60th Annual Report on Research 2015

The fiscal year from 8/31/2014 to 8/31/2015 saw a gradual buildup to the primary activities of our PRF grant. The activities can be grouped into 3 main phases:  (1) recruitment of Christiane Uhlig (AWI) and fieldwork planning, (2) laboratory testing and mesocosm design, and (3) visit of Christiane Uhlig in June.

Recruitment of C. Uhlig:

The primary objective of this project is to evaluate the factors that govern the rate of methane oxidation in the vicinity of ice and sea ice, such as would be found in the Arctic Ocean.  To complete these tests we proposed laboratory mesocosm studies and a short field study in Barrow, AK.    In our budget, 70% of the allocation was directed toward funding a postdoctoral fellow to lead this research, primarily the genomic side, with the support of Brice Loose and Steve D'Hondt at URI.

After considerable recruiting effort, a qualified candidate was identified and hired during the period of March to June, 2015.   The candidate is Christiane Uhlig.  We have attached her CV to this document.  Dr. Uhlig is an expert in microbial genomics of cold tolerant organisms and has carried out multiple field studies in both the Arctic and Antarctic coastal regions.  Currently, she is finishing a postdoctoral fellowship at the Alfred Wegener Institute in Germany, and she will begin her ACS PRF fellowship beginning this December, 2015. 

Consequently, the project timeline has shifted to be later than originally planned.  However, we are on target to carry out the fieldwork in Barrow, AK in Spring of 2016.  We have had conference calls with the logistics provider (UIC Science) in Barrow, AK and they have reserved two weeks for us in early April, 2015 just prior to the beginning of the artisanal whaling season.

Laboratory testing and mesocosm design:

During a parallel period, we began design and testing of the mesocosm tanks.  The mesocosm tanks need to provide a stable ice cover that does not grow or melt so that bacteria are not submitted to abrupt changes in salinity.   The tank must also allow for the introduction of dissolved methane gas beneath the ice.  We have implemented a prototype insulated 33 gallon tank with a heater blanket and temperature controller.  When the tank temperature goes below a set point, the heater increases the water temperature and this provides a negative feedback against the tendency of the ice to grow as a result of heat being removed.  The heat removal mechanism occurs primarily from the ice surface as the tank sides are covered with insulation. Figure 1 contains a picture of the prototype, which has been operating in an automated fashion, maintaining a steady temperature for more than 3 months.

Visit of C. Uhlig:

During June 2015 Christiane Uhlig visited us from Germany in an effort to learn the lab facilities, and to interact with Steve D'Hondt and research scientist John Kirkpatrick.  During the visit, we made the attempts at isolating methanotroph bacteria using the particulate and soluble methane monooxenase amino acids (pMMO and sMMO) that are the signature of methanotroph activity.  We looked for the presence of methanotrophs in the mesocosm tank water (pictured in Figure 1), in deep sea water from the Bering Sea, where low oxygen environment persists, and in sediment cores for a nearby eutrophic salt marsh.   In both Bering Sea and the salt marsh samples we observed strong amplification of pMMO and sMMO chains.  We observed amplification below the detection limit from the mesocosm; this was not surprising considering that the mesocosm had not been dosed with methane gas, and the water was relatively well-oxygenated, precluding natural methane production.  There was some concern that we had amplified the pMMO and sMMO dimers, which would imply a false positive.  By the end of the visit, it was concluded that we should purchase and maintain a viable culture of methanotrophs to use as a positive control against future analyses and methods.  We are currently preparing the laboratory with equipment to isolate and maintain a viable methanotroph feedstock for use a positive control.  We anticipate this capacity to be complete by the time C. Uhlig arrives in January.

Figure  1.  Initial prototype of the laboratory mesocosm operating in the URI Marine Life Science Facility.

Figure  2.  Christiane Uhlig and John Kirkpatrick performing DNA extractions for amplification via PCR and qPCR techniques.

Dr Christiane Uhlig                                                                               Email: Christiane.Uhlig@awi.de

Research interests

Sea ice biogeochemistry and biology

Polar eukaryotic and prokaryotic microbiology

Adaptation mechanisms to extreme environments

Scientific careers