A Long Flight over the Canadian Shield

Recently I flew from Istanbul to Los Angeles, following a great-circle route over Ukraine, Norway, Greenland, and Northern Canada.  As I always do when flying, I got a window seat and spent most of the flight peering out the window, developing a crick in my neck that took several days to loosen.

Much of the European and Greenland portions of the flight were shrouded in clouds, leaving me watching a vast expanse of what looked like glowing cotton.  Occasionally patches would open in the clouds and I would catch a brief glimpse of the land or sea below, and a look at one of the most talked about ecosystems on our planet.

Ice floes on the Arctic Ocean

Ice floes on the Arctic Ocean

The northern polar region, the Arctic.  This is a vast region centered on the bath-tub-like basin of the Arctic Ocean.  Discussing directions in the polar regions is tricky, for in the arctic, pretty much every direction that is not north is south, thus geography is a better indication of location than compass points.  On one side the entryway to the Arctic Ocean is narrow, shallow, and flows over the ancient land-bridge that once connected North America and Asia.  On the other side warm water flows up the Atlantic Ocean to the east of Greenland, keeping Europe warm and pushing the ice away from the Norwegian coast.  This is the primary point of water-flow into the Arctic Ocean.

To the west of Greenland a network of channels in the Queen Elizabeth Islands lets water slowly filter out of the basin, trickling back into the Atlantic via the southern opening of Baffin Bay.  Amongst the islands fierce currents keep polynyas open in the ice, providing open water for eider ducks and other sea-birds that over-winter in the Arctic.  Generally the whales will leave the Arctic during winter, but sometimes they become trapped and these polynyas provide the only places they can find air to breath.

Since we have been keeping records the sea ice extent has been getting smaller and smaller.  Records of sea ice extent and other cold-weather data can be found free of charge at the National Snow and Ice Data Center.

Several years ago, as part of a graduate project on Ringed Seals I looked at the changes in ice extent for the month of April over the last 30 years.  The photo of the broken sea ice above was taken on the eastern side of Greenland, a place where the sea-ice is extremely variable.

1981 - 2010 April Sea Ice Extent:  Darker colors indicate a greater number of years of coverage, lighter colors, fewer years of coverage

1981 – 2010 April Sea Ice Extent: Darker colors indicate a greater number of years of coverage, lighter colors, fewer years of coverage – green indicates areas outside of ice-cover that are shallow enough to provide foraging areas for Ringed Seals

The little flashes of ice I got to see through the grubby Turkish Airlines plane window were tantalizing, but they were only teases.  The interesting views were to come later, as we passed over the Canadian Shield.

Flying over over the Melville Peninsula, looking east to Foxe Basin... I think

Flying over over the Melville Peninsula, looking east to Foxe Basin… I think

Here, over the Canadian Shield, a 3 million square mile (8 million square kilometer) expanse of heavily weathered, exposed bedrock billions of years old the signs of past glaciation are evident.  Not merely evident, the fossil tracks of vast continental glaciers shout their presence to the sky.  Fortunately, I happened to be in the sky, with a camera at the ready.

There is a common misconception about glaciers.  People have heard that glaciers carve channels into the bedrock and grind down mountains.  This is only partially true.  Ice is not very hard, by itself ice can carve channels into rock the hardness of chalk or talc, but not into tough rocks like granite, the rock much of the Canadian Shield is composed of.  Ice levers out whole boulders and picks up loose material where it lies.  These become embedded in the ice and these are what does the scouring and carving.  The ice provides the weight and movement, much like a person provides the force when sanding or filing a piece of wood or metal, but it is the sandpaper or the file that does the actual cutting.

Ice, when it comes in glacier quantities, is an elasto-plastic material.  The upper surfaces are brittle and crack, making crevasses and seracs, but the deeper ice, down below the 50 meter mark, is more akin to a slow, cold silly-putty than to the brittle thing we put in lemonade.  When the ice is kilometers deep it oozes, flowing like spilled molasses over the land, dragging with it the entrained materials, grinding down high points, smoothing jagged surfaces, and hollowing out U-shaped valleys, leaving behind a stream-lined surface replete with the marks of its passage.

Rocky Mountain Trench in the Canadian Rockies - a classic glacially carved valley

Rocky Mountain Trench in the Canadian Rockies – a classic glacially carved valley

In both photos above the U-shaped valleys are clear.  These valleys come in all sizes, some more impressive than others.  The Rocky Mountain Trench in British Columbia is one of the more impressive ones, as is the Gilkey Trench in South-East Alaska.

The Gilkey Trench, the speck in the foreground is a person and each of the ripples in the bottom is 10 meters high

The Gilkey Trench, the speck in the foreground is a person and each of the ripples in the bottom is 10 meters high

These valleys are often found in mountains, places where the glaciers ground out material between the peaks, but left the high places alone.

Billions of years ago the Canadian Shield used to be home to vast mountains, now they are all gone, only their roots remain.  Erosion from various sources and repeated glaciations have scoured the Canadian Shield over and over again, grinding even the great mountains into low mounds, leaving traces that are best seen from the air.

Exposed bedrock showing fault-lines and ancient mountain cores

Exposed bedrock showing fault-lines and ancient mountain cores

The long, straight lines are old fault lines, places where geologic stresses broke the rock and let it slide against itself.  Here the rock is already damaged and the glaciers excavated long channels that look like canals from the air.  The distorted oval in the lower middle of the photo is where a bubble of rock forced its way up in the distant past, creating a mountain or large hill.  Now it has been ground flat and shows up in the surface pattern, much like cut wood shows the pattern of knots and grain despite being smooth to the touch.

Over much of the Canadian Shield soils are shallow to non-existent.  Even south of the tree-line vast areas are sparsely vegetated for lack of soil.  Roads are difficult to make as the land is smooth only at large scale and it is riddled with lakes and rivers.

In the winter the smoothest parts of the Canadian Shield are the lakes themselves and they are where temporary roads are made.

A road on the frozen lakes to the north of Yellowknife

A road on the frozen lakes to the north of Yellowknife

The last major glaciation was relatively recent, only about 20,000 years ago and the land is still recovering from the effects.  The whole Canadian Shield is undergoing isostatic rebound; with the weight of the up to 3 miles (almost 5 kilometers) of ice coming off the Earth’s crust it is now rising, seeking a new equilibrium as it floats on the liquid rock mantle deep beneath the surface.  Rivers and lakes are draining, the courses sometimes shifting as the land rises, carving out new pathways.  Water, like the ice it came from, does not do the work of carving the rock, it is the sediment it carries, but the Canadian Shield is made of hard stuff and it takes time to carve new channels in this durable granite.

Meandering rivers in glacial sediment

Meandering rivers in glacial sediment

Further south, the land is still flat, but has been overlain by a layer of sediment, left behind as the glaciers retreated.  Here rivers carve into the land more easily, looping back and forth and pinching off sections of themselves.  These oxbow lakes and the irregular rocky ones to the north are home to untold numbers of mosquitoes and other insects with aquatic life-phases.  These insects, when they emerge, lure birds from as far away as the southern hemisphere, and the mosquitoes become the bane of any humans wandering in the vastness of northern Canada during the warm season.  These insects, both adult and larval provide feed for numerous fish, making this an excellent place for fishing.  The first time my family and I drove to Alaska much of our food was from fish we caught each evening after only a few minutes with a line in the water.

The glaciers that covered the Canadian Shield were continental in scale.  There are only a few places where vast sheets of ice like that remain, but many places (for now) where small alpine glaciers are present, and even more places where signs of past glaciation are common.

One of the most famous of the post-glacial relics is Half Dome in the Sierra Nevada mountains of California.

Half Dome

Half Dome

The last interesting views I had out the window of my plane were of Half Dome, or Tis-sa-ack in the local native language.  This sheer rock-face is a batholith, a granite upwelling often making the core of a mountain.  Despite its appearance, Half Dome was not split in half, it seems to have formed more or less in the shape it has now.  Glaciers have smoothed and rounded the upper surface and carved out the characteristic U-shaped valley below though.

Glaciers have had a far larger impact on the world than most people realize.  Humans reached Australia some 60,000 years ago, able to walk over-land all the way to where Bali is now, needing boats only for a short stretch from Bali to Lubok.  Fifteen thousand years ago people walked from Siberia to Alaska over a broad grassy plain when the sea level was some 300 feet (91 meters) lower than today as a result of the water locked up in the ice.

When Greenland and Antarctica melt (which they will eventually do with or without our presence, the only difference is when it happens) sea level will rise by some 200 feet (67 meters) above present day levels.  At the moment there is a lot of talk of halting climate change via geo-engineering projects.  This is talk that completely and painfully misses the point.

The climate is a dynamic system, one that experiences wide changes over long periods of time, with the changes sometimes happening rapidly.  Yes, we desperately need to stop messing with the climate by releasing fossil CO2, methane, CFCs, and all the other greenhouse gasses we pump into the atmosphere with such abandon.  We are pushing the natural changes hard, forcing them to be of greater magnitude and to happen faster than they would otherwise.  We need to stop this, but what we do not need to and should not do is compound our mistakes by dumping iron into the oceans, pumping sulfur into the upper atmosphere, or place orbiting mirrors in space to deflect sunlight in a misguided attempt to keep the climate the way it was during the early 1900s.

We are driven by our economic system to keep things in some idealized stasis based on the time when we built our current infrastructure.  We may want things to stay static, but the earth is dynamic and fluid.  In our short-sighted, profit driven efforts to “save” our political and economic systems we will destroy the very thing that those systems and our societies are based on.

Seeing the earth from new perspectives and thinking about what we see tells us about the world is important.  We are on a cusp, we are standing on the edge of our metaphorical Half Dome.  We can tumble off the steep edge with disastrous consequences, or we can ease our way back down the slightly less steep slope, and once more enjoy the rich valley floor below.

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The Frontenac Arch a Critical Linkage

(this is an article I wrote for the summer 2012 newsletter of A2A – Algonquin To Adirondacks Conservation Association – a bi-national conservation association I am an adviser for – I wanted to wait until it was included in the newsletter before posting it here as well)

Between the Algonquin and the St. Lawrence a finger of the Canadian Shield, called the Frontenac Arch, reaches down from the north.  The Canadian Shield is an ancient formation of rock, heavily weathered, marked with meteor craters, and bearing the polishing scars of the ebb and flow of glaciers miles deep. Soils are shallow on the Shield, in many places nonexistent.  Nutrients are hard to come by and wetlands abound.

Red-winged Blackbird (Agelaius phoeniceus)

The bedrock to the east and west of the Frontenac Arch is old seafloor with thicker soils that are rich in minerals and nutrients. Groundwater flows through breaks in the flat bedding planes and does not become trapped in pockets as easily as it does on the Canadian Shield.

When we look at a landscape we often look at the plants growing on the surface and leave our thoughts on the surface with them.  Plants grow where they do because of the chemistry of bedrock, soil, water, and temperature.

On the Frontenac Arch the chemistry of the northern and the southern Canadian forests mix.  This mix shows in the wide and unusual range of plants growing in and around the Frontenac Arch.  The diversity of plants attracts a corresponding diversity in animals. All these plant communities are separated and connected by the dense wetlands, and many animals are drawn to the wetlands.  Frogs, fish, ospreys, turtles, feeding moose, waterfowl of all sorts, beavers, blackbirds, otters, sparrows, loons, and many more.

Male Painted Turtle (Chrysemys picta)

Healthy wetlands are rich in species, both in number and diversity; plant, animal, insect, and bird.  Wetlands are the kidneys of the planet; they filter water and keep it clean.  They slowly recharge aquifers with cool, pure water, they keep rivers and streams clear, they trap sediment, and they eventually fill in, becoming rich, complex soils full of nutrients.

Oddly, perhaps counter intuitively, all this life, more specifically all this diversity, of living things in wetlands is what keeps the water clean.  The water is strained at a molecular level for nutrients by all those living organisms.  Each looks for different things and uses them differently.  Toxins and chemicals are swept up and broken down by this process, but only as long as the diversity of life is present.

When that fabric of diversity is broken the health of the land suffers.  A healthy environment is like good glass, so clear you don’t see it and tough enough to withstand storms.

A large male Snapping Turtle (Chelydra serpentina) and feral biologists

The Frontenac Arch is one of the gems of the region and is critical in connecting the northern and southern forests.

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For those who are interested the Algonquin to Adirondacks Conservation Association website is here, and a map is below:

Algonquin to Adirondacks Conservation Association map of the Frontenac Arch

The Jaws that Bite…

A little while ago I was invited to participate in a wildlife conference in Ontario, Canada (as opposed to the Ontario, California where Mag-Lights are manufactured).  The conference took place on a geologic feature called the Frontenac Arch, a narrow finger of the Canadian Shield that reaches south past Ottawa to the St. Lawrence, separating the calcium rich sedimentary rock formations of south eastern Canada into two portions.

The land here is flat scoured by billions (yes, billions) of years of weathering, and is littered with with numerous lakes, bogs, and marshes that pool on the surface in the wake of the most recent glaciation.  These wetlands are home to a wide variety of animal life, a reptilian subset of which was studied by one of the conference attendees.  He was conducting turtle surveys, looking for stinkpot, or musk, turtles specifically, but interested in all the rest as well.

In one of the wetlands he pointed out two large snapping turtles (Chelydra serpentina) and, to our surprise, reached in and pulled one out so we could see it better.

25 pound male snapping turtle

Assuring us, over our skepticism, that the snapping turtle wouldn’t bite while it was in the water this bold fellow picked up the large male turtle and held it for us to see.

Snapping Turtles are the largest of the freshwater turtles north of Mexico and range from east of the Rockies though southern Canada and down to Florida.  In the wild they live up to 30 or 40 years and eat pretty much whatever they can fit in their mouths, plant or animal.  Their scientific name, Chelydra serpentina, roughly translates into “serpent like turtle”.

Unlike many turtles, snappers cannot fully withdraw their heads unto their shell.  Instead they have evolved long, flexible necks and sharp, powerful jaws with which they both feed and discourage other curious animals.

An upset snapping turtle

Getting bitten by a snapping turtle would be an extremely unpleasant experience, but contrary to popular belief, they are unlikely to be able to sever fingers or toes.  That being said, having been bitten by other animals with beaks, I am not going to volunteer to be bitten by any turtle, let alone a snapping turtle.

Like other predators, snapping turtles are blamed for much more damage to wildlife than they are actually responsible for.  The public misunderstanding of their impact on duck and fish populations results in little support for conservation efforts aimed at snappers.  On the whole this is not a problem, their numbers are good and the IUCN considers them a species of least concern, and in many areas they are caught for soups and such.

Like other turtles, snapping turtles are extremely sensitive to habitat disturbance.  Indeed turtles in general are good indicator species for assessing wetland habitat conditions, and snapping turtle eggs have been used as indicators of environmental contaminate levels.

Snapping turtles will travel great distances overland while dispersing, searching for a wetland that matches their needs.  It is common to find them crossing roads in the spring and summer.  If you do encounter one crossing the road and desire to move it to a safer place, great care must be taken, both for your own safety and for the safety of the turtle. The best place to pick one up from is the rear of the plastron, the lower portion of the shell (see how the turtle is being held in the first photo).  Grabbing from anywhere else can result in injury to both you and the turtle.

When snappers are young they are tiny, extremely cute, and subject to predation from a wide variety of other animals ranging from birds to raccoons and fish.

Baby snapping turtle, shell about 2 inches long

Snapping turtles have been around for a long time without changing much.  Modern snapping turtles are about 40 million years old, but their ancestors looked much like the modern ones and have been around for 215 million years.  That is nearly a quarter billion years.  Pretty much everything that has ever lived is a passing fad to the snapping turtles.

Admire them, show some respect, and keep your fingers clear.