Pliocene oceanic seaways and global climate

Karas, Cyrus; Nürnberg, Dirk; Bahr, André; Groeneveld, Jeroen; Herrle, Jens O.; Tiedemann, Ralf; deMenocal, Peter B

doi:10.1038/srep39842

Cited by 72 publications

(78 citation statements)

References 53 publications

(178 reference statements)

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“…The warming of the Norwegian Sea at 4.0 Ma coincides with several tectonic shifts that could affect the climate development of the Nordic Seas region. A threshold in the closure of the CAS has been suggested to take place at this time (Karas et al, 2017;Steph et al, 2010), and uplift of Greenland and northern Scandinavia took place (Knies et al, 2014a). Enhanced North Atlantic Deep Water (NADW) production and a more vigorous AMOC have been suggested by Steph et al (2010) towards 4.0 Ma based on benthic δ 13 C in the low-latitude Atlantic.…”

Section: Rapid Warming Followed By Extended Interval Of Highmentioning

confidence: 99%

“…A statistically significant increase in global ice volume from 3.6 Ma was noted by Mudelsee and Raymo (2005), who consider this to be the marker for the onset of NHG. Furthermore, a large increase in IRD influx in the North Atlantic (Kleiven et al, 2002), and a crash of productivity in the North Pacific (Haug et al, 2005), indicated an important threshold towards intensified Northern Hemisphere ice build-up at ca. 2.7 Ma.…”

Section: Introductionmentioning

confidence: 99%

“…Sea surface temperatures and %C 37 : 4 provide insights into the changing properties of the surface water masses in the western Nordic Seas, while the IRD record indicates changes in the behavior of glacial margins extending to the Nordic Seas. The records from ODP Hole 642B provide insight on whether Pliocene climate variability on tectonic (> 100 kyr) and orbital timescales (20 to 400 kyr) was important for establishing favorable conditions for sporadic Northern Hemisphere glaciation during the Early Pliocene (De Schepper et al, 2014), and for increasingly widespread glaciation during the Late Pliocene (Kleiven et al, 2002;Shackleton et al, 1984).…”

Section: Introductionmentioning

confidence: 99%

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Highly variable Pliocene sea surface conditions in the Norwegian Sea

et al. 2017

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Section: Rapid Warming Followed By Extended Interval Of Highmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Highly variable Pliocene sea surface conditions in the Norwegian Sea

et al. 2017

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“…The closure of the Central American Seaway (CAS; Panama) has experienced its most critical phase just during this time interval (Haug et al, ; Haug & Tiedemann, ). The constriction and final closure of the CAS led to the intensification of both the Gulf Stream and, in a broader perspective, the Atlantic Meridional Overturning Circulation, leading to commonly higher sea surface temperatures (SSTs; Haug & Tiedemann, ; Haug et al, ; Karas et al, ) and salinities (Keigwin, ) in the Caribbean sector of the western Atlantic. At the same time, the East Pacific experienced a decline in surface temperatures, the intensification of costal upwelling (Dekens et al, ; Ibaraki, ), and the shoaling of the tropical East Pacific thermocline (Steph et al, ).…”

Section: Introductionmentioning

confidence: 99%

“…At the same time, the East Pacific experienced a decline in surface temperatures, the intensification of costal upwelling (Dekens et al, ; Ibaraki, ), and the shoaling of the tropical East Pacific thermocline (Steph et al, ). Ultimately, the closure of the CAS is thought to have preconditioned the initiation of the Northern Hemisphere glaciation (NHG; Haug & Tiedemann, ; Haug et al, ; Karas et al, ; Lunt et al, ). The Indonesian Gateway is also considered as a major driver of the reorganization of the Plio‐Pleistocene oceanic and climatic system (Cane & Molnar, ; Karas et al, ).…”

Section: Introductionmentioning

confidence: 99%

Plio‐Pleistocene Variability of the East Pacific Thermocline and Atmospheric Systems

Williams

Nürnberg

Tiedemann

2020

Paleoceanog and Paleoclimatol

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The transition from the Pliocene to the Pleistocene was accompanied by major tectonic reorganizations of key oceanic gateways. In particular, the gradual closure of the Panama Gateway and the constriction of the Indonesian Gateway significantly affected the structure of the Pacific thermocline. In the East Pacific, the thermocline shoaled from an early Pliocene El Niño-like depth to its modern state, which had significant implications for global climate. Here we use Mg/Ca temperature estimates from subsurface and thermocline dwelling foraminifera to reconstruct the meridional Plio-Pleistocene evolution of the Southeast Pacific thermocline, in relation to atmospheric circulation changes. In combination with similar reconstructions from the north-equatorial Pacific, our data indicate a change in the thermocline, responding to the northward displacement of the Intertropical Convergence Zone/South Pacific High system between~3.8 and 3.5 Ma. After 3.5 Ma, we record a second major phase of thermocline shoaling, which points to the Intertropical Convergence Zone/South Pacific High-system movement toward its modern position along with the gradual cooling of the Northern Hemisphere and its associated glaciation. These findings highlight that a warming globe may affect equatorial regions more intensively due to the potential temperature-driven movement of the Intertropical Convergence Zone/South Pacific High and their associated oceanic systems.Plain Language Summary Over the course of the last 5 million years (Ma), two oceanic gateways experienced changes due to major tectonic reorganizations. At~4.4 Ma, the passage connecting the Atlantic and Pacific closed when the connection between the Americasthe Panama land bridgeformed. On the western side of the Pacific, the formation of volcanic islands around Indonesia and Papua New Guinea at~3.5-3 Ma hampered the transport of tropical water from the Pacific into the Indian Ocean. These processes significantly changed the ocean dynamics and should have altered the tropical Pacific temperature distribution from potential permanent El Niño-like conditions (warm west, warm east) to the modern state. We present sea surface and subsurface temperature reconstructions for the tropical East Pacific off Chile covering the last 5 Ma. Our data imply that the Intertropical Convergence Zone and the South Pacific High moved toward the north along with the warming Northern Hemisphere from~3.8 to 3.5 Ma. Parallel to the subsequent cooling and glaciation of the Northern Hemisphere, the East Pacific Intertropical Convergence Zone/South Pacific High gradually moved toward their modern position. Ultimately, our data show how hemispherical warming/cooling can affect the position of the Intertropical Convergence Zone/South Pacific High and their associated systems of oceanic temperatures.

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Global phylogeography of the smooth hammerhead shark: Glacial refugia and historical migration patterns

Ferrette

Coelho

Peddemors

et al. 2021

Aquatic Conservation

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1. Extreme climate changes during the Cenozoic Era strengthened different biogeographical barriers that decreased the connectivity among populations, triggering lineage diversification of different species worldwide. 2. The mitochondrial DNA control region was employed to explore the phylogeography of Sphyrna zygaena, a globally distributed species threatened by unsustainable, illegal, unreported and unregulated fisheries triggered by the international shark fin trade. It is listed as 'Vulnerable' by the IUCN Red List and its trade is regulated by CITES Appendix II. 3. Only 13 haplotypes were found with low genetic diversity levels (hd = 0.686 ± 0.014; π = 0.00206 ± 0.00004) compared with other species of the Sphyrnidae family. The species has a very strong phylogeographic population structure among the Atlantic, Indian and Pacific Oceans (Φ ST = 0.79132).Worldwide, there are six distinct populations with some haplotype sharing.4. These populations are probably connected by a stepping-stone dispersal of a small number of migrants per generation from the Indo-Pacific towards the Atlantic. Modelling suggests that S. zygaena diverged into two lineages around 6.96 million years ago which have been isolated in glacial refuges in the Atlantic and Indo-Pacific oceans; and after deglaciation, a population expansion probably permitted secondary contact. 5. Conservation plans to establish differentiated management units should be adopted in each of the identified populations. Among these, the Eastern Central Atlantic and West Indo-Pacific are the most important areas for the species considering the historical migration routes that act as a bridge connecting the Atlantic and Indo-Pacific Oceans while the Gulf of Guinea connects the Atlantic populations. Still, further studies are required to know if these populations are also linked with nursery areas for the species.6. The results herein can help to delimit the main evolutionarily significant units to implement effective policies to establish differentiated management units as starting points to genetic monitoring programmes for Sphyrna zygaena.

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Pliocene oceanic seaways and global climate

Cited by 72 publications

References 53 publications

Highly variable Pliocene sea surface conditions in the Norwegian Sea

Highly variable Pliocene sea surface conditions in the Norwegian Sea

Plio‐Pleistocene Variability of the East Pacific Thermocline and Atmospheric Systems

Global phylogeography of the smooth hammerhead shark: Glacial refugia and historical migration patterns

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