scholarly journals Stable Isotope Constraints on Marine Productivity Across the Cretaceous‐Paleogene Mass Extinction

2019 ◽  
Vol 34 (7) ◽  
pp. 1195-1217 ◽  
Author(s):  
Julio Sepúlveda ◽  
Laia Alegret ◽  
Ellen Thomas ◽  
Emily Haddad ◽  
Changqun Cao ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Mass Extinction ◽  
Marine Productivity

scholarly journals Anatomy of an extinction revealed by molecular fossils spanning OAE2

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. M. Forkner ◽  
J. Dahl ◽  
A. Fildani ◽  
S. M. Barbanti ◽  
I. A. Yurchenko ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Cumulative Effect ◽  
Environmental Stresses ◽  
Ecological Change ◽  
Western Interior Seaway ◽  
Oceanic Anoxic Event ◽  
Greenhorn Formation ◽  
Productivity Decline ◽  
Marine Productivity ◽  
New Evidence

AbstractThe Cenomanian–Turonian mass extinction (Oceanic Anoxic Event 2-OAE2) was a period of profound ecological change that is recorded in the sedimentary record in many locations around the globe. In this study, we provide a new and detailed account of repetitive changes in water column ecology by analyzing the organic geochemical record preserved within the OAE2 section of the Greenhorn Formation, Western Interior Seaway (WIS) of North America. Results from this study provide evidence that OAE2 in the WIS was the result of the cumulative effect of reoccurring environmental stresses rather than a single massive event. During OAE2, extreme variations in biotic composition occurred erratically over periods of several thousands of years as revealed by molecular fossil (biomarker) abundances and distributions calibrated to sedimentation rates. These cycles of marine productivity decline almost certainly had follow-on effects through the ecosystem and likely contributed to the Cenomanian–Turonian mass extinction. While the causes behind organic productivity cycling are yet unproven, we postulate that they may have been linked to repeated episodes of volcanic activity. Catastrophic volcanism and related CO2 outgassing have been interpreted as main drivers for OAE2, though this study provides new evidence that repetitive, punctuated environmental stresses were also important episodes within the anatomy of OAE2. Following OAE2, these cycles of productivity decline disappeared, and the WIS returned to conditions comparable to pre-OAE2 levels.

Rapid Resurgence of Marine Productivity After the Cretaceous-Paleogene Mass Extinction

Science ◽  
2009 ◽  
Vol 326 (5949) ◽  
pp. 129-132 ◽  
Author(s):  
J. Sepulveda ◽  
J. E. Wendler ◽  
R. E. Summons ◽  
K.-U. Hinrichs
Keyword(s):  
Mass Extinction ◽  
Marine Productivity

scholarly journals Testing the limits in a greenhouse ocean: Did low nitrogen availability limit marine productivity during the end-Triassic mass extinction?

2016 ◽  
Vol 451 ◽  
pp. 138-148 ◽  
Author(s):  
Shane D. Schoepfer ◽  
Thomas J. Algeo ◽  
Peter D. Ward ◽  
Kenneth H. Williford ◽  
James W. Haggart
Keyword(s):  
Mass Extinction ◽  
Nitrogen Availability ◽  
Marine Productivity ◽  
Low Nitrogen

Stable isotope record implicates aridification without warming during the late Capitanian mass extinction

2018 ◽  
Vol 59 ◽  
pp. 1-8 ◽  
Author(s):  
Kévin Rey ◽  
Michael O. Day ◽  
Romain Amiot ◽  
Jean Goedert ◽  
Christophe Lécuyer ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Mass Extinction ◽  
Isotope Record ◽  
Stable Isotope Record

scholarly journals Bone histology of acipenseriform fishes reveals seasonality during the final years of the Mesozoic.

2021 ◽  
Author(s):  
Jan Smit ◽  
Melanie During ◽  
Camille Berruyer ◽  
Dennis Voeten ◽  
Paul Tafforeau ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Mass Extinction ◽  
Yucatan Peninsula ◽  
Life Cycles ◽  
Bone Histology ◽  
Seasonal Timing ◽  
Boreal Spring ◽  
Biotic Diversity ◽  
Chicxulub Impact ◽  
The Impact

Abstract The Cretaceous-Paleogene (KPg) mass extinction ~66 million years ago (Ma) was triggered by the Chicxulub impact on the present-day Yucatán Peninsula. This event caused the extinction of circa 76% of species, including all non-avian dinosaurs, and represents one of the most selective extinctions to date. The timing of the impact and its aftermath have mainly been studied on millennial timescales, leaving the season of the impact unconstrained. Here, we demonstrate that the impact that caused the KPg mass extinction took place during boreal spring. Osteohistology and stable isotope records of exceptionally preserved dermal and perichondrial bones in acipenseriform fishes from the Tanis impact-induced seiche deposits reveal annual cyclicity across the final years of the Cretaceous. These fishes ultimately perished in boreal spring. Annual life cycles, involving seasonal timing and duration of reproduction, feeding, hibernation, and aestivation, vary strongly across latest Cretaceous biotic diversity. We conclude that the timing of the Chicxulub impact in boreal spring significantly influenced selective biotic survival across the KPg boundary.

Late Ordovician mass extinction in the Selwyn Basin, northwestern Canada: geochemical, sedimentological, and paleontological evidence

1993 ◽  
Vol 30 (9) ◽  
pp. 1870-1880 ◽  
Author(s):  
K. Wang ◽  
B. D. E. Chatterton ◽  
M. Attrep Jr. ◽  
C. J. Orth
Keyword(s):  
Stable Isotope ◽  
Sea Level ◽  
Mass Extinction ◽  
Facies Analysis ◽  
Isotope Geochemistry ◽  
Late Ordovician ◽  
Cold Climate ◽  
Photic Zone ◽  
Toxic Material ◽  
Short Period

We present a detailed study of the trace element and stable isotope geochemistry, sedimentology, and fossil distributions in two Avalanche Lake (AV4B, AV1) Ordovician–Silurian boundary sections in the Selwyn Basin. Trilobites and conodonts indicate a profound extinction at the end of the Ordovician, which is constrained stratigraphically within a <60 cm interval at AV4B. Facies analysis suggests that the extinction interval coincides with the maximum shallowing (low stand of sea level), which was probably caused by a galcioeustatic regression induced by the Late Ordovician Gondwanan glaciation. The extinction crisis is also signalled by the change in carbonate δ13C: a sudden "Strangelove ocean" δ13C excursion (>3‰ in magnitude) is recorded in the extinction interval. Iridium abundances (<0.051 ppb) in the extinction interval are low and fail to provide evidence for an impact. The highest Ir abundance is found to be associated with reduced sedimentation in a condensed horizon. Cerium anomalies indicate a short period of basin ventilation in the otherwise anoxic Selwyn Basin. The extinction occurred during the time of this basin ventilation, which was probably caused by the cold climate during the glaciation. The ventilation may have triggered upwelling of the deep water through vertical advection, bringing up toxic material, poisoning the upper-water photic zone, and causing the extinction.

scholarly journals Palaeoclimatic oscillations in the Pliensbachian (Lower Jurassic) of the Asturian Basin (Northern Spain)

2015 ◽  
Vol 11 (4) ◽  
pp. 4039-4076 ◽  
Author(s):  
J. J. Gómez ◽  
M. J. Comas-Rengifo ◽  
A. Goy
Keyword(s):  
Stable Isotope ◽  
Temperature Interval ◽  
Mass Extinction ◽  
Climatic Changes ◽  
Lower Jurassic ◽  
Northern Spain ◽  
Ice Caps ◽  
Before And After ◽  
Isotope Studies

Abstract. One of the main controversial items in palaeoclimatology is to elucidate if climate during the Jurassic was warmer than present day, with no ice caps, or if ice caps were present in some specific intervals. The Pliensbachian Cooling event (Lower Jurassic) has been pointed out as one of the main candidates to have developed ice caps on the poles. To constrain the timing of this cooling event, including the palaeoclimatic evolution before and after cooling, as well as the calculation of the seawater palaeotemperatures are of primary importance to find arguments on this subject. For this purpose, the Rodiles section of the Asturian Basin (Northern Spain), a well exposed succession of the uppermost Sinemurian, Pliensbachian and Lower Toarcian deposits, has been studied. A total of 562 beds were measured and sampled for ammonites, for biostratigraphical purposes and for belemnites, to determine the palaeoclimatic evolution through stable isotope studies. Comparison of the recorded uppermost Sinemurian, Pliensbachian and Lower Toarcian changes in seawater palaeotemperature with other European sections allows characterization of several climatic changes of probable global extent. A warming interval which partly coincides with a negative δ13Cbel excursion was recorded at the Upper Sinemurian. After a "normal" temperature interval, a new warming interval that contains a short lived positive δ13Cbel peak, was developed at the Lower-Upper Pliensbachian transition. The Upper Pliensbachian represents an outstanding cooling interval containing a positive δ13Cbel excursion interrupted by a small negative δ13Cbel peak. Finally, the Lower Toarcian represented an exceptional warming period pointed as the main responsible for the prominent Lower Toarcian mass extinction.

Vitamin A Value of Plant Food Provitamin A - Evaluated by the Stable Isotope Technologies

2014 ◽  
Vol 84 (Supplement 1) ◽  
pp. 25-29 ◽  
Author(s):  
Guangwen Tang
Keyword(s):  
Stable Isotope ◽  
Vitamin A ◽  
Provitamin A ◽  
Animal Origin ◽  
Plant Food ◽  
Plant Foods ◽  
A Value ◽  
Provitamin A Carotenoids ◽  
Β Carotene

Humans need vitamin A and obtain essential vitamin A by conversion of plant foods rich in provitamin A and/or absorption of preformed vitamin A from foods of animal origin. The determination of the vitamin A value of plant foods rich in provitamin A is important but has challenges. The aim of this paper is to review the progress over last 80 years following the discovery on the conversion of β-carotene to vitamin A and the various techniques including stable isotope technologies that have been developed to determine vitamin A values of plant provitamin A (mainly β-carotene). These include applications from using radioactive β-carotene and vitamin A, depletion-repletion with vitamin A and β-carotene, and measuring postprandial chylomicron fractions after feeding a β-carotene rich diet, to using stable isotopes as tracers to follow the absorption and conversion of plant food provitamin A carotenoids (mainly β-carotene) in humans. These approaches have greatly promoted our understanding of the absorption and conversion of β-carotene to vitamin A. Stable isotope labeled plant foods are useful for determining the overall bioavailability of provitamin A carotenoids from specific foods. Locally obtained plant foods can provide vitamin A and prevent deficiency of vitamin A, a remaining worldwide concern.

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