| NSF Org: |
OCE Division Of Ocean Sciences |
| Recipient: |
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| Initial Amendment Date: | August 7, 2015 |
| Latest Amendment Date: | August 7, 2015 |
| Award Number: | 1536776 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Michael Sieracki
OCE Division Of Ocean Sciences GEO Directorate for Geosciences |
| Start Date: | September 1, 2015 |
| End Date: | August 31, 2019 (Estimated) |
| Total Intended Award Amount: | $141,134.00 |
| Total Awarded Amount to Date: | $141,134.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
8622 DISCOVERY WAY # 116 LA JOLLA CA US 92093-1500 (858)534-1293 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
9500 Gilman Dr., MC 0210 La Jolla CA US 92093-0210 |
| 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 |
| 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
The deepest portion of the ocean is present in ocean trenches, whose steep walls descend from approximately 4 miles down to depths that in some cases are close to 7 miles below the seawater surface. At these locations Earth's crust is recycled. Perhaps not surprisingly given their remoteness, deep ocean trenches are the least understood habitats in the ocean. The researchers participating in this project are working to characterize the microbes present in two of the deepest trenches present on Earth, both in the Pacific Ocean, the Kermadec Trench located north of New Zealand, and the Mariana Trench, located east and south of the island of Guam. Most of the Mariana Trench is located within the United States Mariana Trench Marine National Monument. Relatively little is known about the diversity and adaptations of the microorganisms in deep ocean trenches. An unknown fraction of the microbes present have descended from shallow waters above and are unlikely to participate in any nutrient cycles in the deep sea. Others are adapted to near freezing temperatures and up to pressures greater than 10e7 kilograms per square meter (16,000 pounds per square inch). These latter microbes perform important roles recycling organic matter. But who are they? This project is contributing to the training of diverse undergraduate and graduate students participating in research, additional undergraduate students learning about microbes inhabiting extreme environments in a web-based class, and additional graduate students and postdoctoral scientists participating in an advanced training course being offered in Antarctica.
Experiments being performed include direct counts of prokaryotes and viruses in seawater and sediments, analyses of the abundance and phylogenetic breadth of culturable heterotrophic bacteria at a range of pressures, measurements of bacterial community species diversity and richness both within and across seawater and sediment samples, as well as within and across the two trench systems, measurements of microbial activity as a function of pressure and the identification of high pressure-active cells. The data generated from these analyses are being integrated into the results of additional chemical, geological and biological measurements performed by others as a part of the National Science Foundation funded Hadal Ecosystems Studies Project. Two of the working hypotheses are that prokaryote numbers and diversity are generally positively correlated with surface productivity and proximity to the trench axis and that bacterial taxa exist which are endemic to specific trenches, present in multiple trenches and more widely distributed in deep-sea environments.
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.
Intellectual Merit: This project compared the types of microbes present in bottom water and surficial sediments of two of the deepest locations on Earth. These were the Kermadec Trench located off the north coast of New Zealand, and the Mariana Trench, mostly located within the United States Mariana Trench Marine National Monument, but also occupying a portion of the territorial waters of Micronesia. Trenches can be considered to be upside down mountain ranges. These two trench systems are separately from one another by ~6,000 kilometers. In this grant we compared the microbes in these two trenches using highly quantitative marker gene DNA sequencing and comparative genomics. In addition, the microbes were also examined in terms of their activity and growth characteristics. The results indicated that deep-sea microbial populations consist of a mixture of taxa descending from shallow waters above and taxa adapted to life at great depth, including extremes of high pressure and low temperature. Seawater depth, trench of collection, size fraction, sediment depth, and organic levels were all found to correlate with distinctive types of microorganisms (Figure 2). Long-term incubation of trench sediments at the pressures and temperatures of their natural environment dramatically changed the composition of the microbial community to one containing a majority of previously documented and cultured high pressure-adapted microbes. Seventy-nine draft genome sequences from trench microbes were obtained. Analyses of these genomes indicated that many of the same species are shared between these two widely separated trenches, but that trench-specific strains also exist. This work demonstrated that microbes in deep trenches can be shared across great geographic distances, presumably moving along ocean currents.
Broader Impacts: A detailed description was provided of a free-falling and ascending instrument coupled with a pressure-retaining seawater sampling system. This instrument is of value to the deep-sea science community. The grant provided support for one PhD student, the training of 7 undergraduates (4 serving as coauthors on publications, two in PhD programs, one in a MD-PhD program), and provided the opportunity to host 5 visiting PhD students (Oregon State University, Princeton University, IIT, India, University of Aberdeen, and Southern University of Denmark). It was associated with numerous BCO-DMO datasets and 16 international presentations. Outreach included presentations to >60 middle/high school girls, a microbial ecology booth at the Birch Aquarium, a lecture to 160 K-12 teachers, audio/written interviews for "Science News for Students", numerous undergraduate and graduate lectures by the PI and PhD student, and service as instructor (PI) and TA (PhD student) in the NSF Polar Biology Training Course in Antarctica.
Last Modified: 12/16/2019
Modified by: Douglas H Bartlett
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