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Award Detail

Doing Business As Name:Harvard University
  • Peter Girguis
  • (617) 496-8328
Award Date:03/14/2011
Estimated Total Award Amount: $ 354,080
Funds Obligated to Date: $ 354,080
  • FY 2011=$354,080
Start Date:06/01/2011
End Date:05/31/2015
Transaction Type:Grant
Awarding Agency Code:4900
Funding Agency Code:4900
CFDA Number:47.050
Primary Program Source:040100 NSF RESEARCH & RELATED ACTIVIT
Award Title or Description:Collaborative Research: Characterization of Microbial Transformations in Basement Fluids, from Genes to Geochemical Cycling
Federal Award ID Number:1061934
DUNS ID:082359691
Parent DUNS ID:001963263

Awardee Location

Awardee Cong. District:05

Primary Place of Performance

Organization Name:Harvard University
Cong. District:05

Abstract at Time of Award

Intellectual Merit Current estimates suggest that the volume of ocean crust capable of sustaining life is comparable in magnitude to that of the oceans. To date, there is little understanding of the composition or functional capacity of microbial communities in the sub-seafloor, or their influence on the chemistry of the oceans and subsequent consequences for global biogeochemical cycles. This project focuses on understanding the relationship between microbial communities and fluid chemistry in young crustal fluids that are responsible for the transport of energy, nutrients, and organisms in the crust. Specifically, the PIs will couple microbial activity measurements, including autotrophic carbon, nitrogen and sulfur metabolisms as well as mineral oxide reduction, with quantitative assessments of functional gene expression and geochemical transformations in basement fluids. Through a comprehensive suite of in situ and shipboard analyses, this research will yield cross-disciplinary advances in our understanding of the microbial ecology and geochemistry of the sub-seafloor biosphere. The focus of the effort is at North Pond, an isolated sediment pond located on ridge flank oceanic crust 7-8 million years old on the western side of the Mid-Atlantic Ridge. North Pond is currently the target for drilling on IODP expedition 336, during which it will be instrumented with three sub-seafloor basement observatories. The project will leverage this opportunity for targeted and distinct sampling at North Pond on two German-US research cruises to accomplish three main objectives: 1. to determine if different basement fluid horizons across North Pond host distinct microbial communities and chemical milieus and the degree to which they change over a two-year post-drilling period. 2. to quantify the extent of autotrophic metabolism via microbially-mediated transformations in carbon, nitrogen, and sulfur species in basement fluids at North Pond. 3. to determine the extent of suspended particulate mineral oxides in basement fluids at North Pond and to characterize their role as oxidants for fluid-hosted microbial communities. Specific outcomes include quantitative assessments of microbial activity and gene expression as well as geochemical transformations. The program builds on the integrative research goals for North Pond and will provide important data for guiding the development of that and future deep biosphere research programs. Results will increase understanding of microbial life and chemistry in young oceanic crust as well as provide new insights into controls on the distribution and activity of marine microbial communities throughout the worlds oceans. Broader Impacts There are no data about microbial communities in ubiquitous cold, oceanic crust, the emphasis of the proposed work. This is an interdisciplinary project at the interface of microbial ecology, chemistry, and deep-sea oceanography with direct links to international and national research and educational organizations. It leverages on a long-term collaboration between the PIs and collaborators in both the US and Germany, including the recently formed NSF Science and Technology Center entitled "Center for Dark Energy Biosphere Investigations" (C-DEBI) and the NSF Research Coordination Network focused on the deep biosphere. This work on microbially mediated geochemical transformations in basement fluids is both attainable and timely, and methods development and results from this work will complement current and future microbial and geochemical investigations on the Juan de Fuca Ridge as part of both IODP and the OOI Regional Scale Node. The public outreach effort will utilize The Zephyr Education Foundation's unique marine science program to incorporate a short educational module focused on marine microbiology that will be tailored to the grade levels 7 through college. The module will emphasize the importance of marine microbes to environmental sustainability, human health, and the origin and evolution of life on our planet. The project also supports the research and career development of one graduate student, one undergraduate student, and two postdoctoral researchers. Students and postdocs will to engage with the larger community of researchers interested in deep biosphere microbiology and chemistry through emerging and existing NSF programs.

Project Outcomes Report


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.

NSF-OCE project #1061934 was a collaborative effort in which three complementary labs work towards furthering our understanding of the nature and extent of the microbial communities that live in the seafloor aquifer. Recent studies have shown that cracks and fissures in the seafloor host a seemingly abundant community of microbes. The fluids in these cracks constitute the "subsurface aquifer", which is the largest aquifer on Earth. While it may be odd to think of an aquifer beneath an ocean, it is a distinct feature through which seawater circulates and emerges with some degree of chemical alteration. During this project, we postulated that the microbes that live in this aquifer may play a role in changing the chemical composition of these fluids.  In particular, we wondered if these microbes are living off of organic matter that is entrained with the seawater as it enters the aquifer, or whether they are "making a living", so to speak, via some other means.  We also wondered whether these microbes change the chemical composition of the seawater in a way that benefits the microbes, alga, and animals that live in the upper ocean. We especially wanted to know if the subsurface microbes are helping to release metals and other trace elements into the aquifer water.  These in turn may have a profound influence on the health of organisms living in the overlying water. 

To that end, the goals of my research in this effort was to A) determine the composition of the microbial community, their metabolic rates, and B) the changes -if any- in the geochemistry of the surrounding fluids.  In brief, we found that these microbes are likely changing the abundance of trace elements in marked and biologically-relevant ways, even if they are not altering the concentrations of the major components of seawater.  Also, we found that this microbial community may be engaged in primary production despite living in the absence of sunlight. Primary production is the process of converting carbon dioxide to sugars, which plants do by harnessing energy from the sun. Some microbes can do this using chemical energy, without dependence on sunlight, and those living in the North Pond aquifer have that potential as well.  Finally, our data show that the microbes living in the North Pond aquifer are comparable in density to the overlying water column, which suggests that they are not any more energy-limited (or replete for that matter) than the microbes in the deep ocean water.  In sum, these subsurface microbes are reasonably abundant, quite active, possibly engaged in primary production, and playing a role in altering the composition of the fluids that pass through the aquifer.

Two postdocs, one masters student, and several high school students from a local high school were involved in this research.  Ulrike Jaekel was the first postdoctoral fellow on this project, and she benefited from this effort by learning new techniques in the Girguis lab. She is currently a lead scientist as a major oil company. Beate Kraft was the second postdoctoral fellow on this project, and she benefited by learning new techniques as well as developing hew approaches to study these kinds of samples.  She is leaving my lab in 2016 to a research scientist position, and will be taking these technologies with her.  Jenny Delaney is a Masters student who worked on this project, is now staying on as a lab manager here at Harvard. Finally, through our high school internship program with the Cambridge-Rindge and Latin School (a public high school that is renowned for the socio-economic diversity of its student body), several high school students participated in this research, and have since pursued undergraduate degrees in the sciences and engineering.  

This outcomes of this effort were the cornerstone of our educational and ...

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