| 1. |
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Aad, G, et al.
(författare)
-
Search for Higgs Boson Pair Production in the γγbb[over ¯] Final State Using pp Collision Data at sqrt[s]=8 TeV from the ATLAS Detector.
- 2015
-
Ingår i: Physical Review Letters. - 1079-7114. ; 114:8
-
Tidskriftsartikel (refereegranskat)abstract
- Searches are performed for resonant and nonresonant Higgs boson pair production in the γγbb[over ¯] final state using 20 fb^{-1} of proton-proton collisions at a center-of-mass energy of 8 TeV recorded with the ATLAS detector at the CERN Large Hadron Collider. A 95% confidence level upper limit on the cross section times branching ratio of nonresonant production is set at 2.2 pb, while the expected limit is 1.0 pb. The difference derives from a modest excess of events, corresponding to 2.4 standard deviations from the background-only hypothesis. The limit observed in the search for a narrow X→hh resonance ranges between 0.7 and 3.5 pb as a function of the resonance mass.
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Aad, G., et al.
(författare)
-
- 2015
-
Tidskriftsartikel (refereegranskat)
|
|
| 10. |
- Aad, G., et al.
(författare)
-
- 2015
-
Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; :1
-
Tidskriftsartikel (refereegranskat)
|
|
| 11. |
- Aad, G., et al.
(författare)
-
- 2015
-
Tidskriftsartikel (refereegranskat)
|
|
| 12. |
- Aad, G., et al.
(författare)
-
- 2015
-
Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; :1
-
Tidskriftsartikel (refereegranskat)
|
|
| 13. |
- Aad, G., et al.
(författare)
-
- 2015
-
Ingår i: Journal of High Energy Physics. - : Springer-Verlag New York. - 1029-8479 .- 1126-6708. ; :9
-
Tidskriftsartikel (refereegranskat)
|
|
| 14. |
- Aad, G., et al.
(författare)
-
- 2015
-
Ingår i: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368 .- 1550-7998. ; 91:7
-
Tidskriftsartikel (refereegranskat)
|
|
| 15. |
- Aad, G., et al.
(författare)
-
- 2015
-
Ingår i: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368 .- 1550-7998. ; 91:5
-
Tidskriftsartikel (refereegranskat)
|
|
| 16. |
- Aad, G., et al.
(författare)
-
- 2015
-
Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; :1
-
Tidskriftsartikel (refereegranskat)
|
|
| 17. |
- Aad, G., et al.
(författare)
-
- 2015
-
Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; :3
-
Tidskriftsartikel (refereegranskat)
|
|
| 18. |
- Aad, G., et al.
(författare)
-
- 2015
-
Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; :2
-
Tidskriftsartikel (refereegranskat)
|
|
| 19. |
- Aad, G, et al.
(författare)
-
- 2015
-
swepub:Mat__t
|
|
| 20. |
-
- 2019
-
Tidskriftsartikel (refereegranskat)
|
|
| 21. |
|
|
| 22. |
|
|
| 23. |
- Aad, G., et al.
(författare)
-
- 2015
-
Tidskriftsartikel (refereegranskat)
|
|
| 24. |
- Aad, G., et al.
(författare)
-
- 2015
-
Tidskriftsartikel (refereegranskat)
|
|
| 25. |
- Aad, G., et al.
(författare)
-
- 2015
-
Tidskriftsartikel (refereegranskat)
|
|
| 26. |
- Aad, G., et al.
(författare)
-
- 2015
-
Tidskriftsartikel (refereegranskat)
|
|
| 27. |
- Aad, G., et al.
(författare)
-
- 2015
-
Tidskriftsartikel (refereegranskat)
|
|
| 28. |
- Aad, G., et al.
(författare)
-
- 2015
-
Tidskriftsartikel (refereegranskat)
|
|
| 29. |
- Aad, G., et al.
(författare)
-
- 2015
-
Ingår i: The European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6052. ; 75:1
-
Tidskriftsartikel (refereegranskat)
|
|
| 30. |
- Aad, G., et al.
(författare)
-
- 2015
-
Ingår i: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368 .- 1550-7998. ; 91:5
-
Tidskriftsartikel (refereegranskat)
|
|
| 31. |
- Aad, G., et al.
(författare)
-
- 2015
-
Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; :1, s. 1-67
-
Tidskriftsartikel (refereegranskat)
|
|
| 32. |
- Aad, G., et al.
(författare)
-
- 2015
-
Ingår i: Journal of High Energy Physics. - : Springer-Verlag New York. - 1029-8479 .- 1126-6708. ; :5
-
Tidskriftsartikel (refereegranskat)
|
|
| 33. |
- Aad, G., et al.
(författare)
-
- 2015
-
Tidskriftsartikel (refereegranskat)
|
|
| 34. |
- Adare, A., et al.
(författare)
-
Measurements of Elliptic and Triangular Flow in High-Multiplicity He-3 + Au Collisions at root s(NN)=200 GeV
- 2015
-
Ingår i: Physical Review Letters. - 1079-7114. ; 115:14
-
Tidskriftsartikel (refereegranskat)abstract
- We present the first measurement of elliptic (v(2)) and triangular (v(3)) flow in high-multiplicity He-3 + Au collisions at root s(NN) = 200 GeV. Two-particle correlations, where the particles have a large separation in pseudorapidity, are compared in He-3 + Au and in p + p collisions and indicate that collective effects dominate the second and third Fourier components for the correlations observed in the He-3 + Au system. The collective behavior is quantified in terms of elliptic v(2) and triangular v(3) anisotropy coefficients measured with respect to their corresponding event planes. The v(2) values are comparable to those previously measured in d + Au collisions at the same nucleon-nucleon center-of-mass energy. Comparisons with various theoretical predictions are made, including to models where the hot spots created by the impact of the three He-3 nucleons on the Au nucleus expand hydrodynamically to generate the triangular flow. The agreement of these models with data may indicate the formation of low-viscosity quark-gluon plasma even in these small collision systems.
|
|
| 35. |
- Adare, A., et al.
(författare)
-
Search for dark photons from neutral meson decays in p plus p and d plus Au collisions at root s(NN)=200 GeV
- 2015
-
Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 91:3
-
Tidskriftsartikel (refereegranskat)abstract
- The standard model (SM) of particle physics is spectacularly successful, yet the measured value of the muon anomalous magnetic moment (g - 2)mu deviates from SM calculations by 3.6 sigma. Several theoretical models attribute this to the existence of a "dark photon," an additional U(1) gauge boson, which is weakly coupled to ordinary photons. The PHENIX experiment at the Relativistic Heavy Ion Collider has searched for a dark photon, U, in pi(0), eta -> gamma e(+)e(-) decays and obtained upper limits of O(2 x 10(-6)) on U-gamma mixing at 90% C.L. for the mass range 30 < m(U) < 90 MeV/c(2). Combined with other experimental limits, the remaining region in the U-gamma mixing parameter space that can explain the (g - 2)(mu) deviation from its SM value is nearly completely excluded at the 90% confidence level, with only a small region of 29 < m(U) < 32 MeV/c(2) remaining.
|
|
| 36. |
- Adare, A., et al.
(författare)
-
Charged-pion cross sections and double-helicity asymmetries in polarized p plus p collisions at root s=200 GeV
- 2015
-
Ingår i: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 91:3
-
Tidskriftsartikel (refereegranskat)abstract
- We present midrapidity charged-pion invariant cross sections, the ratio of the pi(-) to pi(+) cross sections and the charge-separated double-spin asymmetries in polarized p + p collisions at root s = p + 200 GeV. While the cross section measurements are consistent within the errors of next-to-leading-order (NLO) perturbative quantum chromodynamics predictions (pQCD), the same calculations overestimate the ratio of the charged-pion cross sections. This discrepancy arises from the cancellation of the substantial systematic errors associated with the NLO-pQCD predictions in the ratio and highlights the constraints these data will place on flavor-dependent pion fragmentation functions. The charge-separated pion asymmetries presented here sample an x range of similar to 0.03-0.16 and provide unique information on the sign of the gluon-helicity distribution.
|
|
| 37. |
- Adare, A, et al.
(författare)
-
Measurement of Long-Range Angular Correlation and Quadrupole Anisotropy of Pions and (Anti)Protons in Central d+Au Collisions at sqrt[s_{NN}]=200 GeV.
- 2015
-
Ingår i: Physical Review Letters. - 1079-7114. ; 114:19
-
Tidskriftsartikel (refereegranskat)abstract
- We present azimuthal angular correlations between charged hadrons and energy deposited in calorimeter towers in central d+Au and minimum bias p+p collisions at sqrt[s_{NN}]=200 GeV. The charged hadron is measured at midrapidity |η|<0.35, and the energy is measured at large rapidity (-3.7<η<-3.1, Au-going direction). An enhanced near-side angular correlation across |Δη|>2.75 is observed in d+Au collisions. Using the event plane method applied to the Au-going energy distribution, we extract the anisotropy strength v_{2} for inclusive charged hadrons at midrapidity up to p_{T}=4.5 GeV/c. We also present the measurement of v_{2} for identified π^{±} and (anti)protons in central d+Au collisions, and observe a mass-ordering pattern similar to that seen in heavy-ion collisions. These results are compared with viscous hydrodynamic calculations and measurements from p+Pb at sqrt[s_{NN}]=5.02 TeV. The magnitude of the mass ordering in d+Au is found to be smaller than that in p+Pb collisions, which may indicate smaller radial flow in lower energy d+Au collisions.
|
|
| 38. |
- Blake, Daniel B., et al.
(författare)
-
A new silurian ophiuroid from the west of Ireland
- 2017
-
Ingår i: Irish Journal of Earth Sciences. - : Project Muse. - 0790-1763. ; 35, s. 57-66
-
Tidskriftsartikel (refereegranskat)abstract
- Silurian echinoderms from Ireland are poorly known; hitherto, only three nominal species have been described, all crinoids and all from the Telychian (Upper Llandovery, Lower Silurian) Kilbride Formation in County Galway. A new species from this formation, Crepidosoma doylei, is the first recorded Irish Silurian ophiuroid (brittle star). The new species is described from five articulated specimens; all are mouldic and none retains a counterpart. The disc and immediately adjacent arm lateral ossicles of the new species differ in shape from those of the type species in that these ossicles are comparatively flat rather than angular or ridged, and the series is marked by a well-defined channelway that appears to have extended from within the disc for the full length of the free arm. Ambital framework ossicles are smooth, and not S- or Z-shaped and ridged as in the type species. The new specimens of C. doylei were recovered from distal storm deposits that are thought to be deep-water equivalents of Benthic Assemblage Zone 5 (Clorinda Community).
|
|
| 39. |
- Bogolepova, Olga, et al.
(författare)
-
New records of brachiopods and crinoids from the Silurian (Wenlock) of the southern Urals, Russia
- 2018
-
Ingår i: GFF. - : Informa UK Limited. - 1103-5897 .- 2000-0863.
-
Tidskriftsartikel (refereegranskat)abstract
- Crinoids and brachiopods are described from the Silurian Uzyan Formation of the Zilair Zone in the southern Urals. The occurrence of the graptolites Coronograptus praedeubeli suggests a late Homerian (Wenlock) age for the strata. A new disparid crinoid, Cicerocrinus gracilis Donovan sp. nov., is the oldest known member of this genus. It has a long, flexible and homeomorphic column, and a tall bryozoan palaeontology terminology (IBr2) (second primibrachial) axillary. All species of Cicerocrinus described previously have been limited to the Ludlow of the British Isles, Sweden and Estonia, and the Pridoli of Estonia. The poorly preserved brachiopod fauna is represented by small atrypid (Atrypa? sp.) and dalmanellid brachiopods (Levenea? sp.). The reported assemblage generally inhabited deep-water environments.
|
|
| 40. |
- Donovan, Stephen K., et al.
(författare)
-
Echinoids as hard substrates : Varied examples from the Oligocene of Antigua, Lesser Antilles
- 2017
-
Ingår i: Proceedings of the Geologists' Association. - : Elsevier BV. - 0016-7878. ; 128:3, s. 326-331
-
Tidskriftsartikel (refereegranskat)abstract
- A collection of unremarkably preserved fossil irregular echinoids from the Upper Oligocene (Chattian) Antigua Formation of Antigua, Lesser Antilles, nonetheless provides evidence of a range of palaeoecological interactions. A dead test of the heart urchin Eupatagus sp. formed a hard substrate for the attachment of gregarious Thecidellina? sp., a thecidoid brachiopod. Although obligate encrusters, these brachiopods more commonly occur as disarticulated valves free of the substrate in the Antillean fossil record. Elongate pits in test fragments were formed, variously, before and after the death of the host echinoids. These depressions on the external surface were formed either by invertebrates excavating domiciles or by claws or teeth; the echinoid later reclaimed the pits and grew new tubercles in the base. Post-mortem pits lack such new tuberculation. A test of Eupatagus sp. bears the boring Oichnus isp., formed either by a predator (gastropod?) or after the death of the echinoid (domicile), and a serpulid worm tube which grew on the test subsequent to the echinoid's death. The echinoid fauna of the Antigua Formation has been easy to collect and specimens are to be found in many museums; they now await re-examination to reveal palaeosynecological data analogous to that determined from the fragments discussed herein.
|
|
| 41. |
- Erlykin, Anatoly D., et al.
(författare)
-
Mass extinctions over the last 500 myr : An astronomical cause?
- 2017
-
Ingår i: Palaeontology. - : Wiley. - 0031-0239. ; 60:2, s. 159-167
-
Tidskriftsartikel (refereegranskat)abstract
- A Fourier analysis of the magnitudes and timing of the Phanerozoic mass extinctions (MEs) demonstrates that many of the periodicities claimed in other analyses are not statistically significant. Moreover we show that the periodicities associated with oscillations of the Solar System about the galactic plane are too irregular to give narrow peaks in the Fourier periodograms. This leads us to conclude that, apart from possibly a small number of major events, astronomical causes for MEs can largely be ruled out.
|
|
| 42. |
- Finnegan, Seth, et al.
(författare)
-
Biogeographic and bathymetric determinants of brachiopod extinction and survival during the late ordovician mass extinction
- 2016
-
Ingår i: Proceedings of the Royal Society B: Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 283:1829
-
Tidskriftsartikel (refereegranskat)abstract
- The Late Ordovician mass extinction (LOME) coincided with dramatic climate changes, but there are numerous ways in which these changes could have driven marine extinctions. We use a palaeobiogeographic database of rhynchonelliform brachiopods to examine the selectivity of Late Ordovician-Early Silurian genus extinctions and evaluate which extinction drivers are best supported by the data. The first (latest Katian) pulse of the LOME preferentially affected genera restricted to deeper waters or to relatively narrow (less than 35°) palaeolatitudinal ranges. This pattern is only observed in the latest Katian, suggesting that it reflects drivers unique to this interval. Extinction of exclusively deeperwater genera implies that changes in water mass properties such as dissolved oxygen content played an important role. Extinction of genera with narrow latitudinal ranges suggests that interactions between shifting climate zones and palaeobiogeography may also have been important. We test the latter hypothesis by estimating whether each genus would have been able to track habitats within its thermal tolerance range during the greenhouse-icehouse climate transition. Models including these estimates are favoured over alternative models. We argue that the LOME, long regarded as non-selective, is highly selective along biogeographic and bathymetric axes that are not closely correlated with taxonomic identity.
|
|
| 43. |
- Finnegan, Seth, et al.
(författare)
-
Identifying the most surprising victims of mass extinction events : An example using Late Ordovician brachiopods
- 2017
-
Ingår i: Biology letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 13:9
-
Tidskriftsartikel (refereegranskat)abstract
- Mass extinction events are recognized by increases in extinction rate and magnitude and, often, by changes in the selectivity of extinction. When considering the selective fingerprint of a particular event, not all taxon extinctions are equally informative: some would be expected even under a ‘background’ selectivity regime, whereas others would not and thus require special explanation. When evaluating possible drivers for the extinction event, the latter group is of particular interest. Here, we introduce a simple method for identifying these most surprising victims of extinction events by training models on background extinction intervals and using these models to make per-taxon assessments of ‘expected’ risk during the extinction interval. As an example, we examine brachiopod genus extinctions during the Late Ordovician Mass Extinction and show that extinction of genera in the deep-water ‘Foliomena fauna’ was particularly unexpected given preceding Late Ordovician extinction patterns.
|
|
| 44. |
- Hammarlund, Emma U., et al.
(författare)
-
The Sirius Passet Lagerstätte of North Greenland—A geochemical window on early Cambrian low-oxygen environments and ecosystems
- 2019
-
Ingår i: Geobiology. - : Wiley. - 1472-4677. ; 17:1, s. 12-26
-
Tidskriftsartikel (refereegranskat)abstract
- The early Cambrian Sirius Passet fauna of northernmost Greenland (Cambrian Series 2, Stage 3) contains exceptionally preserved soft tissues that provide an important window to early animal evolution, while the surrounding sediment holds critical data on the palaeodepositional water-column chemistry. The present study combines palaeontological data with a multiproxy geochemical approach based on samples collected in situ at high stratigraphic resolution from Sirius Passet. After careful consideration of chemical alterations during burial, our results demonstrate that fossil preservation and biodiversity show significant correlation with iron enrichments (FeHR/FeT), trace metal behaviour (V/Al), and changes in nitrogen cycling (δ15N). These data, together with Mo/Al and the preservation of organic carbon (TOC), are consistent with a water column that was transiently low in oxygen concentration, or even intermittently anoxic. When compared with the biogeochemical characteristics of modern oxygen minimum zones (OMZs), geochemical and palaeontological data collectively suggest that oxygen concentrations as low as 0.2–0.4 ml/L restricted bioturbation but not the development of a largely nektobenthic community of predators and scavengers. We envisage for the Sirius Passet biota a depositional setting where anoxic water column conditions developed and passed over the depositional site, possibly in association with sea-level change, and where this early Cambrian biota was established in conditions with very low oxygen.
|
|
| 45. |
- Harper, David A.T., et al.
(författare)
-
Brachiopods : origin and early history
- 2017
-
Ingår i: Palaeontology. - : Wiley. - 0031-0239 .- 1475-4983. ; 60:5, s. 609-631
-
Tidskriftsartikel (refereegranskat)abstract
- Despite many major advances in recent years, three key challenges remain in bringing clarity to the early history of the phylum: (1) identifying the origin, morphology and life modes of the first brachiopods; (2) understanding the relationships of the major groups to each other and higher sister taxa; and (3) unravelling the roles of the Cambrian and Ordovician radiations that set the agenda for much of subsequent brachiopod evolution. Since some 95% of all brachiopod taxa are extinct, the fossil record is the primary source of data to frame and test models for the evolution of the phylum. The acquisition of new, and the redescription of existing faunas, in precise spatial and temporal frameworks, using new and well-established analytical and investigative techniques, are as important as ever.
|
|
| 46. |
- Harper, David A.T., et al.
(författare)
-
Contextualizing the Onset of the Great Ordovician Biodiversification Event
- 2018
-
Ingår i: Lethaia. - : Scandinavian University Press / Universitetsforlaget AS. - 0024-1164. ; 51:2, s. 149-150
-
Tidskriftsartikel (refereegranskat)abstract
- We introduce and briefly summarize a collection of papers contextualizing the onset of the Great Ordovician Biodiversification Event, initiated during the first meeting of IGCP project 653 at Van Mildert College, Durham University, UK, in September 2016.
|
|
| 47. |
- Harper, David A.T., et al.
(författare)
-
Late Ordovician deep-water brachiopod fauna from Raheen, Waterford harbour, Ireland
- 2017
-
Ingår i: Irish Journal of Earth Sciences. - 0790-1763. ; 35, s. 1-18
-
Tidskriftsartikel (refereegranskat)abstract
- The Raheen Formation at Newtown Head in Waterford Harbour is a small isolated section of Ordovician rocks, dominated by volcanics of the Duncannon Group, but with interbedded fossiliferous shales. Although a brachiopod and trilobite dominated fauna has been known since the mid-nineteenth century, only the trilobites and cystoids have been assessed in modern terms. This paper describes the brachiopod fauna for the first time. The assemblage from Raheen is overwhelmingly dominated by the dalmanelloid Onniella, with the small plectambonitoid Sericoidea comprising the second most numerous species; both are represented by new species. This revision has also identified a wide range of other genera, but all in very small numbers. These include an obolid, a paterulid, Paracraniops and Orthisocrania divaricata (M‘Coy) amongst the non-articulated brachiopods. Articulated genera present include the orthoids Nicolella, Ptychopleurella, Sulevorthis, Skenidioides and the plectambonitoid Leptestiina. Very rare forms include Idiospira? and Palaeostrophomena, together with possibly Biscuspina and Sowerbyella. The brachiopod revision supports the late Caradoc (early Katian) age indicated by the trilobite fauna. The trilobite fauna generally indicates a probable deeper-water environment and the brachiopod assemblage confirms an outer-shelf environment. Although elements of the assemblage indicate affinity with the well-defined Late Ordovician Foliomena fauna, it probably occupied a more shoreward position.
|
|
| 48. |
- Harper, David A.T., et al.
(författare)
-
The Furongian (late Cambrian) Biodiversity Gap : Real or apparent?
- 2019
-
Ingår i: Palaeoworld. - Amsterdam : Elsevier BV. - 1871-174X .- 1875-5887. ; 28:1-2, s. 4-12
-
Tidskriftsartikel (refereegranskat)abstract
- Two major, extended diversifications punctuated the evolution of marine life during the Early Palaeozoic. The interregnum, however, between the Cambrian Explosion and the Great Ordovician Biodiversification Event, is exemplified by the Furongian Gap when there was a marked drop in biodiversity. It is unclear whether the gap is apparent, due to sampling failure or lack of rock, or real — associated with unique and fluctuating environments, a distinctive palaeogeography and extreme climates during the late Cambrian. Indications suggest that there has been little attention paid to this interval compared with those below and above, while some of the classical areas for Cambrian research, such as Bohemia, have poor coverage through the Furongian. Moreover, based on information available in databases and the literature, together with the ghost ranges of many higher taxa through the Furongian, data suggest that biodiversity in this stage has been significantly underestimated. Emphasis, to date, has been placed on widespread, deeper-water dark shale facies of the interval, with generally low diversity faunas, whereas shallow-water communities have often been neglected.
|
|
| 49. |
- Harper, David A.T., et al.
(författare)
-
The Sirius Passet Lagerstätte of North Greenland: a remote window on the Cambrian Explosion
- 2019
-
Ingår i: Journal of the Geological Society. - : Geological Society of London. - 0016-7649 .- 2041-479X. ; 176, s. 1023-1037
-
Tidskriftsartikel (refereegranskat)abstract
- The lower Cambrian Lagerstätte of Sirius Passet, Peary Land, North Greenland, is one of the oldest of the Phanerozoic exceptionally preserved biotas. The Lagerstätte evidences the escalation of numbers of new body plans and life modes that formed the basis for a modern, functionally tiered ecosystem. The fauna is dominated by predators, infaunal, benthic and pelagic, and the presence of abundant nekton, including large sweep-net feeders, suggests an ecosystem rich in nutrients. Recent discoveries have helped reconstruct digestive systems and their contents, muscle fibres, and visual and nervous systems for a number of taxa. New collections have confirmed the complex combination of taphonomic pathways associated with the biota and its potentially substantial biodiversity. These complex animal-based communities within the Buen Formation were associated with microbial matgrounds, now preserved in black mudstones deposited below storm wave base that provide insight into the shift from late Neoproterozoic (Ediacaran) to Cambrian substrates and communities. Moreover, the encasing sediment holds important data on the palaeoenvironment and the water-column chemistry, suggesting that these animal-based communities developed in conditions with very low oxygen concentrations.
|
|
| 50. |
- Pohl, Alexandre, et al.
(författare)
-
Possible patterns of marine primary productivity during the Great Ordovician Biodiversification Event
- 2018
-
Ingår i: Lethaia. - : Scandinavian University Press / Universitetsforlaget AS. - 0024-1164. ; 51:2, s. 187-197
-
Tidskriftsartikel (refereegranskat)abstract
- Following the appearance of numerous animal phyla during the 'Cambrian Explosion', the 'Great Ordovician Biodiversification Event' (GOBE) records their rapid diversification at the lower taxonomic levels, constituting the most significant rise in biodiversity in Earth's history. Recent studies suggest that the rapid rise in phytoplankton diversity observed at the Cambrian-Ordovician boundary may have profoundly restructured marine trophic chains, paving the way for the subsequent flourishing of plankton-feeding groups during the Ordovician. Unfortunately, the fossil record of plankton is incomplete. Its smaller members represent the bulk of the modern marine biomass, but they are usually not documented in Palaeozoic sediments, preventing any definitive assumption with regard to an eventual correlation between biodiversity and biomass at that time. Here, we use an up-to-date ocean general circulation model with biogeochemical capabilities (MITgcm) to simulate the spatial patterns of marine primary productivity throughout the Ordovician, and we compare the model output with available palaeontological and sedimentological data.
|
|
