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Honors Marine Biology
Estuary Communities
Module 10
January 31, 2013
Class Challenge
Share your favorite Magic Trick
Quiz 16
Name
January 31, 2013
Question 1
A soft bottomed ecosystem is influenced by
two major parameters. What are they?
Question 2
What is mud made up of?
Question 3
Identify what makes up different colored
sand.
Red:
Green:
Black:
Question 4
How many hours is it between high and low
tide?
Question 5
Explain:
Spring Tide
Neap Tide
Question 1
A soft bottomed ecosystem is influenced by
two major parameters. What are they?
1. Water movement
2. Sediment size and type
Question 2
What is mud made up of?
Clay and Silt
Question 3
Identify what makes up different colored
sand.
Red: Garnet
Green: Feldspar
Black: Black magnetite and Volcanic lava
Question 4
How many hours is it between high and low
tide?
6 hours
Question 5
Explain:
Spring Tide: The sun and the moon are aligned
and it causes the highest gravitational pull.
Neap Tide: The sun and moon are at 45 degree
angles of one another and it produces the lowest
tides.
Environmental Management
Commissioner’s Review
Of last week’s Coastal Erosion Engineering
Presentations.
Estuary Communities
Are a semi-enclosed area at the mouth of a
river where fresh water and seawater meet
and mix.
Some well known estuaries in North
America are:
San Francisco Bay,
Tampa Bay,
Chesapeake Bay, and the
Mississippi River delta.
Important Estuaries Worldwide
Thames River Estuary in England
Heuningnes Estuary in South Africa
Bay of Bengal in India
Phang Nga Bay in Thailand
Gulf of Carpentaria in Australia
Thames River Estuary in England
Heuningnes Estuary in South Africa
Situated within the De Mond State Forest in the Western Cape, the estuary of the
Heuningnes River extends approximately 12 km across the flat coastal plain of the
Zoetendals Vallei farm area before breaking out to sea through a double dune ridge.
Bay of Bengal in India
Phang Nga Bay in Thailand
Gulf of Carpentaria in Australia
Estuaries
Many of these areas have large harbors and
industrial parks. That is because estuaries
provide people with:
1. plentiful food, plus
2. a water pathway inland from the ocean.
Estuaries
Are desirable for the establishment of cities.
We have discussed the impact that people
have on these areas.
Formation of Estuaries
Most estuaries are believed to have been
formed as a result of actions that occurred
during an ice age.
What is an Ice Age?
It is a period in earth’s history when the
average temperature of the earth was
significantly cooler than it is now.
During this time sheets of ice covered as
much as one-third of the earth’s surface.
These ice sheets were the result of accumulated
snow packed down by its own weight into ice.
As the weight of the accumulated snow pushed
down on this ice, it began to flow outward, much
like a lump of clay flows when you press down
on it.
As the ice flowed down into the lower latitudes, it
carved out the land as it moved. These moving
sheets of ice are called glaciers.
Glacial Deposits
In many places throughout the world,
geologists have found deposits of gravel,
dirt, and debris very similar to those found
at the edge of glaciers that exist today.
As the glaciers move across land, they
scour the earth, picking up pebbles, dirt,
and sometimes large rocks.
All of this gets deposited when the glacier
starts to melt.
Since we see deposits like these in areas
that do not currently have glaciers, we
have to assume that glaciers did exist in
those areas at one time.
In addition, geologists have found many places
where there are very large boulders that clearly
did not form where they are now. (the State of
Montana)
Based on their characteristics, it is obvious that
they were transported there.
They could easily traveled on a glacial ice sheet
and then been deposited when the ice sheet
began to melt.
The motion of Glaciers
11 long narrow lakes in northern New York
state called the “Finger-lakes.”
Two of those lakes (Seneca Lake and
Cayuga Lake) are deep, with bottoms that
are actually below sea level. The best
way to explain them is that they were
carved into their present state by the
motion of glaciers.
• These kinds of geological formation can
be found throughout Canada and even
down into the center of the United States.
The formation of Glaciers
1. Needs to be a lot of snowfall and not
much melting. Therefore in the US and
Canada they must have had much cooler
summers so the snow did not melt and it
continued to build up.
2. There would need to be a greater rate of
evaporation of moisture into the air.
If glaciers are formed by the accumulation of
large amounts of snow, there would have
to be a lot of evaporation to supply the
water to make the snow.
3. In order for a lot of evaporation to occur,
the ocean temperatures would have to
be warmer than they are today.
4. There would also have to be extreme
weather patterns for the extra
evaporated moisture to be transported
from the oceans over the continents.
• Giant Glaciers - Wild New World - BBC Planet
• http://youtu.be/eyX0tr9x72Y
• Glaciers and their effects
• http://youtu.be/tM3x6_vb8_s
• Glacier Power
• http://youtu.be/cIBFAke90SI
The 2 different views of the Ice Age
1. There was a slow gradual process that
happened over a very long time.
Uniformitarians. They believe that the
most recent ice age started about 1.75
million years ago and peaked about
18,000 years ago.
2. Other scientists believe that most of the
major geological features of the earth are
a result of wide-scale catastrophes.
Catastrophists. They believe that there
was one major ice age in the history of the
earth, and it was brought about by the
worldwide Flood of Noah’s time.
In the view of Catastrophists, there was only
one ice age in earth’s history, and it came
about quickly and rather recently.
Which group is right?
As mentioned earlier, cooler summers and a
lot of snowfall are necessary for the
continual buildup of ice.
Cooler air cannot hold as much moisture as
warmer air, so cooler temperatures could
not support the moisture required for a
large amount of snowfall.
• In Siberia today, summers are cold, and
not a lot of snow melts during the
summer. However, cold air cannot hold
much moisture, so there is not a lot of
snowfall in the winter. As a result, glaciers
do not form there.
In order for form glaciers, you must ha e
cooler summers, but at the same time you
must have winters that are not incredibly
cold too. That way there will be plenty of
moisture in the air to allow for a lot of
snowfall.
Uniformitarians believe that things change
rather slowly and gradually in the earth.
The formation of the ice age by gradual
climate change is quite difficult to explain.
How would you get the cooler summers
but at the same time have winters that are
not too cold and very wet?
Catastrophists who believe in the world
wide flood of Noah’s time believe that at
the end of the flood, the oceans were most
likely warmer than they are today. This is
because much of the floodwaters came
from the “fountains of the deep” (Genesis
7:11).
These were most likely fountains that
originated in the mantle of the earth, which
is very warm.
The influx of warm water would have added
a lot of heat to the oceans, making them
warmer than normal. This added warmth
and extra moisture could certainly cause
the wet and not-too-cold winters
necessary for the widespread formation of
glaciers.
Shortly after the flood…
The land would have been extremely
saturated with moisture and thus would
reflect rather than absorb much of the
solar radiation coming from the sun. This
would make land temperatures cooler.
Also, the differences in temperature between
the warm oceans and the cool land would
result in constant storms.
Hypothesis of Creationists
Durrng the later stages of the Flood, there
were most likely regular volcanic eruptions
due to the earth’s crust settling back into
balance. The excessive dust propelled
into the atmosphere from the volcanic
eruptions would have reflected the sun’s
radiation back into space, resulting in
cooler summers.
So….
The excess evaporation, cool land, warm
oceans, and cooler summers combined
with extra snowfall, regular storms, and
volcanic activity would result in an ice age
until the earth regained its equilibrium after
the great Flood.
Types of Estuaries
1. Drowned River Valleys (sometimes
called coastal plain estuaries)
2. Bar Build Estuary (barrier island)
3. Fjords
4. River Delta Estuary
5. Tectonic Estuary (Basin that was filled
with water)
Next week
Photo Contest of Estuaries: Birds, Fish, or
any other aspect of the area.
Each person will give a 5 minute
presentation of what they have learned
about an estuary to include their photos.
Homework
1. Estuary Presentation
2. Finish reading Module 10
3. Answer OYO and Study Guide