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Microscopic Antarctic Creatures

12/09/2010, 11:08 PM by Lollie Garay
Inga made these using a fluorescent stain (DAPI) and an epifluorescent microscope.<br/><br/>Credit: Inga Richert
Inga made these using a fluorescent stain (DAPI) and an epifluorescent microscope.
Photo Credit: Inga Richert

 

Dec 9

In transit

 

The fun of the last couple of days was a welcome respite for the team and crew, and provided the opportunity for a unique type of team building.  It also provided the audience back home with a glimpse of life on a ship thousands of mile from home. As the ship nears the Amundsen, thoughts turn again to the work ahead.

 

Inga Richert is one of the graduate students working with Swedish microbiologists Stefan Bertilsson and Lasse Riemann (neither are onboard the ship). She has provided this description of their work, as well as the images of the bacteria and protists.

 

“Our onboard team from Sweden includes Ramiro Logares (ICM, CSIC, Barcelona, Spain /Uppsala University, Sweden), Julie Dinasquet (Linneaus University, Kalmar Sweden) and me, Inga Richert (Centre of Environmental Research, Leipzig, Germany / Uppsala University is studying the microbial diversity of the Amundsen Sea Polynya.

When looking at water samples by microscopy one can see a little microcosm with an immense number of single cells in all varying shapes. The function of those non-photosynthetic microbes in the ocean is the decomposition and remineralization of the dead organic matter into nutrients, which are then used for micro eukaryote (protists and microalgae) growth. Thus, microbes play an important role in the oceans, being the base of the food web.

For our project as part of the ASPIRE, we want to investigate how the bacterial communities are assembled and how they change along the Amundsen Sea Polynya. Among other things, the microbial community composition strongly depends on the outer physical conditions as well as nutrient sources. This means that one will most likely find different bacteria in deep dark water layers compared to light surface waters. 

The same could be observed, when comparing nutrient rich and poor water masses. For that, we’re planning incubation experiments, where we change conditions such as light/dark or nutrient sources, using seawater from different locations. We follow the growth rate of the individual microbial population and identify later the single microbial species based on DNA based sequence analysis.

Viral infection and lysis of bacteria promote overall recycling of nutrients and carbon in the water column and affect the overall biological pump.  As part of the Yager project, we will assess the loss of bacterial recycling of nutrients by studying virus production in the polynya.”

US PI Rob Sherrell (Rutgers) describes the Trace Metal Group Activities:

 “One of the main questions being investigated in ASPIRE is the source of iron to the polynya.  In waters offshore of the Antarctic continental shelf, dissolved iron, an important micronutrient for phytoplankton, is too low for many of the cells to grow at maximum rates.  In the Amundsen Polynya, the high productivity we know is there, from satellite images and data from our 2007-08 expedition, indicates additional sources of iron.  The questions are, where does the iron come from, how does it get into the euphotic zone over the course of the summer growing season, is it abundant enough to keep productivity going at maximum rates in the polynya, and how might the iron supply be altered by climate change?  

Pursuing these questions onboard the NBP are Silke Severmann, Kat Esswein, and myself -all from Rutgers University.  We are collaborating with PI Kuria Ndungu and Maria Lagerstrom of the University of Stockholm.  The photos show the Rutgers team outside the trace metal “bubble”, a plastic clean room built on board by the scientists and Raytheon staff, and the Stockholm team working inside the nicely decorated lab.”

We’ll be hearing more from the trace metal group soon.

I’d like to recognize and give credit to the individuals who snapped those amusing photos from the initiation rites. The photos of Keliang were taken by Neptune’s baby (Povl Abrahamsen) from his vantage point on the throne. The rest of the photos were taken by Kathleen Gavahan, (Raytheon IT) who is running the multibeam on the ship.

Keep those photos coming everyone! We’d like to see some contributions from the ship’s crew too! ☺

Cheers, Lollie

 

 

 

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Question of the Day

  • What are Polynyas and why are they important to study?

    Polynyas, are recurring areas of seasonally open water surrounded by ice.

    Energy and material transfer between the atmosphere, polar surface ocean, and the deep sea in polynas provide polar ecosystems with just the right ingredients needed for high productivity and intense biogeochemical recycling.

    Polynyas may be the key to understanding the future of Polar Regions since their extent is expected to increase with anthropogenic warming.