 |
Morning Mist, October 2001. Copyright © Robert
Williams
http://www.robwilliams.ca |
The Mer Bleue
Bog
In the early days of settlement east of Ottawa, residents often
saw thick fog blanketing a huge area of peat bog, reminiscent of
the ocean, and they named the place “Mer Bleue”, French for “Blue
Sea”. The name has stuck to this day.
Natural
History
Twelve thousand years ago the Laurentide Ice Sheets of the last ice
age were retreating. As they melted away, a large depression was
left from the great weight of the ice. The Atlantic Ocean flooded
in and formed the Champlain Sea. Fine silt, -formed as the ice
sheet ground the rock beneath it- washed in from the surrounding
land creating a thick bed of marine mud.
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| Natural Resources Canada
(http://geoscape.nrcan.gc.ca) |
Gradually the land rebounded and the Champlain Sea drained away,
eroding channels in the seabed. In time the southern most channels
were isolated and only the Ottawa River continued to have flowing
water. One of these abandoned channels, with its bed of clay,
continued to hold water forming a shallow lake. It was replenished
by rain and snow melt, but had little or no drainage. Vegetation,
including Sphagnum mosses, grew along the edges and gradually
encroached toward the center. Each year, as the dead plants fell, a
mat of plant matter formed. Fed only by mineral-poor rain water and
lacking oxygen, the bacteria and fungi that bring about
decomposition decreased. As decomposition slowed the still water of
the lake became more acidic. Gradually the entire lake was filled
with dead plant matter, in places up to 5 meters deep.
Peatlands
Walking on a bog is like walking on water. The top layer is a soft
living carpet which floats on a material which is nearly all water.
Bogs have fewer solids in them than milk. A bog may be up to 98%
water and only 2% solid peat. This great volume of water is held
within the dead Sphagnum fragments. This ability to retain water is
one of the properties which makes Sphagnum peat such a good
gardening material.
A bog consists of two layers: the upper, very thin layer, known as
the acrotelm, is only some 30cm deep, made up of upright stems of
the Sphagnum mosses, largely still alive. Water can move rapidly
through this layer.
Below this is a very much thicker bulk of peat, known as the
catotelm, where individual plant stems have collapsed under the
weight of mosses above them to produce a chocolate-coloured mass of
Sphagnum fragments. Water moves very slowly thorough this layer,
less than a meter a day. This is where most of the rainwater is
stored. From here the water slowly seeps down through the bog over
several weeks or even months.
Biodiversity
The plant species found here are typical of those found in the
Boreal forests and tundra much further north. Black spruce and
tamarack (larch) are able to survive the poor growing conditions.
Among the sphagnum, plants such as leatherleaf, lowbush blueberry
and bog cranberry can be found. You may find rarer species such as
the pitcher plant and sundew. Near open water beaver, muskrat and
mallards can be seen. Among the cattails, Red-winged Blackbirds
nest in the spring. The Mer Bleue bog is home to the elusive
spotted turtle, usually found nearer the center.
Lungs of the
planet
In the study of climate change, scientists try to understand carbon
“sources” and “sinks”; sources put carbon dioxide into the
atmosphere and sinks absorb and store it. Peat bogs are a major
storage area for carbon. Bogs and other terrestrial ecosystems emit
20 times more carbon dioxide than man-made sources. Like a giant
set of lungs, the bog both breathes in and exhales carbon dioxide.
While the rate varies from year to year, generally the bog is a
small carbon sink—meaning it absorbs more carbon than it releases.
Environmental scientists are now asking, “What happens to peat bogs
as the climate changes?” Some of the leading edge research to
answer this question is taking place today in the Mer Bleue Bog
Happy Healthy
Bogs
Drought from increased water evaporation due to warming is not the
only possible threat the health of the plants and mosses in our
peatlands. As people take up more and more land for homes and
businesses, the bog lands become isolated from the surrounding
natural areas. One of the dangers to the ecology of existing too
close to people is exposure to the chemicals and waste products
that they inevitably produce.
To Log a
Find:
Visit the Mer Bleue Bog boardwalk trail and read all the
Interpretive Panels. Send me the answers to the four questions
below
AND complete one of the photo assignments below.
Questions:
1. Two multiple choice questions are posed at Interpretive Panel 3.
Provide the two letters that denote the correct answers.
2. True or False: The water in the Mer Bleue Bog is more acidic
than vinegar.
3. The words “sphagnum” and “peat” are not quite synonymous; these
words don’t quite mean the same thing. What is the difference
between sphagnum and peat?
4. Where is the world’s largest uninterrupted stretch of peatland
located?
Photo
Assignments:
1. Identify and post a photo of one plant species. Interpretive
Panel 11 provides some examples.
OR
2. Post a photograph of a mammal, reptile, bird or insect found in
Mer Bleue. Near coordinates N 45° 23.608 W 075° 30.659 is a feeding
station. You could take up a position 10 to 20 meters from the
station. Stand silent and still for five minutes (which is harder
than it sounds). You will see many birds and the odd small rodent
that come to feed at the station.
BONUS QUESTONS:
If you answer all the questions above, complete BOTH photo
assignments AND answer these two Bonus Questions, you have earned
the designation Mer Bleue Bog Earthcachemiester, and are authorized
to display this graphic on your Geocaching Profile page.
Audio Research, NPR Report Bonus Question: What is the
danger to the environment if global warming causes the bogs of the
earth to dry out?
Think Global Act Local Research Bonus Question: What
proposed local project threatens the health of the Mer Bleue
Bog?
DON'T WAIT FOR A
RESPONSE FROM ME TO LOG YOUR FIND. ONLY LOGS THAT FAIL TO MEET THE
"LEARNING HAS OCCURED" CRITERIA WILL BE DELETED. (Plus I love to
praise the praiseworthy photos!)