| NSF Org: |
OCE Division Of Ocean Sciences |
| Recipient: |
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| Initial Amendment Date: | June 30, 2014 |
| Latest Amendment Date: | June 30, 2014 |
| Award Number: | 1435515 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Michael Sieracki
OCE Division Of Ocean Sciences GEO Directorate for Geosciences |
| Start Date: | September 1, 2014 |
| End Date: | August 31, 2018 (Estimated) |
| Total Intended Award Amount: | $541,804.00 |
| Total Awarded Amount to Date: | $541,804.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
438 WHITNEY RD EXTENSION UNIT 1133 STORRS CT US 06269-9018 (860)486-3622 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
1080 Shennecossett Rd. Groton CT US 06340-6048 |
| 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
Most of the biomass, productivity, and overall metabolism in the ocean are due to microbes, including bacteria, single-celled algae and protozoa. Oxygen depletion, harmful blooms, and other ocean ills are all attributable to these smallest members of the plankton. Their production and processing of organic matter, however, form the basis of the ocean's food web and thus determine the amount of food humans can harvest from the sea. Due to their small size, it is more difficult to assess the biological diversity of microbes than it is for larger organisms, such as the ocean's fish and mammal populations, yet because of their high abundance and dominance of ocean metabolism it is critical that we are able to measure microbial diversity and to understand how it changes over different time and space scales in response to changes in the environment. This project will make an important step forward in helping us to understand microbial biodiversity and set a baseline for changes that are expected in coming decades. In carrying out this research, undergraduate and graduate students as well as post-doctoral scholars will obtain training in the latest sequencing and data-processing technologies, an important goal for maintaining US leadership in biotechnology.
This project will use DNA-based methods to measure microbial diversity in the coastal ocean, employing the deep-sequencing technology to sample hundreds of thousands of microbial species simultaneously. To enable the deepest possible sampling, it will focus on a single group of microbes, the ciliates, using them as a model for similar microbes. Previous use of such methods has revealed a common pattern in which a small group of common ciliate species is accompanied by a very large group of rare ones. Because the new sequencing technologies provide so much information about microbial communities from each sample, this project will be able to evaluate how both the common and rare parts of the community (the latter is often referred to as the "rare biosphere") change with seasons, distance from shore, climate zone, etc. The technical goals for this project are to evaluate how ciliate diversity varies over time and space in the ocean, to evaluate environmental factors, both abiotic and biotic, that drive this variation, and to perform experiments under controlled conditions to test hypotheses about the relationship between diversity and these factors.
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.
This project was focused on measuring the biological diversity of a group of single-celled organisms, the ciliates, that are important in the ocean's plankton food web. Ciliates are one of the principal organisms that eat phytoplankton at the base of the food web and pass the energy from these photosynthetic plankton on to higher organisms, such as zooplankton and fish, that eat them. Because the world ocean is an open system (all oceans are connected to each other and currents circulate plankton everywhere), we do not know if some parts of the ocean have unique species only found there in the same way that terrestrial animals and plants can be restricted in their ranges and habitats, a feature known as endemism. This question is central to understanding overall diversity in the ocean, so we are using the ciliates as an example of how diversity might be controlled in all plankton.
In earlier studies, we found that natural ciliate plankton communities are composed of a small number of abundant species and a very large number of rare ones. Because of this, we used two different DNA-based methods to measure the abundance of different species - one rapid method allowed us to process more samples but only gave us the most abundant forms; the other method was more time-consuming but let us observe even the rarest species (1-2 cells in a liter of seawater). We also used RNA-based methods on some samples, which allowed us to estimate the activity level of the ciliates that we were observing by DNA sequencing.
Using the rapid technique, we found that the same abundant ciliate species dominated the community in both surface and deep waters on the New England continental shelf all the way out to its edge (about 100 miles). We also found a few common species that could only be found offshore (water deeper than about 200 feet). The rare species, measured with the more time-consuming technique, varied from place to place across the shelf, but we did not see any examples where a very rare species at one place became common someplace else. We also found, surprisingly, that the overall diversity (the total number of species, including rare ones) did not decrease appreciably with depth, a finding that contradicts most earlier microscopic estimations of diversity. As indicated by RNA measurements, ciliates in deeper waters were not less active, although we had thought they might be.
As is often the case, sampling the ocean for one thing provides opportunities to sample other things as well. So this project also supported a small study of how satellites could be used to measure the abundance of certain ciliates with unique pigments that occur in enormous blooms that are difficult to predict, and also a study of ciliates that use the photosynthetic apparatus of the phytoplankton they eat to keep it operational inside the ciliate itself.
Some of the broader impacts of this project involved hosting a high school student and a teacher in the lab, public outreach during UCONN's "Marine Science Day", judging middle-school and high school projects related to the ocean at the Connecticut Science Fair, and giving guest lectures on several occasions in the Sea Education Association's Bidiversity Program.
Last Modified: 11/01/2018
Modified by: George B Mcmanus
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