Deglacial Atlantic Ocean Ventilation Rates
Lead Research Organisation:
Imperial College London
Department Name: Earth Science and Engineering
Abstract
This research project addresses a scientific issue that is of first-order importance, deglacial ocean ventilation rates. Ocean ventilation rates describe the time elapsed since a water mass last 'saw' the atmosphere. This age information is important because ocean ventilation rates are intimately linked to climate change through the formation of deep waters at high latitudes. Most of the carbon in the coupled ocean-atmosphere system is located in the deep ocean, which exerts an important influence on climate via the greenhouse gas connection. Small changes in the rate of deep water formation are likely to have a large impact on the atmospheric carbon budget. Geochemical analyses of marine sediments cores show that many such changes in ocean circulation have happened in the geological past. The most recent large amplitude changes occurred during the last deglaciation (~20 to 10 thousand years ago), a time when the large ice sheets in North America and Northern Europe were retreating. Measurements of the radiocarbon content of deep-sea corals indicate that during the last deglaciation, the ocean was flipping back and forth between different modes of operation (i.e., different water mass distributions and different flow rates). However, it is impossible to convert the radiocarbon contents of water mass masses directly into ventilation rates, if we do not know the mixing proportions of water masses derived from high northern and southern latitude sources. This hurdle can be overcome by measuring the neodymium (Nd) isotopic composition in deep-sea corals from the western North Atlantic Ocean. Deep-sea corals are reliable recorders of the Nd isotopic composition of the water mass in which they grow. The Nd isotopic composition of the water mass in turn, is closely tied to the age of the continents in its formation area, leading to very different Nd isotopic signatures for high northern versus southern latitude waters in the Atlantic Ocean. These distinct signatures enable us to 'un-mix' the composition of waters in the western North Atlantic during abrupt climate events of the last deglaciation. Applying this knowledge of water mass mixtures to the existing radiocarbon data set on the same, absolutely dated samples, we can unravel how rapid and from where ventilation of the Atlantic Ocean occurred during the last deglaciation. Information such as this has not been obtained before, and has the potential to revolutionise our understanding of the ocean's role in rapid climate change.
Publications
Wilson D
(2017)
Lead isotopes in deep-sea coral skeletons: Ground-truthing and a first deglacial Southern Ocean record
in Geochimica et Cosmochimica Acta
Wilson D
(2020)
Sea-ice control on deglacial lower cell circulation changes recorded by Drake Passage deep-sea corals
in Earth and Planetary Science Letters
Wilson D
(2014)
Dynamic intermediate ocean circulation in the North Atlantic during Heinrich Stadial 1: A radiocarbon and neodymium isotope perspective
in Paleoceanography
Van De Flierdt T
(2012)
GEOTRACES intercalibration of neodymium isotopes and rare earth element concentrations in seawater and suspended particles. Part 1: reproducibility of results for the international intercomparison
in Limnology and Oceanography: Methods
Van De Flierdt T
(2010)
Deep-sea coral aragonite as a recorder for the neodymium isotopic composition of seawater
in Geochimica et Cosmochimica Acta
Van De Flierdt T
(2010)
Neodymium isotopes in paleoceanography
in Quaternary Science Reviews
Struve T
(2016)
Neodymium isotope analyses after combined extraction of actinide and lanthanide elements from seawater and deep-sea coral aragonite
in Geochemistry, Geophysics, Geosystems
Struve T
(2020)
Middle Holocene expansion of Pacific Deep Water into the Southern Ocean.
in Proceedings of the National Academy of Sciences of the United States of America
Struve T
(2022)
A deep Tasman outflow of Pacific waters during the last glacial period.
in Nature communications
Robinson S
(2021)
Global continental and marine detrital eNd: An updated compilation for use in understanding marine Nd cycling
in Chemical Geology
Robinson L
(2009)
Southern Ocean evidence for reduced export of North Atlantic Deep Water during Heinrich event 1
in Geology
Robinson L
(2014)
Corrigendum to: "The geochemistry of deep-sea coral skeletons: A review of vital effects and applications for palaeoceanography" [Deep-Sea Res. II 99 (2014) 184-198]
in Deep Sea Research Part II: Topical Studies in Oceanography
Robinson L
(2014)
The geochemistry of deep-sea coral skeletons: A review of vital effects and applications for palaeoceanography
in Deep Sea Research Part II: Topical Studies in Oceanography
Pierce E
(2011)
Characterizing the sediment provenance of East Antarctica's weak underbelly: The Aurora and Wilkes sub-glacial basins
in Paleoceanography
Pahnke K
(2012)
GEOTRACES intercalibration of neodymium isotopes and rare earth element concentrations in seawater and suspended particles. Part 2: Systematic tests and baseline profiles
in Limnology and Oceanography: Methods
Margolin A
(2014)
Temporal and spatial distributions of cold-water corals in the Drake Passage: Insights from the last 35,000 years
in Deep Sea Research Part II: Topical Studies in Oceanography
Lambelet M
(2016)
Neodymium isotopic composition and concentration in the western North Atlantic Ocean: Results from the GEOTRACES GA02 section
in Geochimica et Cosmochimica Acta
Henry L
(2014)
Global ocean conveyor lowers extinction risk in the deep sea
in Deep Sea Research Part I: Oceanographic Research Papers
Griffiths J
(2013)
Evidence of silicic acid leakage to the tropical Atlantic via Antarctic Intermediate Water during Marine Isotope Stage 4
in Paleoceanography
Crocket K
(2014)
Measurement of fossil deep-sea coral Nd isotopic compositions and concentrations by TIMS as NdO+, with evaluation of cleaning protocols
in Chemical Geology
Description | The main achievements of this project are twofold: (i) establishment of a new separation and mass spectrometry technique to precisely and accurately measure small abundances of Nd in natural samples (ii) novel constraints on deglacial Atlantic Ocean intermediate water mass dynamics In detail, we discovered very rapid changes in the mid depth water column towards the end of a cold phase, Heinrich Stadial 1, coming out of the last ice age (16,000 to 15,000 years ago). While records from the deep ocean showed a bathing by southern-sourced water masses during this time, the intermediate ocean was subject to highly dynamic changes on sub-millennial to centennial timescales. These changes were characterised by an interplay of northern- and southern-sourced water masses and often happened over the life time of a single coral (less than 100 years). We concluded that corals in 1.7 to 2.6 km water depth in the Northwest Atlantic were probably living close to a hydrographic front, and that the picture of a shutdown of the Atlantic Meridional Overturning circulation during Heinrich Stadial 1 is too simplistic. Overall, the intermediate ocean may have played an important role in the deglacial climate evolution. |
Exploitation Route | Deep sea corals provide unique insights into ocean dynamics for various reasons: (i) they provide absolute and relatively precise uranium-series ages with potential for high-resolution studies; (ii) they are a suitable archive for combined Nd isotope and radiocarbon reconstructions to be made on the same carbonate phase; and (iii) they grow in locations such as the intermediate to mid depth oceans, where sediment cores are not always available and where there appears to have been rapid oceanographic variability. We therefore envisage great potential in future studies of radiogenic isotope tracers in deep-sea corals. |
Sectors | Environment |
Description | Our analytical techniques have already been implemented by other researchers for the broader field of Earth Science research. Our publications on the results derived from deglacial Northwest Atlantic deep sea corals have received high praise, and are well cited. They motivated us (and other groups) to invest more time in constructing intermediate water records based on the skeletons of deep-sea corals in other parts of the global ocean, and covering other time scales. |
First Year Of Impact | 2011 |
Sector | Education,Environment |
Impact Types | Societal |
Description | Deciphering glacial/interglacial climate secrets with Southern Ocean deep-sea corals |
Amount | £170,000 (GBP) |
Funding ID | RPG-398 |
Organisation | The Leverhulme Trust |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 09/2012 |
End | 08/2015 |
Description | NERC standard grant - Bridging the Timing Gap |
Amount | £201,826 (GBP) |
Funding ID | NE/N001141/1 |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start | 10/2015 |
End | 09/2018 |
Description | Deep-sea corals |
Organisation | California Institute of Technology |
Country | United States |
Sector | Academic/University |
PI Contribution | Analyses of deep sea coral skeletons for their Nd isotopic composition to reconstruct past water mass characteristics (and ocean circulation patterns). |
Collaborator Contribution | A number of US funded expeditions to the western North Atlantic to collect deep sea corals, which could subsequently be used as archives of ocean chemistry. |
Impact | This collaboration has been initiated during the time the lead PI was a research scientist in the US and has provided invaluable access to a unique collection of deep-sea corals. Our collaborative work is ongoing and has produced a number of well recognized publications. |
Start Year | 2009 |
Description | Atmosphere exhibiton |
Form Of Engagement Activity | A formal working group, expert panel or dialogue |
Part Of Official Scheme? | Yes |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Helped with scientific advise during the design phase of the atmosphere exhibition in the Science Museum (opened in autumn 2010). I take now every year our new first year students to the exhibition and make them present on some aspect of the atmosphere exhibition. It is well received by visitors of the museum. |
Year(s) Of Engagement Activity | 2010 |
Description | Earthclass |
Form Of Engagement Activity | Participation in an open day or visit at my research institution |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Schools |
Results and Impact | Annual open day event by the Department of Earth Science and Engineering to educate school kids on Earth Science topics. The children loved to see how you can take a fish tank, partnered with a bit of salty water, ice cubes and heating elements, and produce ocean circulation. |
Year(s) Of Engagement Activity | 2011,2012 |
Description | Evening lecture in Cardiff |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Public/other audiences |
Results and Impact | Sparked questions and discussion. |
Year(s) Of Engagement Activity | 2016 |
Description | Gordon Conference |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Postgraduate students |
Results and Impact | Invited talk at a Gordon Conference on Chemical Oceanography. >50 scientists and graduate students attended. The presentation sparked questions and discussion. |
Year(s) Of Engagement Activity | 2017 |
Description | ICP poster |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Other audiences |
Results and Impact | Poster presentation at the International Conference on Paleoceanography for an audience of >500 scientists. The poster sparked questions and discussion. |
Year(s) Of Engagement Activity | 2016 |
Description | MAGIC Elements |
Form Of Engagement Activity | Participation in an open day or visit at my research institution |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Public/other audiences |
Results and Impact | Hundreds of under-12s visited the Imperial Festival stand on MAGIC Elements with their parents. They dressed up as scientists, learned about elements and isotopes, and even about how Antarctica once was a continent with palm trees at its shorelines. |
Year(s) Of Engagement Activity | 2018 |
URL | https://www.imperial.ac.uk/news/185986/imperial-festival-transforms-under-12s-into-mini/ |
Description | Media contact Grantham |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Part of a small group of Grantham affiliates that helps with media requests. My expertise is in the are of palaeoclimate and Antarctic ice sheets |
Year(s) Of Engagement Activity | 2016,2017,2018,2019 |
Description | Open Day 2014 |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Schools |
Results and Impact | Talk about Earth Science at College wide Open Day. Hopefully it inspires pupils to come and study Earth Sciences! |
Year(s) Of Engagement Activity | 2014 |
Description | Podcast interview |
Form Of Engagement Activity | Engagement focused website, blog or social media channel |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | 1 hour interview for the forecast, a podcast about climate science and climate scientists. Long format interviews with Nature's editor for climate science, Michael White. |
Year(s) Of Engagement Activity | 2016 |
URL | http://forecastpod.org/?s=tina+van+de+Flierdt |
Description | Pretty corals and rocky seas - blog |
Form Of Engagement Activity | A magazine, newsletter or online publication |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Blog from a deep-sea coral collection cruise in May-June 2011 in the Drake Passage. Resulted in comments and questions from the general public. Increased recognition of deep-sea coral research by the general public. |
Year(s) Of Engagement Activity | 2011 |
Description | Royal Society meeting |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Other audiences |
Results and Impact | Presentation sparked questions and discussion among the audience and increased interest in related subject areas. |
Year(s) Of Engagement Activity | 2015 |
URL | https://royalsociety.org/events/2015/12/ocean-chemistry/ |
Description | Science Museum Lates |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Public/other audiences |
Results and Impact | Science Museums 'Lates' talk about palaeoclimate research. Sparked questions and discussion. |
Year(s) Of Engagement Activity | 2013 |
Description | Teacher in Residence |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | Yes |
Geographic Reach | Local |
Primary Audience | Schools |
Results and Impact | PDRA Kirsty Crocket participated in the 'Researchers in Residence scheme', spending 20 hours in total at St Michael and All Angels Church of England Academy in Camberwell, London. The goal of the placement was to promote understanding and enthusiasm for science for a large group of 9 year old pupils, which was achieved. Positive feedback from the school. |
Year(s) Of Engagement Activity | 2010 |
Description | |
Form Of Engagement Activity | Engagement focused website, blog or social media channel |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Tweets about climate change, Antarctica, women in science, STEM related topics and (Earth) Science in general. |
Year(s) Of Engagement Activity | 2014,2015,2016,2017,2018,2019,2020 |
Description | iPODS-OC3 Joint Meeting 2014 |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Other academic audiences (collaborators, peers etc.) |
Results and Impact | Oral presentation at a conference on 'Deglacial Deep Ocean Circulation and Biogeochemical Cycling' (iPODS-OC3 Joint Meeting), Bern, Switzerland. Sparked questions and discussion afterwards. Complementary comments from colleagues. |
Year(s) Of Engagement Activity | 2014 |