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Exploring cyanobacterial diversity in Antarctica Blog

7 Posts tagged with the dry_valley tag

This year, we went back to Lake Joyce to study the benthic biology in the McMurdo Dry Valleys. The 3D microbial structures that are growing out of the mat are particularly interesting because most of them have a calcite skeleton. This is the only lake in the Dry Valleys where microbial mats have such distinctive calcite skeletons.


The calcite skeleton makes these microbialites particularly interesting for geobiology, where modern microbial mats are studied to enable a better interpretation of microbialite fossils from early Earth. 


Over the last three weeks we collected samples that will allow us to investigate if the water chemistry, light and sedimentation effect the growth of microbialites in the lake. We also collected mat material to carry out DNA and microscopy analysis to evaluate the role that cyanobacteria, other bacteria and eukaryotes play on the formation of microbialites and their calcite skeleton.



Microscopy image of Phormidium cyanobacterial filaments in Lake Joyce mats. Most of the Phormidium filaments have a strong purple pigmentation though the production of Phycoerythrin for a better utilisation of the limited light that is available in Lake Joyce.



Anne working at the microscope.



Close-up image of microbialites with calcite skeleton covered by thin microbial mat webs .



Microbialite structures with calcite skeleton collected from Lake Joyce by diving.



The team getting ready for a dive to collect microbial mats.


The main efforts of the field event led by researchers from UC Davis, California, were to map the distribution of the microbial structures in the lake and to test what the influence of sedimentation is on the microbial structures.


The imaging is done by a drop camera that is held on a rope through a hole in the ice. The team installed several traps in the ice that will collect sediment from now until next season.Each hole is individually drilled with a jiffy drill in order to insert the traps and document the microbial mas and microbial structures.



The team drilling a hole in the ice.


Here some images from our flight from Scott base, the New Zealand Antarctic station to Lake Fryxell. We crossed the McMurdo Ice Shelf and flew passed Mt Erebus, which seemed more smoky than usual. We then entered Taylor Valley and crossed Commonwealth Glacier and landed at Lake Fryxell. Shortly after our arrival, the remaining camping gear and science equipment arrived on sling load.


Mt Erebus


View from the helicopter over to the Commonwealth Glacier




Campling gear and science equipment arriving with a sling load



Mummified seals can be found all over the Dry Valleys. It is believed that the seals came from the seas ice into the Dry Valleys . It is not known why exactly seals end up far away from the sea ice. Explanations could be that they become disorentiated due to sickness or bad weather conditions, and  starve to death.

Due to dry air and slow degradation processes in Antarctica the seal carcasses mummify and are thought to be hundreds of years old.


                                             Mummified seal near Canada glacier and Lake Fryxcell



                                                             Mummified seal near Koettlitz glacier



Cyanobacteria are also very common in hypolithic communities that are microbial communities growing under translucent rocks such as quartz rock. These communities can be a mixture of cyanobacteria, other bacteria, green algae, protists, mosses, lichen and fungi.

It is still very little known about these hypolithic communities. As environmental conditions in Antarctica are extreme scientists believe that hypolithic habitats can provide some protection from high UV radiation and rapid fluctuation of freeze-thaw processes. The Dry Valleys are cold deserts with very limited liquid water and hypolithic rock habitats provide an increased water availability through water condensation processes on the rock surfaces.

                                                  Quartz rock


                                       Below the same quartz rock    

The green spots on the bottom of the rock are cyanobacterial communities  



                  Green hypolithic community growing around the bottom of a small quartz rock




Although I have been writing already for several weeks about different regions and lakes in Antarctica, I have never posted a map.





Map of Antarctica showing the location of Ross Island with US (McMurdo ) and the NZ Antarctic (Scott Base) stations, and the Dr Valley located in Victoria Land, continental Antarctica.




                                                                                     Dry Valleys (Southern Victoria Land)


Map of the Dry Valleys (McMurdo Dry Valleys ASMA Manual) , showing Pearse Valley with Lake Joyce, Wright Valley with Lake Vanda and Taylor Valley with Lake Hoare, which will be the last lake that we are planning to visit. The Dry Valleys are on continental Antarctica.




Boulder Pavement (77.5227°S, 161.7466°E) is an area ca 1.5 hour hike from the Lake Vanda along the Onyx River. It is the most extensive area of microbial mats in the Wright Valley. When I visited the area it was still too early in the season to have  water running or much growth of microbial mats.


However, i was able to find one spot where the ice had melted and bright orange microbial mats were visible. The orange colour is due to carotenoids, pigments that protect the cyanobacterial cells from UV radiation and reactive oxygen species.


Orange-pigmented cyanobacteria-dominated mats



Dried river bed near Boulder Pavement



The lake floor is covered with cyanobacteria-dominated mats of different thickness. The microbial mats from 59 ft are ca 1 cm thick and have small pinnacles growing out off the flat mats. The cross-section show differently coloured layers with a brown layer on top and a green and purple layer below (the colours are difficult to see under the yellow coloured light of our science tent). The different colours are due to the production of  pigments for efficient uptake of light.



Anne D Jungblut

Anne D Jungblut

Member since: Sep 2, 2010

I'm Anne Jungblut from the Botany Department. Join me as I head to Antarctica to study cyanobacterial diversity in ice-covered lakes of the Dry Valleys and Ross Island where already scientists on Scott's and Shakleton's expeditions made many discoveries.

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