summer layers contributing to the varve (annual) thickness in the two lakes. Our results show that the early and late Holocene annual mean climate was controlled by winter weather variability, while the mid-Holocene has a predominant summer component. The Holocene winter-summer-winter weather pattern in Europe follows the evolution of the regional latitudinal temperature gradient (LTG) supporting current hypothesis that a weakening of the LTG in response to Global Warming is the origin of more persistent summers today.

How to cite: Martin-Puertas, C., Boyall, L., Hernandez, A., Ojala, A., Abrook, A., Kosonen, E., Lincoln, P., and Swingedouw, D.: Estimation of seasonal weather persistence during the Holocene from varved records, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12809, https://doi.org/10.5194/egusphere-egu24-12809, 2024.

X3.120
|
EGU24-15553
|
ECS
Isabella Leonhard, Emilia Jarochowska, Rafał Nawrot, Lovrenc Lipej, Konstantina Agiadi, and Martin Zuschin

Otoliths, the calcified biominerals in the inner ear of teleost fishes, provide a unique opportunity to investigate changes in growth parameters in historical fish populations as they are preserved in large numbers in marine sediments. They exhibit species-specific morphology and serve as life history archives, as they grow continuously in a concentric fashion by the accretion of alternating mineral- and protein-rich layers around a core, making them valuable for ecological and palaeontological studies. We employ sclerochronological analyses on otoliths from fish sampled alive as well as on radiocarbon-dated fossil otoliths derived from a sediment core off the coast of Piran, Slovenia. We want to verify the accuracy of historical growth patterns, which is fundamental to reconstructing reliable long-term chronologies and drawing meaningful conclusions about past fish growth dynamics. We focus here on the non-commercial but very common demersal species, the black goby (Gobius niger Linnaeus, 1758) which inhabits the Adriatic shelf regions in large numbers today and in the Holocene. We aim to test the hypothesis that growth rates and subsequently body sizes of these non-commercial fishes have undergone changes during the late Holocene and Anthropocene in the northern Adriatic Sea due to climate-induced environmental perturbations.

Before applying growth modeling to the fossil otoliths, it is crucial to ensure the preservation and reliability of the incremental record. Accordingly, we employ a comprehensive approach by comparing modern and Holocene gobiid otoliths using visual, structural and microchemical techniques. Our coupled approach includes light microscopy (LM), backscatter electron (BSE) imaging, electron backscatter diffraction (EBSD), and electron probe microanalysis (EPMA). We analyse macro- and micro-optical features, crystallographic structures, and chemical variations within the otolith incremental record. We use a novel technique to determine the geological ages of the fossil specimens in which we cut the otoliths in half, allowing sclerochronological analysis and radiocarbon dating on the same specimen.

Our visual and microchemical analyses revealed that key microincremental features are well preserved in the Holocene otoliths, enabling a direct comparison with modern counterparts. Despite occasional diagenetic alterations that potentially hinder incremental analysis in some of the Holocene specimens, bipartite incremental features, which are essential for growth analysis, are well preserved in both sets of otoliths. Additionally, visual and microchemical patterns indicate that modern otoliths exhibit partially vateritic structures.

Our study bridges the temporal gaps by directly comparing modern and fossil otoliths from the same species and study area. This approach reveals the hidden details in their microstructures and helps to establish a potential growth baseline for fish living in pre-industrial times. By examining historical fish size and growth patterns in populations living before significant human-induced environmental changes, we are providing insights into the effects of climate change on fish populations, which is important for fisheries management and conservation.

How to cite: Leonhard, I., Jarochowska, E., Nawrot, R., Lipej, L., Agiadi, K., and Zuschin, M.: Unveiling past and present fish growth patterns using an integrated structural, microchemical and geochronological analysis of modern and fossil otoliths , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15553, https://doi.org/10.5194/egusphere-egu24-15553, 2024.

X3.121
|
EGU24-17629
|
ECS
|
Lukas Schweigl, Rafał Nawrot, Adam Tomašových, and Martin Zuschin

Anthropogenic disturbances such as pollution, eutrophication and increased frequency of hypoxia led to profound changes in the abundances of marine species and overall community structure. They also led to changes in the population size structure of some species, a phenomenon still little understood. In this project, we use data from sediment cores to document long-term changes in population size structure of two common mollusc species of soft bottom communities of the northern Adriatic Sea (NAS): the bivalve Varicorbula gibba (Olivi, 1792) and the gastropod Turritellinella tricarinata (Brocchi, 1814) (= Turritella communis Risso, 1826). They are similar in their habitat preferences, but V. gibba is an opportunistic species with a higher tolerance of natural and anthropogenic disturbances. Ecological monitoring and analyses of sediment cores have shown that T. tricarinata was replaced by V. gibba as the dominant species of soft bottom communities in the NAS during the 20th century, probably due to increased eutrophication and a higher frequency of hypoxia. It has also been shown that V. gibba did increase in average size.

We test whether size changes have also occurred in T. tricarinata using material from sediment cores from the area off the Po delta in the western-, and Panzano and Koper Bays in the eastern NAS. The cores capture the last 150 to 7,000 years depending on the location. Measurements of shell length and width are used to analyze population size structure. Changes in sediment composition and geochemical proxies of pollution and eutrophication are studied as possible drivers of size changes and are placed in a chronological framework based on radiocarbon-dated shells.

Our preliminary results indicate that although abundance of T. tricarinata decreased throughout the region in the second half of the 20th century, shell length increased in some stations during that time. This pattern contrasts with the results of previous studies, which suggested that larger specimens of molluscs are more vulnerable to hypoxia. Our results may reflect complex interactions between nutrient enrichment and oxygen availability in controlling population dynamics of this species. However, more data are necessary to document long-term trends in population size structure driven by natural environmental change and to establish a baseline for size variability in T. tricarinata and V. gibba in the NAS prior to increased anthropogenic impact. Our study will provide a better understanding of how population size structure of marine benthic species changes in response to anthropogenic disturbances.

How to cite: Schweigl, L., Nawrot, R., Tomašových, A., and Zuschin, M.: Effect of Holocene environmental change on the size structure of mollusc indicator species of the northern Adriatic Sea, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17629, https://doi.org/10.5194/egusphere-egu24-17629, 2024.

X3.122
|
EGU24-22064
|
ECS
Matej Pavlović, Rafał Nawrot, Jan Steger, Borut Mavrič, and Martin Zuschin

The northern Adriatic Sea is one of the most degraded marine ecosystems worldwide and has been under anthropogenic influence for many centuries. Reconstructing pre-human impact benthic communities is vital to establish baseline conditions, allowing a better understanding of how anthropogenic activities and climate warming have influenced and altered marine ecosystems over time. This historical context helps to assess the extent of anthropogenic influence, guiding future conservation efforts and management strategies.

Our primary goal is to uncover the composition of pre-human impact benthic communities on the shallow shelf along the Slovenian coast (Gulf of Trieste) and to reconstruct the natural state of these habitats.

This investigation involved systematic grab sampling of subtidal soft substrates across three distinct areas, encompassing eight stations in the Bay of Koper and Bay of Piran, at water depths ranging from seven to ten meters. We focus on analyzing the composition of mollusc death assemblages, time-averaged accumulations of empty shells present in the uppermost mixed layer of seafloor sediments. Due to high durability of these skeletal remains and generally low sedimentation rates in shelf environments, death assemblages integrate shells over time spans of decades to millennia, making them valuable natural archives of past community states. Our results show that samples collected near the major port of Koper are strongly dominated by the opportunistic and stress-tolerant bivalve Varicorbula gibba, and show significantly lower species richness compared to stations located further away from this potential source of environmental disturbance. Moreover, assemblages from the protected area of the Debeli rtič are compositionally distinct from those of other areas. These patterns likely reflect the combined effects of differential levels of anthropocentric impacts, as well as differences in substrate characteristics and the magnitude of time averaging of the death assemblages among sampling stations.

The obtained community data will be cross-checked with live assemblage data based on the systematic benthic monitoring efforts conducted over the last 15 years (2005–2020) to ascertain changes in the mollusc community. The examination of modern and historic data will provide a robust long-term baseline that is essential for understanding and quantifying the impacts of significant human-induced modern stressors on the northern Adriatic marine ecosystem.

How to cite: Pavlović, M., Nawrot, R., Steger, J., Mavrič, B., and Zuschin, M.: Establishing ecological baselines for benthic communities in the southern Gulf of Trieste (northern Adriatic Sea) using molluscan death assemblages, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22064, https://doi.org/10.5194/egusphere-egu24-22064, 2024.

X3.123
|
EGU24-22193
John Huntley, Erin Fitzgerald, Ryan Delaney, and Daniele Scarponi

Parasites play an essential role in maintaining healthy ecosystems. However, as human activities continue to degrade the environment and contribute to climate change, it is essential to understand if and how parasite-host interactions has been affected. In this study, we examined the relationship between the bivalve species Chamelea gallina and trematodes. Trematodes are a group of parasites with no significant body fossil record. We analyzed the dynamics of the trematode population, including its diversity, prevalence, pit size, and pit aggregation, by studying 193 infested valves and 838 pits retrieved in fossil and dead assemblages of C. gallina from Adriatic Sea Basin (Italy). The samples were collected from Late Holocene marine succession (~3 ky cal B.P. with sub-centennial error) and thanatocoenosis from the modern seabed. Our analysis based on Gaussian finite mixture modeling shows no decrease in the number of trematode taxa infesting C. gallina over the past 3000 years. However, the prevalence of trematode infestation decreased significantly over time (one order of magnitude), along with the average number of pits, median size, and parasite pit aggregation. These changes suggest a severe decline (or collapse) of the trematode-C. gallina interaction in the Adriatic Sea during a time of increasing human influence on this land-locked basin.

How to cite: Huntley, J., Fitzgerald, E., Delaney, R., and Scarponi, D.: Conservation paleobiology: Reconstructing the baseline of parasitic-host interaction for Chamelea gallina in the Northern Adriatic., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22193, https://doi.org/10.5194/egusphere-egu24-22193, 2024.

X3.124
|
EGU24-22498
Ilaria Mazzini, Roberta Parisi, Giuseppe Aiello, Diana Barra, and Jamilah Padma Vitolo

The late Neogene was a time of climate transition in North-African waters, as shown by early Messinian ostracod assemblages recorded both in the Southern Mediterranean (Gulf of Gabès, Tunisia) and in Atlantic (Northwestern Morocco) sites. A cooling trend since the Burdigalian-Langhian Miocene Climate Optimum culminated in the late Miocene, approximately coinciding with the the progressive closure of the connections between Atlantic and Proto-Mediterranean that induced the Messinian Salinity Crisis. During this event all the marine taxa disappeared from the Mediterranean. Some late Miocene ostracods, presently living in shallow tropical western African waters, and not occurring in modern temperate-subtropical environments, re-entered from the Atlantic in the early Pliocene, when the Mediterranean returned to be a fully marine sea. In this number are included the genera Carinovalva and Ruggieria, that became extinct in the Mediterranean during the late Pliocene or in the Pleistocene, possibly coinciding with major cooling phases. Conversely, the genus Chrysocythere was not able to recolonize the Mediterranean waters, probably due to the Pliocene shallow water subtropical-temperate temperatures in the area of the Strait of Gibraltar. Several Miocene endemic Proto-Mediterranean tropical species and a number genera, (e.g.: Syrtica, Okadaleberis, Dallonella), went completely extinct due to the Messinian Salinity Crisis.

How to cite: Mazzini, I., Parisi, R., Aiello, G., Barra, D., and Padma Vitolo, J.: Late Neogene cooling and the disappearance of tropical ostracod taxa in the Mediterranean-Atlantic Region, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22498, https://doi.org/10.5194/egusphere-egu24-22498, 2024.

Posters virtual: Wed, 17 Apr, 14:00–15:45 | vHall X3

Display time: Wed, 17 Apr 08:30–Wed, 17 Apr 18:00
Chairpersons: Jens Zinke, Isabella Leonhard, Niels de Winter
vX3.21
|
EGU24-19957
Evidence of palaeoclimatic changes through marine macrofaunas from the Pleistocene of South-eastern Sicily 
(withdrawn after no-show)
Rossana Sanfilippo, Gianmarco Minniti, Agatino Reitano, Gianni Insacco, and Antonietta Rosso
vX3.22
|
EGU24-22130
|
ECS
Multilayer network analysis of the global ammonoid record informs Cretaceous chronostratigraphy and renews the mid-Cretaceous saga
(withdrawn)
Alexis Rojas-Briceno, Anton Holmgren, Pedro Patarroyo, and Christian Salazar