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  1. AU="Simon A.F. Darroch"
  2. AU="Suzuki, Kenichi G N"
  3. AU="Hu, Yizhong"
  4. AU=Sasaki Kotaro
  5. AU=Abd-Elsayed Alaa
  6. AU="Jung, Hee-Jun"
  7. AU="Struckmann, Stephan"
  8. AU=Coward Richard
  9. AU="Ghazizadeh, Shabnam"
  10. AU="Rebecca A Butcher"
  11. AU="Kimberlyn Roosa"
  12. AU=Chian Ri-Cheng
  13. AU="Alzalzalah, Sayed"
  14. AU=Kaufman Jonathan J
  15. AU="Kim, Jin K"
  16. AU="Zevakov, S A"
  17. AU="Sui Phang"
  18. AU="Kolomeichuk, Lilia V"
  19. AU="Sabuj Kanti Mistry"
  20. AU="Basurto-Lozada, Daniela"
  21. AU="Takashima, Shin-Ichiro"
  22. AU="Teresinha Leal"
  23. AU="Angélique B van 't Wout"
  24. AU="Roberts, Nicholas J"
  25. AU="Chauhan, Gaurav B"
  26. AU=Hanjaya-Putra Donny
  27. AU=Powell James
  28. AU="Russell, Todd"
  29. AU=Forth Scott
  30. AU="Kreutzer, Susanne" AU="Kreutzer, Susanne"
  31. AU="St John, Maie"
  32. AU=Gerhardy A
  33. AU="Qi, Huixin"
  34. AU="Dobosiewicz, May"
  35. AU="Srivastava, Rakesh"
  36. AU="Grevtsov K.I."

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  1. Artikel ; Online: Long-term changes in unionid community in Kentucky Lake

    Beatrice M. Bock / Simon A. F. Darroch / Michelle Casey

    Journal of Freshwater Ecology, Vol 38, Iss

    Implications for understanding the effects of impoundment on river systems

    2023  Band 1

    Abstract: AbstractFreshwater mussels are both critically important in their ecosystems and rapidly declining around the world. Damming is a key reason for this decline in many locations because it affects the flow and turbidity of river systems, leading to ... ...

    Abstract AbstractFreshwater mussels are both critically important in their ecosystems and rapidly declining around the world. Damming is a key reason for this decline in many locations because it affects the flow and turbidity of river systems, leading to numerous detrimental effects on benthic communities. Although the ecological effects of impoundment have been well studied on timescales ranging from years to decades, the ecological effects of impoundment on longer (50–100 years) timescales are less well understood, with a key question being: how long after the building of dams and impoundments do we expect community structure to continue changing? In this study, we explore historical changes in the freshwater mussel assemblages in Kentucky Lake (dammed in 1944) using decades-long collections housed at Murray State University in combination with other historical records. After digitizing these collections and applying a robust rarefaction protocol to account for uneven sampling, we quantify changes in unionid assemblage structure alongside coeval water quality data collected through the Kentucky Lake Long-Term Monitoring Program. We find that subsampled richness exhibited declines after dam construction with losses among opportunistic taxa, channelization-tolerant taxa, and impoundment-intolerant taxa. We also find increases in the proportions of equilibrium taxa throughout the dataset. Overall, the assemblage composition reached an equilibrium by the year 2000 (50 years after impoundment). In concert, river water quality data show a decline in turbidity and increase in light penetration in the period 1988–2020. Although the geohistorical records treated in this study are patchy in time, we argue that they are nonetheless valuable and illustrate that freshwater ecosystems may serve as potential sites of restoration decades after anthropogenic disturbance. In turn, this emphasizes the importance of geohistorical collections to studying long-term changes in community structure and developing strategies for conservation ...
    Schlagwörter freshwater ecology ; Unionidae ; community structure ; conservation biology ; Environmental sciences ; GE1-350 ; Ecology ; QH540-549.5
    Thema/Rubrik (Code) 333
    Sprache Englisch
    Erscheinungsdatum 2023-07-01T00:00:00Z
    Verlag Taylor & Francis Group
    Dokumenttyp Artikel ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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  2. Artikel ; Online: Causes and consequences of end-Ediacaran extinction

    Simon A.F. Darroch / Emily F. Smith / Lyle L. Nelson / Matthew Craffey / James D. Schiffbauer / Marc Laflamme

    Cambridge Prisms: Extinction, Vol

    An update

    2023  Band 1

    Abstract: Since the 1980s, the existence of one or more extinction events in the late Ediacaran has been the subject of debate. Discussion surrounding these events has intensified in the last decade, in concert with efforts to understand drivers of global change ... ...

    Abstract Since the 1980s, the existence of one or more extinction events in the late Ediacaran has been the subject of debate. Discussion surrounding these events has intensified in the last decade, in concert with efforts to understand drivers of global change over the Ediacaran–Cambrian transition and the appearance of the more modern-looking Phanerozoic biosphere. In this paper we review the history of thought and work surrounding late Ediacaran extinctions, with a particular focus on the last 5 years of paleontological, geochemical, and geochronological research. We consider the extent to which key questions have been answered, and pose new questions which will help to characterize drivers of environmental and biotic change. A key challenge for future work will be the calculation of extinction intensities that account for limited sampling, the duration of Ediacaran ‘assemblage’ zones, and the preponderance of taxa restricted to a single ‘assemblage’; without these data, the extent to which Ediacaran bioevents represent genuine mass extinctions comparable to the ‘Big 5’ extinctions of the Phanerozoic remains to be rigorously tested. Lastly, we propose a revised model for drivers of late Ediacaran extinction pulses that builds off recent data and growing consensus within the field. This model is speculative, but does frame testable hypotheses that can be targeted in the next decade of work.
    Schlagwörter Community ecology ; ecosystem ; evolution ; macroevolution ; volcanic eruptions ; QH359-425
    Sprache Englisch
    Erscheinungsdatum 2023-01-01T00:00:00Z
    Verlag Cambridge University Press
    Dokumenttyp Artikel ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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  3. Artikel ; Online: Reconstructing the feeding ecology of Cambrian sponge reefs

    Brandt M. Gibson / Max Chipman / Paolo Attanasio / Zaid Qureshi / Simon A. F. Darroch / Imran A. Rahman / Marc Laflamme

    Royal Society Open Science, Vol 10, Iss

    the case for active suspension feeding in Archaeocyatha

    2023  Band 11

    Abstract: Sponge-grade Archaeocyatha were early Cambrian biomineralizing metazoans that constructed reefs globally. Despite decades of research, many facets of archaeocyath palaeobiology remain unclear, making it difficult to reconstruct the palaeoecology of ... ...

    Abstract Sponge-grade Archaeocyatha were early Cambrian biomineralizing metazoans that constructed reefs globally. Despite decades of research, many facets of archaeocyath palaeobiology remain unclear, making it difficult to reconstruct the palaeoecology of Cambrian reef ecosystems. Of specific interest is how these organisms fed; previous experimental studies have suggested that archaeocyaths functioned as passive suspension feeders relying on ambient currents to transport nutrient-rich water into their central cavities. Here, we test this hypothesis using computational fluid dynamics (CFD) simulations of digital models of select archaeocyath species. Our results demonstrate that, given a range of plausible current velocities, there was very little fluid circulation through the skeleton, suggesting obligate passive suspension feeding was unlikely. Comparing our simulation data with exhalent velocities collected from extant sponges, we infer an active suspension feeding lifestyle for archaeocyaths. The combination of active suspension feeding and biomineralization in Archaeocyatha may have facilitated the creation of modern metazoan reef ecosystems.
    Schlagwörter Archaeocyatha ; Cambrian ; computational fluid dynamics ; reefs ; suspension feeding ; Science ; Q
    Thema/Rubrik (Code) 551
    Sprache Englisch
    Erscheinungsdatum 2023-11-01T00:00:00Z
    Verlag The Royal Society
    Dokumenttyp Artikel ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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  4. Artikel ; Online: The Importance of Size and Location Within Gregarious Populations of Ernietta plateauensis

    Brandt M. Gibson / Simon A.F. Darroch / Katie M. Maloney / Marc Laflamme

    Frontiers in Earth Science, Vol

    2021  Band 9

    Abstract: Ernietta plateauensis is a semi-infaunal macroscopic eukaryote of unknown affinities common in latest Ediacaran (∼548–539 Ma) shallow marine settings in Namibia. The discovery of in-situ assemblages of Ernietta has demonstrated that these organisms lived ...

    Abstract Ernietta plateauensis is a semi-infaunal macroscopic eukaryote of unknown affinities common in latest Ediacaran (∼548–539 Ma) shallow marine settings in Namibia. The discovery of in-situ assemblages of Ernietta has demonstrated that these organisms lived in aggregated populations, while studies employing computational fluid dynamics (CFD) modeling have supported the hypothesis that these organisms were likely behaving as gregarious suspension feeders, analogous to many extant invertebrate phyla in present-day marine environments. Careful census and measurement of individuals within these in-situ populations offers an opportunity to examine how their size and location within a larger population affect nutrient delivery dynamics. In this study, we build on previous work by simulating fluid flow over aggregations of Ernietta comprising individuals of disparate sizes, and additionally reconstruct a population of Ernietta preserved in-situ from Farm Hansburg, Namibia. We use a combination of stationary and time-dependent CFD to reconstruct nutrient carrying flow paths, and compare the efficiency with which nutrients are partitioned between individuals of different shapes and sizes. Our results demonstrate that smaller Ernietta experience limited recirculation within their cavities compared to larger individuals. Furthermore, in spatially-accurate distributions, reduced recirculation is limited to isolated individuals of any size, while smaller individuals found downstream of larger ones receive enhanced cavity mixing. These reconstructed flow patterns illustrate that the disadvantage associated with small size is apparently mediated by location within the overall aggregation, suggesting a complex interplay of controls on feeding efficiency. This in turn suggests that aggregations of adult Ernietta would likely have performed a ‘nursery’ function, creating localized conditions ideal for the settlement and growth of younger individuals.
    Schlagwörter Ediacara biota ; computational fluid dynamics (CFD) ; large eddy simulation (LES) ; Spalart-Allmaras ; Nama assemblage ; Science ; Q
    Thema/Rubrik (Code) 612
    Sprache Englisch
    Erscheinungsdatum 2021-10-01T00:00:00Z
    Verlag Frontiers Media S.A.
    Dokumenttyp Artikel ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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  5. Artikel ; Online: The rangeomorph Pectinifrons abyssalis

    Simon A.F. Darroch / Susana Gutarra / Hale Masaki / Andrei Olaru / Brandt M. Gibson / Frances S. Dunn / Emily G. Mitchell / Rachel A. Racicot / Gregory Burzynski / Imran A. Rahman

    iScience, Vol 26, Iss 2, Pp 105989- (2023)

    Hydrodynamic function at the dawn of animal life

    2023  

    Abstract: Summary: Rangeomorphs are among the oldest putative eumetazoans known from the fossil record. Establishing how they fed is thus key to understanding the structure and function of the earliest animal ecosystems. Here, we use computational fluid dynamics ... ...

    Abstract Summary: Rangeomorphs are among the oldest putative eumetazoans known from the fossil record. Establishing how they fed is thus key to understanding the structure and function of the earliest animal ecosystems. Here, we use computational fluid dynamics to test hypothesized feeding modes for the fence-like rangeomorph Pectinifrons abyssalis, comparing this to the morphologically similar extant carnivorous sponge Chondrocladia lyra. Our results reveal complex patterns of flow around P. abyssalis unlike those previously reconstructed for any other Ediacaran taxon. Comparisons with C. lyra reveal substantial differences between the two organisms, suggesting they converged on a similar fence-like morphology for different functions. We argue that the flow patterns recovered for P. abyssalis do not support either a suspension feeding or osmotrophic feeding habit. Instead, our results indicate that rangeomorph fronds may represent organs adapted for gas exchange. If correct, this interpretation could require a dramatic reinterpretation of the oldest macroscopic animals.
    Schlagwörter Zoology ; Evolutionary biology ; Paleobiology ; Science ; Q
    Thema/Rubrik (Code) 532
    Sprache Englisch
    Erscheinungsdatum 2023-02-01T00:00:00Z
    Verlag Elsevier
    Dokumenttyp Artikel ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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  6. Artikel ; Online: Pentaradial eukaryote suggests expansion of suspension feeding in White Sea-aged Ediacaran communities

    Kelsie Cracknell / Diego C. García-Bellido / James G. Gehling / Martin J. Ankor / Simon A. F. Darroch / Imran A. Rahman

    Scientific Reports, Vol 11, Iss 1, Pp 1-

    2021  Band 9

    Abstract: Abstract Suspension feeding is a key ecological strategy in modern oceans that provides a link between pelagic and benthic systems. Establishing when suspension feeding first became widespread is thus a crucial research area in ecology and evolution, ... ...

    Abstract Abstract Suspension feeding is a key ecological strategy in modern oceans that provides a link between pelagic and benthic systems. Establishing when suspension feeding first became widespread is thus a crucial research area in ecology and evolution, with implications for understanding the origins of the modern marine biosphere. Here, we use three-dimensional modelling and computational fluid dynamics to establish the feeding mode of the enigmatic Ediacaran pentaradial eukaryote Arkarua. Through comparisons with two Cambrian echinoderms, Cambraster and Stromatocystites, we show that flow patterns around Arkarua strongly support its interpretation as a passive suspension feeder. Arkarua is added to the growing number of Ediacaran benthic suspension feeders, suggesting that the energy link between pelagic and benthic ecosystems was likely expanding in the White Sea assemblage (~ 558–550 Ma). The advent of widespread suspension feeding could therefore have played an important role in the subsequent waves of ecological innovation and escalation that culminated with the Cambrian explosion.
    Schlagwörter Medicine ; R ; Science ; Q
    Thema/Rubrik (Code) 333
    Sprache Englisch
    Erscheinungsdatum 2021-02-01T00:00:00Z
    Verlag Nature Portfolio
    Dokumenttyp Artikel ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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  7. Artikel ; Online: Increase in metazoan ecosystem engineering prior to the Ediacaran–Cambrian boundary in the Nama Group, Namibia

    Alison T. Cribb / Charlotte G. Kenchington / Bryce Koester / Brandt M. Gibson / Thomas H. Boag / Rachel A. Racicot / Helke Mocke / Marc Laflamme / Simon A. F. Darroch

    Royal Society Open Science, Vol 6, Iss

    2019  Band 9

    Abstract: The disappearance of the soft-bodied Ediacara biota at the Ediacaran–Cambrian boundary potentially represents the earliest mass extinction of complex life, although the precise driver(s) of this extinction remain unresolved. The ‘biotic replacement’ ... ...

    Abstract The disappearance of the soft-bodied Ediacara biota at the Ediacaran–Cambrian boundary potentially represents the earliest mass extinction of complex life, although the precise driver(s) of this extinction remain unresolved. The ‘biotic replacement’ model proposes that an evolutionary radiation of metazoan ecosystem engineers in the latest Ediacaran profoundly altered marine palaeoenvironments, resulting in the extinction of Ediacara biota and setting the stage for the subsequent Cambrian Explosion. However, metazoan ecosystem engineering across the Ediacaran–Cambrian transition has yet to be quantified. Here, we test this key tenet of the biotic replacement model by characterizing the intensity of metazoan bioturbation and ecosystem engineering in trace fossil assemblages throughout the latest Ediacaran Nama Group in southern Namibia. The results illustrate a dramatic increase in both bioturbation and ecosystem engineering intensity in the latest Ediacaran, prior to the Cambrian boundary. Moreover, our analyses demonstrate that the highest-impact ecosystem engineering behaviours were present well before the onset of the Cambrian. These data provide the first support for a fundamental prediction of the biotic replacement model, and evidence for a direct link between the early evolution of ecosystem engineering and the extinction of the Ediacara biota.
    Schlagwörter ediacaran ; trace fossil ; ecosystem engineering ; cambrian ; extinction ; Science ; Q
    Thema/Rubrik (Code) 551
    Sprache Englisch
    Erscheinungsdatum 2019-09-01T00:00:00Z
    Verlag The Royal Society
    Dokumenttyp Artikel ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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  8. Artikel ; Online: Skeletal correlates for body mass estimation in modern and fossil flying birds.

    Daniel J Field / Colton Lynner / Christian Brown / Simon A F Darroch

    PLoS ONE, Vol 8, Iss 11, p e

    2013  Band 82000

    Abstract: Scaling relationships between skeletal dimensions and body mass in extant birds are often used to estimate body mass in fossil crown-group birds, as well as in stem-group avialans. However, useful statistical measurements for constraining the precision ... ...

    Abstract Scaling relationships between skeletal dimensions and body mass in extant birds are often used to estimate body mass in fossil crown-group birds, as well as in stem-group avialans. However, useful statistical measurements for constraining the precision and accuracy of fossil mass estimates are rarely provided, which prevents the quantification of robust upper and lower bound body mass estimates for fossils. Here, we generate thirteen body mass correlations and associated measures of statistical robustness using a sample of 863 extant flying birds. By providing robust body mass regressions with upper- and lower-bound prediction intervals for individual skeletal elements, we address the longstanding problem of body mass estimation for highly fragmentary fossil birds. We demonstrate that the most precise proxy for estimating body mass in the overall dataset, measured both as coefficient determination of ordinary least squares regression and percent prediction error, is the maximum diameter of the coracoid's humeral articulation facet (the glenoid). We further demonstrate that this result is consistent among the majority of investigated avian orders (10 out of 18). As a result, we suggest that, in the majority of cases, this proxy may provide the most accurate estimates of body mass for volant fossil birds. Additionally, by presenting statistical measurements of body mass prediction error for thirteen different body mass regressions, this study provides a much-needed quantitative framework for the accurate estimation of body mass and associated ecological correlates in fossil birds. The application of these regressions will enhance the precision and robustness of many mass-based inferences in future paleornithological studies.
    Schlagwörter Medicine ; R ; Science ; Q
    Thema/Rubrik (Code) 531
    Sprache Englisch
    Erscheinungsdatum 2013-01-01T00:00:00Z
    Verlag Public Library of Science (PLoS)
    Dokumenttyp Artikel ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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