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Exploring cyanobacterial diversity in Antarctica Blog

53 Posts tagged with the antarctica tag
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In Lake Hoare the mats are vertically stratified. Each year one layer is formed and they can be used as indicators of growth and environmental conditions just like tree rings. Similar to microbial mats in other lakes the layers have different pigmentations for light capturing and protection.

 

                                                                                Cyanobacterial mats in Lake Hoare

 

                                                                      LHmat1.jpg

 

After the divers had brought up mat samples from a depth of ca 10 m, we went back to the lab and identified the diversity using light microscopy. The microbial mats contained different cyanobacteria including the genera Oscillatoria, Phormidium, Leptolyngbya and Nostoc.

 

After returning to the Natural History Museum, we will carry out DNA-based methods to characterise their evolutionary relationship to other Antarctica cyanobacteria.

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After 10 days at Lake Vanda and collection of many fascinating samples, it was time again to pack and move on.  This time half of our team would go back to McMurdo station as they were finished with their field work and three of us would move on to Lake Hoare.  Lake Hoare is in the Taylor valley next to the Canada Glacier. Lake Hoare is part of the US Long Term Ecological Research Program (LTER). The LTER does important long-term research on for example glacial systems and the ecology of streams and soils in the Dry Valleys.

 

                                                                                              Lake Hoare camp

 

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Lake Hoare is one of the bigger camps in the Dry Valleys and run by Rae and Sandra . It has a main hut with a  huge kitchen, computer area and some bunk beds, several small laboratories and even shower facilities (Sunday is shower day). Rae and Sandra cook the most delicious food and  fresh cookies keep appearing everyday in a magical way. It was a real treat after being in the field with only a small kitchen tent and no shower or proper toilet facilities for several weeks.

 

 

                                                                                             My tent site

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The tents are nestled between the wall of Canada Glacier and Lake Hoare – the most beautiful place I have camped. My tent is right next to the glacier and I could hear the meltwater running of the glacier in small waterfalls during the night.

 


                                                                                         Canada Glacier

 

                                                            LakeHoare3.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.

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                                                                                     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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Extreme wind conditions

Posted by Anne D Jungblut Dec 15, 2010

The last several days, we had very windy weather, and made it impossible for our dive team to do any diving from our second dive hole that is further out on the lake. Winds out in the mountains and towards the polar plateau were far more extreme than at the lake, as we could see enormous snow plumes.

 

 

                                                                                    Snow plumes on the mountain peaks

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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

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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.

 

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At Lake Vanda we also want to explore microbial communities and the microbial structures forming within the lake. However, before we can get started with the science we had to wait for our equipment to be flown into the camp from Lake Joyce,  and drill and melt a hole in the lake ice big enough for the divers to get into the water.

 

Science equipment is flown in by helicopter

 

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Drilling a hole into the lake ice

 

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Lake Vanda  is in the Wright Valley and a lot bigger than Lake Joyce with a length of around five km. It is also ice-covered but the ice is in average only 4 meters thick. Lake Vanda is meromictic, which means that the deeper layers never mix with the upper layers. This creates very different condition in the shallower and deeper parts of the lake, and therefore very different microbes will likely be found in the different sections of the water column.

 

Lake Ice

In contrast to Lake Joyce the lake ice is very smooth with millions of fine cracks and trapped bubbles, creating amazing patterns and shapes.

 

Lake Vanda

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Lake Vanda ice... just like an abstract painting

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Ice flowers

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After one week at Lake Joyce it was time to pack and move our entire camp to Lake Vanda. Although i only stayed one week at Lake Joyce the rest of the team had spend close to a month there. It took two days to pack and four days to move all of the team and the equipment to Lake Vanda. This was also partly due to strong winds, which stopped the helicopter traffic.

 

Packing  Lake Joyce  camp

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Lake Vanda is also an ice-covered lake of the Dry Valleys and located in the Wright Valley. In order to get there we flow over the Asgard Range with amazing views over glaciers and mountain peaks.

 

Asgard Range

 

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Lake Vanda, Wright Valley

 

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Lake Joyce camp

Posted by Anne D Jungblut Dec 9, 2010

Our camp at Lake Joyce is only a few minutes walk from the lake. It is a fairly big camp with a large kitchen tent and a tech-tent, where we stored all our fragile electronic equipment.  The kitchen tent was  heated which makes it very cosy to hang out in the evening. We usually took turns with the cooking.  Even though we only have a small kitchen , we had everything ranging from Thai and Indian Curries to Burgers and Pasta for dinner.

 

Lake Joyce camp

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Kitchen tent

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The objectives of our project are to study the cyanobacterial mats and microbial structures in Lake Joyce to better understand the diversity and processes that create these microbial structures.

 

In order to study the structures the samples need to be collected by  diving. Once they are brought back to our field lab directly on the ice of Lake Joyce, they are documented, the diversity studied using microscopy and samples preserved for further analysis back at our home institutions. I am particularly interested in collecting material for DNA-based tools to study cyanobacterial diversity.

 

 

Diving in Lake Joyce

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Microscopy analysis of cyanobacteria from Lake Joyce

 

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Filtration of water samples

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Life in Lake Joyce is dominated by microbes. The water of Lake Joyce is nutrient-depleted and only little light makes it through the ice. The nutrient concentrations are so low in the water column that microbes remain at low concentrations, however diverse microbial communities can be found a long the bottom and the sides of the lake.

 

Much of the microbial communities are cyanobacterial mats and many unusual structures can be found.

 

Some of the structures are several centimeters  tall and have  a orange-purple colour. The colour is due to the  production of cyanobacterial pigments that help capture light for photosynthesis.

Mats1.jpg

 

 

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Lake Joyce, Antarctica

Posted by Anne D Jungblut Dec 4, 2010

Lake Joyce is in the Pearse Valley, a westward extension of the Taylor Valley next to the Taylor Glacier and fed by the meltwater of the glacier. Lake Joyce is one of the smaller Dry Valley lakes. It is perennially ice-covered and the ice is about five meters thick and the ice is not smooth as known from lakes in Europe. The ice is rugged due to irregular freeze-thawing of the top-layer of the ice and deposition of soil from the surrounding hills by the wind.

 

 

Lake Joyce and Taylor Glacier with research tents

 

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Lake ice

 

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Research tents on Lake Joyce ice

 

As the lake is ice-covered samples are collected through diving. The diving is done by three members of our team that are very experienced scientific divers. In order to directly process our samples we had two tents on the ice next to the dive hole.

 

JL3.jpg

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Lake Joyce is in the Dry Valleys. The Dry Valleys are located in southern Victoria Land near the McMurdo Sound and are the largest ice-free region of continental Antarctica. They often also called a polar desert because the humidity is extremely low ; and in many of the areas there is no or only little snow fall. The ground is mainly barren rocks and gravel without a soil layer as known from temperate environment.

 

The environmental conditions of Dry Valley habitats are so extreme, that most of the life is microbial and even lichens and mosses can only be found in very few areas such as near glaciers, where meltwater stream form during the austral summer months.

 

 

 

DV1.jpg.

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Much of the travel around Ross Island and the Dry Valleys is done by helicopter because this is often the only way to reach many of the remote research locations.  Therefore, it was also the means of transportation for me to get to my first field site Lake Joyce in Pearce Valley (Dry Valleys, Antarctica).

 

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I was scheduled to fly early in the morning and my cargo did not only contain my science equipment but also the much awaited  food resupplies for our camp including frozen eggs, olive oil, muesli and plenty of salsa sauce etc.

 

 

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The flight took me along Ross Island and many incredibly beautiful mountain ranges and glaciers. 

 

Ross Island with Mt Erebus

 

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Dry Valleys

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Arrival at Lake Joyce

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Lake Joyce

 

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