Photosymbiosis in planktonic foraminifera across the Paleocene–Eocene thermal maximum

Paleobiology ◽  
2021 ◽  
pp. 1-16
Author(s):  
Jack O. Shaw ◽  
Simon D'haenens ◽  
Ellen Thomas ◽  
Richard D. Norris ◽  
Johnnie A. Lyman ◽  
...  
Keyword(s):  
Global Warming ◽  
Isotope Composition ◽  
Planktonic Foraminifera ◽  
Significant Loss ◽  
Adaptive Responses ◽  
Central Pacific ◽  
Algal Symbionts ◽  
Thermal Maximum ◽  
A Site ◽  
Isotope Analyses

Abstract Under stress, corals and foraminifera may eject or consume their algal symbionts (“bleach”), which can increase mortality. How bleaching relates to species viability over warming events is of great interest given current global warming. We use size-specific isotope analyses and abundance counts to examine photosymbiosis and population dynamics of planktonic foraminifera across the Paleocene–Eocene thermal maximum (PETM, ~56 Ma), the most severe Cenozoic global warming event. We find variable responses of photosymbiotic associations across localities and species. In the NE Atlantic (DSDP Site 401) PETM, photosymbiotic clades (acarininids and morozovellids) exhibit collapsed size-δ13C gradients indicative of reduced photosymbiosis, as also observed in Central Pacific (ODP Site 1209) and Southern Ocean (ODP Site 690) acarininids. In contrast, we find no significant loss of size-δ13C gradients on the New Jersey shelf (Millville) or in Central Pacific morozovellids. Unlike modern bleaching-induced mass mortality, populations of photosymbiont-bearing planktonic foraminifera increased in relative abundance during the PETM. Multigenerational adaptive responses, including flexibility in photosymbiont associations and excursion taxon evolution, may have allowed some photosymbiotic foraminifera to thrive. We conclude that deconvolving the effects of biology on isotope composition on a site-by-site basis is vital for environmental reconstructions.

scholarly journals Changes in Independency between Two Types of El Niño Events under a Greenhouse Warming Scenario in CMIP5 Models

2015 ◽  
Vol 28 (19) ◽  
pp. 7561-7575 ◽  
Author(s):  
Yoo-Geun Ham ◽  
Yerim Jeong ◽  
Jong-Seong Kug
Keyword(s):  
Global Warming ◽  
El Niño ◽  
El Nino ◽  
Western Pacific ◽  
Cmip5 Models ◽  
Greenhouse Warming ◽  
Central Pacific ◽  
El Niño Events ◽  
The Western Pacific ◽  
El Nino Events

Abstract This study uses archives from phase 5 of the Coupled Model Intercomparison Project (CMIP5) to investigate changes in independency between two types of El Niño events caused by greenhouse warming. In the observations, the independency between cold tongue (CT) and warm pool (WP) El Niño events is distinctively increased in recent decades. The simulated changes in independency between the two types of El Niño events according to the CMIP5 models are quite diverse, although the observed features are simulated to some extent in several climate models. It is found that the climatological change after global warming is an essential factor in determining the changes in independency between the two types of El Niño events. For example, the independency between these events is increased after global warming when the climatological precipitation is increased mainly over the equatorial central Pacific. This climatological precipitation increase extends convective response to the east, particularly for CT El Niño events, which leads to greater differences in the spatial pattern between the two types of El Niño events to increase the El Niño independency. On the contrary, in models with decreased independency between the two types of El Niño events after global warming, climatological precipitation is increased mostly over the western Pacific. This confines the atmospheric response to the western Pacific in both El Niño events; therefore, the similarity between them is increased after global warming. In addition to the changes in the climatological state after global warming, a possible connection of the changes in the El Niño independency with the historical mean state is discussed in this paper.

Calcium isotope composition of Morozovella over the late Paleocene–early Eocene

Geology ◽  
2021 ◽  
Author(s):  
Gabriella D. Kitch ◽  
Andrew D. Jacobson ◽  
Dustin T. Harper ◽  
Matthew T. Hurtgen ◽  
Bradley B. Sageman ◽  
...  
Keyword(s):  
Isotope Composition ◽  
Calcium Isotope ◽  
Ocean Drilling Program ◽  
Ocean Drilling ◽  
Carbonate Ion ◽  
Kinetic Isotope ◽  
Carbon Isotope Excursion ◽  
Thermal Maximum ◽  
Igneous Province ◽  
North Atlantic Igneous Province

Ocean acidification (OA) during the Paleocene-Eocene thermal maximum (PETM) likely caused a biocalcification crisis. The calcium isotope composition (δ44/40Ca) of primary carbonate producers may be sensitive to OA. To test this hypothesis, we constructed the first high-resolution, high-precision planktic foraminiferal δ44/40Ca records before and across the PETM. The records employ specimens of Morozovella spp. collected from Ocean Drilling Program Sites 1209 (Shatsky Rise, Pacific Ocean) and 1263 (Walvis Ridge, Atlantic Ocean). At Site 1209, δ44/40Ca values start at –1.33‰ during the Upper Paleocene and increase to a peak of –1.15‰ immediately before the negative carbon isotope excursion (CIE) that marks the PETM onset. Values remain elevated through the PETM interval and decrease into the earliest Eocene. A shorter-term record for Site 1263 shows a similar trend, although δ44/40Ca values are on average 0.22‰ lower and decrease shortly after the CIE onset. The trends support neither diagenetic overprinting, authigenic carbonate additions, nor changes in the δ44/40Ca value of seawater. Rather, they are consistent with a kinetic isotope effect, whereby calcite δ44/40Ca values inversely correlate with precipitation rate. Geologically rapid Ca isotope shifts appear to reflect the response of Morozovella to globally forced changes in the local carbonate geochemistry of seawater. All data combined suggest that the PETM-OA event occurred near the peak of a gradual reduction in seawater carbonate ion concentrations during a time of elevated atmospheric pCO2, potentially driven by North Atlantic igneous province emplacement.

scholarly journals Quantifying sea surface temperature ranges of the Arabian Sea for the past 20 000 years

2011 ◽  
Vol 7 (4) ◽  
pp. 1337-1349 ◽  
Author(s):  
G. M. Ganssen ◽  
F. J. C. Peeters ◽  
B. Metcalfe ◽  
P. Anand ◽  
S. J. A. Jung ◽  
...  
Keyword(s):  
Arabian Sea ◽  
Isotope Composition ◽  
Planktonic Foraminifera ◽  
Sediment Cores ◽  
Maximum Temperature ◽  
Physical Parameters ◽  
Seasonal Temperature ◽  
Mean Values ◽  
The Past ◽  
Temperature Ranges

Abstract. The oxygen isotopic composition of planktonic foraminifera tests is one of the widest used geochemical tools to reconstruct past changes of physical parameters of the upper ocean. It is common practice to analyze multiple individuals from a mono-specific population and assume that the outcome reflects a mean value of the environmental conditions during calcification of the analyzed individuals. Here we present the oxygen isotope composition of individual specimens of the surface-dwelling species Globigerinoides ruber and Globigerina bulloides from sediment cores in the Western Arabian Sea off Somalia, inferred as indicators of past seasonal ranges in temperature. Combining the δ18O measurements of individual specimens to obtain temperature ranges with Mg/Ca based mean calcification temperatures allows us to reconstruct temperature extrema. Our results indicate that over the past 20 kyr the seasonal temperature range has fluctuated from its present value of 16 °C to mean values of 13 °C and 11 °C for the Holocene and LGM, respectively. The data for the LGM suggest that the maximum temperature was lower, whilst minimum temperature remained approximately constant. The rather minor variability in lowest summer temperatures during the LGM suggests roughly constant summer monsoon intensity, while upwelling-induced productivity was lowered.

scholarly journals Oxygen isotope composition of zircons from the Talnakh economic intrusion of the Noril’sk province: first data

2019 ◽  
Vol 489 (2) ◽  
pp. 170-173
Author(s):  
I. Yu. Badanina ◽  
E. A. Belousova ◽  
K. N. Malitch ◽  
S. F. Sluzhenikin
Keyword(s):  
Oxygen Isotope ◽  
Isotope Composition ◽  
Oxygen Isotope Composition ◽  
Primary Magma ◽  
Crustal Component ◽  
Layered Series ◽  
Isotope Data ◽  
Oxygen Isotope Data ◽  
First Results ◽  
Isotope Analyses

This study presents the first results of oxygen isotope analyses (18O) collected on zircons from the Talnakh economic intrusion within the Norilsk province. Zircons from gabbro-diorite, gabbroic rocks of the layered series and plagioclase-bearing wehrlite have similar mantle-like mean 18O values (5,39 0,49; 5,64 0,48 and of 5,28 0,34, respectively), which differ from 18O in zircons from sulfide-bearing melanocratic troctolite with a taxitic texture in the lower part of the intrusion (mean 18O = 6,50 0,98). These new oxygen isotope data support (i) the mantle-derived origin of the primary magma(s), parental to the Talnakh intrusion, and (ii) possible involvement of a crustal component during the formation of sulfide-bearing taxitic-textured rocks.

Application of a mechanistic model of methanogenesis in the lactating dairy cow. The fate of hydrogen during fermentation and strategies to mitigate methane emissions

2001 ◽  
Vol 2001 ◽  
pp. 122-122
Author(s):  
J A N Mills ◽  
J. Dijkstra ◽  
A. Bannink ◽  
E. Kebreab ◽  
S.B. Cammell ◽  
...  
Keyword(s):  
Global Warming ◽  
Dairy Cattle ◽  
Causative Agent ◽  
Dairy Cow ◽  
Dietary Intervention ◽  
Mechanistic Model ◽  
Methane Emissions ◽  
Significant Loss ◽  
Lactating Dairy Cattle

Dietary intervention to reduce methane emissions from lactating dairy cattle is both environmentally and nutritionally desirable due to the importance of methane as a causative agent in global warming and as a significant loss of feed energy. This investigation involved the development of a dynamic mechanistic model of whole rumen function (Dijkstra et al. 1992), with the objective to simulate whole-animal methane emissions for a range of dietary inputs.

Anions and Cations in Ice Cores from Dolleman Island and the Palmer Land Plateau, Antarctic Peninsula

1988 ◽  
Vol 10 ◽  
pp. 121-125 ◽  
Author(s):  
Robert Mulvaney ◽  
David A. Peel
Keyword(s):  
Antarctic Peninsula ◽  
Isotope Composition ◽  
Seasonal Pattern ◽  
Austral Summer ◽  
Ice Cores ◽  
Late Summer ◽  
Ionic Species ◽  
Weddell Sea ◽  
Seasonal Maximum ◽  
A Site

High-resolution anion profiles of Cl-, NO3- and SO4 2− are presented for two cores from the Antarctic Peninsula. A 47.2 m core from a site on the Palmer Land plateau (74°01’S, 70°38’W), spans the period 1942–80, and a 10.5 m core from Dolleman Island (70°35.2’S, 60°55.5’W), on the east coast of the peninsula, spans the period 1973–85. The seasonal pattern of deposition of these species has been determined by reference to the oxygen-isotope composition. Averaged over 38 years, the annual cycle of SO4 2− at Gomez shows a seasonal maximum during the austral summer, and minimum during the winter, whereas the Cl- cycle is more complex and may show the influence of equinoctial storms. The Dolleman core is significantly influenced by the proximity of the Weddell Sea, with a mean Cl- concentration five times greater than in the core from the plateau, and it shows a clear seasonal maximum in late-summer snowfall. There is no significant long-term trend in the 38 years’ data from the plateau site, suggesting that global pollution does not contribute significantly to the anion budget. Both anions and the cations Na+, K+ and H+ have been measured for more than a complete year of snowfall and the balance of ionic species is excellent.

RESPONSE OF CALCAREOUS NANNOPLANKTON TO PALEOCENE–EOCENE THERMAL MAXIMUM IN NORTHERN IRAQ

2020 ◽  
Vol 02 (01) ◽  
pp. 2050001
Author(s):  
RAGHDA SAAD AL-HYALY ◽  
OMAR AHMED AL-BADRANI
Keyword(s):  
Global Warming ◽  
Calcareous Nannofossils ◽  
Calcareous Nannoplankton ◽  
Geological Record ◽  
Northern Iraq ◽  
Thermal Maximum

The Paleocene–Eocene Thermal Maximum (PETM) was an abrupt global warming event in the geological record. Based on calcareous nannofossils from thirteen samples of Aaliji Formation from K-116 well, Northern Iraq, sixty species are identified and can be used to divide the studied section into five biozones. Especially, the transition in the Discoaster multiraditus Biozone (CP8) occurred which is marked by higher speciation for calcareous nannofossils and the occurrences of Discoaster Tan. Such atransition is closely related to global warming during the transition from Paleocene to Eocene.

scholarly journals Productivity feedback did not terminate the Paleocene-Eocene Thermal Maximum (PETM)

2010 ◽  
Vol 6 (2) ◽  
pp. 265-272 ◽  
Author(s):  
A. Torfstein ◽  
G. Winckler ◽  
A. Tripati
Keyword(s):  
Biological Pump ◽  
Accumulation Rates ◽  
Excess Carbon ◽  
Export Production ◽  
Initial Carbon ◽  
Thermal Maximum ◽  
Carbon Release ◽  
Rapid Removal ◽  
Sudden Release ◽  
A Site

Abstract. The Paleocene-Eocene Thermal Maximum (PETM) occurred approximately 55 million years ago, and is one of the most dramatic abrupt global warming events in the geological record. This warming was triggered by the sudden release of thousands of gigatons of carbon into the atmosphere and is widely perceived to be the best analogue for current anthropogenic climate change. Yet, the mechanism of recovery from this event remains controversial. A massive increase in the intensity of the marine biological pump ("productivity feedback") has been suggested to cause a drawdown of atmospheric CO2 and subsequent carbon sequestration in the ocean. A re-evaluation of the "productivity feedback hypothesis", based on biogenic barium mass accumulation rates (Ba-MARs) for a site in the Southern Ocean, finds that any increase in export production lagged the initial carbon release by at least ~70 000 years. This implies that export production did not facilitate rapid removal of excess carbon from the atmosphere. Thus, the most likely mechanism for carbon removal appears to be silicate weathering, which occurred at much slower rates than previously assumed.

scholarly journals Late Paleocene event chronology; unconformities, not diachrony

2000 ◽  
Vol 171 (3) ◽  
pp. 367-378 ◽  
Author(s):  
Marie-Pierre Aubry ◽  
Benjamin S. Cramer ◽  
Kenneth G. Miller ◽  
James D. Wright ◽  
Dennis V. Kent ◽  
...  
Keyword(s):  
Planktonic Foraminifera ◽  
Calcareous Nannoplankton ◽  
Lower Eocene ◽  
Late Paleocene ◽  
Relative Chronology ◽  
Carbon Isotope Excursion ◽  
Thermal Maximum ◽  
Unequivocal Identification ◽  
Upper Paleocene ◽  
Reference Section

Abstract The chronology of the events associated with the late Paleocene thermal maximum (LPTM, Chron C24r) has been established through the construction of a composite reference section that involved chemomagnetobiostratigraphic correlations and assumed minimum diachrony of biostratigraphic events. On this basis, discrepancies between correlations in different sections were explained by inferred unconformities. However, diachrony between distant sections cannot be ruled out. We report here on two geographically close sections drilled onshore New Jersey that yield different records of chemomagnetobiostratigraphic correlations in the interval representing Chron C24r. Because of their proximity ( approximately 40 km apart), diachrony of biostratigraphic events between the two sections can be ruled out. In contrast, the marked lithologic disconformities in the sections explain well the different records of events. We thus conclude that the current relative chronology for Chron C24r is firmly based and that the upper Paleocene-lower Eocene stratigraphic record yields multiple unconformities, with Subzone NP9b rarely sampled. We examine the implications that undeciphered unconformities may have on the identification of proxies for paleoceanographic reconstruction, in particular with regard to the identification of the carbon isotope excursion (CIE) that reflects a dramatic latest Paleocene disturbance of the carbon cycle. We propose biostratigraphic means (short-lived calcareous nannoplankton and planktonic foraminifera taxa) that permit the unequivocal identification of the CIE not only in the oceanic realm but also in neritic settings.

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