scholarly journals Influence of quaternary sea-level variations on a land bird endemic to Pacific atolls

2010 ◽  
Vol 277 (1699) ◽  
pp. 3445-3451 ◽  
Author(s):  
Alice Cibois ◽  
Jean-Claude Thibault ◽  
Eric Pasquet

Little is known about the effect of quaternary climate variations on organisms that inhabited carbonate islands of the Pacific Ocean, although it has been suggested that one or several uplifted islands provided shelter for terrestrial birds when sea-level reached its highest. To test this hypothesis, we investigated the history of colonization of the Tuamotu reed-warbler ( Acrocephalus atyphus ) in southeastern Polynesia, and found high genetic structure between the populations of three elevated carbonate islands. Estimates of time since divergence support the hypothesis that these islands acted as refugia during the last interglacial maximum. These findings are particularly important for defining conservation priorities on atolls that endure the current trend of sea-level rise owing to global warming.

2017 ◽  
Author(s):  
Nicky M. Wright ◽  
◽  
Maria Seton ◽  
Simon E. Williams ◽  
R. Dietmar Müller

Author(s):  
Elizabeth Sinn

This chapter takes a broad look at the Pacific Ocean in relation to Chinese migration. As trade, consumption and capital flows followed migrants, powerful networks were woven and sustained; in time, the networks fanned across the Pacific from British Columbia along the West Coast of the United States to New Zealand and Australia. The overlapping personal, family, financial and commercial interests of Chinese in California and those in Hong Kong, which provide the focus of this study, energized the connections and kept the Pacific busy and dynamic while shaping the development of regions far beyond its shores. The ocean turned into a highway for Chinese seeking Gold Mountain, marking a new era in the history of South China, California, and the Pacific Ocean itself.


Author(s):  
Peter Dauvergne

Chapters 2–6 survey the political and socioeconomic forces underlying the global sustainability crisis. Understanding the scale and depth of contemporary forces of capitalism and consumerism requires a close look at the consequences of imperialism and colonialism on patterns of violence and exploitation. This chapter begins this process of understanding by sketching the history of ecological imperialism after 1600, seeing this as a reasonable starting date for the beginning of what many scholars are now calling the Anthropocene Epoch (or the age of humans, replacing the geologic epoch of the Holocene beginning 12,000 years ago). It opens with Captain Pedro Fernandes de Queirós’s voyage across the Pacific Ocean in 1605–06 to “discover” modern-day Vanuatu, before turning to look more globally at the devastation of imperialism – and later colonialism – for the South Pacific, the Americas, Africa, and Asia. Over this time conquerors enslaved and murdered large numbers of indigenous people; cataclysmic change came as well, however, from the introduction of European diseases, plants, and animals. This chapter’s survey of imperialism, colonialism, and globalization sets the stage for Chapter 3, which explores the devastating history of the South Pacific island of Nauru after 1798.


2019 ◽  
Vol 220 (1) ◽  
pp. 384-392
Author(s):  
T Pico

SUMMARY Locally, the elevation of last interglacial (LIG; ∼122 ka) sea level markers is modulated by processes of vertical displacement, such as tectonic uplift or glacial isostatic adjustment, and these processes must be accounted for in deriving estimates of global ice volumes from geological sea level records. The impact of sediment loading on LIG sea level markers is generally not accounted for in these corrections, as it is assumed that the impact is negligible except in extremely high depositional settings, such as the world's largest river deltas. Here we perform a generalized test to assess the extent to which sediment loading may impact global variability in the present-day elevation of LIG sea level markers. We numerically simulate river sediment deposition using a diffusive model that incorporates a migrating shoreline to construct a global history of sedimentation over the last glacial cycle. We then calculate sea level changes due to this sediment loading using a gravitationally self-consistent model of glacial isostatic adjustment, and compare these predictions to a global compilation of LIG sea level data. We perform a statistical analysis, which accounts for spatial autocorrelation, across a global compilation of 1287 LIG sea level markers. Though limited by uncertainties in the LIG sea level database and the precise history of river deposition, this analysis suggests there is not a statistically significant global signal of sediment loading in LIG sea level markers. Nevertheless, at sites where LIG sea level markers have been measured, local sea level predicted using our simulated sediment loading history is perturbed up to 16 m. More generally, these predictions establish the relative sensitivity of different regions to sediment loading. Finally, we consider the implications of our results for estimates of tectonic uplift rates derived from LIG marine terraces; we predict that sediment loading causes 5–10 m of subsidence over the last glacial cycle at specific locations along active margin regions such as California and Barbados, where deriving long-term tectonic uplift rates from LIG shorelines is a common practice.


2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Angela Schottenhammer

Abstract Background Connections between China and the new Spanish colonies in America are known for an exchange of silver for silks and porcelains. That also medicinal drugs and medicinal knowledge crossed the Pacific Ocean is hardly known or discussed. Myroxylon balsamum (L.) Harms var. pereirae (Royle) Harms (“New World“ or “Peruvian balsam“) is a botanical balsam that has a long history of medicinal use, particularly as antiseptic and for wound healing. Except for a Chinese article discussing the reception of balsam in China and Japan, no scientific studies on its impact in China and Japan and the channels of transfer from the Americas to Asia exist. Methods Description: (1) This section provides a general introduction into Commiphora gileadensis (“Old World” balsam) as a medicinal category and discusses the specific medicinal properties of Myroxylon balsamum (L.) Harms var. pereirae (Royle) Harms. The section “Historical research and uses” provides a brief survey on some historical analyses of balsam. Aim, design, setting: (2) Applying a comparative textual and archaeological analysis the article critically examines Chinese and Japanese sources (texts, maps) to show (i) what Chinese and Japanese scholars knew about balsam, (ii) where and how it was used, and (iii) to identify reasons why the “digestion” of knowledge on balsam as a medicinal developed so differently in China and Japan. Results and discussion This chapter discusses the introduction of “Peruvian balsam” into, its uses as a medicinal as well as its scholarly reception in early modern China and Japan and introduces the channels of transmission from Spanish America to Asia. It is shown that Myroxylon balsamum (L.) Harms var. pereirae (Royle) Harms was partly a highly valued substance imported from the Americas into China and Japan. But the history of the reception of medicinal knowledge on Peruvian balsam was significantly different in China and Japan. Conclusions In Japan, the knowledge on Myroxylon balsamum was continuously updated, especially through mediation of Dutch physicians; Japanese scholars, doctors and pharmacists possessed a solid knowledge on this balsam, its origin and its medicinal uses. In China, on the contrary, there was no further “digestion” or development of the knowledge on either Myroxylon balsamum (L.) Harms var. pereirae (Royle) Harms or Commiphora gileadensis. By the late nineteenth century, related medicinal and even geographic knowledge had mostly been lost. The interest in “balsam” in late Qing scholarship was pure encyclopaedic and philosophic.


2019 ◽  
Vol 36 (4) ◽  
pp. 689-698 ◽  
Author(s):  
Lingsheng Meng ◽  
Wei Zhuang ◽  
Weiwei Zhang ◽  
Angela Ditri ◽  
Xiao-Hai Yan

AbstractSea level changes within wide temporal–spatial scales have great influence on oceanic and atmospheric circulations. Efforts have been made to identify long-term sea level trend and regional sea level variations on different time scales. A nonuniform sea level rise in the tropical Pacific and the strengthening of the easterly trade winds from 1993 to 2012 have been widely reported. It is well documented that sea level in the tropical Pacific is associated with the typical climate modes. However, sea level change on interannual and decadal time scales still requires more research. In this study, the Pacific sea level anomaly (SLA) was decomposed into interannual and decadal time scales via an ensemble empirical mode decomposition (EEMD) method. The temporal–spatial features of the SLA variability in the Pacific were examined and were closely associated with climate variability modes. Moreover, decadal SLA oscillations in the Pacific Ocean were identified during 1993–2016, with the phase reversals around 2000, 2004, and 2012. In the tropical Pacific, large sea level variations in the western and central basin were a result of changes in the equatorial wind stress. Moreover, coherent decadal changes could also be seen in wind stress, sea surface temperature (SST), subtropical cells (STCs), and thermocline depth. Our work provided a new way to illustrate the interannual and decadal sea level variations in the Pacific Ocean and suggested a coupled atmosphere–ocean variability on a decadal time scale in the tropical region with two cycles from 1993 to 2016.


2006 ◽  
Vol 43 (8) ◽  
pp. 1149-1164 ◽  
Author(s):  
James M Eros ◽  
Markes E Johnson ◽  
David H Backus

Arroyo Blanco Basin on Isla Carmen preserves a 157 m thick, nearly complete record of Pliocene–Pleistocene history in the Gulf of California. Examples of rocky-shore geomorphology occur on all margins of this trapezoidal-shaped, 3.3 km2 basin. A shoreline is developed in low relief on Miocene andesite from the Comondú Group at the rear of the basin parallel to the long axis of the island. Two end walls trace normal faults that stayed active during the life of the basin and maintained steep rocky shores. The basin is 64% filled by calcarudite and calcarenite derived from crushed rhodolith debris. Other facies include shell beds and stringers of andesite conglomerate that define a 4°–6° ramp. The ramp expanded onshore through Pliocene time, based on a succession of overlapping range zones for 22 macrofossils typical of Lower through Upper Pliocene strata in the Gulf of California. The unconformity exposed 1 km inland at the rear of the basin is between Miocene volcanics and Pleistocene cap rock at an elevation of 170 m above sea level. Whole rhodoliths encrusted on andesite pebbles occur above this unconformity. Presumably, the older Miocene-Pliocene unconformity is buried beneath the ramp. Four marine terraces with sea cliffs notched in Pliocene limestone occur at elevations of 68, 58, 37, and 12 m. The 12 m terrace is associated regionally with the last interglacial epoch between 120 000 and 135 000 years ago. Juxtaposition of ramp and terrace features in the same exhumed basin supports a long history of gradual Pliocene subsidence followed by episodic Pleistocene uplift.


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