Skip navigation

Exploring cyanobacterial diversity in Antarctica Blog

2 Posts tagged with the glacier tag
0

Part of this year's objectives was to sample cryoconite holes on the Upper Wright Glacier. They are vertical water-filled holes in the gaciers that are up to ca. 1 m in diameter and up to ca. 60 cm deep. At the bottom of these holes there is always a layer of sediment or small rocks, and many of these cryoconite holes have an ice lid. These cryoconite holes are formed by wind-blown dust and small rocks that melt into the ice. Some of our aims are to characterise the microorganisms living in these ice-entombed habitats and evaluate the relationships to microbial communities in other aquatic ecosystems in Antarctica.

 

 

Upper Wright Glacier and the large ice fall that is coming down from the polar plateau

 

IMG_6030.jpg

 

Stunning geological strata

 

IMG_5898.jpg

 

Hunting for croconite holes on Upper Wright Glacier

 

IMG_5891.jpg

 

 

Ian and Hannah are drilling into a cryoconite hole

 

IMG_6061.jpg

0

I am going to Antarctica to study cyanobacteria because they are  very important for the ecology of Antarctic freshwater system such as lakes, ponds and meltwater ponds on ice shelves.

 

 

Cyanobacteria were initially described as algae in the 18th century, before scientists realised they were bacteria. Therefore, they are also called Cyanophyta or blue-green algae based on their blue-green coloration.

 

Antarctic cyanobacteria are generally characterised by their ability to cope with the harsh conditions of Antarctica, which include:

 

  • low temperatures
  • ice formation
  • high salt concentrations
  • several months of darkness during the Antarctic winter
  • high ultraviolet radiation during the summer
  • large variations in nutrient supply
  • Many Antarctic cyanobacteria produce antifreeze compounds and UV screens and are able to grow with very limited nutrients.

 

 

 

Cyanobacteria colonise Antarctic freshwater sediments, and  biofilms are formed when cyanobacteria  grow to such a high number that they form a continuous layer on top of a substrate. As they are filamentous - hair-like - they form a web or three-dimensional matrix.

 

They stay attached to the substrate by producing sticky substances. These so-called exopolymeric substances also enhance the matrix-structures.

Once the matrix structure is formed, other bacteria and microbial eukaryotes colonise the cyanobacterial biofilms and it becomes a microbial mat.

Microbial mats are characterised by a vertical stratification of different microorganisms. The chemical and physical gradients along the mat matrix are a result of the different metabolic activities of the inhabiting organisms and surrounding environmental conditions.

IMG_3682_test.jpg

Cyanobacterial mat community

Jungblut_Image2_sized.jpg

Cyanbacterial mat community in a meltwater pond on the McMurdo Ice Shelf, Antarctica

 

 

Image1.jpg

Cyanobacteria isolated from a meltwater pond on the McMurdo Ice Shelf, Antarctica