Download Individual Lesson Descriptions 19

OC15 Introduction to Oceanography
Lessons 11- 25: Summaries and Questions
Dr. J. Anastasia
Lesson 11: Going with the Flow
The world ocean contains a number of very large currents that are found at the surface and at depths.
Surface currents transfer water and heat from tropical to polar regions and influence weather, climate, and
upper-water biological activity. These wind-pushed water masses tend to form in the major ocean basins
and to “pile up” in their windward direction, establishing a pressure gradient. The Coriolis effect deflects
surface currents to the right or left depending on the hemi-sphere, and a circular flow pattern is established.
This pattern is modified by the continental boundaries of each ocean basin, and a balance is reached
between the pressure gradient and the Coriolis effect creating a geostrophic gyre. There are five great
geostrophic gyres in the world ocean, each characterized by the configuration of its basin. A sixth great
circumglobal current moves around Antarctica, unaffected by basin boundaries. The Ekman circuit of
water movement is a complex interaction between the wind-driven surface waters and thin, sequential
layers of water extending down to about 100 meters. While the water is driven by the wind it is also subject
to the Coriolis effect, moving each layer at about 45° from the one above it, establishing a spiral pattern
within this water column called the Ekman spiral. All of this comes together to form and move these gyres,
transporting water and heat poleward. Alterations in the normal flow can affect water mass characteristics
and cause changes in weather patterns. In order to better understand and predict these atmosphere/sea
surface interactions, more must be know about surface currents. Accurate and long-term measurements are
difficult to obtain, but current technology is making progress.
Questions to Answer:
1. List and briefly discuss the physical factors that cause surface currents.
2. Describe the characteristics and dynamics of the geostrophic gyre, including the effects of wind, Coriolis
effect, gravity, and the ocean basin boundary.
3. List and be able to locate on a map the six great surface currents of the world ocean.
4. Compare and contrast the characteristics of the eastern and western boundary currents.
5. How are the surface currents involved in the poleward transfer of water and heat?
6. List and describe, briefly and in order, the events leading to an ENSO event and the effect that ENSO
events have.
Lesson 12: Deep Connections
Movement of surface water is wind-powered; movement of water beneath the pycnocline is density
propelled, and is called the thermohaline circulation. This slow-moving mechanism involves both vertical
and horizontal patterns. Once formed, most water masses move and many sink, but all retain the “history”
of their formation over long distances and long periods of time. The Antarctic Bottom Water is the most
dense in the world ocean and is remarkable for its rapid rate of formation and its massive movement toward
the equator. Thermohaline circulation plays a major role in global heat transfer, and has been given added
importance as a possible component in the phenomenon of global warming. In addition to heat transfer,
these major water masses are also important in the distribution of dissolved gases and nutrients. The
methodology for studying ocean currents has become more accurate and technologically complex over
time. Certain chemicals and isotopes released in the past have been used as chemical tracers to study time
frames involved in atmosphere and sea surface interaction because their release times are generally known.
Some marine organisms can also act as indicators of past water mass formation and composition.
Questions to Answer:
1. Describe and characterize the three basic oceanic water masses (the layers in the ocean: surface or mixed
layer, pycnocline and deep layer).
2. What two factors affect the density of sea water and how do they affect density?
3. Describe where, and under what conditions, the ocean’s water masses are formed, how they retain a
history of that formation over time, and how they eventually lose it.
4. Describe and discuss the Antarctic Bottom Water—its formation, characteristics, and migration.
5. Explain the basic thermohaline circulation patterns and mechanisms, including what happens when
different water masses encounter each other.
6. Describe the roles played by both thermohaline flow and surface flow in the transferring heat around the
globe.
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OC15 Introduction to Oceanography
Lessons 11- 25: Summaries and Questions
Dr. J. Anastasia
Lesson 13: Surf’s Up
Broadly defined, a wave is a disturbance caused by the movement of energy from a source through a
medium. When wind contacts the ocean surface, some of its energy is transferred to the water beneath,
causing it to move in an orbital pattern and creating the wave form. As a general rule, the speed of a wave
is related to its wavelength—the longer the wavelength the faster the energy will move through the water.
Wind is a major disturbing force, but waves can also be formed by earthquakes, landslides, erupting
volcanoes, and tides. Most of the energy involved in large storm waves originates in the Southern
Hemisphere and around the equator, and then moves northward. Subsurface internal waves form where
density-different water masses meet, usually at a deep thermocline. Internal waves are important in
transporting and mixing natural nutrients which, in turn, affect midwater and coastal plankton populations.
World War II increased the importance of wave study because of the need to plan amphibious landings; the
study has continued to be important, encouraged by technological innovations. Knowledge of wave
formation and propagation helps in monitoring nutrient dispersal, movement of pollutants, and the global
carbon budget.
Questions to Answer:
1. Describe how water moves as a wind wave passes through it.
2. Explain how waves are classified and named based on the strength and character of the forces that affect
them.
3. Define each of the following terms used in describing wind waves and their effects—wave length, wave
height, crest-and-trough, surf, period and frequency.
4. Describe the chronological sequence of events that occur from the time a deep-water wave begins to
approach a shore until it breaks as surf.
5. Briefly discuss the refraction exhibited by waves as they encounter a shoreline.
Lesson 14: Look Out Below
Wind is not the only disturbing force. Earthquakes, cyclones, and tidal effects can also cause large waves,
many of which will impact shorelines causing damage and loss of life. These “immense” waves include
storm surge, seiches, and tsunami. Storm surge is often produced when low atmospheric pressure forms a
“dome” of water at the center of a hurricane. Strong winds add to that dome and move it shoreward, where
it can move onto land as a high, fast-moving water mass. A seiche is a type of standing wave that can result
when a progressive wave encounters a vertical barrier and is reflected back from the obstruction. On an
open coast the effect is usually negligible, but in an enclosed or semi-enclosed space like a lake, bay, or
harbor, it can result in a standing wave large enough to cause shoreline damage and interfere with shipping.
Tsunami are probably the best-known and most feared of the immense wave types. They can result from
any disturbing force that causes direct displacement of the sea surface—undersea earth-quakes, landslides,
volcanic activity, or calving glaciers—and are common along the tectonically-active subduction zones of
the Pacific Rim. Globally-oriented sea level fluctuations have occurred over geologic time, but the present
pattern appears to be more rapid. Scientists are addressing this concern from several directions— by
analysis of past sea-level rises, the monitoring of changes in the physical ocean, and satellite-carried sea
surface elevation recorders.
Questions to Answer:
1. Describe the three types of immense waves—storm surge, seiche, and tsunami—and the disturbing
forces that cause them.
2. Describe the seismic sea wave—its formation, behavior, and impact on a shoreline.
3. What are some of the present concerns about rising sea levels and their association with global warming?
Lesson 15: Ebb and Flow
Tides are defined as periodic, short-lived changes in sea level, controlled by the combined gravitational
force of the sun and moon, and by Earth’s motion. The rhythmic rise and fall of water levels, especially
along continental coasts, has been noted and studied since the earliest seafaring civilizations. To
thoroughly explain Earth’s tides, Newton’s (1687) equilibrium model and Laplace’s (1775) dynamic theory
must be considered. Spring tides occur when the sun, moon, and Earth are in line, causing exaggerated
height differences between successive high and low tides. If the bodies are at right angles there is less
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OC15 Introduction to Oceanography
Lessons 11- 25: Summaries and Questions
Dr. J. Anastasia
difference between high and low tides; these are the neap tides. Tidal cycles vary in different coastal
regions. When studying and predicting tidal phenomena, it is necessary to have a standard reference point
from which to measure, which is usually based on the historical means of low water and is called the zero
point or tidal datum. The tidal phenomenon is associated with a lot of energy, most of which is dissipated
as heat. This has been of interest as a potential power source, and has been successfully exploited by
several countries.
Questions to Answer:
1. Describe the contributions of Newton and Laplace in describing and explaining the tidal phenomenon.
2. Explain the roles of gravity and inertia (centrifugal force) as they affect the formation of the tidal bulges
(the formation of the crest/trough configuration of the tidal “wave”)
3. Explains what causes the daily high-tide/low-tide fluctuations and what causes the differences between
spring and neap tides.
4. Define the terms tidal range, ebb current, flood current and slack water.
5. List the pros and cons of using the tides as a source of power.
6. Characterize the basic intertidal zone that is inhabited by marine organisms.
Lesson 16: On the Coast
The terms beach, shore, and coast are used almost interchangeably to describe the junction where the land
meets the ocean. A universal classification of the coastal zone is difficult to find since a variety of
descriptive terms have been developed by oceanographers over time. With the acceptance of plate tectonic
theory the terminology has been modified to include the characteristics of those areas affected by tectonic
activity. Oceanographer Francis Shepard introduced the idea of primary and secondary coasts. A highenergy coast has much wave action and rapid erosion while a low-energy coast is less active.
Oceanographically speaking, a beach is a feature of secondary coasts, formed by some kind of sediment
covering all or part of a shore. Coastal and nearshore features may also be a result of biological activity,
such as coral reefs. The three basic U.S. coasts—Pacific, Atlantic, and Gulf—have different histories and
features. The Pacific Coast is tectonically active, while the Atlantic is more gentle. The Gulf Coast is most
influenced by the activities of man, such as dredging and oil/gas removal. A steady migration to the coasts
since the 1950s is causing concern in the United States about the impact of this population surge on the
coastal resources and natural ecosystems. Coastal management plans are in development for many coastal
areas, combining input from national, state, and local governments, sociologists and coastal engineers, and
ecologists.
Questions to Answer:
1. Characterize the basic differences in appearance, structure, and dynamics between the three main U.S.
coasts—Pacific, Atlantic, Gulf.
2. Discuss the general concept of a beach (as opposed to other shoreline structures), and describe the
terminology used to describe the various beach shapes and slopes (winter vs summer profile), features
(dunes, berm, scarp, low tide terrace, sandbars) and material compositions (sediment sizes).
3. Describe the major points of controversy and discussion relating to human interaction with natural
coastlines, and some of the possible management solutions and strategies.
Lesson 17: Due West
This lesson is based on case studies done at four locations along the southern California coast. All
the sites have some concerns in common, but each has problems that are unique to its location. The four
studies focus on the natural structures and processes of their area, and the effects of human interaction and
population growth on them. The northernmost site is the man-made Ventura Marina in the city of Ventura.
This harbor was built in the 1950s with apparently little or no consideration of the natural longshore
processes that move sand from the upcoast beaches to those downcoast. Point Mugu Naval Air Station is
an example of human impact on one of the largest southern California wetlands and its resident and
migratory waterfowl populations and their habitats. The United States Navy is attempting to mitigate those
impacts while carrying out their military mission. Downcoast, the Malibu area is well known as a location
for the wealthy to build homes on the cliffs overlooking the ocean. This urbanization has caused the
contamination of the Malibu Lagoon by septic tank effluent overflow, and created the potential for major
landslides where the homes are located. Further south, the town of Laguna Beach and its adjacent Aliso
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OC15 Introduction to Oceanography
Lessons 11- 25: Summaries and Questions
Dr. J. Anastasia
Creek are studied. While the coastal geology in the area is fairly stable, the urbanization along the Aliso
Creek watershed has significantly altered the soil conditions and processes, resulting in significant erosion
of the creek bed, the flow of pollutants into marine ecosystems, and the threat of bacterial contamination to
nearby beaches. Each of these locations has its own peculiar concerns, but they all share the need for more
governmental and regulatory agency involvement at all political levels, as well as the best coastal
ecologists and geologists to study the issues and provide the data necessary to address the problems and
take the steps to correct them.
Questions to Answer:
1. Characterize each of the four southern California study sites, in terms of location, general
physiography, and geology.
2. Describe and explain, for each case site, the human factors and their potential impacts and effects,
including urbanization, contamination runoff, and road-building.
3. Discuss the plans or processes being used or considered to mitigate the negative effects of human
intervention for each case study.
4. Identify and discuss the various levels of involvement of area residents, regulatory agencies, politicians,
and scientists, in addressing the problems and concerns of each location studied.
Lesson 18: Building Blocks
This is the first of several lessons about ocean life. A minimalist definition of life developed by NASA is:
“Life is a self-sustained chemical system that is capable of undergoing Darwinian evolution.” Three of the
most important ideas of biology are that biology is explicable via the laws of physics and chemistry; that
living things are composed of cells; and that living things evolve by natural selection. Evolution by natural
selection is biology’s most important unifying concept, an idea proposed by Darwin and Wallace in 1859.
Diversity is an obvious feature of life. Less obvious is life’s underlying biochemical unity. The linkage
between DNA translated into proteins, which then orchestrate the processes of life
(DNRNProteinLife) is fundamental to all life. Living things are highly organized and selfregulating and they utilize energy, cycle matter, reproduce, and evolve. How and where life began is
vigorously debated. The idea that simple organic molecules accumulated in the oceans and led to the origin
of life—the pre-biotic soup hypothesis—is a popular belief. However it began, life is a chemical system in
which matter and energy interact according to the laws of physics and chemistry. Today, four billion years
of amplification, mutation, and selection has brought us Earth’s approximately five million extant species
and innumerable extinct ones.
Questions to Answer:
1. Define life and discuss scientific hypotheses about how it might have begun.
2. Outline the theory of evolution by natural selection and discuss its importance in biology in general, and
biological oceanography in particular.
Lesson 19: Water World
The marine environment is complex and its biodiversity great. Systems of classification help in dealing
with this complexity by fostering organization, communication, and understanding. Marine organisms are
classified by their evolutionary relationships, ecological relationships, and behavior. Aristotle was
classifying organisms 2,300 years ago, but modern taxonomic classification stems from Linnaeus, an
eighteenth century Swedish botanist. Taxonomists currently divide life into six kingdoms. The Archaea and
Bacteria are unicellular prokaryotes. The four eukaryotic kingdoms are the Protista, Fungi, Plantae, and
Animalia. It is widely held in biology that each species occupies a unique niche, a multidimensional
description of where an organism lives and all the factors that affect its survival. Particular factors present
in intolerable amounts are called limiting factors. Organisms flourish within their optimal ranges of
tolerance, are under stress at higher or lower rages, and perish outside the high and low extremes of
tolerance. Each species requires a proper mix of physical, chemical, and biological factors to survive and
flourish. Both terrestrial and marine organisms are composed largely of slightly salty water but marine
species are also surrounded by slightly salty water and terrestrial organisms are surrounded with air.
The difference is striking and the peculiar forms of life in the sea, along with their adaptations to this alien
world perhaps explains the widespread interest in marine biology.
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OC15 Introduction to Oceanography
Lessons 11- 25: Summaries and Questions
Dr. J. Anastasia
Questions to Answer:
1. Discuss the physical limiting factors—light, temperature, salinity, dissolved nutrients and gasses, pH,
and hydrostatic pressure—as they relate to marine life.
2. Define osmosis and discuss its importance to life in the sea.
3. Discuss the relationships between viscosity and movement. Explain some adaptations organisms have to
deal with this problem.
4. Describe how the marine environment is classified on the basis of light penetration and on the basis of
location.
Lesson 20: Food for Thought
Marine biology is fueled by phytoplankton. These microscopic, unicellular organisms are the major
photosynthesizers of the oceans, producing 90 to 96 percent of the ocean’s food. The rate of production
measures how rapidly glucose is being manufactured. As light penetrates the ocean it diminishes.
The depth at which respiration and gross production are equal is the compensation depth. Two major
factors—light and nutrients—limit primary production in the ocean. Patterns of primary production
distinguish tropical, temper-ate, and polar regions. A well established tropical thermocline traps nutrients
below, preventing high rates of productivity over much of the open tropics. Polar regions lack a permanent
ther-mocline, so light is the critical factor regulating productivity. There is a spike of production in the
well-lit polar summer. The temperate zone has a seasonal thermocline. Diatoms and dinoflagellates are
larger phy-toplankton and have long been known to be major ocean producers. Previously overlooked tiny
species are called nanoplankton, picoplankton, and even ultraplankton include certain cyanobacteria and
other prokaryotes whose discovery has revolutionized science’s understanding of marine primary
production. Their numbers are staggering and they may be responsible for as much as 70 percent
of the primary production in some ocean regions.
Questions to Answer:
1. Define the term primary production, explain how it is measured and describe its importance.
2. Define phytoplankton and zooplankton
3. Compare and contrast diatoms and dinoflagellates and discuss the role of dinoflagellates in
harmful algal blooms. (in text)
4. Compare how light and nutrients interact to produce the general seasonal patterns of primary
production in tropical, temperate, and polar oceans.
5. Compare and contrast foraminifera, copepods, and krill. (in text)
6. Outline the major groups of macroalgae (seaweeds) and angiosperms (vascular plants) and discuss their
role in marine primary production.
Lesson 21: Survivors
One of a number of current theories on the origin of life is that it originated in the ocean, and that the first
organisms probably fed on organic molecules synthesized in the ocean water. According to this theory,
some organisms acquired the ability to gather and store energy from the sun by photo-synthesis, and to
release free oxygen into the atmosphere as a part of that process. This caused the atmospheric oxygen
content to rise to about 20 percent, which facilitated the rapid evolution of a great variety of life forms.
These simple animal-like organisms evolved in complexity and increased in numbers, eventually forming
the complex, multi-cellular organisms we now call animals. In attempting to classify both fossil and
present-day animals, the term phylum is used to group organisms having similar body forms and
characteristics. Within these groups are more specific subdivisions. More than 90 percent of all animals,
fossil and living, are classified as invertebrates, and are represented by about 33 very diverse phyla.
Nowhere is their adaptability and survivability more evident than in the inter-tidal zone. Invertebrates that
live in this environment have evolved a multitude of ways to survive the extreme conditions. This lesson
gives some examples of organisms in the better-known marine invertebrate.
— jelly fish from the Phylum Cnidaria
— cephalopods (squids and octopus) from the phylum Mollusca
— crustaceans (krill, shrimp, crabs and lobsters) from the Phylum Arthropoda
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OC15 Introduction to Oceanography
Lessons 11- 25: Summaries and Questions
Dr. J. Anastasia
— seasquirts, salps and larvaceans from the Phylum Chordata
Questions to Answer:
1. Describe Earth’s earliest life forms, and how they got their energy.
2. Describe how photosynthetic organisms relate to the oxygen revolution and the evolution of early
animals.
3. Define the term invertebrate as it is used to describe groups of animals, both living and fossil.
4. Discuss the organisms (see list above) presented in this lesson, noting their basic taxonomy, ecology, and
unique structural characteristics.
5. Describe the intertidal zone of the marine environment, including both rocky and sandy/muddy shores—
what physical conditions prevail there, and how the organisms that live there survive.
Lesson 22: Life Goes On
This lesson deals primarily with the marine vertebrates, which dominate the phylum Chordata. Chordates
have three salient anatomical characteristics—a dorsal notochord, a dorsal tubular nerve cord, and
pharyngeal gill slits. Invertebrate chordates include the sessile, gill-feeding sea squirts whose microscopic
tadpole larvae clearly exhibit all three chordate characteristics. Another invertebrate chordate is
Amphioxus. This transitional form more closely resembles a fish as an adult, demonstrates the chordate
characteristics, and also uses its gill slits to feed. Life in the aquatic world has shaped the evolution of fish
differently than that of their terrestrial relatives, the reptiles, birds, and mammals. Water is denser, more
viscous, and has different thermal properties and less oxygen than air. Ectothermy, and hydrodynamic and
respiratory adaptations resulted. Adaptations for defense and offense in active mobile organisms such as
fish include well developed sensory structures and camouflage. Amphibians are almost totally absent from
the marine environment because their skin is semipermeable and they cannot tolerate the ocean’s salt. The
partly aquatic amphibians gave rise to the first truly terrestrial vertebrates, the reptiles. The reptiles, in turn,
gave rise to both the mammals and the birds. Reptiles, birds, and mammals all have members that have reentered the aquatic world.
Questions to Answer:
1. Describe the three features of the chordate body plan and contrast the two groups of invertebrate
chordates (sea squirts and Amphioxus).
2 Describe the two classes of fishes discussed in the text.
3. Discuss the problems that fish face and some adaptations that they use to overcome these problems (ex:
swim bladder, countershading)
4. Discuss the general characteristics of the class Mammalia and discuss four features shared by marine
mammals.
5. Describe the three orders of marine mammals and discuss the major groups within each order.
Lesson 23: Living Together
Ecology studies the interactions of populations and attempts to explain the distribution and abundance of
organisms. This involves understanding biological interrelationships such as competition, predation,
symbiosis, and physical limiting factors such as light, temperature, and salinity. Both competition and
predation can be intraspecific or interspecific. Less obvious than predation and competition, but pervasive
in community structure is symbiosis including mutualism, commensalism, and parasitism. A new species
introduced into an environment with infinite resources will exhibit J-shaped population growth. As the
population grows it will encounter environmental resistance from factors such as competition for food,
disease, and predation, increasing the death rate. The population levels off at some maximum size that the
environment can sustain. At carrying capacity, births and deaths are approximately in balance. Although it
is exposed to a constant pounding of waves, the rocky intertidal is a place of abundant life. In contrast to
the densely-populated rocky intertidal, life is sparse on cobble, gravel, and sandy shores where pounding
stones and scouring sands and gravels create some of the harshest conditions for marine life. Protected
beaches are much more hospitable. The low-energy waves allow the accumulation of silt and clay muds.
Nutrients are delivered continuously from land drainage and the shallow water is generally well mixed.
Estuaries and coral reefs are both shallow, near-shore communities that are highly productive and highly
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OC15 Introduction to Oceanography
Lessons 11- 25: Summaries and Questions
Dr. J. Anastasia
impacted by human activity. Most of the ocean floor is sparsely populated with life. It is an extensive,
constant, cold, aphotic, hypersaline, hyperbaric environment that depends on a drizzle of particulate organic
food from the photic zone above. The hydrothermal vent community is also an abyssal benthic community
but is, by contrast, highly productive and rich in life. The primary production of the vent community is
accomplished by chemosynthetic bacteria and archaea using energy from sulfide and methane molecules to
manufacture carbohydrates. Less than one percent of the ocean’s life is found deeper than 3,000 meters.
The bathypelagic zone is often hypoxic and there is no light, no photosynthesis, no chemosynthesis and
almost no life. The creatures of this region include some of Earth’s strangest.
Questions to Answer:
1. Define community and relate the terms niche, habitat, and biodiversity to the study of communities.
2 Compare competition within a species and competition between species and explain how these regulate
the distributions of barnacles and limpets (in text) in the rocky intertidal community.
3. Describe the major features of each of the following communities and be prepared to compare and
contrast any one of these with the others.
a. rocky intertidal
b. salt marsh/estuary
c. coral reef
d. hydrothermal vent/cold seep
Lesson 24: Treasure Trove
This lesson surveys the major physical, biological, energy, and nonextractive resources of the oceans and
details their economic worth, means of extraction, distribution, abundance, present status, and future
prospects. Oil and natural gas are the ocean’s most valuable mineral resources. Extraction is often
controversial because it can damage beaches, increase the water’s turbidity, increase shoreline erosion, and
damage habitat. Other physical resources include several sea salts, which are collected profitably by
evaporation or other extractive processes. Sea-water is also rich in magnesium and various magnesium
compounds. Potable water is becoming a scarce commodity and this situation is likely to worsen.
Desalination of seawater by evaporation, freezing, and reverse osmosis will become an ever-increasing
necessity to supply our fresh water as existing sources of ground water, streams, rivers, and lakes are
depleted or polluted. Energy of the motion of waves, currents, and tides can be harnessed to generate
electricity but is not presently competitive with traditional generation modes. The ocean’s biological
resources are renewable, but demand has resulted in widespread overfishing. Mariculture is a rapidly
growing enterprise. Historically, fisheries are a common property resource so management and
conservation are difficult. Other marine bio-resources include fur-bearing mammals, seaweeds, algae, and
other marine organisms. Damage to marine ecosystems is probably at or close to crisis levels in most parts
of the world ocean. A rational, enforceable, international law of the sea is necessary.
Questions to Answer:
1. Distinguish among marine physical, biological, energy, and nonextractive resources and give several
examples of each. Describe the characteristics and extent of utilization of each resource.
2. Discuss fisheries and their management including the concepts of maximum sustainable yield,
overfishing, bykill, and marine sanctuaries.
3. Describe, discuss, and compare aquaculture, mariculture, and marine ranching.
Lesson 25: Dirty Water
Marine pollution deals with the effect of pollutants on the ocean environments, recognizing that
there are both natural and human-generated materials involved and that the controlling factors are the
amounts of these pollutants being introduced into the ocean and the ability of the ocean’s ecosystems to
deal with them. Even where natural materials are involved, excessive amounts can be problematic.
Depending on the types of pollutants involved and the characteristics of the ecosystem affected, cleanup or
mitigation can be more damaging than the actual event. Although oil spills tend to get the most attention,
other types of pollution are also of concern. Synthetic chemicals are especially dangerous because they
tend to resist natural degradation, remaining in the food web and working their way through the food chains
to the higher trophic levels. Eutrophication is a process that involves nutrients, either natural or introduced,
that enter an ecosystem in excessive amounts, upsetting the natural balances of the system and causing
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OC15 Introduction to Oceanography
Lessons 11- 25: Summaries and Questions
Dr. J. Anastasia
certain organisms to grow and spread abnormally, often to the detriment of other species. Coastal power
plants contribute significant pollution through the disposal of waste heat energy, which can significantly
affect nearshore ecosystems over a period of time. A new concern is exotic or introduced species that are
introduced when ships fill their ballast tanks at their home ports, then discharge the ballast water at their
destination port, transporting marine organisms into “foreign” waters, where they often overrun the resident
species. Of even broader concern are the processes of ozone layer depletion and global warming.
Questions to Answer:
1. Discuss oil pollution—types of polluting agents, their sources, and the habitats and organisms affected.
2. Define and explain eutrophication, including the substances involved, their sources, and how organisms
and habitats are affected.
3. Explain the concept of biological amplification using organic pollutants (such as DDT or PCBs) as an
example.
4. Explain the concepts of environmental alteration at the global level, especially ozone layer depletion,
global warming/greenhouse effect, sea level rise.
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