| NSF Org: |
OCE Division Of Ocean Sciences |
| Recipient: |
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| Initial Amendment Date: | September 18, 2012 |
| Latest Amendment Date: | August 7, 2015 |
| Award Number: | 1241247 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Michael Sieracki
OCE Division Of Ocean Sciences GEO Directorate for Geosciences |
| Start Date: | January 1, 2013 |
| End Date: | December 31, 2017 (Estimated) |
| Total Intended Award Amount: | $540,001.00 |
| Total Awarded Amount to Date: | $559,255.00 |
| Funds Obligated to Date: |
FY 2015 = $19,254.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
4333 BROOKLYN AVE NE SEATTLE WA US 98195-1016 (206)543-4043 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
4333 Brooklyn Ave NE Seattle WA US 98195-1202 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): |
BIOLOGICAL OCEANOGRAPHY, Dimensions of Biodiversity |
| Primary Program Source: |
01001516DB NSF RESEARCH & RELATED ACTIVIT |
| 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
This project will survey the taxonomic, genetic, and functional diversity of the organisms found in marine lakes, and investigate the processes that cause gains and losses in this biodiversity. Marine lakes formed as melting ice sheets raised sea level after the last glacial maximum and flooded hundreds of inland valleys around the world. Inoculated with marine life from the surrounding sea and then isolated to varying degrees for the next 6,000 to 15,000 years, these marine lakes provide multiple, independent examples of how environments and interactions between species can drive extinction and speciation. Researchers will survey the microbes, algae, invertebrates, and fishes present in 40 marine lakes in Palau and Papua, and study how diversity has changed over time by retrieving the remains of organisms preserved in sediments on the lake bottoms. The project will test whether the number of species, the diversity of functional roles played by organisms, and the genetic diversity within species increase and decrease in parallel; whether certain species can greatly curtail diversity by changing the environment; whether the size of a lake determines its biodiversity; and whether the processes that control diversity in marine organisms are similar to those that operate on land.
Because biodiversity underlies the ecosystem services on which society depends, society has a great interest in understanding the processes that generate and retain biodiversity in nature. This project will also help conserve areas of economic importance. Marine lakes in the study region are important for tourism, and researchers will work closely with governmental and non-governmental conservation and education groups and with diving and tourism businesses to raise awareness of the value and threats to marine lakes in Indonesia and Palau. The project will reach out to the public by developing a marine lakes website, a tourist booklet and posters for Papua, and a student club that promotes scholarship, professional development, and evidence-based public education. The project will contribute to scientific infrastructure by providing online access to specimens and associated metadata, and content for the prize-winning website of the Museum of Paleontology at the University of California at Berkeley. Finally, the project will help build the workforce for science by involving early career scientists and by training undergraduate and graduate students and a postdoctoral researcher.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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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.
Palau’s marine lakes and the thick sediment sequences they contain provide a treasure trove of climatic and evolutionary history. Over 150 meters of sediment cores were collected from 11 lakes during month-long field campaigns in 2013 and 2016. Radiocarbon dating has shown that several of these lakes contain sediments from lake inception as long ago as 11,000 years, the beginning of the Holocene period. The analysis of molecular fossils and their hydrogen isotopic composition in many of these sediments have revealed a dynamic climate and environmental history. While Palau, at 7.5 degrees north latitude, has a very wet climate today, receiving over ten feet of rain per year, it appears to have been much drier during the period from 6,000 to 2,000 years ago. Curiously, other researchers have found that conditions closer to the equator in the western tropical North Pacific were wetter at that time. For instance, rainfall reconstructions from cave deposits in central and northern Borneo indicate the wettest conditions of the last 10,000 years occurring just when Palau was driest. Because both Palau and Borneo experience the same rainfall anomaly in response to El Niño, when they suffer drought, and La Niña, when they both become even wetter, changes in the El Niño system cannot explain the differing climates during the mid-Holocene period. Another clue to the cause of this mid-Holocene climate condition comes from reconstructions of the strength of monsoons in Asia, India, Africa, and South America, which all show weakening during the same time. The most parsimonious explanation is that the tropical rain band--known as the Intertropical Convergence Zone, or ITCZ--was driven south by a decline in solar radiation in the northern tropics caused by changes in Earth’s orbital geometry.
Analyses of the hydrogen isotopic composition of molecular fossils from four of Palau’s marine lakes have also demonstrated that the period known as the Little Ice Age, that lasted from 1400 to 1850 A.D. was characterized by dry conditions relative to the preceding centuries the modern climate. Climate reconstructions from other islands in the Pacific lend support to our interpretation of the Little Ice Age also being a time when the ITCZ was located further south than it is today. Research with computer models of the climate system show that a combination of increased volcanic activity and diminished solar activity were likely responsible for a tropical rain band located closer to the equator during the Little Ice Age.
Last Modified: 04/02/2018
Modified by: Julian P Sachs
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