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Exploring cyanobacterial diversity in Antarctica Blog

6 Posts tagged with the dry_valley tag
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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

MTErebus.jpg

View from the helicopter over to the Commonwealth Glacier

flight.jpg

 

 

Campling gear and science equipment arriving with a sling load

slingload.jpg

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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

                                                  Seal1.jpg

                                                

                                                             Mummified seal near Koettlitz glacier

                                            seal2.jpg          

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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

              Hypo1.jpg

                                       Below the same quartz rock    

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

                   Hypo2.jpg

                             

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

                         Hypo3.jpg

                   

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

 


 

                                                                                                         Antarctica

 

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.

                                     Ant1.jpg

 

 

                                                                                     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.

 

                              DryValleymap.jpg

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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

BoulderP1.jpg

 

Dried river bed near Boulder Pavement

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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.

 

LakeV_mat.jpg