Sophia Hines

Sophia Hines
Woods Hole Oceanographic Institution | WHOI · Department of Marine Chemistry and Geochemistry

PhD

About

38
Publications
6,761
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424
Citations
Introduction
Sophia Hines is an Assistant Scientist in the Marine Chemistry and Geochemistry Department at the Woods Hole Oceanographic Institution. Sophia does research in Paleoclimatology, Oceanography and Geochemistry.
Additional affiliations
April 2021 - present
Woods Hole Oceanographic Institution
Position
  • Researcher
April 2018 - April 2021
Lamont-Doherty Earth Observatory
Position
  • PostDoc Position
Education
September 2011 - June 2018
California Institute of Technology
Field of study
  • Geochemistry
September 2007 - June 2011
Carleton College
Field of study
  • Chemistry

Publications

Publications (38)
Article
The mid-Pleistocene transition (MPT) [~1.25 to 0.85 million years ago (Ma)] marks a shift in the character of glacial-interglacial climate ( 1 , 2 ). One prevailing hypothesis for the origin of the MPT is that glacial deep ocean circulation fundamentally changed, marked by a circulation “crisis” at ~0.90 Ma (marine isotope stages 24 to 22) ( 3 ). U...
Article
Full-text available
Ocean dissolved oxygen (DO) can provide insights on how the marine carbon cycle affects global climate change. However, the net global DO change and the controlling mechanisms remain uncertain through the last deglaciation. Here, we present a globally integrated DO reconstruction using thallium isotopes, corroborating lower global DO during the Las...
Article
Oxygen is essential for marine ecosystems, and it is linked by respiration to carbon storage in the deep ocean. Reconstructing oxygen concentrations in the past has been limited by the absence of quantitative, rather than qualitative, proxies, but several new (semi-) quantitative oxygen proxies have recently been developed. In this study we explore...
Article
Full-text available
Using new and published marine fossil radiocarbon ( ¹⁴ C/C) measurements, a tracer uniquely sensitive to circulation and air-sea gas exchange, we establish several benchmarks for Atlantic, Southern, and Pacific deep-sea circulation and ventilation since the last ice age. We find the most ¹⁴ C-depleted water in glacial Pacific bottom depths, rather...
Article
Understanding the contribution of ocean circulation to glacial–interglacial climate change is a major focus of paleoceanography. Specifically, many have tried to determine whether the volumes and depths of Antarctic- and North Atlantic–sourced waters in the deep ocean changed at the Last Glacial Maximum (LGM; ∼22–18 kyr BP) when atmospheric p CO 2...
Article
Full-text available
The interoceanic exchange of water masses is modulated by flow through key oceanic choke points in the Drake Passage, the Indonesian Seas, south of Africa, and south of Tasmania. Here, we use the neodymium isotope signature (εNd) of cold-water coral skeletons from intermediate depths (1460‒1689 m) to trace circulation changes south of Tasmania duri...
Article
Full-text available
Spatially distant sources of neodymium (Nd) to the ocean that carry different isotopic signatures (εNd) have been shown to trace out major water masses and have thus been extensively used to study large-scale features of the ocean circulation both past and current. While the global marine Nd cycle is qualitatively well understood, a complete quanti...
Article
Prior to ~1 million years ago (Ma), variations in global ice volume were dominated by changes in obliquity; however, the role of precession remains unresolved. Using a record of North Atlantic ice rafting spanning the past 1.7 million years, we find that the onset of ice rafting within a given glacial cycle (reflecting ice sheet expansion) consiste...
Preprint
Full-text available
Spatially distant sources of neodymium (Nd) to the ocean that carry different isotopic signatures (εNd) have been shown to trace out major water masses, and have thus been extensively used to study large-scale features of the ocean circulation both past and current. While the global marine Nd cycle is qualitatively well understood, a complete quant...
Article
Full-text available
A common conception of the deep ocean during ice age episodes is that the upper circulation cell in the Atlantic was shoaled at the Last Glacial Maximum compared to today, and that this configuration facilitated enhanced carbon storage in the deep ocean, contributing to glacial CO2 draw‐down. Here, we test this notion in the far South Atlantic, inv...
Article
Full-text available
Paired radiocarbon and clumped isotope temperature records from U/Th‐dated Desmophyllum dianthus corals in the North Atlantic and Southern Ocean provide unique information about the history of intermediate waters (∼1,500–1,700 m) across the late glacial and deglaciation (∼35–10 ka). These measurements allow for the construction of radiocarbon‐tempe...
Article
Paired radiocarbon and clumped isotope temperature records from U/Th‐dated Desmophyllum dianthus corals in the North Atlantic and Southern Ocean provide unique information about the history of intermediate waters (~1500‐1700 m) across the late glacial and deglaciation (~35‐10 ka). These measurements allow for the construction of radiocarbon‐tempera...
Article
The last glacial period is punctuated by abrupt changes in Northern Hemisphere temperatures that are known as Dansgaard–Oeschger (DO) events. A striking and largely unexplained feature of DO events is an interhemispheric asymmetry characterized by cooling in Antarctica during periods of warming in Greenland and vice versa—the bipolar seesaw. Methan...
Article
Full-text available
High‐latitude Northern Hemisphere climate during the last glacial period was characterized by a series of abrupt climate changes, known as Dansgaard‐Oeschger events, which were recorded in Greenland ice cores as shifts in the oxygen isotopic composition of the ice. These shifts in inferred Northern Hemisphere high‐latitude temperature have been lin...
Article
The exchange of water masses between the Indian Ocean and the Atlantic constitutes an integral interocean link in the global thermohaline circulation. Long‐term changes in deep water flow have been studied using seismic reflection profiles but the seismic stratigraphy was poorly constrained and not resolved for the time period from the late Miocene...
Article
A detailed paleoenvironment reconstruction from the Mozambique Channel, western Indian Ocean, based on the calcareous nannoplankton assemblages was conducted for the interval between 2.85 and 1.85 Myr. This study covers the period during which the successive extinction of the last five species of discoasters occurred. New productivity data obtained...
Article
Full-text available
Significance The concentration of atmospheric carbon dioxide ( p CO 2 ) varies by 80–100 ppm on glacial–interglacial timescales, with lower p CO 2 during the ice ages. In the modern Southern Ocean, the surface nutrients are not fully consumed by phytoplankton, resulting in leakage of deeply sequestered CO 2 to the atmosphere. It has been suggested...
Article
Isotopes of the actinide elements protactinium (Pa), thorium (Th), and uranium (U), and the lanthanide element neodymium (Nd) are often used as complementary tracers of modern and past oceanic processes. The extraction of such elements from low abundance matrices, such as seawater and carbonate, is however labor-intensive and requires significant a...
Article
Full-text available
We have developed a simple, rapid method to screen carbonates for survey applications, which provides radio-carbon dates with decreased precision at lower cost. The method is based on previous work by Longworth et al. (2011) and involves mixing pulverized CaCO 3 with Fe powder, followed by pressing into aluminum target holders for direct 14 C accel...

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