March 15, 2004

Glaciers and Glaciation

To the west of us at the moment is the South Patagonian Ice Field. with 1300 square kilometers of surface area it is the third largest ice field in the world, after Greenland and Antarctica. On March 12th 2004 a couple of weeks after we were at the foot of the Perito Moreno Glacier, the water from Brazo Rico lake broke through the mouth of the glacier to create a tunnel river to the Argentina Lake. It happened at 5 in the morning; so no one was there to witness the collapse but the footage we saw on television of water rushing through a tunnel in the glacier was amazing. The Perito Moreno Glacier flows east from the South Patagonian ice field and is one of the few advancing glaciers in the world. It had been 16 years since the waters of Brazo Rico on the south side of the glacier mouth had been building up. The glacier creates a natural ice dam by pushing up against the bottom of a mountain that acts as a Nunatak. A Nunatak is a rock that is usually in the center of a glacial valley that is harder than the rocks around it and resists the erosion of the glacier. Sometimes it can even be an island sourrounded by a sea of ice.


Check out the pictures.

Glaciers are often referred to by climatologists and geographers as good indicators of climate change. Currently almost all glaciers in the world are receeding. However with climate change, (which at the moment is arguably global warming) not all parts of the world get warmer uniformly. Some places actually get colder while others get wetter or dryer. It seems that the west coast of southern South America is getting more snow in the winter and therefore the South Patagonian Ice field has more ice to push the glacier forward. This is only speculation as the delay between a couple years of more snow and its effect on the glacier is pretty long. Glaciers only move a few meters a year.

All around Patagonia there is evidence of past ice ages and the effects of the glaciers that covered the land. Like Canada much of Patagonia was covered by ice in the last period of glaciation. What is great down here is that the large Patagonian Icefield is several hundred meters thick and is a leftover of the larger icefield that covered all of Patagonia. This makes it possible to see the types of continental glaciers that shape the valleys I grew up with near Vancouver.

Most of Canada was once covered in ice during the last ice age as well. So as a classroom exercise I would like you to find evidence of those ancient glaciers near your school.

1) see if you can find evidence of rocky deposits that could part of a lateral or end moraine.

2) Find a valley that has been scoured into a U-shape by a big glacier.

3) Look at a map of Canada and discuss with your class where you might find alpine glaciers now.

4) Are there any continental icefields left in Canada now?

5) Can you find evidence of a Nunatak in you area?

If you need any help with understanding the terminology that describes the different parts of the glacier please let me know and I will help you.
The following links should also be helpful:

The university of Manitoba has a good list

One of my past professors at the University of Victoria, Dr. Dan Smith is doing really neat research.


The European Space Agency has an excellent article explaining the collapse of the Barrage of the Perito Moreno Glacier.

Posted by gwendal at 12:24 PM | Comments (0)

February 18, 2004

The Lenga Tree

NEW INFO Please see the addendum below

Since our departure from Ushuaia we have travelled through several climatic zones.
Around Ushuaia the influence of the ocean on the climate is evident when you look around at the vegetation. The area is surrounded by mountains which trap the clouds. Lush vegetation that can survive the cold winters is in the valleys, while in the higher elevations there is very little. As we move north of the range of mountains in southern Tierra del Fuego we entered a much drier area with rolling hills and lenga trees.
I was not immediately aware of it, but the forests we were seeing were dying.
Not knowing what I was seeing I thought the climate was very arid and the trees were not getting enough water. As we progressed further north in Tierra del Fuego the trees disapeared altogether and we were in the flat grasslands that are called pampas in Patagonia. I assumed that since the climate was changing, the trees near the pampas were going to die and the forest would also become pampas. However it is not until we reached Rio Grande (If you have a map of South America, check it out) that we learned that the reason we had seen so many dead trees is that there was a parasite affecting them.

Question 1) What is a Parasite?

The particular tree that is being affected is called the Lenga tree and it growes in many parts of Tierra del Fuego and the rest of Patagonia. More recently when entering the Torres del Paine national park in Chile we noticed many forests that had dead lenga trees.
What interested me is that I have seen the parasite that affects the Lenga tree in Canada many times. Here it is called the "barbas de viejos" I know it as old man's beard. It grows on trees where there is a humid climate and in Canada it takes a fairly long time to grow. To my knowlege it is not parasitic to trees in Canada.

Question 2) Can you find a parasite that is affecting trees in your province?
Question 3) How is the forest being affected by these parasites?

Question 4) How big an area is affected by the parasite in your province?


For now, there are hundreds of dying trees.
It still has to be determined if the old man's beard is the parasite and why it is doing so well and what might be done to control it in the future.

I will continue to research this during our travel from Puerto Natales to Calafate in Argentina. Hopefully I will be able to give you more information.
I look forward to your answers.

Addendum February 29th 2004
Wow! I am realizing how hard it is to do research in spanish when my comprehention is not always 100%
I have discovered that my information is not totally correct.
The old man's beard is not actually a parasite at all but just a lichen that need very pure air to survive. It is actually a very good indicator of the purity of the air in the region. The reason that it is so common is that the dead lenga trees offer a great habitat for the "barbas de viejos" to grow.
The lenga tree is in fact affected by an altogether different parasite!
It is affected by a parasite that does not have any clorophyl (no posen clorophyl) and therefore cannot photosynthesise solar energy into shugars itself.
It is commonly called the Llao-llao whose scientific name is the Cyttaria which is from the (hongos) mushroom family. To survive the Llao-llao creates a type of tumour on the Lenga tree and steals its photosynthesised shugars. Another parasitic mushroom that affects the lenga is the "El pan de indios" which is smaller and grows little mushrooms bulges on the trunk and branches of the lenga tree. These little 1-3 cm in diameter mushrooms are in fact edible. I tried one and found it to be pretty much tasteless, but probably fine if you cooked it in a sauce.

Posted by gwendal at 06:01 PM | Comments (0)

January 15, 2004

The Climate of Tierra Del Fuego

Part of the preparation for an expedition of this type is to realize that you are going to be exposed to the elements. This means that we need to do careful research to find out what the climate is like along the way. Tierra Del Fuego is famous for its climate. Check out this landsat 7 image mosaic:
View image
You can browse the entire globe for images at the following website:
http://glovis.usgs.gov/ImgViewer/ImgViewer.html

My questions to you are:
1)What is the climate going to be like when I am starting off from Ushuaia?
A good place to start is www.worldclimate.com

2)What will be the biggest meteorological challenge at the beginning of the expedition?

3)What kind of clothing should I make sure I have with me?

I look forward to hearing your answers. - Gwendal

Posted by gwendal at 04:57 PM | Comments (1)

November 24, 2003

The Classroom Program

The Canadian Classroom Program will be an interactive endeavour with teachers and students. Through this site we aim to use the expedition as a topic to "extend the boundaries of the classroom" and bring geography in the classroom.

As the expedition progresses through the continents they will be able to follow. The aim is to post a question on this page relevant to your curriculam every two weeks. This is the opportunity for the classroom to split into groups and research the question.

If you are a teacher and would like to participate please contact Tania and we will prepare a kit for your classroom.
Email: classroom@antipodes-expeditions.com
My number is: 604-787-9577

Posted by gwendal at 04:49 PM | Comments (0)