Name:
_______________________
Period: _______________________
Teacher: _______________________
What is Oceanography?
Oceanography is the study of the earth’s oceans. Scientists who study the
oceans are called oceanographers. An oceanographer might study the size and
depth of the oceans, the living things in the ocean, or even the geography of the
ocean floor. Although recent technology has allowed the curious and the brave
to reach the ocean depths, it is still off limits in places where it drops too deeply.
Plenty of mysteries still exist.
In Greek mythology, Poseidon was the god of the sea. Poseidon
was relied upon by sailors for a safe voyage on the sea. Many men
drowned horses in sacrifice of his honor.
Why Is Earth the Water Planet?
If you look at a picture of Earth taken from space, you will see that much of
our planet looks blue. That is because so much of Earth is covered by water.
Water covers nearly three quarters of Earth’s surface. No other planet in the solar
system has a covering of liquid water. Only one percent of the world’s water is
fresh water available for drinking.
Salty ocean water covers about 71 percent
of Earth’s surface. Earth’s four main oceans are
the Pacific, the Atlantic, the Indian, and the
Arctic. The Pacific Ocean is so big that all the
land on Earth could fit into it easily. More than
half of the earth’s ocean water is in the Pacific
Ocean. The Pacific Ocean is also the earth’s
deepest ocean with an average depth of 2.4
miles (3.9 km). The Arctic Ocean is the smallest
ocean. But it is still bigger than the United
States. All of Earth’s oceans are connected.
Water can move from one ocean into another.
Together the four oceans make up one big world
ocean. The word sea is used to describe a
smaller part of an ocean. The Caribbean Sea is
off the southeastern coast of the United States. This sea is part of the Atlantic
Ocean. Seas are typically enclosed partially or completely by land.
Areas of an ocean or sea that are partly enclosed by land are called gulfs
or bays. A gulf is bigger than a bay. The coast is often curved around a gulf or
bay, forming a wide opening to the ocean or sea. The Gulf of Mexico is located
between the United States and Central America. San Francisco Bay is between
San Francisco and Oakland, California.
1.
4.
3.
2.
EXERCISE 1: Label the four oceans of the world. Color the oceans blue and the
land masses brown.
1. Put the four oceans in order from largest to smallest. __________
_____________________________________________________
2. What is the difference between an ocean and a sea? __________
_____________________________________________________
3. Which countries are bordered by both the Atlantic and Pacific Oceans?
____________________________________________
_____________________________________________________
4. What two main types of water are there? ___________________
5. Which ocean borders the New Jersey coastline? ______________
Ocean Water
The oceans’ water contains many
dissolved salts and minerals. One
kilogram (about 2.2 pounds) of ocean
water usually has about 35 grams (1.25
ounces) of salts. Most of this salt is
sodium chloride, or common table salt.
Salinity is the measure of how
salty water is. Salinity is usually
measured as the number of grams of
dissolved salt in 1000 g of ocean water.
Ocean water contains about 33 to 37
grams of salt in every 1000 grams (or 1
liter) of water. Thus, the average
salinity of ocean water ranges from
3.3% to 3.7%. In some areas ocean
water is saltier than in others. Salinity
is typically lower near the surface and
in areas where fresh water mixes with
salt water. On the other hand, salinity
increases in hot and dry climates where
evaporation happens quickly. Salinity
can also be higher near the poles. As
the surface water freezes into ice, the
salt is left behind in the remaining
water.
Water pressure is the force
caused by the weight of water pushing
down on the ocean floor. The deeper
you go, the more water there is above
you. So the water pressure increases
with depth.
About 33 feet (10 meters) below the
ocean’s surface, the pressure is about
two times as great as the air pressure
at sea level.
Density is the amount of matter
in a given volume of something. The
density of ocean water depends mostly
on its temperature, salinity, and
pressure. Cold, salty water is denser
than warm, less-salty water. A layer of
dense water will sink below a layer of
less-dense water. The top layer of
ocean water is the least dense. The
bottom layer is the densest.
Near the surface, temperature is
affected by the weather above. Heat from
the sun warms the water in the oceans.
The water is warmest at the surface and
coldest at the bottom of the ocean. From
top to bottom, there are three different
temperature layers in the ocean. The
surface layer is about 300 to 900 feet
(100 to 300 meters) deep. The
thermocline, or transition layer, extends
from bottom of the surface layer to about 1
km. The temperature rapidly drops to
39oF (4oC). The deep layer extends from
about ¾ mile (1 km) to the ocean floor.
Remember that as depth increases,
pressure increases and temperature
decreases.
Surface Layer
(300 to 900 feet)
Thermocline
(from surface layer to about ¾ mile)
Deep Layer
(extends from thermocline)
Name __________________________ Date _______ Period ____
Salinity
What is Salinity?
Salinity is the amount of dissolved solids found in one kilogram of water.
The average salinity of seawater is 3.5%. The most abundant components in
seawater are hydrogen, oxygen, chlorine, and sodium. Other components
include sulfate, magnesium, calcium, and potassium. Seawater also contains
dissolved gases, such as carbon dioxide, nitrogen and oxygen.
Which Areas of the Oceans are Saltier than Others?
High concentrations of salinity are usually found in the center of the ocean
basins away from the mouths of rivers that pour in fresh water. They are also in
sub-tropical regions due to high rates of evaporation. Low salinity is found in the
high latitudes. This is because of the lower rates of evaporation and the melting
of ice that dilutes the water. There are low rates of salinity where precipitation
is greater than evaporation.
Why is the Ocean More Salty than a Lake?
Lakes are an active part of the ground water cycle, in which huge amounts
of water travel on the surface and underground on their way back to the ocean.
Most lakes are not final destinations for the water traveling through them, but
just temporary resting-places. Water leaves not only through outgoing streams,
rivers, and underground passages, but also through evaporation. Ground water
carries a small amount of dissolved salts and minerals. When water flows out of
a lake, it carries this dissolved material with it. When water evaporates, these
dissolved minerals are left behind. In most cases, the flow of water through a
lake is much greater than the rate of evaporation, and the water remains fresh.
The lakes that are salty are usually in hot dry areas. The dry climate means that
little water flows through the lake, and the high temperatures promote
evaporation. The ocean is constantly losing pure fresh water through
evaporation and receiving small amounts of dissolved salt from ground water
coming in. There are certain chemical, biological, and geological processes that
remove slats from the oceans in amounts that keep seawater salinity in balance.
Parts taken from: Jim Stringer: Physiology, Palo Alto Medical Clinic, California
Name _______________________ Date ________
Period ____
*** Use with packet page ____ (“Salinity”).
DIRECTIONS: Answer the following questions based on the class
demonstration (floating egg) and the attached reading.
1. Why do objects float easier in salt water than in fresh water?
2. What is the average salinity of seawater?
3. Why are hydrogen, oxygen, chlorine, and sodium the MOST abundant
components of seawater? (Hint: think of the parts of “salt” and “water”)
4. In what area of the oceans is there the LOWEST salinity? Why?
5. What are the two main reasons why oceans are saltier than lakes?
The Tide Turns
Up and down, up and down, day in, day out. That’s the rise and fall of the
water level at the ocean’s shore, which we observe at the water’s edge. This
regular rise and fall of sea level is called the tide. When the sea level rises to its
highest point, we have high tide. Later in the day, the sea level drops; this is
known as low tide. You might think the tides would get seasick. What causes
this variation in the waterline, which occurs in most places twice daily?
Tides occur because of the Moon’s gravity and Earth’s motion in space. The
Moon’s gravity pulls on Earth. High tide occurs when the moon is directly above
a particular part of the coastline. At the same time, a smaller high tide occurs in
the part of the world directly opposite, because the Moon’s pull on the opposite
side is not as strong. The Moon’s orbit around the earth is an oval, not a circle.
Moon
Earth
Gravity between the Moon and Earth,
together with Earth’s motion in space,
causes bulges of water to form on
Earth’s surface. We call these bulges
tides. As Earth spins on its axis, tides
occur at different places on Earth.
The difference between the height of the water level at high tide and at low tide is
called the tidal range. In some places the tidal range can be more than 33 feet
(about 10 meters).
Ocean in Motion
Everything from earthquakes to ship wakes
creates waves; however, the most common
cause is wind. Wind passes over the water's
surface causing it to ripple. The strength of
the wind, the distance the wind blows and the
length of the gust determine how big the
ripples will become. Waves are divided into
several parts. The crest is the highest point
on a wave, whereas the trough, or valley
between two waves, is the lowest point.
Wavelength is the horizontal distance, either between the crests or troughs of
two consecutive waves.
In water, a wave is a forward motion of energy, not water. In fact, the
water does not even move forward with a wave. If we followed a single drop of
water during a passing wave, we would see it move in a vertical circle, returning
to a point near its original position at the wave's end. These vertical circles are
more obvious at the surface. As depth increases, their effects
slowly decrease until completely disappearing about half a
wavelength below the surface.
The Killer Waves of Maui
About once a month, storms in the North Pacific
send swells south toward the Hawaiian Islands at
about 50 mph (80 kmph). One island in the chain,
Maui, has a huge underwater ridge extending about a
half mile (0.8 km) from its north shore. When the
swells reach the shallow water, they begin to break.
And do they ever break! The speed of the waves is
cut to about 25 mph (40kmph). But they also begin
to rise to more than 50 feet (15 m) as they approach
the shore. It’s like skiing down a five-story building.
“When you fly down one of these waves, it’s not a wave anymore,” says one
surfer. “It’s a mountain moving 25 miles an hour.”
People strolling along a Washington beach one May day in 1990
could hardly believe their eyes. Hundreds of Nike ® sneakers, in all
colors and sizes, were washing ashore from the Pacific Ocean.
Puzzled, people gathered up the soggy shoes and took them
home, wondering where the sneakers had come from. Eventually,
the sneaker spill was traced to a cargo ship from South Korea. Containers had
washed overboard in a storm and broken open, spilling thousands of shoes into
the water off the coast of South Korea (45oN, 152oE).
From the shoes’ drifting, oceanographers could infer both the path and
speed of water movement in the Pacific. Using what they already knew about
these movements, they predicted when and where more sneakers would come
ashore. Right on schedule, sneakers washed up in Oregon and British
Columbia, Canada. The shoes that did not sink could have traveled all the way
back to South Korea!
Exercise 2: From the time they spilled in May 1990 through the last recorded
recovery at 54°N, 133°W, the Nike® sneakers traveled in four different currents.
Name the currents from first to last.
a.
b.
c.
d.
The water in the earth’s oceans is always moving. Earlier in this unit
you learned how the oceans move as a result of wave action and tides. A third
type of water movement is currents. Currents are like rivers of water that move
through the ocean. Unlike waves, which do not actually transport water from one
place to another, currents carry water great distances. Some currents move
water at the surface of the ocean, while other currents move the deep water.
Currents can have different speeds, temperatures, and densities.
SURFACE CURRENTS
The force and direction of winds and the movement of Earth cause
surface currents. Most surface currents flow in curved paths because of Earth’s
rotation on its axis. This effect of Earth’s rotation on the direction of winds and
currents is called the Coriolis effect (kawr ee OH lis effect). In the Northern
Hemisphere, the
Coriolis effect causes
the currents to curve to
Coriolis Effect
the right (clockwise).
In the Southern
The Earth’s rotation
Hemisphere, the
causes currents to
Coriolis effect causes
flow clockwise in the
the currents to curve to
Northern hemisphere
the left (counter
and counterclockwise). The Gulf
Stream and the
clockwise in the
California Current are
Southern hemisphere.
surface currents near
the United States.
DEEP CURRENTS
Differences in the density of water cause deep-water currents.
These currents are sometimes called density currents. Cold water is denser
than warm water. Cold water around the poles sinks to the ocean bottom. Water
around the equator is warm. Different amounts of salt in ocean water also cause
density currents. Water with a lot of salt is denser than water with a little salt.
Dense, salty water sinks. Less salty water rises.
For example, cold, salty water north of Iceland sinks several
kilometers deep. The water slowly flows south along the Atlantic Ocean floor.
Warm, less salty surface water flows north to take the cold water’s place. Deep
ocean currents flow much more slowly than surface currents. They may take as
long as 1,000 years to make the round trip from pole to the equator and back
again!
UPWELLING
In some parts of the ocean, the surface waters mix with the deep
ocean waters. Upwelling is the upward movement of cold water from the ocean
depths. As winds blow away the warm surface water, cold water rises to replace
it. Upwelling brings up tiny ocean organisms, minerals, and other nutrients from
the deeper layers of the water. Without this motion, the surface waters of the
open ocean would be very scarce in nutrients. Because of the increased supply
of nutrients, zones of upwelling are usually home to enormous schools of fish.
Upwelling: The upward movement of cold water from the ocean depths. Provides nutrients to
higher levels of water by sweeping the nutrients from the lower levels.
Scientists know more about the surface of the moon than they know
about the ocean floor! It may seem hard to believe, but only five percent of the
land beneath the ocean has even been mapped. All the same, oceanographers
have developed a list of terms to describe the world beneath the waves. We’ve
emptied the water so you can really see what’s down there.
Imagine walking from the shallow end of a swimming pool toward the
deep end. Can you feel the bottom slopes gradually downward, until your head
is no longer above the water? Now imagine taking a walk off a sandy beach into
the ocean. The land slopes into the water. Along the land is a rim or shelf. This
rim of underwater land is called the continental shelf. This part of the ocean
has the greatest concentration of plants and animal life. Sunlight can reach the
floor in many places and large numbers of fish make their home in this region of
the ocean. This is also the area of the ocean where most commercial fishing
takes place.
At the edge of the continental shelf is the continental slope. This
slope is the beginning of the big drop-off to the ocean floor. This area often
consists of deep canyons, some of which are considerably deeper than the
Grand Canyon.
Now pretend you can walk along the ocean floor. What would that
walk be like? The ocean floor is a series of hills, mountains and valleys. You
might get tired from climbing these underwater hills. These underwater
mountains are known as seamounts. Seamounts were once active underwater
volcanoes. Some seamounts have flattened tops. These seamounts are called
guyots (GEE ohs).
In some parts of the ocean the floor is flat. The flat parts of the ocean
floor are called abyssal plains. Plains cover about half of the ocean floor.
Ranges of high mountains run through the middle of the oceans. These ranges
are called mid-ocean ridges. The longest mountain range in the world, called
the Mid-Atlantic Ocean Ridge, is found in the Atlantic Ocean. In some places,
seamounts reach high enough above the
water to form islands.
Underwater volcanoes formed the
Hawaiian Islands. The most recent
Hawaiian volcanoes are still active. They
make up the larger islands to the
southeast. The older Hawaiian Islands, to
the northwest are smaller. Their volcanoes
are no longer active, and they are slowly
eroding back into the Pacific.
Another type of island grouping is an atoll (A tawl). An
atoll is a ring of islands resulting from coral reef formation
around a shallow central lagoon.
EXERCISE 3: What is Earth’s largest mountain? Use the
following data to answer the question. Mauna Kea projects
about 13,860 feet above sea level. Its base is on the floor of
the Pacific Ocean, approximately 18,315 feet below sea level.
Mt. Everest rises 29,035 feet from base to summit. Its base is
located on land.
Trenches, or underwater canyons, are found scattered on the ocean floor. The
deepest of these is the Marianas Trench in the Pacific Ocean. This trench is
about 6.8 miles deep.
EXERCISE 4: Which is bigger, Mt. Everest or the Marianas Trench?
Object
Marianas Trench (Pacific Ocean)
Mt. Everest (Tibet)
Mt. McKinley (Alaska)
Grand Canyon (Arizona)
Sears Tower (Chicago)
Tallest tree (California)
Depth/Height
6.8 miles
5.5 miles
3.8 miles
1.0 miles
0.3 miles
0.06 miles
The ocean is an aquatic biome that is home to a wide variety
of living things, from sea turtles and sharks to kelp and killer
whales. Most marine plants and animals have adapted to life
in the ocean. Adaptations are body parts or behaviors that
help organisms to survive in their habitats.
Along shorelines is the intertidal zone. This area is covered
with water at high tide, but it is exposed to air at low tide. The
organisms that live in tide pools are adapted to live under harsh,
changing conditions. Some plants and animals attach themselves
to rocks. Others burrow in the sand. Crabs, clams, and snails are
some of the animals that live in the intertidal zone.
Farther from shore, in shallow water, is the near-shore zone.
Kelp forests exist in some parts of this zone. Animals such as
kelp bass, sea otters, sea urchins, and sponges are adapted to
living at various levels of the kelp forest.
Coral reef ecosystems form in warm, clear, shallow ocean
water, typically around the slopes of a volcanic island. Coral are
tiny animals that are related to sea jellies and take calcium out of
the water to make hard limestone skeletons. Over thousands of
years as new coral grows on top of dead ones, the hard skeletons of millions of
coral form a stony reef. Reefs provide shelter for many animals, such as
sponges, jellyfish, sea star, turtles, and reef sharks.
The Great Barrier Reef off the coast of Australia is the world’s largest coral
reef system. It is more than 1,560 miles long and almost 120 miles wide in
some places.
Tiny living organisms called plankton float in the upper
layers of the water. Most plankton are microscopic and drift
with the currents. Phytoplankton are plant-like plankton.
They are able to photosynthesize using sunlight.
Phytoplankton are a source of food for animal plankton,
known as zooplankton.
Animals that swim, rather than drift in the currents, are called nekton.
Fish, whales, turtles, shrimp, and squid are nekton. Animals that swim are able
to search more areas to find food. Some, such as herring, swim to the surface
to feed. Others stay in deeper water. Nekton reside in the pelagic division, or
oceans’ water.
Organisms that live on the ocean floor
are classified as benthos. Benthos are
found in shallow waters along a coast or in
the deepest parts of the ocean. Some
benthos attach themselves to the ocean
floor. They stay in that spot until they die.
Mussels, barnacles, and some seaweeds
are benthos that remain attached to the
ocean floor. Some benthos bury
themselves in sand or mud. Others crawl
along the ocean bottom. Benthos live in
the benthic division, or ocean floor zone.
EXERCISE 5: Give some examples of benthos and nekton.
1. Benthos _____________________________________________
2. Nekton _____________________________________________
Salt makes up a large a part of the soil and rocks on land. That salt reaches the
ocean as part of the water cycle. How? All oceans lose water through
evaporation. That water vapor returns to Earth as precipitation. Water is carried
back from rivers and other waterways to the ocean. Along the way, minerals are
washed from the soil and rocks to the ocean. When the cycle begins again the
minerals including salt, are left behind in the ocean.
The deep ocean is one of the last places on Earth to be explored. The ocean
has an average depth of 12,500 feet. Deep below the surface, the water pressure
is tremendous. It is very dark and cold. In order to study the deep ocean, people
have developed submersibles, underwater vehicles. Submersibles are designed
so that they are strong enough to hold up under extreme water pressure and
temperature. One of the first submersibles was a bathysphere (BATH uh sfir). A
bathysphere is a round diving vessel that is lowered into the ocean on a steel
cable from a ship. Another kind of submersible is called a bathyscaphe (BATH ih
skaf). A bathyscaphe is a small submarine.
Scientists can also study the ocean floor by drilling into the crust beneath the
ocean. The Deep Sea Drilling Project is an ocean research program in which
scientist study samples of rock taken from the ocean floor.
Scientists can map the ocean floor by using sonar. The word “sonar” comes
from the letters in sound navigation and ranging. Sonar is a method of
echolocation, or the usage of sound to determine distance, size, and location of
objects. Sonar is used to calculate the depth of the ocean. Sound waves travel
through water at a speed of 4921 ft/sec. A transmitter bounces a sound wave off
the ocean. A receiver picks up the returning sound wave, or echo. Scientists can
measure the time it takes for the echo to return and calculate the depth of the
ocean floor.
ESTUARIES
An estuary is a partially enclosed body of water formed where fresh
water from rivers and streams flows into the ocean, mixing with the salty
seawater. They are fascinating and beautiful ecosystems distinct from all other
places on earth. Estuaries may extend for many miles beyond the bay and they
come in all shapes and sizes and go by many different names such as bays,
lagoons, harbors, inlets, or sounds.
The sheltered waters of estuaries are homes for plants and animals,
specially adapted for life at the edge of the sea. They are the basis of survival
for many species of animals. Thousands of birds, mammals, fish, and other
wildlife depend on this ecosystem as a place to live, feed, and reproduce.
Animals such as migratory birds use estuaries as places of rest and feeding
grounds on their long journeys.
Estuaries filter out sediments and pollutants that are carried by
flowing water to their new ocean home. This filtration process creates cleaner,
clearer water. Plants and soil in estuaries act as natural buffers between the
land and ocean, absorbing floodwaters and calming storm surges. Salt marsh
grasses and plants help prevent soil erosion and stabilize the shoreline.
Because salt water is denser than fresh water, the salt water tends to
enter into the estuary along the bottom. The lighter, fresh water will flow in
along the surface. When a river brings in extra water, such as
during periods of flooding, the salinity in the bay will be
reduced. On the other hand if drought causes the flow of fresh
water to be reduced, the salinity of the bay may be increased.
This means that the plants and animals of estuary areas must
be able to adapt to the changing salinity or migrate out of the
area. Despite the large amount of plant material available for food, estuaries do
not contain a large diversity of animal species. This is because it is difficult for
many animals to constantly adapt to the changing temperatures and salinity.
The animals that are able to survive are usually found in large numbers.
Coastal areas provide natural beauty therefore there has been an
increasing concentration of people in these areas. People have been upsetting
the natural balance of the estuary ecosystem. Dams on rivers have reduced the
amount of water flowing into the estuaries, allowing salt water to flow into the
areas that used to be mostly fresh water. Dams have also stopped the migration
of fish into rivers for their annual spawning runs. Shorelines are often
reconstructed to accommodate housing for people by filling in marshes and tidal
flats.
Estuaries provide us with many resources most of which cannot be
measured in dollars and cents. They must be carefully managed to ensure that
these benefits are around for years to come.
Name __________________________ Date __________ Period _____
Estuaries – Questions
***Directions: Use with packet page ______.
1. What is an estuary?
2. What are some other names for estuaries?
3. How are estuaries the basis of survival for many species?
4. How do estuaries act as filters?
5. How do estuaries act as a buffer between land and ocean?
6. Would salinity increase or decrease in an estuary during periods of flooding?
Why?
7. Why is there NOT a large diversity of animal species in the estuaries?
8. What are three ways that humans can affect an estuary?
a. _______________________________________________________
b. _______________________________________________________
c. _______________________________________________________
Salt Marsh
The most likely place to find a salt marsh is around a bay. The
shoreline around bays is usually flat and is easily flooded at high tide. Just as
important, most of New Jersey’s bays are protected from direct exposure by a
series of barrier islands or peninsulas that stretch all the way from Sandy Hook
to Cape May.
For a salt marsh to exist,
it must be on land that is
regularly washed over by salt
waters. This means that it
must be near either an ocean
or a bay. It also means that it
must be a tidal area that is
soaked with each high tide and
dried with each low tide. As
the tide recedes, the water
retreats, leaving muddy flats
around much of the marsh.
Since most marshes are low
lying areas surrounded by
higher ridges, some water remains and the ground always stay a little wet. For
this reason, marshes are often called wetlands. This wet, salty place is an ideal
place for all sorts of plants to grow and an ideal home or feeding ground for
many small fish, birds, and animals. Each incoming tide carries with it
organisms and plant materials that bring life to the salt marsh. Each outgoing
tide cleans the marsh by straining out organic materials and wastes that are
produced there by decaying plants or animals.
A salt marsh is fragile environment that can exist in only a limited
number of places. It must be protected from direct exposure to the ocean, since
the pounding waves would ruin the fragile makeup of a salt marsh. For this
reason, there cannot be salt marshes directly on an ocean beach. Most often,
salt marshes are along the banks of protected bodies of water.
At first glance, a salt marsh may look like a simple sea of grass, and the
mud flats that surround it at low tide may seem devoid of life. Because these
places appear almost barren, we may not pay much attention to them.
However, if you look carefully, you will see that the water, mud, and sand that
make up the marsh are home to a multitude of living creatures.
A salt marsh is the spawning ground for our coastal and marine
fishes. Perhaps 80% to 90% of the edible marine fish gathered for market
around the world come from shallow coastal waters. Marshes provide feeding
and resting areas for shorebirds and waterfowl. Several species of birds,
mammals, and many aquatic animals breed in the marsh.
The tall, dense cover of Marsh Elder and Cord Grass and the nutrient
rich muck of the marsh floor provide the growing stage for most of the important
creatures of the salt marsh. Here, a variety of snails and tiny periwinkles exist in
seclusion. Fiddler Crabs scoop up algae with their claws and seek hiding places
in small burrows in the mud. Clams, Scallops, Mussels, and Sponges are the salt
water filters feeders. These animals strain the microscopic plant and animal
plankton from the water and serve an important role in the marsh food chain.
Other important links in the chain are fishes like Killies and Sticklebacks.
Over the years, the water quality at Sandy Hook has steadily
decreased and today the bay waters along the Hook are no longer suitable for
shellfishing. Pollution is just one of the many problems facing salt marshes
today. Environmental threats to salt marshes are ever increasing. With today’s
continually growing population and expanding urban areas, greater demands are
being placed upon “space.” Not outer space but space for people to live, work,
and for travel. Thousands of acres of tidal marshes have been drained or filled
in for housing developments, industrial sited, parking lots, trash and garbage
dumps, highways, and airport extensions. Many marshes have been dredged for
sand or gravel or for channels to boat marinas.
During its history, New Jersey has lost about 30% or 60,000 acres of
its tidal marshes; 230,000 acres remain. The salt marshes at Sandy Hook are
strictly protected and are left entirely undisturbed. However, this doesn’t mean
that changes are not occurring in the marsh. They are primarily the slow, steady
changes of nature.
Name __________________________ Date __________ Period _____
Directions: Answer the following questions about Salt Marshes – based on
information found on pages _____ and _____.
1. Wetlands are often called _______________________.
2. True_____/False________ Tidal areas are soaked with each low tide and
dried with each high tide.
3. Salt marshes are homes to a multitude of _____________________.
4. The most likely place to find a salt marsh is around an ocean or ___________.
a) lake
b) pond
c) bay
d) stream
5. The environment of a salt marsh is _____________________.
6. True____/False____ Salt marshes are regularly washed over by fresh water.
7. New Jersey has lost about ______ thousand acres of its tidal marshes.
a) 30
b) 60
c) 23
d) 80 to 90
8. ___________________ protect salt marshes and bays from direct exposure to
the ocean.
9. Which animal is an example of a filter feeder?
a) Fiddler Crab
10.
b) Stickleback
c) Marsh Elder
d) Scallop
True____/False____ Each incoming tide cleans the marsh.
11. The water quality at Sandy Hook has steadily __________________.
12. Muddy flats are left around the salt marsh as the _________ recedes.
13.
Marsh Elder and ___________________ are examples of salt marsh plant
life.
14.
List 3 examples of what salt marshes have been replaced with:
a)
b)
c)
15.
What percent of edible marine fish gathered for market around the world
come from shallow coastal waters? ________ %
The Dune Ecosystem
The dune ecosystem is one of the most important areas for study in the
nearshore (beach) environment. It is the dunes that protect the barrier islands
and peninsulas from the massive erosion caused by a major storm. The health
and size of the dunes are important factors in the protection of the breeding
grounds (salt marshes and back bays) of animals. The dunes also serve as
protection for man-made structures often found along the shoreline.
Dunes are described as little sand hills
formed by the action of the wind and waves.
The wind carries the sand, which is in turn
caught and held in place by the vegetation,
which in turn provides the soil for more
vegetation. As the dune accumulates sand,
it builds its characteristic shape.
The wind dominates the ocean side of
the dune. It dries and sand blasts the plants and often coats them with a fine
mist of salt spray. The dunes slow the wind, which causes it to drop much of its
load. Its main force is directed upward over the plants that grow in the
sheltered zones behind the peaks of the dunes. The main effects felt by this salt
spray are felt during the stormy winter months, when the salt spray and stormblown sand reach the uppermost limit of the plants, leaving dead tops and
effectively pruning the plants to specific heights.
Usually, barrier beaches are made up of two main dunes: the one closest
to the ocean, which develops in the salt spray horizon, is called the primary
dune and the one behind it is called the secondary dune. In the primary
dune, a few hardy pioneer plants anchor themselves in the shifting sand and
these plants in turn help to trap the sand. Pioneer plants are plants that start
a new life cycle in a barren area. Not only do these pioneer plants serve to
anchor the dune with a spreading root system, they also enrich the soil when
they die and decay. The most prominent plants found on the primary dunes of
Sandy Hook are the dune grasses, which not only can tolerate salt spray, but
they have the ability to grow upward as they become buried by accumulating
sand. Other pioneer plants found on the primary dunes are Seaside Goldenrod,
Bayberry, Sea Rocket, Dusty Miller, Sea Rocket, and probably most important
and abundant of all, Poison Ivy.
As you move away from the ocean beach and primary dunes, the
vegetation increases in abundance and variety. The more sheltered and stable
areas of the secondary dunes produce the environment necessary for the growth
of pioneer shrubs and trees like the Beach Plum, Wild Black Cherry, Eastern Red
Cedars, Winged Sumac, and Holly.
Seashore dune areas resemble deserts in some ways; the shore dune
plants often have deep penetrating roots (Ex: Beach Plum) and are good sand
stabilizers; some have small leathery, spiny, or waxy leaves (Ex: Holly), and
some are succulents capable of storing their own water supply (Ex: Cactus).
Many dune plants grow vigorously, and are resistant to wind, salt spray, and
drought. The Cactus and Golden Heather compete with each other for growing
space by releasing poisonous chemicals from their roots.
One thing that the dune plants, especially the
dune grasses, have in common is their lack of
tolerance to the destructive activities of man.
Though the dune grasses may appear tough, they
are quite fragile and once trampled by dune
explorers, horses, motorbikes, jeeps, and feet … the
plants will die. Weak areas in the dune exist because
of loss of vegetation, human traffic, or building on the dunes. These areas
become susceptible to the devastating beating by any storm. You must
understand, the ocean is always trying to push the beach shoreward … and
beach erosion and dune loss is problem that cannot be ignored by those
interested in the shore environment. In short, STAY OFF THE DUNES!
Animal Adaptations: It is not unusual for the temperature of
the sun-heated sands to rise above 1200 F. Thus, it is safe to
say that the animals living in the dunes must have special
adaptations for life in such a unique environment. Animals
such as the yellow-and-black Digger Wasps make burrows in
the sand while hunting. Another dune inhabitant, the Velvet
Ant (actually a wasp) protects itself from the heat with its fur insulation. The
Dune Wolf Spider lives in silk lined burrows and carries its young in pouches.
Small mammals such as the Cottontail Rabbit can live in the dune environ ment
and have in fact adapted to eating the Prickly Pear Cactus to obtain fresh water.
As the dunes stabilize and the vegetation becomes more
permanent with the growth of more diverse vegetation, a
climax community of vegetation and animal life begins to
emerge. Freshwater is an important factor in the formation of
this climax community. Although most of Sandy Hook is dry and salty, there are
some low lying areas that reach into the freshwater table, creating ponds. These
freshwater ponds attract a variety of wildlife and plants that need freshwater to
survive.
The longest mountain range in the
world is located at the bottom of the
ocean. Called the Mid-Atlantic
Ocean Ridge, it almost circles the
globe completely, running from the
Arctic Ocean through the Atlantic
Ocean, then around Africa to the
Indian and Pacific oceans. It comes
to an end at the west coast of North
America. The Mid-Atlantic Ocean
Ridge is four times longer than the
Rockies, Andes, and Himalayas
combined.
The deeper you go in the ocean,
the greater the pressure is over
you. This is due to the accumulated
weight of the water. At the deepest
point in the ocean floor, the Mariana
Trench, the pressure is 8 tons per
square inch. To put this in human
terms, imagine one person trying to
hold up the weight of 50 jumbo jets!
The largest iceberg ever measured
was 550 feet high, found off the
western coast of Greenland. This is
only 5 feet 6 inches shorter than the
Washington Monument in
Washington, D.C.
Ninety percent of the entire world’s
volcanic activity takes place under
the ocean surface. Many volcanoes
are located on the edges of the
Pacific Ocean. This area is known
as the Ring of Fire.
The largest animal ever to live on
the earth is the blue whale, which
makes its home in the ocean. The
blue whale’s heart is the size of a
small car. Larger even than the
dinosaurs, blue whales can grow to
110 feet long and weigh 200 tons.
The largest bony fish in the sea is
the oar fish, which can grow to 50
feet long. Its strange appearance –
horse-like face, blue gills, and
distinctive long red fin – had some
sea voyagers believing they had
spotted a sea monster of some
kind.
Coral reefs are diminishing
because of pollution, so some
nations have established protected
area, known as marine parks, to
help protect them. Coral is a crucial
part of the food web in tropical
areas and is also important in
medical research. Coral can be
used in place of bone grafts to
accelerate the healing of human
bone fractures.
British warships often fired their
cannons as a greeting. Because
the guns that meant no harm took a
long time to reload, firing them was
a sign that the ship was disarming
itself. Most warships had 21
cannons on each side. This is the
origin of the 21-gun salute often
used at military funerals.
There are more than 300 species
of shark.
If all the salt were removed from the
ocean, it would cover every part of
dry land on Earth to a depth of five
feet!
VOCABULARY
Vocabulary Term
1. Oceanography
Definition
Study of the earth’s oceans
2. Salinity
The measure of the amount of salt in water
3. Density
5. Wave
The amount of matter in a given volume; density of oceans depends on
temperature, salinity, and pressure
Transition layer that extends from the bottom of the surface layer to about
1 km
A forward motion of energy
6. Currents
Water movement throughout the ocean
7. Surface Currents
8. Coriolis Effect
Water movement on the surface caused by the force and direction of
winds and movement of the Earth
The effect of Earth’s rotation on the rotation of winds and currents
9. Density Currents
Deep water currents caused by differences in water density
10. Upwelling
11. Continental Shelf
The upward movement of cold water from the ocean depths; increases
supply of nutrients
A rim of underwater land that has the greatest concentration of life
12. Continental Slope
A steep drop after the continental shelf consisting of deep canyons
13. Seamount
Underwater mountains that were once active underwater volcanoes
14. Guyot
Seamounts with flattened tops
15. Abyssal Plains
The flat parts of the ocean floor
16. Mid-ocean ridges
17. Phytoplankton
Ranges of high mountain ranges running through the middle of the ocean
floors
Microscopic plant-like organisms
18. Zooplankton
Microscopic animal-like organisms
19. Nekton
21. Pelagic Division
Animals that swim. Examples include fish, whales, turtles, squid, and
shrimp.
Organisms that live on the ocean floor. Examples include mussels,
barnacles, and coral.
Open ocean water zone
22. Benthic Division
Ocean floor zone
23. Submersible
Underwater vehicle used in ocean exploration
24. Echolocation
The usage of sound to determine distance, size, and location of objects
25. Tide
The regular rise and fall of sea level due to the moon’s gravity pull on
Earth
4. Thermocline
20. Benthos