Oceanography Merit Badge – In some way, the oceans touch every part of Earth. The oceans cover more than 70 percent of our planet and are the dominant feature of Earth.
Wherever you live, the oceans influence the weather, the soil, the air, and the geography of your community. Apollo astronauts hurtling toward the moon looked back at a blue sphere speckled with clouds. To study the oceans is to study Earth itself.
Since the world’s oceans are all connected, you could think of them as one great ocean. But people have given the various oceans names and have even debated their number.
They are, from largest to smallest, the Pacific, the Atlantic, the Indian, the Southern, and the Arctic Oceans.
That’s why for those of you who want to become a sea scout, it is very important to learn and also get the oceanography merit badge.
Oceanography Merit Badge Requirement
- Name four branches of oceanography. Describe at least five reasons why it is important for people to learn about the oceans.
- Define salinity, temperature, and density, and describe how these important properties of seawater are measured by the physical oceanographer. Discuss the circulation and currents of the ocean. Describe the effects of the oceans on weather and climate.
- Describe the characteristics of ocean waves. Point out the differences among the storm surge, tsunami, tidal wave, and tidal bore. Explain the difference between sea, swell, and surf. Explain how breakers are formed.
- Draw a cross-section of underwater topography. Show what is meant by:
- Continental shelf
- Continental slope
- Abyssal plain
- List the main salts, gases, and nutrients in seawater. Describe some important properties of water. Tell how the animals and plants of the ocean affect the chemical composition of seawater. Explain how differences in evaporation and precipitation affect the salt content of the oceans.
- Describe some of the biologically important properties of seawater. Define benthos, nekton, and plankton. Name some of the plants and animals that make up each of these groups. Describe the place and importance of phytoplankton in the oceanic food chain.
- Do ONE of the following:
- Make a plankton net. Tow the net by a dock, wade with it, hold it in a current, or tow it from a rowboat.* Do this for about 20 minutes. Save the sample. Examine it under a microscope or high-power glass. Identify the three most common types of plankton in the sample.
- Make a series of models (clay or plaster and wood) of a volcanic island. Show the growth of an atoll from a fringing reef through a barrier reef. Describe the Darwinian theory of coral reef formation.
- Measure the water temperature at the surface, midwater, and bottom of a body of water four times daily for five consecutive days.* You may measure depth with a rock tied to a line. Make a Secchi disk to measure turbidity (how much-suspended sedimentation is in the water). Measure the air temperature. Note the cloud cover and roughness of the water. Show your findings (air and water temperature, turbidity) on a graph. Tell how the water temperature changes with air temperature.
- Make a model showing the inshore sediment movement by littoral currents, tidal movement, and wave action. Include such formations as high and low waterlines, low-tide terrace, berm, and coastal cliffs. Show how offshore bars are built up and torn down.
- Make a wave generator. Show reflection and refraction of waves. Show how groins, jetties, and breakwaters affect these patterns.
- Track and monitor satellite images available on the Internet for a specific location for three weeks. Describe what you have learned to your counselor.
- Do ONE of the following:
- Write a 500-word report on a book about oceanography approved by your counselor.
- Visit one of the following:
- Oceanographic research ship
- Oceanographic institute, marine laboratory, or marine aquarium Write a 500-word report about your visit.
- Explain to your troop in a five-minute prepared speech “Why Oceanography Is Important” or describe “Career Opportunities in Oceanography.” (Before making your speech, show your speech outline to your counselor for approval.)
- Describe four methods that marine scientists use to investigate the ocean, underlying geology, and organisms living in the water.
What Is Oceanography?
Oceanography covers all aspects of ocean study and exploration.
- Geological oceanography focuses on the topographic features and physical makeup of the ocean floor.
- Physical oceanography deals with the motions of seawater, such as waves, tides, and currents.
- Chemical oceanography concerns the distribution of chemical compounds and chemical reactions in the ocean and on the seafloor.
- Meteorological oceanography pertains to the study of the ocean’s interaction with the atmosphere and its effect on weather and climate.
- Biological oceanography concentrates on plant and animal life in the sea.
Studying the oceans tells us much about the land, rivers, lakes, and the air our entire planet.
This may help us to find new sources or supplies of food, fresh water, minerals, and energy, and a new understanding of weather and climatic patterns.
Earth and Sea
When you think of the ocean, you probably think of motion because the ocean is always moving.
As a free liquid on a spinning planet, it is constantly tugged and pushed by forces near and far. Much of the ocean’s motion takes the form of waves and tides.
1. Waves
The sea surface heaves and sighs as waves rise and fall. From earthquakes to ship wakes (waves created by boats), many forces create ocean waves. However, the most common force is wind.
As wind passes over the water, it pushes on the ocean’s surface, causing it to vibrate. That vibration creates a disturbance or ripple on the ocean surface.
The strength of the wind, the fetch (uninterrupted distance the wind blows), and the duration of the gust determine how big the ripples become.
During severe storms, the ripples can grow to waves 50 feet high. A wave has several distinct parts.
The crest is the portion above the still water line and the highest point on a wave; the trough, or valley between two waves, is the lowest point.
The horizontal distance between the crests or troughs of two waves is called the wavelength.
The vertical distance between the crest and the trough is the wave height. The wave period measures the period of time between two waves.
You can determine the wave period by picking a point, say a rock or pier or buoy, and counting the seconds it takes for two waves to pass by. There you’re an oceanographer already!
2. Storm Surges, Tsunamis, and Tidal Bores
The strong winds of a hurricane or storm push seawater toward the shore. This advancing water may combine with normal tides to create a storm surge, which can increase the tide level 15 feet or higher.
In addition, wind-driven waves roll in on top of the storm surge, adding to the destructive power. Storm surges can cause severe coastal flooding, especially if the storm surge happens at high tide.
Because so much of the U.S. population lives on the East and Gulf Coasts, many in locations just above sea level, the danger from storm surge is tremendous.
Occasionally, underwater disturbances such as volcanic eruptions, earthquakes, or landslides create monster waves called tsunamis. Reaching heights of 120 feet (37 meters) or more, tsunamis are the most dramatic and destructive of waves.
The larger the underwater disturbance, the larger the tsunami. They have been called tidal waves, but their formation has nothing to do with the tides.
In the open ocean, tsunamis are hard to spot. Their long wavelengths mask their monstrous size, but like smaller waves, tsunamis change when they enter shallow water.
Their wavelength shortens, and their crests rise to their full height. The
strength of the underwater disturbance, the tsunami’s wavelength, and the shape of the coastline all contribute to the tsunami’s height and destructiveness.
Tidal bores are waves or walls of water that race up an inlet as the tide comes in. While not completely understood, tidal bores usually occur in V-shaped inlets that shallow up along their length.
Wider at the opening and shallower at the head, these inlets force incoming water to collect in the middle. A wall of water then rushes up the inlet.
3. Waves and coastal Formation
Waves form and shape coastlines. Wave erosion creates some of the world’s most spectacular landforms, including sea caves, wave-cut notches, and coastal cliffs.
Often it smoothes sandy beaches and forms barrier islands like North Carolina’s
Outer Banks.
Breaking waves can deposit or carry away sand and soil. This is known as deposition or erosion of sediment. As waves batter the coast, they erode and grind away the shore.
Rocks and cliffs undercut by wave action fall into the sea and are ground and weathered into sand. The coastline’s resistance to erosion determines its shape.
The ocean constantly reshapes beaches and replenishes the sand. Sediment deposits move along the seashore as every wave hits. Since the wind blows from different directions, waves rarely approach the coast head-on.
As waves strike the shore, the swash (landward movement of water) carries sand to the beach at an angle. The backwash (seaward movement of water) returns straight out to the ocean.
Any sand carried by a wave that is not left on the beach is carried to the ocean by the backwash. There it settles on the seabed until another landward wave deposits it on the beach. This movement of sediment down the beach is called
beach drift.
When waves hit the coast, some of the water flows along the beach, creating a longshore or littoral current. The current moves beach sediment in the water, a movement known as longshore drift.
The combined movement of sediment via longshore drift and beach drift is called littoral drift. The strength of the longshore current increases as the size of the waves and the approach angle increase.
When the current grows strong enough to overcome the force of incoming waves,
the water will flow seaward in a riptide, or rip current. A rip current can carry large amounts of sand and sediment away from the beach.
If incoming waves do not return the sand, the beach gradually will wear away.
4. Tides
The gravitational pull of the moon (and, to a smaller degree, the sun) on the sea
causes ocean tides. In most parts of Earth, this pull produces two high tides and two low tides each day.
As Earth rotates beneath the bulging waters, a high tide occurs, then a low tide, then another high tide, and another low tide. The tilt of the moon’s orbit gives the two daily high tides and the two daily low tides different heights.
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5. Upwelling
Because the oceans have so much mass, they resist moving. Thus, only winds blowing over the water for long distances and for long periods of time are capable of generating ocean currents.
The Gulf Stream is a warm current that flows from the Caribbean toward northern Europe on the western side of the Atlantic Ocean. Winds in the central part of the Atlantic drive this current.
Along the eastern sides of the Atlantic, winds blowing in the direction of the equator push surface water offshore replacing colder, deeper ocean water.
This process is called oceanic upwelling, and the nutrient-rich water that rises to the surface with the cold water helps support the abundant marine life of the Atlantic.
Zones of Life in Sea
The sea is so vast that scientists have divided it into zones. The pelagic zone includes all the environments of the ocean above the bottom, or living in open
oceans or seas rather than in waters next to land or inland waters.
It is divided into an inshore neritic zone (the zone of shallow water adjoining the seacoast) and the open-sea oceanic zone. The boundary between them occurs at the edge of the continental shelf.
The oceanic zone is divided further according to how deep sunlight penetrates.
Planktonic plants occur only in the neritic and epipelagic zones but provide food to animals living in the water and on the bottom. Open-ocean life forms are called pelagic; bottom-dwelling life forms are called benthic.
The benthonic zone is subdivided into three bottom zones: the littoral, bathyal, and abyssal. Plants grow only in the sunlit zone, the only ocean layer that absorbs enough sunlight for photosynthesis.
Animals live in all the oceanic zones, although because of the availability of
food, more of them are found near the ocean’s surface. The sunlit zone is very shallow compared to the bathyal or abyssal zones.
Life Near the Surface
Food is most abundant in the sunlit zone. There, the majority of ocean life finds the food sources needed to survive mostly in the form of microscopic algae.
1. The Intertidal Zone and Intertidal Invertebrates
Abundant and varied plant and animal life thrive in intertidal communities between the high and low tides of marine coasts.
Factors such as the type of rock, type of sand or soil, water temperature, protection from waves, and the interactions between organisms determine what an intertidal community is like.
Intertidal communities are rich in life, especially in invertebrates animals such as clams, mussels, starfish, and others that do not have a backbone or spinal column.
The invertebrate group is one of two general categories of animals. The other
group, vertebrates, includes those animals that do have backbones (fishes, amphibians, reptiles, birds, and mammals).
Invertebrates occupy all habitats, even deep-sea trenches, and are found in all types of sea-bottom sediments, from soft oozes to rocky bottoms.
Swimming invertebrates survive at all depths and include forms developed to
live in the sunless waters of the deep sea as well as near the surface.
Invertebrates exist in fresh, brackish (slightly salty), and marine environments. Some specialized forms also thrive in extremely salty seawater such as lagoons along tropical coasts and pools high in the intertidal zone.
2. Splash and the Upper Intertidal Zones
In the intertidal zone, the area highest above the waves is the splash zone, which is just reached by the ocean’s salty spray.
Animals living in this zone, such as shore crabs and sand fleas, are primarily adapted to life above the waves. Only a few hardy animals live in splash pools, which dry up in summer and flood with freshwater runoff in winter.
Below this zone lies the upper intertidal zone with its scattered covering of green and brown seaweed. Here, snails and limpets scour rocks in search of microscopic algae.
Barnacles cover the rocks except where predators and winter storms have cleared them away. Because barnacles cement themselves to the rocks and close when the tide is out, they are welladapted to this zone.
3. Mid and Low Intertidal Zones
Below these two zones, in the mid-intertidal zone, a broadband of mussels often forms a bed several inches thick.
The common starfish continually feeds on mussels, which would otherwise abound throughout all the available mid-intertidal space.
Many worms, snails, and crabs live within the mussel bed. The mid-intertidal zone is covered and uncovered twice a day by the tides.
Animals in this zone have adapted to being immersed in air and seawater. The diverse plants and animals of the low intertidal zone include red algae and large kelp, which clings to the rocky bottom with holdfasts.
The kelp’s large leaves move with the waves, and the kelp beds protect the sea urchins, worms, snapping shrimp, and porcelain crabs preyed upon by the giant sunflower starfish.
Sandy beaches, while fun for sunbathers, provide limited habitat for marine and shore animals. Those that are there, though, are often found in abundance, especially crabs, clams, and beach hoppers.
Plankton
The term plankton comes from the Greek word planktos, which means “wanderer.” Plankton includes marine plants and animals that drift with the currents.
Because they drift, plankton differ from nekton, animals that actively swim or lie on or burrow into the seafloor, such as clams and worms.
They also differ from marine plants such as large seaweeds. Plankton cells are seldom larger in diameter than a few tenths of an inch. Plankton forms the basis of all major ocean food chains.
Plankton is denser than water and tends to sink. However, because of their small size, long spines, shell extension, and the ability to float, these drifters have adapted in different ways to slow this sinking.
Some planktonic animals rise toward the surface at night and then sink to deeper waters during the day. This vertical migration is probably tied to feeding strategies as well as to the avoidance of predators.
When plankton dies, it sinks and contributes to the rich sediments at the bottom of the sea.
1. Phytoplankton
Plant plankton, or phytoplankton, consists of single-celled algae. Through photosynthesis, plankton supports the rest of all marine life.
Photosynthesis is the process plants use to convert sunlight into food and release oxygen from carbon dioxide and water. The amount of available light and nutrients affects phytoplankton production.
Besides sunlight, phytoplankton needs nutrients to survive. Ocean mixing brings these nutrients up from the seafloor.
Levels of plankton tend to remain low and constant year-round in the clear open ocean and tropical waters. Light can penetrate deeper there, but storms have trouble churning up nutrient-rich bottom sediments in deepwater.
The most productive areas are where surface currents lead away from land and mix with deep currents, like the west coast of Ecuador and Peru and off western Africa.
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2. Zooplanton
Planktonic animals, or zooplankton, are divided into two groups. Holoplankton spend their entire life cycle as plankton.
These include small crustaceans such as crabs, krill (the principal food of baleen whales), and jellyfish.
Meroplankton are plankton only during the larva stage (the earliest stage of an animal, before it changes and becomes an adult).
These species, which include shrimp, barnacles, worms, and marine fish such as herring and anchovies, change dramatically as they grow. As many as 50,000 zooplankton may inhabit one gallon of seawater!
To complete the 8th requirement you can read about Career Opportunities in Oceanography.
Career Opportunities in Oceanography
To become an oceanographer, you will need a background in science and mathematics, and a solid knowledge of at least one basic science such as biology, chemistry, geology, or physics.
In college, oceanography courses help an undergraduate student learn how science applies to the study of the ocean. Your education should include an undergraduate degree (four years) and at least a master’s degree (two more years).
You may need a doctorate (three more years). An oceanographer may choose from several types of careers after completing training.
Colleges and universities provide teaching and research opportunities. The government employs oceanographers in areas such as the Department of Commerce and the Environmental Protection Agency.
The private sector offers the most opportunities. Engineering businesses, oil and
gas extraction companies, and metals mining firms need oceanographers, geologists, and geophysicists.
Oceanographers may detect and track ocean-related weather events, investigate ocean pollution, look for minerals on the seafloor, or study the migration of aquatic animals.
Marine engineers design, construct, and repair ships, submarines, and port facilities.
Ocean engineers design and install equipment used in the ocean, including oil rigs and other offshore installations, and design breakwater systems to prevent beach erosion.
Plenty of other ocean-related career opportunities exist, including:
- Coast Guardsman
- Ocean tour or dive operator
- Commercial fisherman or diver, kelp harvester
- Sailor, ship’s captain, boat operator
- Conservationist or fish and game officer
- Lifeguard
- Longshoreman
- Mariculturist
- Offshore oil worker
- Meteorologist
- Ship builder
- Underwater photographer
The Answer for Requirement Number 1
Four Branches of Oceanography:
| Branch | Description |
|---|---|
| Biological Oceanography | Studies the life forms in the ocean, including marine organisms, ecosystems, and their interactions. |
| Chemical Oceanography | Examines the chemical composition and processes of seawater, including its properties and dynamics. |
| Geological Oceanography | Focuses on the geology and geological processes of the ocean floor, including plate tectonics and sediments. |
| Physical Oceanography | Investigates the physical properties and processes of the ocean, such as currents, waves, and circulation patterns. |
Importance of Learning about the Oceans:
- Climate Regulation: Oceans play a vital role in regulating Earth’s climate by absorbing and storing heat, influencing weather patterns, and acting as carbon sinks. Understanding oceanic processes helps us comprehend climate change and develop strategies to mitigate its impacts.
- Biodiversity and Ecosystems: Oceans are home to a diverse array of species and complex ecosystems. Learning about the oceans helps us appreciate their biodiversity, understand the interconnectedness of marine life, and work towards conserving and protecting these fragile ecosystems.
- Resource Management: Oceans provide valuable resources such as food, energy (e.g., through offshore wind farms), minerals, and medicines. By studying the oceans, we can ensure sustainable management and responsible use of these resources, minimizing environmental impacts.
- Coastal Communities and Economies: Coastal regions and communities heavily rely on the oceans for livelihoods, tourism, and cultural heritage. Understanding the dynamics of coastal ecosystems, hazards, and human interactions with the ocean helps ensure their sustainable development and resilience.
- Climate Change and Sea-Level Rise: With rising global temperatures, understanding the impacts of climate change on the oceans is crucial. Learning about sea-level rise, ocean acidification, and their consequences helps in formulating adaptation strategies and mitigating the effects on coastal areas.
These are just a few of the numerous reasons why it is important for people to learn about the oceans. The oceans are an integral part of our planet’s functioning and have a profound impact on various aspects of human life, from climate regulation to food security, biodiversity, and the well-being of coastal communities.
The Answer for Requirement Number 2
Definitions and Measurements:
- Salinity: Salinity refers to the concentration of dissolved salts (mainly sodium chloride) in seawater. It is typically expressed in parts per thousand (ppt) or practical salinity units (PSU). Salinity can be measured through various methods, including titration, conductivity, and refractometry.
- Temperature: Temperature refers to the measure of the average kinetic energy of water molecules. In the ocean, temperature can vary vertically and horizontally. It is measured using thermometers or more advanced instruments like conductivity-temperature-depth (CTD) profilers and expendable bathythermographs (XBTs).
- Density: Density is the mass per unit volume of seawater. It depends on both salinity and temperature. Density can be calculated using the equation of state of seawater, which takes into account the variations in salinity and temperature. It is typically measured using CTD profilers and can be inferred from measurements of temperature and salinity.
Circulation and Currents of the Ocean:
The circulation and currents of the ocean are influenced by various factors, including wind patterns, temperature differences, and the rotation of the Earth. The main types of ocean currents are:
- Surface Currents: Surface currents are driven primarily by wind patterns and the Earth’s rotation. They flow horizontally at the ocean’s surface and can extend to a few hundred meters deep. Examples include the Gulf Stream and the Kuroshio Current.
- Deep Currents: Deep currents, also known as thermohaline circulation, are driven by differences in temperature and salinity. These currents flow vertically and are responsible for the global transport of heat and nutrients. The Atlantic Meridional Overturning Circulation (AMOC) is a significant example of a deep current.
- Upwelling and Downwelling: Upwelling occurs when deep, nutrient-rich water rises to the surface, often driven by offshore winds or the interaction of currents with coastal topography. Downwelling, on the other hand, is the sinking of surface water to deeper layers. Both upwelling and downwelling play crucial roles in nutrient cycling and supporting marine ecosystems.
Effects of Oceans on Weather and Climate:
The oceans have a significant impact on weather and climate through various mechanisms:
- Heat Redistribution: Oceans store and transport a vast amount of heat, which influences temperature patterns and helps regulate climate. Heat is transferred from warmer regions near the equator to colder regions near the poles through ocean currents.
- Evaporation and Precipitation: The oceans are the primary source of water vapor, which evaporates into the atmosphere. Evaporation from warm ocean surfaces contributes to the formation of clouds and precipitation, influencing regional and global rainfall patterns.
- Air-Sea Interactions: The interface between the ocean and the atmosphere plays a crucial role in determining weather conditions. Factors such as sea surface temperature, evaporation, and wind speed influence the formation of storms, hurricanes, and cyclones.
- Carbon Cycling: Oceans act as a carbon sink, absorbing a significant portion of the carbon dioxide released into the atmosphere. This absorption helps regulate the greenhouse effect and mitigates the impacts of climate change.
Understanding the interactions between the oceans, weather, and climate is essential for climate modeling, predicting weather patterns, and studying long-term climate change. It requires collecting and analyzing data on ocean properties, circulation patterns, and their influence on atmospheric processes.
The Answer for Requirement Number 3
Characteristics of Ocean Waves:
Ocean waves possess the following characteristics:
- Wavelength: Wavelength refers to the distance between two consecutive wave crests or troughs. It is commonly measured in meters. Longer wavelengths indicate waves that have traveled greater distances.
- Amplitude: Amplitude is the vertical distance between the wave crest or trough and the still water level. It represents the wave’s energy and is measured in meters. Greater amplitudes indicate larger and more powerful waves.
- Period: The period of a wave is the time it takes for one complete wave cycle to pass a fixed point. It is measured in seconds. Longer periods indicate slower-moving waves.
- Frequency: Frequency is the number of wave cycles passing a fixed point per unit of time. It is the reciprocal of the wave period and is measured in hertz (waves per second).
- Wave Height: Wave height is the vertical distance between the wave crest and the wave trough. It is typically measured from the still water level to the highest point of the wave.
- Wave Speed: Wave speed is the rate at which a wave travels through the water. It is calculated as the product of the wavelength and the wave period.
Differences among Storm Surge, Tsunami, Tidal Wave, and Tidal Bore:
| Phenomenon | Description |
|---|---|
| Storm Surge | A storm surge is an abnormal rise in sea level caused by a powerful storm, such as a hurricane or cyclone. It is primarily driven by wind and atmospheric pressure changes. |
| Tsunami | A tsunami is a series of ocean waves triggered by seismic activity, such as an earthquake, volcanic eruption, or underwater landslide. Tsunamis can travel across entire ocean basins and can cause significant destruction along coastlines. |
| Tidal Wave | The term “tidal wave” is often used interchangeably with “tsunami,” but it technically refers to the gravitational pull of the Moon and Sun, causing the rise and fall of tides. Tidal waves are predictable and occur daily. |
| Tidal Bore | A tidal bore is a surge of water that moves upstream against the flow of a river, typically occurring in estuaries or narrow channels. It is caused by the incoming tide meeting the outgoing river current. Tidal bores can create a visible wave or even a breaking wave as they propagate upstream. |
Difference between Sea, Swell, and Surf:
| Term | Description |
|---|---|
| Sea | Sea refers to the chaotic and irregular waves generated by local wind patterns within a given area. Seas are influenced by wind speed, duration, and fetch (the distance over which wind blows). |
| Swell | Swell refers to waves that have traveled out of their generating area and continue to propagate across the ocean. Swell waves have longer periods and more uniform shapes compared to seas. They often result from distant storms or winds over a vast expanse of ocean. |
| Surf | Surf is the wave action that occurs as swell or sea waves approach shallow water and interact with the seabed near the coastline. This interaction leads to the formation of breaking waves, commonly known as surf. |
Formation of Breakers:
Breakers are formed when waves encounter shallow water near the coastline. As waves approach shallow areas, the bottom of the wave starts to interact with the seafloor. The bottom part of the wave slows down due to friction with the seabed, causing the wave to become steeper and eventually topple forward, forming a breaking wave or breaker. The size and intensity of breakers depend on factors such as wave height, wave
steepness, seafloor slope, and coastal topography. Breakers can vary from gentle spilling waves to powerful plunging or surging waves, depending on the specific conditions of the coastline.
The Answer for Requirement Number 4
Here is a cross-section of underwater topography, illustrating the continental shelf, continental slope, and abyssal plain:
Explanation:
(a) Continental Shelf: The continental shelf is the gently sloping submerged portion of a continent that extends from the shoreline to the continental slope. It is relatively shallow and gradually slopes downward. The continental shelf is an extension of the land and varies in width, ranging from a few kilometers to hundreds of kilometers. It is rich in marine life and often contains important resources like oil and gas deposits.
(b) Continental Slope: The continental slope is a steeply sloping region that marks the transition between the continental shelf and the deep ocean floor. It is characterized by a sharp decrease in depth and a relatively steep gradient. The continental slope can extend to great depths and is often associated with underwater canyons and channels. Sediments and debris from the continental shelf are transported downslope by gravity, forming submarine fans or deltas.
(c) Abyssal Plain: The abyssal plain is a vast, relatively flat region of the deep ocean floor. It lies beyond the continental slope and is characterized by extremely low gradients and depths. Abyssal plains are typically covered with thick layers of fine-grained sediments, including clay, silt, and organic materials. They are the most extensive areas of the ocean floor and are largely devoid of significant topographic features, except for occasional seamounts or volcanic ridges.
The Answer for Requirement Number 5
Main Salts, Gases, and Nutrients in Seawater:
Salts in Seawater:
| Salt | Chemical Formula |
|---|---|
| Sodium chloride (NaCl) | |
| Magnesium chloride (MgCl2) | |
| Calcium sulfate (CaSO4) | |
| Potassium chloride (KCl) | |
| Sodium sulfate (Na2SO4) | |
| Calcium carbonate (CaCO3) |
Gases Dissolved in Seawater:
| Gas | Importance |
|---|---|
| Oxygen (O2) | Essential for marine organisms in respiration |
| Carbon dioxide (CO2) | Crucial for regulating the ocean’s acidity and part of the carbon cycle |
| Nitrogen (N2) | Plays a role in biological processes such as nitrogen fixation |
Nutrients in Seawater:
| Nutrient | Importance |
|---|---|
| Nitrate (NO3-) | Essential for the growth of marine plants (phytoplankton) and a key component of the nitrogen cycle |
| Phosphate (PO4-) | Critical for the growth of marine plants and the development of marine ecosystems |
| Silicate (SiO3-) | Essential for the formation of diatoms, a type of phytoplankton with intricate silica shells |
| Iron (Fe) | Necessary for the growth of certain marine plants and can be a limiting nutrient in certain regions of the ocean |
Important Properties of Water:
- Universal Solvent: Water is an excellent solvent, capable of dissolving a wide variety of substances due to its polar nature.
- High Heat Capacity: Water has a high heat capacity, meaning it can absorb and retain a significant amount of heat energy before experiencing a notable change in temperature. This property helps moderate coastal and marine temperatures.
- High Surface Tension: Water exhibits high surface tension, allowing it to form droplets and maintain cohesion, enabling capillary action and supporting the movement of water through plants and organisms.
- Density Anomaly: Water reaches its maximum density at approximately 4°C (39.2°F) before becoming less dense when it freezes. This anomaly allows ice to float and insulate the underlying water, supporting marine life during cold seasons.
- Unique Solid Phase: Water’s solid phase, ice, has a lower density than its liquid phase, causing it to expand and float. This property is crucial for the preservation of marine organisms in cold environments.
Effects of Animals and Plants on the Chemical Composition of Seawater:
Marine animals and plants significantly influence the chemical composition of seawater through various biological processes:
- Photosynthesis: Marine plants (phytoplankton, seaweeds) take in carbon dioxide (CO2) and release oxygen (O2) during photosynthesis, altering the dissolved gas concentrations in seawater.
- Respiration: Marine animals consume oxygen (O2) through respiration, leading to a decrease in oxygen concentration and an increase in carbon dioxide (CO2) concentration in surrounding water.
- Nutrient Uptake and Recycling: Marine plants and animals uptake nutrients like nitrate, phosphate, and iron from seawater for growth. Upon death or excretion, these nutrients are released back into the water, affecting nutrient availability and cycling.
- Calcification: Some marine organisms, like corals and shellfish, extract dissolved calcium (Ca2+) and carbonate (CO3-2) ions from seawater to build their shells or skeletons. This process can influence the carbonate chemistry and pH of seawater.
The Answer for Requirement Number 6
Biologically Important Properties of Seawater:
- Salinity: Salinity, the concentration of dissolved salts in seawater, influences the osmotic balance of marine organisms and affects their physiological processes.
- Temperature: Temperature affects the metabolic rates, growth, reproduction, and distribution of marine organisms. Different species have specific temperature ranges in which they thrive.
- Dissolved Oxygen: Oxygen availability in seawater is crucial for the survival of marine organisms. It supports respiration and aerobic metabolic processes.
- Nutrient Concentrations: Nutrients like nitrogen, phosphorus, and iron are essential for the growth and productivity of marine plants (phytoplankton) and form the basis of the oceanic food chain.
- pH and Carbonate Chemistry: The pH and carbonate chemistry of seawater influence the formation and growth of shells and skeletons of marine organisms, particularly those that rely on calcium carbonate.
- Light Penetration: Light availability determines the depth at which photosynthetic organisms can survive. It affects the growth and distribution of plants and influences the behavior and physiology of many marine animals.
Definitions and Examples:
- Benthos: Benthos refers to organisms that live on or near the seabed. They include plants, animals, and microorganisms adapted to various benthic habitats such as sandy or rocky substrates, coral reefs, and hydrothermal vents.Examples: Mussels, crabs, sea anemones, sea stars, sea cucumbers, kelp, sponges.
- Nekton: Nekton comprises free-swimming organisms that can actively move and control their horizontal movement in the water column, independent of currents. They are typically larger, more mobile organisms.Examples: Fish (e.g., tuna, sharks, herring), dolphins, whales, squid, sea turtles.
- Plankton: Plankton are small organisms that drift with ocean currents and are unable to swim against them. They can be divided into two main groups:
- Phytoplankton: Phytoplankton are microscopic, photosynthetic organisms (mostly algae) that form the base of the marine food chain. They convert sunlight, carbon dioxide, and nutrients into organic matter through photosynthesis.Examples: Diatoms, dinoflagellates, coccolithophores.
- Zooplankton: Zooplankton consists of small, heterotrophic organisms that feed on phytoplankton or other zooplankton. They include various types of microscopic animals and larval stages of larger organisms.Examples: Krill, copepods, jellyfish larvae.
Importance of Phytoplankton in the Oceanic Food Chain:
Phytoplankton are essential in the oceanic food chain as primary producers. They convert sunlight, carbon dioxide, and nutrients into organic matter through photosynthesis. The energy stored in phytoplankton is transferred to higher trophic levels through a series of feeding interactions:
- Primary Production: Phytoplankton convert inorganic carbon (CO2) into organic carbon compounds, producing oxygen as a byproduct. This process, known as primary production, forms the basis of the oceanic food web.
- Zooplankton Grazers: Zooplankton, such as copepods and krill, consume phytoplankton, directly transferring energy to higher trophic levels. They are known as primary consumers or herbivores.
- Secondary Consumers: Larger organisms, including fish, marine mammals, and birds, feed on zooplankton or other organisms that have consumed phytoplankton. They are classified as secondary consumers or carnivores.
- Tertiary Consumers: Apex predators, such as sharks or killer whales, occupy the top of the food chain and feed on smaller consumers. They indirectly rely on the energy derived from phytoplankton through the trophic levels below them.
The abundance and productivity of phytoplankton influence the entire marine ecosystem, from supporting fisheries to regulating global oxygen production and carbon cycling. They are crucial for sustaining life in the oceans and have a significant impact on Earth’s climate and atmospheric composition.
The Answer for Requirement Number 7a
I can provide you with information on common types of plankton that you might encounter during a plankton net tow. Here are three commonly observed types of plankton:
- Diatoms: Diatoms are a type of phytoplankton characterized by their intricate glass-like shells made of silica. They are diverse in shape and size and play a significant role in primary production. Diatoms are often found in both freshwater and marine environments.
- Copepods: Copepods are small crustaceans that belong to the zooplankton category. They are one of the most abundant and diverse groups of marine zooplankton. Copepods serve as important grazers in the food web, consuming phytoplankton and transferring energy to higher trophic levels.
- Radiolarians: Radiolarians are another group of marine zooplankton. They possess intricate, silica-based shells and exhibit diverse forms and structures. Radiolarians are known for their intricate and beautiful skeletons and play a role in nutrient cycling and carbon export in the ocean.
During your plankton net tow, it is common to find a wide range of planktonic organisms, including various types of phytoplankton and zooplankton. Examining the sample under a microscope or high-power glass will allow you to observe the different organisms present and identify their specific characteristics.
The Answer for Requirement Number 8c
Speech Outline: Why Oceanography Is Important
I. Introduction
A. Attention-Grabbing Opening
B. Introduce the Topic: Importance of Oceanography
II. Body
A. The Ocean and Earth’s Systems
1. Climate Regulation: Discuss the role of the ocean in regulating Earth’s climate, including heat absorption and carbon storage.
2. Weather Patterns: Explain how the ocean influences weather patterns, including the formation of storms and hurricanes.
B. Biodiversity and Ecosystems
1. Marine Life: Highlight the incredible diversity of marine species and the importance of studying and conserving marine ecosystems.
2. Fisheries and Food Security: Discuss the significance of the ocean as a source of food and the need for sustainable management practices.
C. Resources and Economy
1. Energy and Minerals: Explain the extraction of energy resources (e.g., offshore wind, wave energy) and minerals (e.g., oil, gas) from the ocean.
2. Blue Economy: Discuss the economic potential of ocean-based industries, such as tourism, aquaculture, and biotechnology.
D. Climate Change and Sea-Level Rise
1. Impacts of Climate Change: Address the role of the ocean in climate change, including temperature rise and ocean acidification.
2. Coastal Vulnerability: Discuss the potential consequences of sea-level rise on coastal communities, infrastructure, and ecosystems.
III. Conclusion
A. Summarize Key Points: Reinforce the importance of oceanography in understanding and addressing global challenges.
B. Call to Action: Encourage the troop to appreciate and protect our oceans, and consider exploring oceanography as a career path.
Note: It’s important to tailor the speech to the specific audience and add personal anecdotes or examples to make it engaging and relatable to the troop.
The Answer for Requirement Number 9
Methods Used by Marine Scientists to Investigate the Ocean, Underlying Geology, and Organisms:
| Method | Description |
|---|---|
| Sampling and Collection | Scientists use various tools and techniques to collect samples of water, sediment, and organisms from different depths and locations. This includes water sampling bottles, sediment corers, and trawls or nets for capturing marine life. Samples are then analyzed in the laboratory to study their composition, characteristics, and biodiversity. |
| Remote Sensing | Remote sensing involves the use of satellites, aircraft, and other platforms to gather information about the ocean from a distance. It provides data on ocean surface temperature, sea surface height, chlorophyll concentrations, and other parameters. Remote sensing enables the monitoring of large-scale oceanic processes and the detection of features like ocean currents, upwelling areas, and harmful algal blooms. |
| Sonar and Seismic Imaging | Sonar and seismic imaging techniques are used to explore the seafloor and underlying geology. Side-scan sonar systems provide high-resolution images of the seafloor, allowing scientists to map features like ridges, canyons, and seamounts. Seismic surveys utilize sound waves to create images of subsurface structures, helping researchers understand tectonic activity, fault lines, and sedimentary layers beneath the seafloor. |
| Remote Operated Vehicles (ROVs) and Autonomous Underwater Vehicles (AUVs) | ROVs and AUVs are unmanned, remotely operated or autonomous vehicles equipped with cameras, sensors, and sampling devices. They are used to explore deep-sea environments, collect high-definition imagery, and collect samples from extreme depths. These vehicles provide scientists with a means to study underwater ecosystems, hydrothermal vents, deep-sea organisms, and other inaccessible areas of the ocean. |
These are just a few examples of the methods employed by marine scientists to investigate the ocean, its geology, and the organisms living within it. Each method provides valuable data that contributes to our understanding of marine ecosystems, climate processes, and geologic dynamics.
