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OCEAN LITERACY
OCEAN LITERACY
Essential Principles & Fundamental Concepts of Ocean Science
PRINCIPLE 5
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ESSENTIAL PRINCIPLE 5
5
The ocean supports a great diversity
of life and ecosystems.
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5 | THE OCEAN SUPPORTS A GREAT DIVERSITY OF LIFE AND ECOSYSTEMS
5(a) Ocean life ranges in size from the smallest virus to the largest
animal that has lived on Earth, the blue whale.
Extremes
Ocean life is full of extremes with some of the smallest and largest
creatures found there.
Some of the smallest organisms found in the oceans include viruses,
bacteria and other microbes.
The largest creature that has ever lived on Earth is the blue whale.
Adult females are the largest and measure 33m (108 ft) in length.
Their tongue alone weighs the same as an elephant. The lion’s
mane jellyfish can also be very long reaching 30m (100 ft) in length.
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5 | THE OCEAN SUPPORTS A GREAT DIVERSITY OF LIFE AND ECOSYSTEMS
5(b) Most life in the ocean exists as microbes. Microbes are the
most important primary producers in the ocean. Not only are they
the most abundant life form in the ocean, they have extremely fast
growth rates and life cycles.
Primary Producers
Most life in the ocean exists as micro-organisms or microbes
including
bacteria,
blue-green
bacteria
and
plankton.
Microorganisms such as blue-green bacteria and phytoplankton
(plant plankton) are the most important primary producers in the
ocean. Not only are they the most abundant life form in the ocean,
they also have extremely fast growth rates and life cycles.
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5 | THE OCEAN SUPPORTS A GREAT DIVERSITY OF LIFE AND ECOSYSTEMS
5(c) Some major groups are found exclusively in the ocean. The
diversity of major groups of organisms is much greater in the ocean
than on land.
Diversity
We do not know how many species there are in the ocean or,
indeed, on Earth. Estimates range from a few million to as many as
30 million of which we only know a small fraction!
Biodiversity is a measure of the number of species in an ecosystem.
For example, there are many different species of fishes but only a
few species of sea otters. Fishes are, therefore, considered much
more diverse than sea otters. The diversity of major groups of
organisms is much greater in the ocean than on land with some
major groups found exclusively in the ocean.
One of the most diverse groups of animals in the ocean is the
crustaceans. The crustaceans consist of some 39,000 known
species distributed worldwide. Crabs, lobsters, and shrimps are
among the best-known crustaceans but the group also includes an
enormous variety of other forms.
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5 | THE OCEAN SUPPORTS A GREAT DIVERSITY OF LIFE AND ECOSYSTEMS
5(d) Ocean biology provides many unique examples of life cycles,
adaptations and important relationships among organisms
(symbiosis, predator-prey dynamics and energy transfer) that do not
occur on land.
Ocean Biology
Ocean biology provides many examples of life cycles, adaptations
and important relationships between organisms including symbiosis
and predator-prey dynamics.
Adaptation
An “adaptation” is a characteristic that generally increases an
organism's ability to survive within a changing environment. For
example, a fish’s mouth, teeth and jaws are adapted to the type of
diet that specific fish eats. A fish’s body shape, color, and various
appendages (e.g. barbels) are also adaptations.
Relationships
Food Pyramid – e.g. producers & consumers arranged in a hierarchy
Predator-Prey – e.g. more effective predators-more evasive prey
Symbiosis – e.g. clownfish/sea anemone, corals/zooxanthellae
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5 | THE OCEAN SUPPORTS A GREAT DIVERSITY OF LIFE AND ECOSYSTEMS
5(e) The ocean is three-dimensional, offering vast living space and
diverse habitats from the surface through the water column to the
seafloor. Most of the living space on Earth is in the ocean.
Living Space
3-D
Vast
Many diverse habitats from the surface to the seafloor
Most of the living space on Earth is in the ocean.
Life in the open ocean
Life in the deep ocean
However, this living space is “uneven”. Certain parts of the ocean
are more hostile and difficult to live in than others.
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5 | THE OCEAN SUPPORTS A GREAT DIVERSITY OF LIFE AND ECOSYSTEMS
5(f) Ocean habitats are defined by environmental factors. Due to
interactions of abiotic factors such as salinity, temperature, oxygen,
pH, light, nutrients, pressure, substrate and circulation, ocean life is
not evenly distributed temporally or spatially, i.e., it is “patchy”. Some
regions of the ocean support more diverse and abundant life than
anywhere on Earth, while much of the ocean is considered a desert.
“Patchy”
Ocean life is not evenly distributed temporally or spatially.
Temporal
For example, zooplankton migrate daily from the relative safety of
the deep to the surface at night. During the day, the zooplankton
move back. In addition, parts of the ocean experience seasonal
blooms of plankton. This is a time of abundance for predators.
However, this period is only temporary and, for the rest of the year,
pickings are much leaner. In order to survive, predators must adapt
by changing their diet or migrating to find other prey.
Spatial
Some regions of the ocean, such as coral reefs, support more
diverse and abundant life than anywhere on Earth while much of the
open ocean is considered a desert.
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5 | THE OCEAN SUPPORTS A GREAT DIVERSITY OF LIFE AND ECOSYSTEMS
5(g) There are deep ocean ecosystems that are independent of
energy from sunlight and photosynthetic organisms. Hydrothermal
vents, submarine hot springs, methane cold seeps, and whale falls
rely only on chemical energy and chemosynthetic organisms to
support life.
Deep Ocean Ecosystems
• Hydrothermal Vents
• Submarine Hot Springs
• Methane Cold Seeps
• Whale Falls
Different To “Normal” Ecosystems
Independent of energy from sunlight and photosynthetic organisms
Use chemical energy and chemosynthetic organisms
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5 | THE OCEAN SUPPORTS A GREAT DIVERSITY OF LIFE AND ECOSYSTEMS
5(h) Tides, waves and predation cause vertical zonation patterns
along the shore, influencing the distribution and diversity of
organisms.
Living Along Coasts
The coast is one of the most difficult habitats in which to live. Tides,
waves and predators cause vertical zonation patterns along the
shore, influencing the distribution and diversity of organisms.
Some of the challenges organisms face include:
1. Winds
2. Waves
3. Currents
4. Temperature changes
5. Salinity changes
6. Drying out as the tide recedes
7. Predation
Different life inhabits rocky coasts, sandy coasts and estuaries, with
estuaries providing important and productive nursery areas for many
marine and aquatic species. Each type of coast presents a different
set of challenges to the animals and plants that lives there.
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5 | THE OCEAN SUPPORTS A GREAT DIVERSITY OF LIFE AND ECOSYSTEMS
5(i) Estuaries provide important and productive nursery areas for
many marine and aquatic species.
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