Biophysical Features
Biotic and Abotic characteristics of coral reefs
Coral reefs are mainly made up of tiny individual polyps, polyps are individual corals. These corals have a tough exoskeleton which is made of calcium carbonate. They are also sessile which means that they are permanently stuck in one place. Polyps grow very slowly and form different shapes, colours and sizes as they grow. Shape, colour and size depends on the species of coral.
Coral is assisted by different species of animal with calcium carbonate skeletons, and also coralline algae. When coral reefs grow they form complexes of three dimensional reefs. Coral reefs provide an important ecosystem for all different types of marine life. It offers food and homes for fish, molluscs, sea urchins and sponges.
Corals are found around the world, in tropical temperature to freezing temperature, but coral reefs are only developed in tropical places around the world in shallow waters.
The biggest coral reef and most well known in the Great Barrier Reef on the east coast of Australia. It is about 2300 kilometres long.
The most biologically diverse reef in the world is the coral triangle in southeast Asia.
Biotic factors of the Great Barrier Reef
Biotic factors in a reef are all the living elements that make the reef what it is, so all the coral, fish organisms and other particles. Coral reefs are populated with all different sort of fish, coral and plants, and different organisms rely on each other for food, shelter and sometimes protection from predators. This is called an ecosystem or food chain.
The Great Barrier Reef's ecosystem provides for:
1500 different species of fish
400 different species of coral
4000 different species of mollusc
240 different species of birds
What is a food chain?
A food chain is the process of an organism acquiring nutrients and energy by consuming another organism. In the food chain you have your producer, first, second and third (or more) consumers, and then the decomposer.
The first organism is also know as the producer. In a reef ecosystem it is usually a plant or single-celled organism such as plankton, algae, or seaweed. The first-order consumer eats the producer, the second-order consumer eats the first-order consumer, and so on.
The last organism of the food chain is the decomposer. This is the organism that when it dies it releases all the energy and nutrients into the environment or ecosystem which feeds a new plant or producer and the chain starts all over again.
The food chain is a biotic factor of the ecosystem because it is living organisms that create the process.
What is a food web?
A food web is all the food chains that exist in an ecosystem. While a food chain describes a particular system, a food web describes all the systems in an ecosystem and the overlaps within and across different food chains.
Producer: Single-celled organisms and plants are often the producers or first level in the food chain.
First LevelSecond-level consumers: Small crustaceans such as krill are the second-level organisms in the marine food chain.
Small fishThird-level consumers: Small fish eat the krill and other small organisms.
Large fishFourth-level consumers: Large fish and other predators feed on small fish and molluscs.
DecomposersDeomposers: Large predatory species are the decomposers in the food chain.
A simple food chain
Example of a food chain
On the Great Barrier Reef there are lots of different food chains/webs because all different types are living on the reef, for example, fish, coral, algae, plankton, turtles and lots of others.
On the reef the organism that starts the food chain is the producer which is normally, plankton, algae and seaweed, so plant based organisms. Then this is followed by smaller fish normally who live off little pieces of plants floating in the water, from there the nutrients and energy from the plant will transfer into the fish.
This can keep going on until we get to the decomposer, which is normally also the predator (predator means that nothing else can eat it, but it eats everything else) the predator would normally be a shark, but when the shark receives the energy and then when it dies with the energy inside it, it will slowly be released into the ground as it decomposes, and that's where the cycle will start again.
Some food chains on the Great Barrier Reef
Here is a simple example of a real food web on the Great Barrier Reef.
This one is quite easy to read and see where everything goes. So in this one clams wound be the producer, the turtle, little fish, starfish and fish would be our first order consumers, octopuses, crabs and jellyfish would be our second order consumers, and lastly the shark would be our decomposer/predator.
This is an example of a more complex food web. This is where the food webs become a bit more confusing because of all the crossovers.
Seaweed, coral and blue-green algae are our producers.
Parrot fish, butterfly fish, sea turtle, angelfish, shrimp and sea urchin would be our first order consumer.
Spider crab would be our second order consumer, cuttle fish would be our third order consumer, and lastly white bellied sea eagle and black tip reef shark would be our decomposer/predators.
Abiotic factors of the Great Barrier Reef
On the Great Barrier Reef there are lots of different factors that make up the ecosystem, not just its life, there are also bits like buoyancy (buoyancy is the flotation of an object on a fluid), viscosity (this is expressing the magnitude of an internal friction in a fluid), light penetration (this is where the light shines on the water), salts (this is the measure of salt in the water), gases (this is the gases that are in the water or air around the water) and water density (this is the weight of the water in pure volume).
Buoyancy
Buoyancy is the force of an object to somewhat float in the water.
For example: when you throw something in the deepest part of the pool and you dive to grab it it's so hard to do. This is because the force of the water tries to push you back up to the top of the water.
That force pushing on an object upward is buoyant force. Buoyancy is important to the coral reef because it keeps the reef's pressure equal to make sure the reef is kept preserved.
Viscosity
The reef also has viscosity. Viscosity acts as a calmer in the water to stop water movement and dissipate energy.
Viscosity is the mass of the water and how it works when pulling against each other, for example, in a current.
Viscosity is very important to the reef because it helps provide nutrients for little creatures and that provides a sturdy base for the ecosystem.
Light
In the coral reef the water is crystal clear and a bit blue, this is because of light penetration, light penetration is the penetration of light into and on the water, when the light goes through the water you can see everything and sun beams sometimes pass through the water, when the light is on top of the water is looks glassy and shine. Light provides a couple of different aspects to the reef, like photosynthesis, this is where plants use energy and light from the sun to grow, without light there would be no photosynthesis and without that there would be no place for creatures to live hence why light is crucial for coral reefs.
Salt
In the water there is salt, salt is important to the reef when it's at the right level, if the salt level rises it can be dangerous to cells in the coral causing them to dry out and cause biochemical responses in the coral this is similar to marine heat waves. But when the salt is kept right it is important to the reef in its ways of absorbing nutrients and trace elements, it helps with the flow of nutrients to the coral.
Gases
There are also gases in the water such as nitrogen, oxygen and carbon dioxide. Nitrogen is important to the coral reef when it goes through the nitrogen cycle, it is important because it provides a fundamental importance to the algae and coral. Oxygen is class for everything in the reef because with our oxygen in the water nothing would be able to live because i can’t breathe, so without oxygen there would be no reef. Meanwhile, carbon dioxide isn't the best for the reef because it is resorting to coral bleaching and all sorts of illnesses and diseases in the coral.
Density
Lastly the factor of density is important if it is kept right, if the density of the water took a turn it would cause all sorts of damage to the coral reef, for example, it would cause competitive dynamics in the coral and this might cause the coral population to rebound and start reducing in numbers.
Spheres
Four spheres make up our earth: the atmosphere, lithosphere, hydrosphere and biosphere. The atmosphere is the air and gases around us, the lithosphere is the earth and what the earth is, the biosphere is all the living elements of earth, and the hydrosphere is the water on the earth.
The atmosphere is the mix of gases that surround our earth. Without the atmosphere, life wouldn't be possible here on earth. It helps provide us with air to breathe and a shield to stop harmful ultraviolet rays.
It traps the right amount of heat to keep us warm or cool enough to survive inside the planet, and it also prevents extreme temperature changes between night and day.
If we didn't have the atmosphere, temperatures would be below freezing everywhere you went on the earth's surface. Instead, the heat is absorbed and then trapped by the atmospheric gases that keep our lovely planet's average surface temperature at a balmy 15 degrees Celsius.
Some of the atmosphere's gases, for example, carbon dioxide, are particularly good at absorbing and trapping radiation. Changes in the amounts of these gases directly affect our climates.
There are two types of lithospheres: the oceanic lithosphere and the continental lithosphere.
The oceanic lithosphere consists of the ocean floor, which is the crust of the earth that is below the sea.
The continental lithosphere is the rocky outer layer of the earth. This consists of the solid upper layer of the mantle, this layer extends for about 60 miles under the earth's surface.
The lithosphere also includes plate tectonics, which are solid layers of rock that float off the layer of magma below the surface of the earth. The Tectonic plates are split into pieces like a jigsaw puzzle that all slot together under the earth. These pieces have gaps in between them that have the ability to expand and shrink which causes the plates to move. This movement can cause earthquakes and tsunamis.
Where the plate tectonics meet there will normally be a volcano, mountain, and deep ocean trenches.
The biosphere exists wherever there is life on Earth. The biosphere extends all over Earth, from dark seas to tall mountains, to plains of open space to lush rainforests.
The biosphere consists of plants, animals, organisms, fungi, and bacteria. The biosphere is crucial for all ecosystems because the biosphere is what gives the ecosystem life and allows it to thrive and create our beautiful planet.
The biosphere is also crucial for climate regulation.
Water moves through the hydrosphere in a cycle. In this cycle, water starts in oceans and lakes and rivers.
All exposed water eventually evaporates and turns into clouds that move around until they are so full of water molecules that they have to let them go. This then causes rain to the pour down on lands, crops and ecosystems that help us live. This givers us a drinking source and water to water our plants and crops. The rain that doesn't get used up then goes back into the exposed water sources such as the ocean where the cycle starts all over again.