| NSF Org: |
OCE Division Of Ocean Sciences |
| Recipient: |
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| Initial Amendment Date: | July 13, 2021 |
| Latest Amendment Date: | July 13, 2021 |
| Award Number: | 2102909 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Alan Wanamaker
awanamak@nsf.gov (703)292-7516 OCE Division Of Ocean Sciences GEO Directorate for Geosciences |
| Start Date: | July 15, 2021 |
| End Date: | June 30, 2024 (Estimated) |
| Total Intended Award Amount: | $39,478.00 |
| Total Awarded Amount to Date: | $39,478.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
360 HUNTINGTON AVE BOSTON MA US 02115-5005 (617)373-5600 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
5000 MacArthur Boulvard Oakland CA US 94613-1301 |
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Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | Marine Geology and Geophysics |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
Microscopic organisms called foraminifera live in the ocean, in shells of calcium carbonate the size of a small grain of sand. Every foraminifer has its own living preferences - surface or deep ocean, warm or cold water, the amount of food or the availability of light. In seafloor sediments the foraminifers? shells become fossils; they provide a record of the living conditions in the overlying water. One such species called Globorolatia truncatulinoides looks like little party hats made from coiling paper either to the right or the left. The left coilers like it warm. They prefer to live in areas where a layer of warm water extends from the surface to a water depth as deep as 300 m, including waters that today are found off the coast of Florida in the Gulf Stream. Their fossil record tells scientist about one aspect of climate - the presence of warm waters in a particular location. This project will study changes in the abundance of fossil remains of these left coilers along the path of the Gulf Stream from the east coast of North America, turning east toward Europe, and then traveling north past Ireland. Imagine finding a whole bunch of these left coiling party hats in ocean sediments as far north as Ireland! It would mean that oceanic conditions and hence climate in the past may have been similar to Florida. Finding these fossil remains requires laboratory work involving sieving deep-sea mud to isolate foraminifera, in which the party hats can be identified and counted. The laboratory work will provide undergraduate research experience to undergraduates at both PI?s schools. It will give the students an opportunity for hands-on work in a laboratory setting, including dividing up the sampling locations and time intervals so that each student can ?own? a portion of the data. The students will then be responsible for interpreting their data with respect to past oceanic and climate change. In this manner each student can develop their own success story and present their results at a professional meeting. The project will also support a graduate student at the University of Delaware.
This project aims to provide a record of low to high latitude oceanographic links during intervals of global warmth. The study will test the hypothesis that poleward extension of the subtropical gyre and enhanced warm water transport in the North Atlantic Current contributed to the warmth of the past five interglacial intervals, and in particular, their maxima (MIS 1, 5e, 7a-c, 7e, 9e, 11c, PAGES et al., 2016). Each of the interglacial maxima corresponds to different boundary conditions (e.g., insolation, CO2, ice volume, PAGES et al., 2016), yet there is no relationship between the degree of warming and the amplitude of the forcing (PAGES et al., 2016). The proposed study contributes another climate parameter, warm water advection, that may have played a role in amplifying high latitude warmth during these intervals of time. To reconstruct warm water advection, the study will use the coiling direction of Globorolatia truncatulinoides as a proxy for upper water column structure at three sites in the North Atlantic Ocean spanning the past 450 kyr. It will focus on Marine Isotope Stages (MIS) 1, 5, 7, 9, and 11 in order to resolve differences in upper ocean hydrography that may relate to the relative warmth reconstructed for these intervals of time. Three proposed study sites provide a spatial transect between the northern subtropical and subpolar North Atlantic Ocean (U1313, U1308, and Site 980), and published orbital-scale age models provide a means for temporal correlations. The abundance of G. truncatulinoides (sinistral) in relation to total G. truncatulinoides (sinistral plus dextral) reflects the relative depth of the permanent thermocline and hence the relative size of the heat reservoir in the upper ocean of the subtropical to subpolar North Atlantic. An increase in the ratio of sinistral to total G. truncatulinoides tests at U1313 would reflect a northward expansion of the subtropical gyre. Such an increase in sinistral tests at U1308 would suggest enhanced warm water transport in the North Atlantic Current, and if the influence of this current is significant at subpolar Site 980, sinistral tests will increase there as well. The proposed records will have a temporal resolution of 0.5 kyr in order to monitor the relative stability of warm water advection in the northern gyre and the North Atlantic Current during the interglacial intervals. The proposed project is a collaboration between professors at a Hispanic serving small liberal arts college for women and gender nonbinary students (Mills) and a major research University (University of Delaware). The project will provide a concrete research experience to two undergraduate students from Mills by having them participate in the University of Delaware?s NSF sponsored REU site. The laboratory work is designed to provide the undergraduates with a meaningful research experience, with the goal of solidifying their interest in a STEM related career. The project will also support a graduate student and an undergraduate student assistant at the University of Delaware.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Intellectual Merit:
In this project, we investigated northward flow of warm surface water in the North Atlantic Ocean during five interglacial (warm) intervals (Marine Isotope Stages, MIS 1, 5, 7, 9, and 11). We tested the hypothesis that poleward extension of the subtropical gyre and enhanced warm water transport in the North Atlantic Current contributed to the warmth of these intervals, and in particular, their maxima. To do so, we used the relative abundance of Globorolatia truncatulinoides, a subtropical foraminiferal species whose test morphology (calcareous shell) displays two coiling directions. Sinistral coiling varieties prefer in areas where a thick layer of warm water extends from the surface to a water depth as deep as 300 m such as the center of the subtropical gyre. The presence of this species and its sinistral versus dextral coiling ratio in sediment cores along a spatial transect spanning the northern boundary of the subtropical gyre (ocean drilling Sites U1313 and U1308) through subpolar North Atlantic (Sites 980 and U1314) provides evidence for the influence of warm surface currents in those regions.
Results indicate that G. truncatulinoides sinistral (s) abundances differ among the interglacial intervals studied (MIS, 1, 5, 7, 9, and 11), and they do not consistently align with warm versus cold climate background conditions characterizing the interglacial substages (lettered a-e). For example, enhanced northward warm water advection in the North Atlantic Current reaching all study sites including both subpolar regions occurred during MIS 1 (about 11,000 years ago), cool substages MIS 5d (about 100,000 years ago), MIS 7d (about 220,000 years ago), and warm substage MIS 11e (440,000 years ago). For MIS 11e, results from subpolar Site U1314 agree well with published reconstructions of oceanic warmth based on ice rafted debris and sea surface temperatures. During insolation maxima of MIS 1 and MIS 5e, counts of G. truncatulinoides (s) are higher at the western more subpolar site U1314 than in the core top, and higher than at the eastern more Site 980 suggesting that the North Atlantic Current path was located to the west with respect to the modern perhaps associated with a steeper meridional Arctic Front. During the insolation maximum relating to warm substage MIS 11c, higher G. truncatulinoides (s) coiling ratios at the gyre boundary site U1308 with respect to core top suggest a more northern location than in the modern ocean (no data are available for the subpolar sites for this interval). These results indicate that warm intervals are associated with enhanced poleward warm water flow in the Atlantic Ocean, but not exclusively. The strength of poleward warm water flow and/or its poleward path may have been quite variable during the past interglacial intervals.
Broader Impacts:
This project was a multi-institution collaboration between two investigators, one at a small liberal arts college for women and nonbinary students that was a federally designated HSI (Mills College, after a merger now Mills College at Northeastern University [MCNU]) and a major research university (University of Delaware, UD). The project was designed to enhance the undergraduate research experience by not only giving students an opportunity for hands-on work in a laboratory setting, but importantly, by dividing up the sampling locations and time intervals so that each student could own a portion of the data that they are responsible for interpreting with respect to past oceanic and climate change. In this manner each student developed their own success story.
At MCNU, undergraduate student participants benefited from integrated mentorship from their undergraduate advisor, from the research university professor, and from graduate students during two academic years and a summer research experience at UD. The students had the opportunity of presenting their results at an annual meeting of the American Geophysical Union. As a result of the project, these students are now pursuing careers in oceanography. An additional first year undergraduate was recruited to participate in disseminating findings of this project in an informational website friendly to secondary school students, and a one-day learning experience for a local public middle school science program. Both the website and the collaboration with the school will continue beyond the lifetime of the grant. Overall, this project successfully contributed to the professional development of several students from under-represented groups in science who are continuing their education in STEM related fields and resulted in educational outreach and dissemination of scientific findings to the local community.
Last Modified: 10/24/2024
Modified by: Kristina L Faul
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