SSP4.3 | Biocalcifier resilience during global changes

The Earth has experienced several environmental disturbances, with varied tempos and modes of ecosystem resilience, occasionally reaching tipping-points that triggered permanent modification in abundance, biodiversity, ecological range and biomineralization processes of marine calcifiers. Given enough time, a resilient ecosystem may be able to fully recover from perturbations, but continuing stress can severely compromise that resilience. Benthic and planktic marine calcifiers (e.g., molluscs, brachiopods, corals, calcareous algae, foraminifera, calcareous nannoplankton) are greatly impacted by these global perturbations. With this session we encourage contributions analysing the adaptative (or not) response of marine biocalcifiers from pelagic and neritic ecosystems to global stresses and the effects on their ability to mineralize, on marine biodiversity and on changes in species distribution during global perturbations.
We welcome studies on modern biota, that are vital for measuring ecosystem resilience at short-term, as well as those from the geological record that are fundamental to scrutinize the medium- and long-term response prior to human disturbances. We invite research based on multidisciplinary approaches (e.g., morphometric analysis, species abundance, distribution patterns and biodiversity, sclerochronology and growth rate, biomineralization, geochemistry, stratigraphic paleontology, paleoecology) in order to investigate the tempo and mode of response of marine biocalcifiers to (paleo)environmental and (paleo)climatic perturbations.

Convener: Gaia Crippa | Co-conveners: Liz Harper, Antonino Briguglio, Mariano Parente
Orals
| Tue, 25 Apr, 16:15–18:00 (CEST)
 
Room -2.31
Posters on site
| Attendance Tue, 25 Apr, 10:45–12:30 (CEST)
 
Hall X3
Posters virtual
| Attendance Tue, 25 Apr, 10:45–12:30 (CEST)
 
vHall SSP/GM
Orals |
Tue, 16:15
Tue, 10:45
Tue, 10:45

Orals: Tue, 25 Apr | Room -2.31

Chairpersons: Gaia Crippa, Liz Harper
16:15–16:25
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EGU23-16549
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SSP4.3
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On-site presentation
Martin R. Langer

Over the past two centuries, fossil fuel burning and other anthropogenic activities have caused the atmospheric CO2 concentration to rise from 280 ppm to 419 ppm. Over the same time interval, the surface oceans have absorbed more than 500 billion tons of carbon dioxide from the atmosphere, or approximately 30 % of the total anthropogenic carbon dioxide emissions. This absorption of CO2 from the atmosphere has benefitted human mankind significantly by reducing the greenhouse gas levels in the atmosphere. When anthropogenic CO2 is absorbed by seawater, chemical reactions occur that reduce seawater pH, concentrations of carbonate ions, and the saturation states of the biominerals aragonite and calcite in a process commonly referred to as ocean acidification. When the pH and carbonate saturation drop in seawater, carbonate biominerals in shells and skeletons may begin to dissolve, and the water become corrosive for this reason.

Atmospheric CO2, pH and carbonate saturation have fluctuated significantly over the Phanerozoic history in the oceans. This research presentation focuses on the on the abundance, biodiversity and biogeography of larger benthic symbiont-bearing foraminifera during the Phanerozoic. Benthic and planktic foraminifera produce approximately 20 % of the overall carbonate in modern oceans and as such they are major components of the carbonate budget. How did larger benthic foraminifera react to changes in the oceans over the course of the Phanerozoic history? How did high CO2 and low pH levels impact this important group and what lesson can we learn from the fossil record for future developments?

This presentation illustrates the reaction of modern and fossil larger benthic symbiont-bearing foraminifera (LBF) to major perturbations in the ocean systems. Larger symbiont-bearing foraminifera have an excellent fossil record, are ubiquitous components of tropical and subtropical biotas and contribute significantly to the carbonate produced in the tropical world's oceans. The fossil record of larger symbiont-bearing foraminifera provides a unique archive to assess the impact of decreasing pH and calcite saturation on environments in future oceans.

 

How to cite: Langer, M. R.: The fossil record of larger symbiont-bearing foraminifera: A unique archive to assess the impact of decreasing pH and calcite saturation, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16549, https://doi.org/10.5194/egusphere-egu23-16549, 2023.

16:25–16:35
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EGU23-4839
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SSP4.3
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ECS
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Virtual presentation
Marco Viaretti, Gaia Crippa, and Lucia Angiolini

The Late Permian was a time interval characterized by extreme environmental perturbations, culminating with the Siberian Traps-related gas emissions and the subsequent global warming and ocean acidification, which produced the most severe mass extinction of the Phanerozoic (Dal Corso et al., 2022). Evidence of these perturbations are recorded in fossil archives, as pristine brachiopod shells (Garbelli et al., 2017). Here, we show shell microstructural variations and stable isotopes profiles recorded by specimens of Araxilevis intermedius (Abich, 1878), a large-sized and thick-shelled brachiopod species abundant in the Upper Permian of Iran. Nine specimens of A. intermedius were selected from several Wuchiapingian beds of the Hambast Formation in the Abadeh Section and of the Julfa Formation in the Ali Bashi Mountains Main Valley section (Iran), following the correlation by Viaretti et al. (2021). Prior to the isotope analysis different screening tests were performed on the brachiopod shells from both sections: Scanning Electron Microscope microstructural analysis, cathodoluminescence (CL) and trace elements analyses. Specimens of A. intermedius are characterized by a three-layered shell, comprising a secondary layer of cross-bladed laminae and a tertiary columnar layer; the primary layer is not preserved. The specimens from the Hambast Formation of Abadeh show a partially altered shell, whereas those from the Julfa Formation of the Ali Bashi Mountains show a well-preserved microstructure, despite CL analysis indicating that all the specimens were non-luminescent, both the microstructurally well-preserved and the altered ones. After having checked the shell preservation, 12 to 29 powder samples were collected from the longitudinal shell section of each pristine specimen of A. intermedius using a sclerochronological approach. This method allowed to investigate the seasonal environmental changes recorded by the brachiopod shells of A. intermedius from Iran and to test if this species of the Class Strophomenata, abundant in this time interval also outside Iran, can be considered a good archive for paleoclimatic and paleoenvironmental reconstructions in the Late Permian.

 

Dal Corso J., Song H., Callegaro S., Chu D., Sun Y., Hilton J., Grasby S.E., Joachimski M.M. & Wignall P.B. 2022. Environmental crises at the Permian–Triassic mass extinction. Nat. Rev. Earth Environ, 3, 197-214.

Garbelli C., Angiolini L. & Shen S.Z. 2017. Biomineralization and global change: A new perspective for understanding the end-Permian extinction. Geology, 45(1), 19-22.

Viaretti M., Crippa G., Posenato R., Shen, S.Z. & Angiolini L. 2021. Lopingian brachiopods from the Abadeh section (Central Iran) and their biostratigraphic implications. Boll. Soc. Paleont. It., 60(3), 213-254.

How to cite: Viaretti, M., Crippa, G., and Angiolini, L.: Selecting the best brachiopod biomineral archive of the Wuchiapingian climate change, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4839, https://doi.org/10.5194/egusphere-egu23-4839, 2023.

16:35–16:45
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EGU23-7095
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SSP4.3
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ECS
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On-site presentation
Chiara Bettoni, Cinzia Bottini, Silvia Castiglione, Elisabetta Erba, and Pasquale Raia

Calcareous nannofossil Watznaueria barnesiae is a resistant and tolerant species and previous morphometric studies have evidenced minor (Erba et al., 2010; Lubke et al.2016) or no size changes during Oceanic Anoxic Events (OAEs) (Bornemann et al. 2006; and Faucher et al. 2017b) as well as during the Cenomanian to Maastrichtian (Linnert et al. 2014). Here, we present the morphometric record from the western Tethys (Cismon core from the Belluno Basin; Piobbico core and the Monte Petrano section from Umbria-Marche Basin, Italy) across the latest Barremian- late Cenomanian which represents a relatively long-time interval (ca. 26 Myrs) marked by interludes of profound changes in the ocean and climatic conditions named (OAE 1a, 1b and 1d). Our study shows that indeed W. barnesiae experienced coccolith and central unit variations during the studied interval. Specifically, smaller coccoliths with also smaller central unit marked the early Aptian to early Albian. The middle Albian to the early Cenomanian was characterized by larger and rounded coccoliths without significant changes in the central unit dimension. Short-term size changes are detected in correspondence of OAE 1a and OAE 1b marked by W. barnesiae size decrease. Particularly, OAE 1a was characterized by the smallest and most elliptical specimens of the studied interval. During the OAE 1b W. barnesiae coccoliths were characterized by a moderate decrease in the mean size, because specimens were already smaller before the event. The morphometric data were correlated with calcareous nannofossil temperature and nutrient indices calculated on the same samples investigated for morphometry. Long-term size changes do not show a clear correspondence with temperature and nutrient variations. W. barnesiae size changes across the early Aptian to early Albian may be related to large igneous province activity. Short-term size variations during OAE 1a and OAE 1b were influenced by the combination of large CO2 emissions, temperature and fertility increase. In conclusion, although W. barnesiae is a resistant and tolerant species it shows morphometric changes both in short- and long-term, probably in response to partially different causes.

 

 

How to cite: Bettoni, C., Bottini, C., Castiglione, S., Erba, E., and Raia, P.: Short and long-term size changes of calcareous nannofossil Watznaueria barnesiae across the latest Barremian- late Cenomanian interval (Cretaceous) in the western Tethys., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7095, https://doi.org/10.5194/egusphere-egu23-7095, 2023.

16:45–16:55
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EGU23-6659
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SSP4.3
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ECS
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Virtual presentation
Giulia Amaglio, Maria Rose Petrizzo, Ann Holbourn, Wolfgang Kuhnt, and Erik Wolfgring

The Cenomanian-Turonian boundary interval is characterized by environmental perturbations related to the Oceanic Anoxic Event 2 (OAE 2), affecting marine biota, including benthic and planktonic foraminifera. This study shows a continuous record of benthic foraminifera that, together with published planktonic foraminiferal and geochemical data, allow to interpret the paleoceanographic changes in surface and bottom waters across the OAE 2 interval in the Clot Chevalier section (Vocontian Basin, SE France). The Clot Chevalier section is located at an outer shelf-upper bathyal environment according to benthic foraminifera, and their composition and abundance changes allow the identification of seven distinct faunal intervals. Below the OAE 2 (middle Cenomanian), the seafloor shows moderately oxic conditions and oligotrophic regimes suggested by high species diversity and abundance of infaunal and epifaunal taxa. Within the OAE 2 (upper Cenomanian), characterized by the highest values of Total Organic Carbon (TOC), the benthic calcareous taxa (Gavelinella sp., Gyroidinoides sp., Praebulimina elata, Tappanina laciniosa) are abundant and radiolaria dominate the microfossil assemblages (> 50%) suggesting eutrophy and suboxic conditions at the seafloor. The lowest part of the OAE 2 shows high abundance of the benthic agglutinated taxa Ammobaculites sp., Ammodiscus cretaceus, Gaudryina sp., Textulariopsis bettenstaedti that gradually disappear close to the top of OAE 2. Moreover, at ~1 m above the onset of the OAE 2, and simultaneously to the Plenus Cold Event (PCE), a repopulation event and ventilation at the seafloor is documented by the occurrence of the oxic benthic foraminiferal taxa Frondicularia sp. and Ramulina aculeata. Above the OAE 2 (lowermost Turonian), calcareous and agglutinated taxa re-occur with high species diversity and abundance, identifying moderately oxic conditions and mesotrophic regimes. In conclusion, oxygen and organic carbon variations at the seafloor associated to the OAE 2 can be inferred by the benthic foraminiferal composition and distribution.

How to cite: Amaglio, G., Petrizzo, M. R., Holbourn, A., Kuhnt, W., and Wolfgring, E.: Benthic foraminiferal response to the paleoenvironmental changes during the Late Cretaceous Oceanic Anoxic Event 2 at Clot Chevalier (Vocontian Basin, SE France), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6659, https://doi.org/10.5194/egusphere-egu23-6659, 2023.

16:55–17:05
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EGU23-10956
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SSP4.3
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On-site presentation
Cinzia Bottini and Elisabetta Erba

Oceanic Anoxic Event (OAE)2 (latest Cenomanian, ca. 94 Ma) represents a major palaeoceanographic phenomenon that took place during an interval of extreme global warmth. High-resolution climate records reveal considerable changes in temperature, carbon cycling, and ocean chemistry during this climatic perturbation. In particular, a transient fall in temperature has been detected in the English Chalk on the basis of invasion of boreal faunas and bulk oxygen-isotope excursions: it was called Plenus Cold Event (PCE) characterized by two cooler water intervals punctuated by an intervening warmer episode.

Being calcareous nannoplankton sensitive to changes in surface water conditions, the nannofossil record is ideal to implement our understanding of the paleoceanographic perturbations occurring during OAE 2, and specifically the climatic variability. Previous studies documented how some calcareous nannofossil species, in particular B. constans, underwent size reduction during OAE 2 in response to increased pCO2 and trace metal concentrations with a temporary size recovery in correspondence of the PCE.

Here, we integrate the nannofossil morphometric datum by reconstructing calcareous nannofossil abundance and assemblage composition in the same three sections (Eastbourne, UK; Clot Chevalier, France; Novara di Sicilia, Italy) previously studied for morphometries. In addition, we performed morphometrics of B. constans and nannofossil quantitative analyses on Tarfaya (Morocco) section. Correlation between the four studied sites is achieved by biostratigraphy and carbon-isotope stratigraphy (δ13Ccarb and δ13Corg).

Nannofossil temperature and nutrient index are calculated to detect if variations in temperature and/or nutrients a) are coeval and similar in the four sections; b) depend on the latitude and/or the paleoceanographic context; c) during the PCE are registered in all studied sections; d) correlate with the nannofossil size changes.

Results highlight some similarities in the fluctuations of the relative abundance of the cold-water species E. floralis in Eastbourne and Clot Chevalier around the PCE interval not mirrored at lower latitudinal sites possibly suggesting that the inflow of cooler waters did not reach the lower latitudes.

How to cite: Bottini, C. and Erba, E.: Calcareous nannoplankton response to the latest Cenomanian Oceanic Anoxic Event 2, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10956, https://doi.org/10.5194/egusphere-egu23-10956, 2023.

17:05–17:15
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EGU23-7874
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SSP4.3
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Virtual presentation
Maria Rose Petrizzo, Giulia Amaglio, Erik Wolfgring, David K. Watkins, Kenneth G. MacLeod, Brian T. Huber, and Takashi Hasegawa

Oceanic Anoxic Event 2 (OAE 2), spanning the Cenomanian/Turonian boundary (93.9 Ma) was an episode of major perturbations in the global carbon cycle with a δ13C excursion of 2-3‰ documented worldwide. To investigate the response of biota to OAE 2 at high latitudes, we present data from Integrated Ocean Discovery Program (IODP) Sites U1513 and U1516 drilled in the Mentelle Basin (Indian Ocean, offshore SW Australia; paleolatitude of 59°-60° S in the mid-Cretaceous).

The distribution and variations in abundance of planktonic and benthic foraminifera, radiolaria, and calcipheres and their paleoecological preferences permit interpretation of their response to the dynamics of the water mass stratification during the OAE 2.

The lower OAE 2 interval is characterized by the abundance of the opportunistic Microhedbergella that alternates with common eutrophic radiolaria in the surface waters. The concomitant high abundance of benthic foraminifera, especially gavelinellids, might suggest episodes of enhanced oxygenation at the sea floor. The eutrophic feature of the water masses seems more pronounced at Site U1513 because of the rarity of the intermediate dwelling planispiral taxa and the consistent occurrences of the opportunistic and eutrophic calcispheres. In this interval biota indicate a reduced water mass stratification with alternating episodes of enhanced surface water productivity and variations of the thickness of the mixed layer.

Lithologies in the middle OAE 2 interval are characterized by a very low CaCO3 content and are marked by the near absence of calcareous foraminifera. Radiolaria are the sole microfossils present except for a couple of isolated samples that contain three benthic foraminifera at Site U1516 and calcispheres at Site U1513.The high abundance of radiolaria and the rarity of calcareous microfossils indicate very high fertility conditions and, possibly, shoaling of the CCD which resulted from the emission of volcanogenic CO2 from the Kerguelen Plateau Large Igneous Province making waters more corrosive.

Conditions moderate after this extreme perturbation as reflected by the sudden increase in abundance of foraminifera and return of carbonate deposition presumably after deepening of the CCD. At Site U1513 the dominance of Microhedbergella over the other planktonic foraminiferal genera, the presence of lower mixed layer planispiral and scattered keeled taxa, and the radiolaria distributions and abundances might suggest the presence of a thick mixed layer with significant thermal differences between surface and thermocline waters. Benthic agglutinated taxa, the epifaunal Gavelinella and Stensioeina and the opportunist Praebulimina show a significant increase in abundance that suggests the presence of oxic-dysoxic bottom waters. On the contrary at Site U1516 Microhedbergella is progressively replaced in abundance by Muricohedbergella to indicate a relatively stable water column with a thick mixed layer and a thin thermocline and frequent episodes of eutrophy toward the top.

At both sites the termination of OAE 2 does not correspond to modifications in the microfossils assemblages; rather, they maintain the same features observed in the underlying interval.

Finally, this study provides a complete record of the microfossil response to the palaeonvironmental perturbation associated to the OAE 2 at southern high latitudes.

How to cite: Petrizzo, M. R., Amaglio, G., Wolfgring, E., Watkins, D. K., MacLeod, K. G., Huber, B. T., and Hasegawa, T.: Response of microfossils to the Late Cretaceous Oceanic Anoxic Event 2 at southern high latitudes, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7874, https://doi.org/10.5194/egusphere-egu23-7874, 2023.

17:15–17:25
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EGU23-6982
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SSP4.3
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ECS
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Highlight
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Virtual presentation
James Witts, Heather Birch, Amy Flower, Calum MacFie, and Daniela Schmidt

The Cretaceous-Paleogene (K-Pg) boundary 66 Ma coincides with the most recent of the ‘Big Five’ Phanerozoic mass extinctions. The extinction was driven by rapid and extreme environmental changes, which included global cooling, surface ocean acidification, and productivity decline, following an extra-terrestrial impact at Chicxulub in the Gulf of Mexico. The excellent global fossil record of the K-Pg extinction and recovery allows examination into how severe environmental perturbations affect calcifying organisms across different oceanographic settings. Combining samples from the expanded shelf section on Seymour Island, Antarctica, and IODP sites 690 and 1135 (paleolatitude 65°S), we present new quantitative morphometric and μ-computed tomography data from large collections of well-preserved macro- and microfossil taxa (benthic molluscs, planktonic and benthic foraminifera) across the K-Pg boundary in the southern high latitudes. Planktonic foraminifera show large extinctions and a size decrease in survivors at the K-Pg boundary itself, but the magnitude of size change is smaller than at lower latitude localities. Surviving shallow marine bivalves from Seymour Island show increased variability of body size and volume at the K-Pg boundary persisting for ~300 kyrs into the Paleogene. Surviving deep-sea benthic foraminifera from Site 690 in the same ocean basin and at the same paleolatitude, respond to both events at the boundary itself and the initial re-stabilisation of the global carbon cycle some 300 kyrs after the K-Pg, with shifts in size, growth rate, and surface:volume ratio. These data reveal the importance of morphological plasticity for promoting resilience and survival in calcifiers across this mass extinction event. They also suggest that trait changes across the K-Pg event occur at different times in different environmental settings and groups, supporting the hypothesis that environmental heterogeneity plays an important role in modulating resilience.

How to cite: Witts, J., Birch, H., Flower, A., MacFie, C., and Schmidt, D.: Morphological plasticity and environmental heterogeneity drove resilience of high latitude marine calcifying taxa across the Cretaceous-Paleogene mass extinction, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6982, https://doi.org/10.5194/egusphere-egu23-6982, 2023.

17:25–17:35
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EGU23-7934
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SSP4.3
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ECS
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On-site presentation
Giulia Filippi, Silvia Sigismondi, Roberta D'Onofrio, Massimo Tiepolo, Enrico Cannaò, Gerald Dickens, Bridget Wade, Thomas Westerhold, and Valeria Luciani

Modern studies on marine ecosystems are limited in time so the evaluation of their stability under the ongoing CO2 emissions and global warming remains uncertain and necessarily requires a long-term perspective. The dynamic early Paleogene climate offers the crucial opportunity to detect relationships among calcareous plankton, past carbon cycle perturbations and climate. Specifically, the EECO (~53-49 Ma) represents a key interval to investigate the planktic foraminiferal resilience on a long-term perspective as it records the peak temperature and pCO2 of the entire Cenozoic. We investigated the Pacific Sites 1209-1210 and eastern Indian Ocean Site 762 following the evidence that the EECO marked impacted planktic foraminiferal assemblages at the Atlantic Oceans. Abrupt and permanent abundance decline (more than one-third) of the symbiont-bearing genus Morozovella occurred at the EECO beginning (J event, ~53 Ma) at sites 1209-1210, whereas Acarinina concomitantly increased, as from the Atlantic sites. Site 762 recorded the southern high-latitude migration of the warm Acarinina species coupled with the decline of the ‘cold’ subbotininds. Another major change documented at the Pacific and Indian Oceans revealed to be similar to the Atlantic record and involved the coiling direction (ability to add chambers clock- or counter-clockwise) of the genus Morozovella. Indeed, the morozovellid coiling direction is dominantly dextral below the EECO but became sinistral within the EECO, although this change is registered ~ 200 kyr later at the Pacific Ocean and ~ 200 kyr before at Site 762 where it occurred at the K/X event (~52.8 Ma). Therefore, the morozovellids crisis observed in the Atlantic and Pacific Oceans can be mainly read as the dextral forms decline. Searching for the driving causes of the observed modifications, we performed stable isotope analysis on sinistral and dextral morozovellids morphotypes (possibly cryptic species) from sites 1209-1210 and 762. Results show that the sinistral forms generally record lower d13C values, once again as recorded for the Atlantic Ocean. This evidence suggests a reduced symbiosis relationship and/or a slightly deeper habitat, probably a strategy to sustain the stressors induced by the EECO. Our record advises on a causal relationship to chemical-physical modifications in the surface waters, such as the temperature increase. The increased temperature of at least 1°C [Mg/Ca (LA)-ICP-MS] recorded by sinistral morozovellids within the EECO may have acted in the reduced photosymbiotic activity. Conversely, acarininids do not show preferential coiling nor below neither within the EECO and they reveal d13C values that imply major ecological flexibility, possibly enabling them to proliferate. The EECO also induced the virtual disappearance of the genus Chiloguembelina after the K/X event at all the Atlantic, Pacific and Indian sites investigated. This disappearance appears to be related to thermocline warming and Oxygen Minimum Zone enhanced oxygenation. Our records demonstrate the wide geographic and possibly global character of the striking modifications occurred in the planktic foraminiferal assemblages during the first ~800 kyr of the EECO. Our derived paleobiology gives new insights into planktic foraminiferal strategies adopted under long-term global warming.

How to cite: Filippi, G., Sigismondi, S., D'Onofrio, R., Tiepolo, M., Cannaò, E., Dickens, G., Wade, B., Westerhold, T., and Luciani, V.: Planktic foraminiferal changes and the Early Eocene Climatic Optimum (EECO, ~ 53-49 Ma): crisis or resilience strategy to global warming?, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7934, https://doi.org/10.5194/egusphere-egu23-7934, 2023.

17:35–17:45
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EGU23-5721
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SSP4.3
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On-site presentation
Daniele Scarponi, Alexis Rojas, Rafał Nawrot, Alessandro Cheli, and Michał Kowalewski

Preserving adaptive capacities of coastal ecosystems in the Anthropocene requires an understanding of their natural variability prior to modern times. We quantified responses of nearshore molluscs assemblages to past environmental changes using 101 samples (~57300 specimens) retrieved from the subsurface Holocene succession and present-day seabed of the Po-Adriatic System (Italy). Present-day assemblages shifted in their faunal composition with respect to their mid-late Holocene counterparts. Major differences are observed in lower nearshore settings, where present-day samples show higher heterogeneity, reduced standardised richness, reduced relative abundance of Lentidium mediterraneum, and increased relative abundance of Varicorbula gibba, scavengers (genus Tritia), and deposit feeders (nuculid bivalves). A dominance of infaunal opportunistic species and shifts towards detritus-feeding and scavenging are often associated with disturbed benthic habitats. Our results suggest that the ongoing anthropogenic stressors (mainly bottom trawling and non-native species) are currently shifting benthic communities into novel states outside the range of natural variability archived in the fossil record.

How to cite: Scarponi, D., Rojas, A., Nawrot, R., Cheli, A., and Kowalewski, M.: Assessing biotic response to anthropogenic forcing using mollusc assemblages from the Po-Adriatic System (Italy), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5721, https://doi.org/10.5194/egusphere-egu23-5721, 2023.

17:45–17:55
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EGU23-7210
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SSP4.3
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Highlight
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On-site presentation
Michael Kaminski, Sinatrya Diko Prayudi, Asmaa Korin, and Bassam S Tawabini

Summer temperatures in excess of 60°C, have been measured in surficial substrates in the exposed areas of intertidal mudflats along the coast of the Arabian Gulf in Bahrain and Saudi Arabia. The incoming flood tide in coastal lagoons may have a temperature as high as 42°C. As a result, large swaths of the intertidal zone in the western Arabian Gulf are barren of living meiofauna (e.g., foraminifera, ostracods, gastropods, and worms) during the hottest months of the year. Samples collected from the intertidal zone in summer yield only dead assemblages of foraminiferal, ostracod, and gastropod shells. Dead assemblages of the foraminifer Peneroplis collected from the upper reaches of the intertidal zone consist largely of juvenile specimens, implying that the living populations, when present, do not reach maturity. In summer, the full range of living meiofaunal organisms is only observed in tidal channels that remain submerged during low tide.

Our laboratory experiments have determined the upper temperature limit for the survival of gastropods and ostracods collected from coastal lagoons of the Western Arabian Gulf is in the range of 47 to 48.5 degrees C. At 50°C total mortality is observed. In Saudi Arabia, substrate temperatures exceeding the lethal temperature for these organisms are already observed in late April, and persist until late October.

The presence of a summer dead zone for intertidal calcifying organisms is consistent with predictions of climate models, which suggested that by 2050 portions of the Arabian Gulf may become too hot to support animal life. On the western coast of the Arabian Gulf, these predictions have already become a fact. 

How to cite: Kaminski, M., Prayudi, S. D., Korin, A., and Tawabini, B. S.: Intertidal lagoons in the western Arabian Gulf are summer dead zones, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7210, https://doi.org/10.5194/egusphere-egu23-7210, 2023.

17:55–18:00

Posters on site: Tue, 25 Apr, 10:45–12:30 | Hall X3

Chairpersons: Gaia Crippa, Liz Harper
X3.89
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EGU23-6767
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SSP4.3
Cesare Andrea Papazzoni and Andrea Benedetti

Modern global warming is proven to affect shallow water calcifiers among which are symbiont-bearing larger foraminifera (LF). To better understand the possible effects on modern faunas, we can explore the response of LF to past global events, referring to the last greenhouse megacycle terminated near the end of the Paleogene. Here we present a biodiversity analysis based on a comprehensive and critical review of the scientific literature on LF and other accompanying shallow-water foraminifera of the Neotethys. It has been obtained by compiling a list of over 1,300 species belonging to 215 genera in the interval from the Danian to the Langhian, currently subdivided into 26 biozones (Shallow Benthic Zones SBZ).

The results show that LF, after their abrupt extinction at the end of Cretaceous, underwent a rapid radiation, with high origination rates at both genus and species level in the Danian, followed by a rather constant biodiversity throughout the rest of the Paleocene. The Paleocene-Eocene Thermal Maximum (PETM) recorded one of the most important LF turnover ever recorded, followed by a rapid radiation of K-strategists species, mainly grouped in the genera Alveolina,Nummulites, Discocyclina, Orbitoclypeus and Assilina.

Immediately after the Early Eocene Climatic Optimum (EECO), roughly corresponds to the SBZ10 and 11, we see a second minor turnover, with a rapid differentiation in SBZ12. 

Within the general cooling trend recorded during the Lutetian and Bartonian, the Middle Eocene Climatic Optimum (MECO) seems having no effects on the final decline of most Eocene LF whose generalized extinction coincides with the Eocene/Oligocene transition (EOT) with a cooling event.

The Oligocene is characterized by the radiation of lepidocyclinids and miogypsinids in the Neotethys, but at the end of SBZ23, right after the Late Oligocene Warming Event (LOWE), a new extinction of LF set their diversity to very low levels. Therefore, our data cannot resolve their response to the last global warming event of the studied interval: the Middle Miocene Climatic Optimum (MMCO).

Study funded by the Italian Ministry of University and Research (MUR), funds PRIN 2017: project “Biota resilience to global change: biomineralization of planktic and benthic calcifiers in the past, present and future” (prot. 2017RX9XXY).

How to cite: Papazzoni, C. A. and Benedetti, A.: Paleocene to Miocene larger foraminiferal biodiversity as a response to climate changes in the Neotethys, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6767, https://doi.org/10.5194/egusphere-egu23-6767, 2023.

X3.90
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EGU23-7590
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SSP4.3
Gaia Crippa

The Early Pleistocene was a time interval characterized by several climatic oscillations linked to glacial/interglacial cycles and by a progressive climatic cooling which culminated with the onset of Middle-Late Pleistocene large continental glaciations in the Northern Hemisphere. After the Last Glacial Maximum the Earth underwent a progressive warming, up to nowadays conditions. The Mediterranean area was strongly affected by these climatic changes both in marine and continental settings. The Lower Pleistocene Emilian marine successions (northern Italy) represent excellent case studies where to study how mollusk fossil assemblages changed over time in response to climate modifications.

In particular, the Venus-Ostrea assemblage, reported in several Lower Pleistocene marine successions of northern Italy (Arda, Stirone and Chero sections), has never been studied in detail. Here, the Venus-Ostrea assemblage of the Arda River section has been analyzed from a systematic and a paleoecological point of view, resulting in the identification of 23 taxa belonging to bivalves and gastropods. As the majority of the retrieved taxa is represented by living species, a comparison between their fossil and present-day environment has been carried out to observe if there were changes in their habitat from the Early Pleistocene to nowadays.

Three different species-specific responses to climate changes were observed: 1) some species, namely Turritellinella tricarinata, Aporrhais uttingeriana and Nassarius semistriatus, were unable to adapt to the climatic cooling and became extinct at the end of the Pleistocene; 2) other species have changed their bathymetric distributions from cooler Pleistocene to warmer present-day conditions; for instance, Venus nux, which during the Early Pleistocene was abundant in the Adriatic Sea at shallow water depths (20-40 m), currently lives in restricted areas of the Mediterranean Sea at water depths of 75-100 m, where seawater temperatures are cooler and thus more favorable for the proliferation of the species; 3) finally, other species do not show variations in their geographic or bathymetric distribution.

This study reveals the occurrence in the Lower Pleistocene marine successions of northern Italy of an association of taxa which is no longer present in the modern Adriatic Sea, stressing the importance that environmental and climatic conditions have on the distribution of organisms.

How to cite: Crippa, G.: The Venus-Ostrea assemblage in the Lower Pleistocene Arda River section: species-specific responses to climate change, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7590, https://doi.org/10.5194/egusphere-egu23-7590, 2023.

X3.91
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EGU23-2086
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SSP4.3
Poliakova Anastasia

Harmful algal bloom (HAB) is a known negative phenomenon that can result in a series of deleterious effects, such as beach fouling, paralytic shellfish poisoning, mass mortality of marine species and a threat to human health, especially if toxins pollute drinking water or occur near by the public resorts. In the South China the problem of HABs has an ultimately important meaning. For this study, we used a 1.5 m sediment core LX-2018-2 collected from the Zhanjiang Mangrove National Nature Reserve (109°03´E, 20°30´N), Guangdong Province, South China. High-resolution coastal environment reconstruction with a specific focus on the HABs history during the last ca 2500 yrs was attempted. Age control was performed with the five radiocarbon dates obtained from benthic foraminifera. A total number of 71 dinoflagellate cyst types was registered. The most common types found consistently throughout the sediment sequence were autotrophic Spiniferites spp., Spiniferites hyperacanthus and S. mirabilis, S. ramosus, Operculodinium centrocarpum sensu Wall and Dale 1966, Polysphaeridium zoharyi, and heterotrophic Brigantedinium ssp., cyst of Gymnodinium catenatum and cysts mixture of Protoperidinium. Three local dinoflagellate zones LX-1 to LX-3 were established based on the results of the constrained cluster analysis and data ordination; additionally, the middle zone LX-2 was derived into two subzones, LX-2a and LX-2b, based on the dynamics of toxic and heterotrophic cysts as well as on the significant changes (probability, P=0.89) in percentages of eutrophic indicators. The total cyst count varied from 106 to 410 cysts per slide with 177 cyst types on average. Dinocyst assemblages were characterized by the high values of the post-depositional degradation index (kt) that varies between 3.6 and 7.6 (averaging 5.4) which is relatively high and typical for the areas with selective dinoflagellate cyst preservation that is related to bottom-water oxygen concentrations.

How to cite: Anastasia, P.: Last ca 2500 Yr history of the harmful algal blooms in the South China reconstructed based on the sediment record of the organic-walled dinoflagellate cysts, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2086, https://doi.org/10.5194/egusphere-egu23-2086, 2023.

Posters virtual: Tue, 25 Apr, 10:45–12:30 | vHall SSP/GM

Chairpersons: Gaia Crippa, Liz Harper
vSG.26
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EGU23-11574
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SSP4.3
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Erik Wolfgring, Giulia Amaglio, and Maria Rose Petrizzo

At Site U1516 (Mentelle Basin, southeast Indian Ocean, offshore western Australia), the International Ocean Discovery Program (IODP) Expedition 369 recovered an almost complete record of the Upper Cretaceous, including the Oceanic Anoxic Event 2 (OAE 2). Benthic foraminiferal assemblages indicate a distal, outer neritic to bathyal depositional environment. For a better understanding of the paleoenvironmental changes across the OAE 2, we analysed 32 samples for benthic foraminiferal abundance data. The dataset represents one of the few deep water benthic foraminiferal records of the OAE 2 in the southern high latitudes.

The record of the OAE 2 can be subdivided in pre OAE 2, pre max-CIE, low CaCO3, and post low CaCO3 intervals. The interval of low CaCO3 content covers a prominent positive Carbon Isotope Excursion (CIE). The Cenomanian-Turonian boundary records an extreme decline in benthic foraminifera during OAE 2. The post low CaCO3 interval documents a strong repopulation event in benthic foraminifera.

During the pre OAE2 and pre-max-CIE intervals, taxa like the calcareous deep-water gavelinellids, lingulogavelinellids and gyroidinids are dominant. In the overlying low-carbonate interval, the microfossil record documents a substantial increase in Radiolaria while foraminifera become a rare faunal element. Remarkable changes in benthic foraminiferal assemblage composition are recorded in the initial low CaCO3 interval directly underlying the maximum CIE. Rather than acting as the trigger, it appears that the max CIE merely interrupted environmental change in the bottom waters.  Furthermore, the comparison of pre- and post-CIE benthic foraminiferal assemblages highlights a distinct repopulation event during the post max- CIE interval mainly represented by a profound increase in the abundance of agglutinated foraminifera and the calcareous epibenthic taxon Osangularia. The dataset collected at Site U1516 documents one of the most complete benthic foraminiferal records across the OAE 2 that registers the Late Cretaceous environmental changes in the Southern Hemisphere.

How to cite: Wolfgring, E., Amaglio, G., and Petrizzo, M. R.: Benthic foraminiferal assemblage changes during OAE 2 in the southern high latitudes - IODP Site U1516, Indian Ocean, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11574, https://doi.org/10.5194/egusphere-egu23-11574, 2023.

vSG.27
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EGU23-4427
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SSP4.3
Vlasta Cosovic, Katica Drobne, Đurđica Pezelj, Damir Bucković, Igor Felja, Dražen Kurtnjek, Marina Čančar, igor Pejnović, and Željko Ištuk

The study of Eocene deposits from the Dinaric foreland basin (Outer Dinarides, eastern Adriatic coast) documents a 300 m thick sequence of shallow-water carbonates originated on ramps that formed intermittently during the tectonic evolution of the basin. During the intense tectonic activity in this area, global sea-level changes, and warming events occurred (Early Eocene Climatic Optimum, EECO, Late Lutetian Thermal Maximum, LLTM and Middle Eocene Climatic Optimum, MECO). Up to 60% of all skeletal debris in these carbonates are larger benthic foraminifera (LBF). Ramp successions are rarely complete in terms of inner-, mid- and outer-ramp environments (availability of suitable benthic habitats for different LBF group) and very often stratigraphically incomplete. The LBF rich deposits document three distinctive groupings: i) the post - PETM phase (SBZ4 - SBZ10); ii) the EECO phase (from pre - to post - EECO phase, SBZ 10/11 - SBZ12/13); and iii) the late post - EECO phase including short-lived LLTM (SBZ13 - SBZ17). The studies of the dominant LBF (Drobne & Ćosović, 2009, 2010; Drobne et al., 2011; Pavlovec, 2012), showed no significant generic and species diversity across the foreland basin, from SBZ4 to SBZ17, but differences in species richness were found. The LBF assemblages included representatives of alveolinids, nummulitids, complex miliolids, conical agglutinated foraminifera, orthophragiminids, encrusting foraminifera and larger rotaliids. For this study, the diversity of the genera Alveolina, Assilina, Nummulites and conical foraminifera and complex miliolids was compared. The post-PETM stage showed similar species diversity of Alveolina, Nummulites, and Assilina (14-18-16) in contrast to the presence of three species of complex miliolids. In the EECO stage, representatives of Nummulites (32 species) were preferred over eighteen species of Alveolina, while the low species diversity showed conical foraminifera (8 species), Assilina (5 species) and complex miliolids (4 species). In the post - EECO and LLTM stages, Nummulites species were most abundant (39 species), Assilina less abundant (16 species), while the diversity of other groups decreased sharply (3 species of Alveolina and six species of complex miliolids). From the Ypresian to the Bartonian, LBF maintained high species diversity, with differences in species richness most likely due to competition (e.g., alveolinids vs. complex miliolids), local shifts in the paleoenvironment and long-term evolution, rather than global atmospheric or oceanic conditions.

The study was funded by the Croatian Science Foundation (HRZZ) through Project IP-2019-04-5775 (BREEMECO).

Drobne K., Ćosović V., 2009, Palaeobiogeography of the Late Cretaceous to Paleogene larger Miliolids from topical to subtropical sea belts (Neotethys to Caribbean). Bull. Soc. Geol. Fr., 180/4, 317-331.

Drobne K., Ćosović V., 2010, Paleogene conical agglutinated walls foraminifera in the Tethyan realm. Abstract book, Forams2010, 78-79, Bonn.

Drobne K., Ćosović V., Moro A., Bucković D., 2011, The role of the Paleogene Adriatic platform in the spatial distribution of alveolinids. Turkish Journal of Earth Sciences, 20/6, 721-751.

Pavlovec R., 2012, The Nummulitins from the Outer Dinarids. Folia Biologica and Geologica, 53/3, 85-109.

 

How to cite: Cosovic, V., Drobne, K., Pezelj, Đ., Bucković, D., Felja, I., Kurtnjek, D., Čančar, M., Pejnović, I., and Ištuk, Ž.: Response of larger benthic foraminifera to Eocene warming episodes in the Dinaric foreland basin, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4427, https://doi.org/10.5194/egusphere-egu23-4427, 2023.

vSG.28
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EGU23-7334
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SSP4.3
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ECS
Antonella Gandolfi, Victor-Manuel Giraldo Gomez, Valeria Luciani, Michele Piazza, and Antonino Briguglio

The early Paleogene is characterized by several warming episodes that are evaluated as analogues to the ongoing climate change. Specifically, we focalize on the Middle Eocene Climatic Optimum (MECO, centered at ~40 Ma) which is one of the major Eocene global warming events, characterized by ~4–6°C warming, shifts in the global carbon cycle and rise in atmospheric pCO2. Even though the MECO is a still enigmatic event, studies on paleobiotic effects across this interval are yet rather limited. We present here new quantitative analysis on planktic and benthic foraminifera to evaluate the impact of the MECO on the investigated biotic groups along the Sealza section (Liguria, NW Italy). This succession is interpreted as the result of a drowning ramp that was affected by continuous tectonic activity and offers the exceptional opportunity to compare the biotic variations across the MECO in shallow-water assemblages with the deep-water communities. The MECO interval at Sealza is constrained by the stable isotope oxygen data and by the occurrence of the species Orbulinoides beckmanni that has a range mostly coincident with the MECO event. Planktic foraminiferal abundance is generally scarce, as expected from a shallow-water succession. The most abundant genus is Subbotina, which however records its lowest abundance within MECO interval. We interpret this record as a response to the MECO warming because this genus is a cold-water index. The genera Acarinina and Morozovelloides show low abundance in the lower part of the section, but they record an increase across the MECO interval, as expected by these warm indices. The most abundant genus among benthic foraminifera that are well preserved and easy recognizable, is the epifaunal? Cibicidoides, adapted to oxygenated conditions. This genus records a marked decrease across the MECO. Similarly, the opportunistic genus Heterolepa shows an increase in abundance across the MECO interval. Another abundant genus is Anomalinoides that is very abundant in the lower part of the section but also displays a decrease across the interval corresponding to the MECO but differently from Cibicidoides, it did not recover in the post-MECO and is absent at the top of the section. This suggests that Cibicidoides was more resilient than Anomalinoides which proved to be less flexible to the paleoenvironmental changes induced by the MECO warming. The decrease of Cibicidoides coupled to the increase in abundance across the MECO by the genera Uvigerina and Bolivina, infaunal forms tolerating low-oxygen conditions, possibly indicate less oxygenation at the bottom and a change in the quality of organic matter (i.e., more labile) reaching the seafloor.

How to cite: Gandolfi, A., Giraldo Gomez, V.-M., Luciani, V., Piazza, M., and Briguglio, A.: Resilience of planktic and benthic foraminifera across the Middle Eocene Climatic Optimum (MECO) along a shallow water mixed siliciclastic and carbonate succession in NW Italy, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7334, https://doi.org/10.5194/egusphere-egu23-7334, 2023.

vSG.29
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EGU23-8731
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SSP4.3
Antonino Briguglio, Victor Manuel Giraldo Gomez, Michele Piazza, Andrea Benedetti, Andrea Baucon, Erik Wofgring, Antonella Gandolfi, Cesare Andrea Papazzoni, and Johannes Pignatti

During this work we have sampled and analysed over 150 meters of sedimentary succession outcropping in three localities in NW Italy near Ventimiglia (Olivetta San Michele, Capo Mortola and Sealza) as they were deposited during the Bartonian and therefore possibly containing signals for the Middle Eocene Climatic Optimum (MECO) event.

The MECO has been identified in all three sections by means of both isotopic shifts and biostratigraphic markers (larger benthic foraminifera, planktonic foraminifera and nannofossils). The three sections have been studied for gamma ray emissions variations, microfacies analyses, Rockeval and lithostratigraphic variations. Even if the three sections are all deposited in a relatively similar environment and are separated by few kilometers today, they display three different sedimentary successions both before, during and after the MECO. We observed that each succession has its peculiar lithological variations that do not seem to correlate with the other sections. The only similarity is that they record a transgressive trend from very shallow deposits to deeper settings as testified by the nummulite rich calcarenites covered by planktonic foraminifera marls. In spite of this similarity, some successions have heterolithic conglomerates at their base, whereas others have thick Microcodium-rich successions almost barren of any body fossils. The successions develop very different taxonomic richness, from extremely rich in nummulites, to much more diverse with abundant corals, mollusks, echinoids and a highly diversified foraminiferal association. The MECO in two sections is characterized by a drastic change in faunal composition, whilst in the other does not seem to be characterized by any faunal variation. From a lithological perspective, we observed that a sharp increase in the marly component seems to be present exactly during the MECO; but again this is only true for two out of three sections. Data also cannot completely rule out whether the finer material can be either caused by enhanced runoff due to instable climatic conditions, or if tectonic activity has increased its stress on the sedimentary conditions, or, alternatively, both factors combined.

How to cite: Briguglio, A., Giraldo Gomez, V. M., Piazza, M., Benedetti, A., Baucon, A., Wofgring, E., Gandolfi, A., Papazzoni, C. A., and Pignatti, J.: Shallow-water sedimentary environments across the MECO as recorded in NW Italy: palaeodiversity and palaeoecological constraints., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8731, https://doi.org/10.5194/egusphere-egu23-8731, 2023.

vSG.30
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EGU23-15742
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SSP4.3
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ECS
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Highlight
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Alessandro Cheli, Arianna Mancuso, Giuseppe Falini, Stefano Goffredo, and Daniele Scarponi

This study investigates the variation of skeletal and growth parameters of the bivalve Chamelea gallina in the Holocene of the Po-Adriatic System (Italy). C. gallina is a valuable economic species in the Mediterranean Sea, expected to be impacted by numerous anthropogenic stressors that threaten the biological and economic sustainability of its fishery. Here, skeletal parameters (micro-density and apparent porosity) and growth parameters (bulk density, linear extension and net calcification rates) of C. gallina shells were investigated in four shoreface-related C. gallina shell-rich deposits. Two from present-day Adriatic shoreface seabeds and two from comparable settings of the middle Holocene, when regional sea temperatures were higher than today. In each horizon, 30 right valves of different sizes were measured and aged using three independent methods (shell surface growth rings, shell internal bands and 18O/16O ratio) to determine the Von Bertalanffy growth functions. Which, in turn, allowed us to estimate targeted parameters for each assemblage investigated. Differences in the skeletal and growth properties of C. gallina shells were also investigated in relation to animal sexual maturity. C. gallina appears to be sensitive to changes in environmental conditions, showing macro-scale variations in bulk and micro-density. Shells from the middle Holocene presented a denser exoskeleton than modern ones, probably because of different mineralization rates mainly driven by temperature. Nevertheless, linear extension and net calcification rates showed no differences between past and modern assemblages, also when immature and mature individuals were analyzed separately. C. gallina biomineralization dynamics evaluated on timescales well beyond ecological monitoring offer insights into its adaptive capacities to face near-future global warming.

How to cite: Cheli, A., Mancuso, A., Falini, G., Goffredo, S., and Scarponi, D.: Assessing Chamelea gallina biomineralization dynamics in the Holocene of the Northern Adriatic (Italy), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15742, https://doi.org/10.5194/egusphere-egu23-15742, 2023.