EGU2020-5799
https://doi.org/10.5194/egusphere-egu2020-5799
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

The impact of the Messinian Salinity Crisis on marine biota

Konstantina Agiadi1, Niklas Hohmann2, Giorgio Carnevale3, Elsa Gliozzi4, Constanza Faranda4, Francesca Lozar3, Mathias Harzhauser5, George Iliopoulos6, Antonio Caruso7, George Kontakiotis1, Marco Taviani8, Alan Maria Mancini3, Enrico Borghi9, Ildefonso Bajo Campos10, Pierre Moissette1, Danae Thivaiou1, Stergios Zarkogiannis1, Eva Besiou1, Daniel Garcia-Castellanos11, and Angelo Camerlenghi12
Konstantina Agiadi et al.
  • 1Department of Historical Geology and Paleontology, National and Kapodistrian University of Athens, Athens, Greece (kagiadi@geol.uoa.gr)
  • 2Friedrich-Alexander-Universität GeoZentrum Nordbayern, Erlangen, Germany
  • 3Department of Earth Sciences, University of Torino, Torino, Italy
  • 4Dipartimento di Scienze-Sezione Scienze Geologiche, Università Roma 3, Rome, Italy
  • 5Natural History Museum, Vienna, Austria
  • 6Faculty of Geology, University of Patras, Rio, Greece
  • 7Dipartimento di Scienze della Terra e del Mare, Università degli studi di Palermo, Palermo, Italy
  • 8University of Bologna, Institute of Marine Science - National Research Council ISMAR-CNR, Bologna, Italy
  • 9Società Reggiana di Scienza Naturali
  • 10Sección de Paleontología, Museo de Alcalá de Guadaíra, Seville, Spain
  • 11ICTJA-CSIC, Barcelona, Spain
  • 12OGS Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, Trieste, Italy

The Messinian Salinity Crisis (MSC) was the greatest paleoenvironmental perturbation the Mediterranean has ever seen. The literature is abundant in hypotheses on the repercussions of the MSC on organisms. However, all these are based on incomplete and still uncertain scenarios about the MSC evolution, as well as on the assumption that such a paleoenvironmental perturbation must have completely reset marine biota. Having prevailed for many decades now, this assumption has leaked from paleontology and geosciences to biological sciences, with numerous studies taking this scenario for granted instead of using it as a starting hypothesis to be tested. Here, we review and revise the marine fossil record across the Mediterranean from the Tortonian until the Zanclean to follow the current rules of nomenclature, correct misidentifications, and control for stratigraphic misplacements. We examine the composition of marine faunas, both taxonomically and considering the function of each group in the marine ecosystem and the transfer of energy through the marine food web. Specifically, we investigate the following functional groups: 1) primary producers, 2) secondary producers, 3) primary consumers, 4) secondary consumers, and 5) top predators. Our study includes sea grasses, phytoplankton, corals, benthic and planktonic foraminifera, bivalves, gastropods, brachiopods, echinoids, bryozoans, fishes, ostracods, and marine mammals. We calculate biodiversity indexes to provide independent evidence quantifying to what degree the marine fauna underwent:

  1. A drop of overall regional biodiversity of the Mediterranean due to environmental stress during the Messinian.
  2. A taxonomic and functional change between the Tortonian, Messinian, and the Zanclean, that is before and after the MSC, as well as during the precursor events to that actual crisis taking place after the Tortonian/Messinian boundary.
  3. The onset of the present-day west-to-east decreasing gradient in species richness, which has been related to the sea temperature and productivity gradients and the distance from the Gibraltar connection to the Atlantic.

How to cite: Agiadi, K., Hohmann, N., Carnevale, G., Gliozzi, E., Faranda, C., Lozar, F., Harzhauser, M., Iliopoulos, G., Caruso, A., Kontakiotis, G., Taviani, M., Mancini, A. M., Borghi, E., Bajo Campos, I., Moissette, P., Thivaiou, D., Zarkogiannis, S., Besiou, E., Garcia-Castellanos, D., and Camerlenghi, A.: The impact of the Messinian Salinity Crisis on marine biota, EGU General Assembly 2020, Online, 4–8 May 2020, https://doi.org/10.5194/egusphere-egu2020-5799, 2020

Comments on the presentation

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Presentation version 1 – uploaded on 01 May 2020
  • CC1: Comment on EGU2020-5799, Kenneth De Baets, 01 May 2020

    Very nice summary of the Messinian salinity crisis on the biota. I have some questions:

    1) I found the use of the term Pre-evaporitic Messinian a bit confusing in the beginning as in my mind i associate the Messinian with the salinity crisis. I suspect this term is used here as the evaporites contain little to no fossils so that only the gradual restriction before this time can be meaningfully be assessed. Is this correct? 

    2) I found it interesting to see that the calcareous nannoplankton increases in the pre-evaporitic Messinian in Eastern part while it decreases in the other parts of the Mediterranean. Is the Eastern Mediterranean more suited for calcareous nannoplankton - are groups normally present in other parts of the Mediterranean migrating and thriving there during this time-interval (as oppossed to before)?

     

    • AC1: Reply to CC1, Konstantina Agiadi, 01 May 2020

      Pre-evaporitic Messinian refers to the interval from the Tortonian/Messinian boundary to 5.97 Ma, when the Messinian Salinity Crisis started. Indeed, we do not analyze the fossil record during the crisis because the data point were not enough for this kind of analysis.

    • AC2: Reply to CC1, Konstantina Agiadi, 03 May 2020

      About your second question (after consulting with F. Lozar and A.M. Mancini, our nannos experts): Today the Eastern Mediterranenathe due to its oligotrophic nature hosts a more diverse calcareous nannoplankton assemblage compared with more eutrophic regions, as the calcareous nannofossil are  well adapted to exploit this kind of environment. It could be inferred that during the pre-evaporitic Messinian the Eastern Mediterranean was predominantly oligotrophic.

    • AC3: Reply to CC1, Angelo Camerlenghi, 04 May 2020

      Yes, the Messinain does not start with the evaporitic deposition. The early Messinian (7.2515.97 Ma) also called " pre-conditioning phase " is made of sediments that indicate gradual marine restriction (diatom or opal-rich sediments, authigenic calcite precipitation, disappearance of planktonic forams in various marignal basins. Nothing is known of the pre-evaoritic sedimentary record in the deep basins.

      In essence, the evaporitic precipitation marks the onset of the Messinian Salinity Crisis at 5.97 Ma, not the Messinian.

      A nice short summary can be found in Roveri et al, 2014 Marine Geology

    • AC9: Reply to CC1, Daniel Garcia-Castellanos, 04 May 2020

      In response to 1),

      Because the MSC spans only the last third of the Messinian stage, and because the MSC is very poor in data and therefore excluded from this study, "pre-evaporitic Messinian" (or pre-MSC Messinian) is the most appropriate name for our 2nd period of study.  Hopefully will the MSC itself be addressed with the same technique, one day.

  • CC2: Comment on EGU2020-5799, Stefano Dominici, 04 May 2020

    Hi Konstantina & co-authors and thanks for this interesting contribution, in line with my current research. In fact I'm working on Mediterranean diversity (alpha-beta-gamma) of marine benthic molluscs. They should have the best record, but the literature on Zanclean alpha-diversity is scanty and unevenly distributed. The Messinian is possibly worse. My first quesiton is: how did you collect data on the bivalves? And the second: how can we reconstruct beta-diversity if we don't have enough alpha?

    • AC4: Reply to CC2, Angelo Camerlenghi, 04 May 2020

      Hi, thanks.

      I leave this to Koinstantina!

    • AC5: Reply to CC2, Konstantina Agiadi, 04 May 2020

      For all taxonomic groups, we use the published, and some of our own unpublished, data. Indeed, we faced the same issue of lack of data especially in the Zanclean. However, one of our goals is to gather all existing data and, at the same time, identify gaps that should be the target of future research.

      • CC3: Reply to AC5, Stefano Dominici, 04 May 2020

        @Stefano sorry, I was trying to respond to this in the discussion at the same time, but it got stuck. We do what we can with what is available. We encountered the same problem as you with lack of data for some intervals, taxa, or areas. The most important goal is to assemble what we know so far on the marine fauna, because this has never been done before and it undermines the importance of paleontology with regard to the study of the Messinian Salinity Crisis 

        As I wrote in the chat, we did publish a paper in Palaeo3 on the fate of benthic molluscs across the MSC -- which have the best and the best studied record in the Mediterranean. Our point there was, and still is, that unless we frame paleontological data with facies, we might be comparing apples with oranges. On eastern Med bivalves there are no abundance data available to my knowledge (but you might be using unpublished data, of course, and that takes us to Silvia's question). Is the problem getting worse when dealing with, say, fishes and diatoms, where the record is possibly scantier?

        • AC7: Reply to CC3, Konstantina Agiadi, 04 May 2020

          We do not use abundance data, only presences. Regarding diatoms, I cannot say yet, but for fish the dataset is not that bad because we have a lot of data from otoliths (my field)

    • AC6: Reply to CC2, Konstantina Agiadi, 04 May 2020

      We subsample the datasets we compare at 80%. So if the data points are not enough, we do not calculate beta diversity.

      • CC4: Reply to AC6, Stefano Dominici, 04 May 2020

        Thanks Konstantina -- my final point is that when you write the paper you should explain what facies you have sampled, so the reader knows that you are comparing in space and time the same facies. You contribution is very complex, dealing with different ecological groups, intervals and regions, and by the presentation facies control is not understood. Compliments for you work on otoliths, which I have been reading for my ongoing studies on the Zanclean. We are about to submit a paper, follow @deeptime on Twitter!

        • AC8: Reply to CC4, Konstantina Agiadi, 04 May 2020

          Thank you for your feedback; this is very valuable for us.

          The facies distribution is an issue we definitely have to address!

          I look forward to your paper.