Award Abstract # 1756877
Collaborative Research: Probing the Metabolic and Electrical Interactions of Cable Bacteria in Anoxic Sediments

NSF Org: OCE
Division Of Ocean Sciences
Recipient: UNIVERSITY OF MARYLAND CENTER FOR ENVIRONMENTAL SCIENCE
Initial Amendment Date: February 21, 2018
Latest Amendment Date: May 16, 2022
Award Number: 1756877
Award Instrument: Standard Grant
Program Manager: Cynthia Suchman
csuchman@nsf.gov
 (703)292-2092
OCE
 Division Of Ocean Sciences
GEO
 Directorate For Geosciences
Start Date: July 1, 2018
End Date: June 30, 2024 (Estimated)
Total Intended Award Amount: $318,311.00
Total Awarded Amount to Date: $376,561.00
Funds Obligated to Date: FY 2018 = $318,311.00
FY 2022 = $58,250.00
History of Investigator:
  • Sairah Malkin (Principal Investigator)
    smalkin@umces.edu
Recipient Sponsored Research Office: University of Maryland Center for Environmental Sciences
2020 HORNS POINT RD
CAMBRIDGE
MD  US  21613-3368
(410)221-2014
Sponsor Congressional District: 01
Primary Place of Performance: UMCES, Horn Point Laboratory
2020 Horns Point Rd
Cambridge
MD  US  21613-0775
Primary Place of Performance
Congressional District:
01
Unique Entity Identifier (UEI): JHTYTGKYWLL9
Parent UEI:
NSF Program(s): BIOLOGICAL OCEANOGRAPHY
Primary Program Source: 01002223DB NSF RESEARCH & RELATED ACTIVIT
01001819DB NSF RESEARCH & RELATED ACTIVIT
Program Reference Code(s): 097Z, 102Z, 8811, 9117
Program Element Code(s): 1650
Award Agency Code: 4900
Fund Agency Code: 4900
Assistance Listing Number(s): 47.050

ABSTRACT

Marine sediments represent the world's largest repository of stored organic carbon, and understanding how microorganisms break down this carbon is an imperative for understanding global carbon cycling. Yet long-standing questions remain regarding how networks of microorganisms work together to accomplish the complete breakdown of organic carbon in marine sediments. Sediment microbes interact in a myriad of ways that couple their metabolism to the break down of organic carbon, including by sharing products of metabolism. Accumulating evidence further suggests that some microorganisms can interact by transferring electrons directly to other unrelated microorganisms. This ability occurs across diverse microorganisms and appears to be widespread in the biosphere, particularly in anaerobic environments such as marine sediments. This project addresses emerging questions about the identity and metabolic linkages between microorganisms that work together in natural anaerobic marine and estuarine sediments to break down organic carbon. The investigators approach these questions by focusing on the influence of a keystone bacterium on its surrounding microbial community. "Cable bacteria" are a recently discovered group of long filamentous bacteria that act as electrical conductors in aquatic sediments providing a conduit for electrons to commute from deeper sulfidic sediments up to the surface oxygen layer by the process of centimeter-scale electron transport. Since their discovery about 6 years ago, these bacteria have been observed in a wide range of depositional sedimentary environments, often at extremely high cell densities. Where these bacteria are abundant, such as in coastal marine muds, they drive intense localized changes in pH and strongly influence the mineral cycling. This research explorew the direct and indirect influence of cable bacteria on the metabolic activity of associated microorganisms. This project also advance the education and training of two early-career investigators, two PhD students, and undergraduate students. The skills and expertise gained from these PhD research projects will enable the students to be competitive in academic pursuits and in bioinformatics and technology applications relevant to private industry. The scientific discoveries emerging from this work is being incorporated into undergraduate and graduate level courses in marine microbial ecology. The research team will reach out to the broader community by hosting public lectures promoting a better understanding of environmental microbial ecology.

The proposed work is to investigate the role of cable bacteria in structuring sediment microbial communities. Due to their growth strategy and morphology, cable bacteria are particularly amenable to experimental manipulation, providing an outstanding opportunity to better understand community interactions among microorganisms in a natural and complex anaerobic environment. The investigators will explore the interactions and relationships between cable bacteria and their associated microbial community by manipulating the growth and activity of cable bacteria and quantifying the resultant microbial community response. Specifically, this project aims to (1) identify microorganisms whose growth is enhanced by cable bacteria, (2) identify metabolic processes linked with cable bacteria activity using metatranscriptomics, (3) test specific metabolic links between sediment microorganisms and cable bacteria activity using a DNA-stable isotope probing (SIP) approach, and (4) visually confirm the identity and quantify key microorganisms associated with cable bacteria using microscopy. As more is learned about the identity and the mechanisms by which microorganisms are metabolically linked in anoxic sediments, we will be better able to understand and make predictions about how microorganisms function in their environment and how they can be utilized in bioengineered systems.

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.

PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH

Note:  When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

Hantsoo, Kalev and Gomes, Maya and Malkin, Sairah and Brenner, Dana and Kenney, William F. "Sedimentary Pyrite Formation in a Seasonally Oxygen?Stressed Estuary: Potential Imprints of Microbial Ecology and Position?Specific Isotope Fractionation" Journal of Geophysical Research: Biogeosciences , v.128 , 2023 https://doi.org/10.1029/2022JG007324 Citation Details
Powers, Leanne C. and Lapham, Laura L. and Malkin, Sairah Y. and Heyes, Andrew and Schmitt-Kopplin, Philippe and Gonsior, Michael "Molecular and optical characterization reveals the preservation and sulfurization of chemically diverse porewater dissolved organic matter in oligohaline and brackish Chesapeake Bay sediments" Organic Geochemistry , v.161 , 2021 https://doi.org/10.1016/j.orggeochem.2021.104324 Citation Details
Malkin, Sairah and Cardini, Ulisse "Facilitative interactions on the rise: cable bacteria associate with diverse aquatic plants" New Phytologist , v.232 , 2021 https://doi.org/10.1111/nph.17664 Citation Details
Malkin, Sairah Y. and Liau, Pinky and Kim, Carol and Hantsoo, Kalev G. and Gomes, Maya L. and Song, Bongkeun "Contrasting controls on seasonal and spatial distribution of marine cable bacteria ( Candidatus Electrothrix ) and Beggiatoaceae in seasonally hypoxic Chesapeake Bay" Limnology and Oceanography , v.67 , 2022 https://doi.org/10.1002/lno.12087 Citation Details
Liau, Pinky and Kim, Carol and Saxton, Matthew A. and Malkin, Sairah Y. "Microbial succession in a marine sediment: Inferring interspecific microbial interactions with marine cable bacteria" Environmental Microbiology , v.24 , 2022 https://doi.org/10.1111/1462-2920.16230 Citation Details

Please report errors in award information by writing to: awardsearch@nsf.gov.

Print this page

Back to Top of page