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Ice Nucleation by Marine Psychrophiles

Entry ID: NSF-ANT08-01392

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Summary

Abstract: The primary objective of this research is to investigate polar marine psychrophilic bacteria for their potential to nucleate ice using a combination of microbiological, molecular biological and atmospheric science approaches in the laboratory. Very little is known about how psychrophiles interact and cope with ice or their adaptations to conditions of extreme cold and salinity. This work will ... involve a series of laboratory experiments using a novel freeze-tube technique for assaying freezing spectra which will provide quantitative information on: (i) the temperature-dependent freezing rates for heterogeneously frozen droplets containing sea-ice bacteria, (ii) the proportional occurrence of ice-nucleation activity versus anti-freeze activity among sea-ice bacterial isolates and (iii) the temperature-dependent freezing rates of bacteria with ice-nucleation activity grown at a range of temperatures and salinities. The compound(s) responsible for the observed activity will be identified, which is an essential step towards the development of an in-situ bacterial ice-nucleation detection assay that can be applied in the field to Antarctic water and cloud samples. One of the goals of this work is to better understand survival and cold adaptation processes of polar marine bacteria confronted with freezing conditions in sea ice. Since sea ice strongly impacts polar, as well as the global climates, this research is of significant interest because it will also provide data for accessing the importance of bacterial ice nucleation in the formation of sea ice. These measurements of ice-nucleation rates will be the first high-resolution measurements for psychrophilic marine bacteria. Another goal is to better understand the impact of bacterial ice initiation processes in polar clouds by making high-resolution measurements of nucleation rates for cloud bacteria found over Arctic and Antarctic regions. Initial measurements indicate these bacteria nucleate ice at warmer temperatures and the effect in polar regions may be quite important, since ice can strongly impact cloud dynamics, cloud radiative properties, precipitation formation, and cloud chemistry. If these initial measurements are confirmed, the data collected here will be important for improving the understanding of polar cloud processes and models. A third goal is to better understand the molecular basis of marine bacterial ice nucleation by characterizing the ice-nucleation compound and comparing it with those of known plant-derived ice-nucleating bacteria, which are the only ice-nucleating bacteria examined in detail to date. The proposed activity will support the beginning academic career of a post-doctoral researcher and will serve as the basis for several undergraduate student laboratory projects. Results from this research will be widely published in various scientific journals and outreach venues.

Related URL

Link: GET DATA

Description: U.S. Antarctic Program (USAP)
Original data submitted.

Link: VIEW RELATED INFORMATION

Description: NSF Award Abstract #0801392

Geographic Coverage

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Spatial coordinates

N: -60.0

S: -90.0

E: 180.0

W: -180.0

Temporal Coverage

Start Date: 2007-10-01

Stop Date: 2010-01-31

Location Keywords

OCEAN > SOUTHERN OCEAN

GEOGRAPHIC REGION > POLAR

VERTICAL LOCATION > SEA SURFACE

Science Keywords

CRYOSPHERE > SNOW/ICE

BIOLOGICAL CLASSIFICATION > BACTERIA/ARCHAEA

BIOLOGICAL CLASSIFICATION > VIRUSES

ISO Topic Category

GEOSCIENTIFIC INFORMATION

Project

NSF/OPP > Office of Polar Programs, National Science Foundation

Data Set Progress

COMPLETE

Data Center

Data Coordination Center, United States Antarctic Program

Data Center URL: http://www.usap-data.org/
Dataset ID: NSF-ANT08-01392

Data Center Personnel
Name: ROBERT A. ARKO Email: info at usap-data.org Contact Address: Lamont-Doherty Earth Observatory 61 Route 9W City: Palisades Province or State: NY Postal Code: 10964 Country: USA