WELCOME TO THE RESOURCE REEF!
Here you will find recorded interactive webinars with marine experts. You'll learn about ocean zones and the animals that live in each one. Explore the anatomy of sharks and how coral reefs are formed. Scroll down to get started!
OUR LIVING SEA
A rich assortment of living things calls the ocean home. Big and small, long and short, multicolored and drab, active and inactive, sea life ranges from microscopic plankton to the largest creatures on Earth. Some organisms even light up, like ghostly neon lights.
When you hear the word “animal,” chances are that you think of a dog, a cat, a bear, or a squirrel. And you’re right, of course. Sometimes, though, the word “animal” is used in its scientific meaning. To a scientist, the word covers a much broader field. It includes insects, birds, fish, amphibians, reptiles, shellfish, worms, and many other living things. In fact, it includes everything that can move on its own power and a few creatures that can’t. The sponge, for example, spends its whole adult life attached to the bottom of the ocean, but it is an animal.
Why? Because it does not manufacture its own food. Light in combination with chlorophyll,
the substance that gives grass and other vegetation its green color, enables plants to make
sugars from water and carbon dioxide. Animals cannot do this. But when we get down to
the simplest living organisms, even scientists can’t always agree on whether they are plants
or animals. We can say that:
Most animals move on their own; plants cannot.
All green plants make their food; animals cannot.
Most plants have cellulose cell walls; animals do not.
ZONES OF LIFE
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.
The epipelagic zone — more commonly called the sunlit zone—is the top section of the ocean. This is the only section shallow enough for sunlight to penetrate, allowing photosynthesis to take place.
The mesopelagic zone — also called the twilight zone—is dimly lit. There are no plants in this zone because it does notget enough sunlight to generate photosynthesis.
HOVER OVER ME!
Some call the bathypelagic zone the midnight zone. No sunlight penetrates this area of the ocean because it’s too deep—about 21/2 miles down. The only light that this deep ocean layer gets comes from bioluminescent marine life.
In the abyssal zone, the ocean’s lowest layer, it is pitch-black and—since it is unaffected by weather— calm. The temperature is nearly freezing at this depth, around 6,600 to 20,000 feet (2,012 to 6,096 meters) below the ocean’s surface.
The hadal zone comprises the ocean’s deepest waters, found in its narrow trench walls and floors—some deeper than 6 miles (nearly 10 kilometers)
ANIMALS IN THE HIGH SEAS
Humpback whales are known for their magical songs, which travel for great distances through the world's oceans. These sequences of moans, howls, cries, and other noises are quite complex and often continue for hours on end. Scientists are studying these sounds to decipher their meaning. It is most likely that humpbacks sing to communicate with others and to attract potential mates.
Atlantic mackerel have a slender, streamlined body that narrows towards a strongly forked tail. Their back has a bright, metallic-blue to green colour that becomes a lighter silver on the sides and white on their belly. They can be distinguished by dark, wavy vertical bars that start on their back and, like most other forage fish, have a protruding lower jaw.
Jellyfish have drifted along on ocean currents for millions of years, even before dinosaurs lived on the Earth. The jellylike creatures pulse along on ocean currents and are abundant in cold and warm ocean water, in deep water, and along coastlines. But despite their name, jellyfish aren't actually fish—they're invertebrates, or animals with no backbones.
PACIFIC BLUEFIN TUNA
At up to 10 feet long and weighing over half a ton, Pacific bluefin tuna are among the world’s largest fish. These tuna are highly prized on the seafood market and can sell for tens of thousands of dollars apiece. Now, just a fraction of Pacific bluefin tuna populations remain.
Like rays and skates, sharks fall into a subclass of fish called elasmobranchii. Species in this subclass have skeletons made from cartilage, not bone, and have five to seven gill slits on each side of their heads (most other fish have only one gill slit on each side), which they use to filter oxygen from the water.
Wandering Albatrosses make shallow dives when hunting. They’ll also attempt to eat almost anything they come across and will follow ships in the hopes of feeding on its garbage. They can gorge themselves so much that they become unable to fly and just have to float on the water.
ALL ABOUT SHARKS
Sharks are fishes and most have the typical fusiform body shape. Like other fishes, sharks are ectothermic (cold-blooded), live in water, have fins, and breathe with gills. However, sharks differ from Osteichthyes fish. One difference is that a shark's skeleton is made of cartilage instead of bone. Another visible difference is that bony fish tend to have a single gill slit, whereas all but two species of shark have 5 gill slits.
FAST FACTS ABOUT SHARKS
Sharks live all over the world, from warm, tropical lagoons to polar seas. Some even inhabit freshwater lakes and rivers!
Sharks are fishes. Like other fishes, sharks are cold-blooded, have fins, live in the water, and breathe with gills. A shark's skeleton is made of cartilage.
A shark's fusiform (rounded and tapering at both ends) body shape reduces drag and requires minimum energy to swim.
Sharks eat far less than most people imagine. Cold-blooded animals have a much lower metabolism than warm-blooded animals. In fact, in a zoological environment, a shark eats about 1-10% of its total body weight each week. Studies on sharks in the wild show similar food intake.
Only 32 (of roughly 350) shark species have ever been known to attack people. Like other wild animals, most sharks would rather avoid you. Sharks that have attacked probably mistook people for food or may have attacked to protect their territory.
Unlike bony fish, sharks teeth are not anchored in their jaw and sharks often lose teeth, especially when feeding. Sharks are equipped with three or more rows of teeth, so when a tooth is lost another tooth quickly replaces it. A single shark may have as many as 30,000 teeth throughout the course of its life.
WEBINAR WITH SHARK EXPERT
Click below to find the recorded webinar with marine biologist and shark expert, Susana Ramirez.
Susana Ramirez grew up around the water, and always had a deep passion for
the ocean and its' inhabitants. While doing her undergraduate studies, Susana
helped graduate students with shark research in the everglades. It was during
that time that she fell in love with sharks, and she vowed to do all that she
could to help the animals out. She has since volunteered for many non-profit
organizations and has gained valuable knowledge about grassroots
campaigning. In 2014, she officially ran Save The Sharks full time, and has had a great deal of success. Susana has been a part of CITES implementations, she has led local and international rallies, school presentations, she has written for magazines and much more. Her hope is that Save The Sharks can inspire anyone to do something; because together, we can make a difference.
Aquatic ecosystems are an umbrella term for all ecosystems that exist in water. Aquatic Ecosystems, in simple terms, is an ecosystem type that depends on water (both marine and freshwater) most or part of the time. A scientist who studies inland water ecosystems (limnology) is called a limnologist. The opposite will be terrestrial ecosystems, which are all ecosystems that exist on land.
Water-based ecosystems can be put into two main groups, namely Freshwater Ecosystems and Marine Ecosystems. Marine Ecosystems describe the biotic and abiotic interactions that occur in the oceans. Marine waters are very different from freshwaters because of the high salt content of seawater. Freshwater ecosystems include two major categories, Lentic and Lotic Systems. Lentic systems describe all standing water ecosystems. Lotic systems describe all flowing water ecosystems. In both Lentic and Lotic ecosystems, abiotic factors such as light, temperature, pH, alkalinity, pressure, depth, etc. of the water are key and determine what kind of living and non-living interactions can exist there.
In all the above water types, living activities occur in different zones: such as the surface of the waters, middle parts, and at the bottom of the water. The scientific names for life forms in the water are Plankton, Nekton, and Benthos. Then, there are also interactions on the surface of and along these waters. As you can tell already, there are complex food webs that exist in aquatic ecosystems.
What are ways you can help aquatic ecosystems and wetlands?
THE BALANCE OF NATURE
When you figure out the food chain in an ecosystem, you can see how animals, plants, and their habitat are connected. The ecosystem is in balance when all the necessary parts of its community are present. The ecosystem is out of balance when there is not enough habitat and food for animals to survive.
After some natural events, like a forest fire started by lightning, the original ecosystem may slowly recover. Nature eventually adjusts the balance. The needs and plans of humans often alter the balance of nature quickly and permanently. When people clear forest and brush and turn it into agricultural land, much of the animal life may disappear from the area, except for animals that can adapt to the farming environment. When a huge shopping center is built and surrounded by a paved parking lot, animals cannot adapt to that environment. Pollution of air or water can damage or wipe out an ecosystem.
Losing one link in the food chain can upset the balance, too. Here’s an example: Wolves hunt deer, and that helps keep the deer population under control. But since wolves also hunt livestock, many ranchers have tried to reduce their numbers. When the wolf population goes down, the deer population goes up because they have fewer natural predators. When that happens, deer begin eating more vegetation than an area can produce. Eventually, overgrazing can cause soil erosion, making it harder for vegetation to grow.
As humans, we can all help maintain the balance of nature. Land developers often plant trees to replace those they cut down for their buildings. When hunters and fishermen buy licenses for their activities, part of the money goes to conservation efforts. Many people volunteer in parks and forests to pick up trash, plant trees, and remove invasive species that crowd out native species. As a Webelos Scout, you can help with those activities. You can also feed native species and conserve natural resources. When feeding native species, be sure to give them appropriate food (such as birdseed instead of table scraps); check with a local nature center for guidelines.
ELEMENTS OF AN ECOSYSTEM:
PRODUCERS, CONSUMERS, AND DECOMPOSERS
Here are the elements of an ecosystem:
The sun: Without the sun, there would be no life on Earth. The energy of the sun flows through a cycle in the ecosystem. Plants are the first to use this energy.
Producers: All green plants—trees, shrubs, grasses, flowers, etc.—use the energy of the sun to grow. Plants also take up nutrients and minerals from the soil. The plants produce leaves, bark, fruits, nuts, and seeds that many animals eat.
Consumers: Animals are consumers. They use the stored energy, nutrients, and minerals in their food to grow and to maintain their health.
Decomposers: These are the fungi, lichens, bacteria, and insects that break down dead plants and animals. This process returns organic matter and minerals to the soil, making them available to trees and other plants—the producers. Nature is a good recycler.
CORAL REEF ECOSYSTEMS
A coral reef is a rise or mound of coral, coral sands, or solid limestone at or below sea level. Coral may make up less than half of the reef; other organisms such as mollusks (snails or clams), zooplankton, and sponges form the rest. Finally, coralline algae commonly help to bind these organisms together to form the framework of the coral reef. Coral reefs have three forms: fringing reefs, barrier reefs, and atolls. In tropical areas, fringing reefs form just offshore, separated from land by shallow water. In other areas, barrier reefs form far from land, separated by water more than 30 feet (9 meters) deep. Atolls, found far offshore, are rings of coral encircling a lagoon.
HOW CORAL REEFS FORM
During his scientific expedition aboard the HMS Beagle from 1831 to 1836, Charles Darwin developed a theory about how coral reefs form. First, a volcano grows thousands of feet from the ocean floor to rise above the surface of the ocean. It becomes a volcanic island surrounded by shallow water. A shelf of coral extending from the shore forms a fringing reef around the volcano top. Gradually, the volcano sinks, but the coral continues to grow. As the volcano continues to sink, the reef becomes separated from the landmass by a lagoon. It is now a barrier reef. Finally, the volcano disappears far below the ocean’s surface and leaves only an atoll, a ring of coral with a lagoon at its center. Coral reefs are largely made of the skeletons of colonial corals. Not all corals form into reefs. Some live a solitary existence, like their relatives, the sea anemones. Temperature, water depth, salinity, and wave action all help determine the growth and health of corals.
Tropical corals require waters warmer than 65°F. These reef corals rely upon algae for
nutrients and oxygen. Algae require sunlight for photosynthesis. Tropical reefs, therefore,
are found in water shallow and clear enough for sunlight to penetrate. The framework of the
coral reef is provided by coral and some minor organisms, then cemented by the coralline
algae. The loose sediment used in this framework is made up of eroded reef rock, sand, gravel, and a small amount of silt and clay. Cold-water reefs (also known as deepwater reefs), on the other hand, exist in waters between 39°F and 54°F, at depths that have limited or no sunlight. These reefs have not been studied nearly as much as tropical reefs, and much is still unknown about cold-water reefs. However, they are gaining more attention in ocean research, and they continue to be discovered and explored all over the world. Like their tropical counterparts, researchers have found them to be home to a wide variety of organisms.
Did you know?
Coral reefs benefit from heavy wave action. Waves agitate the water, bring in food and oxygen, and remove sediment.
CORAL REEF LIFE
Tropical coral reefs are usually found in warm shallow waters on the eastern coasts of continents and around oceanic islands. Most of the world’s tropical reefs are found in the Indian and Pacific Oceans and the Caribbean Sea. Cold-water reefs are found in colder, deeper waters.
Numerous examples have been found in the Atlantic Ocean, but they have also been found in the Indian and Pacific Oceans. Coral reefs seem to have few plants, but reef-building corals often house microscopic single-celled algae called zooxanthellae. The zooxanthellae supply food through photosynthesis. The association between coral and zooxanthellae benefits both. The coral gives a place for the algae to form, and the algae provides nutrients for the coral. Also, corals feed upon plankton and organic debris.
Because some corals must spread out in search of light much like a tree grows branches, the association between coral and algae explains why many coral reefs grow like a forest. Corals spread out and compete for light just like plants on land do. Just as with plants on land, rapidly growing corals shade out slower growing colonies, which eventually die.
Today, tropical and cold-water coral reefs in some parts of the world are in peril. When stressed by pollution or a change in temperature or sea quality, or for as yet undetermined reasons, some reef corals expel the algae, weaken, and die. This condition is known as “bleaching.” Human activities, such as tourism and commercial fishing, also threaten the reefs. To make matters worse, the rate of growth—and therefore recovery—of coral reefs is slow.
WEBINAR WITH MARINE EXPERT
Click below to find the recorded webinar with marine biologist and expert, Shelby Thomas.
Shelby Thomas is the Co-founder and CEO of the Ocean Rescue Alliance, a
marine conservation and restoration nonprofit organization, specializing in
implementing innovative techniques to restore marine environments. She
specializes in marine conservation and restoration, receiving her master’s in
marine Ecology and is currently completing her PhD in Marine Biology with
the University of Florida. She is an environmentalist and marine conservation
advocate who hopes to inspire others to protect our environments. She
has worked with various restoration projects including coral, seagrass, oyster, sea-urchin, and scallop restoration.
She is passionate about preserving our natural ecosystems and creating a foundation for their appreciation. She now has worked with over 20 different restoration projects and continues to conduct research in this field. Through her research and outreach, she plans to assist in conserving, restoring, and better managing our ecosystems. She would like to make a lasting impact, conserving our environments while also improving peoples lives around the world.
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