If you have not yet witnessed the majestic beauty and diversity of a coral reef, then you may not be aware that beneath the waves there exists a living and breathing ecosystem full of extraordinary wonder.
Like the world’s tropical rain forests, which are absolutely critical to the health of the planet, the world’s coral reefs are necessary to the health of our oceans, and, therefore, our own well-being. These marine metropolises are critically important for thousands of species of fish and hundreds of other species. In addition, they protect our shores from erosion, feed millions around the world and even sustain economies in places like Florida in the United States.
Knowing how incredibly important these natural wonders are to a multitude of animals – including ourselves – you may ask: How are coral reefs formed?
As you might expect, these delicate ecosystems have some important requirements needed to grow into vibrant ecosystems. Once the conditions are right, they can grow into one of three types of coral reefs. These are known as fringing reefs, barrier reefs and atolls.
These majestic ecosystems can take many thousands of years to form ( in some cases millions of years), and yet can be destroyed in a relatively short time. Threats include natural and human made factors. The latter is one we have control over and represents the greatest threat to these indispensable habitats.
The United States government has taken steps to protect coral reefs. However, regular folks like you and I can increase the level of protection exponentially. After all, we are among the countless creatures who stand to greatly benefit from their survival or face peril by their demise.
Read on and see for yourself how coral reefs are formed and the many challenges they face.
Settle Down Baby
I’m certain that you are well aware nature operates in cycles; birth and death is probably the one we are most familiar with. When it comes to coral reefs, we can start by focusing on the coral larvae found swimming freely in the ocean waters. These came from the resulting union of male and female gametes released by the adult corals (polyps related to jellyfish and sea anemones) in an attempt redistribute their genes throughout the reef and beyond (NOAA).
These larvae drift about facing many dangers from predators while in search for an adequate hard surface to become attached to, such as a rock or another coral. The few that survive become affixed to a solid surface for their entire lives. They now extract calcium from the water and as a result deposit calcium carbonate – this begins to build a new coral structure or adds to one that already exists.
This process of creation will continue unchecked if it weren’t for bioeroders like the sea sponge. This important member of the reef burrows holes in the coral and converts calcium carbonate (now limestone due to pressure) into fine sand. It serves to enhance the landscape of the coral as well as supply tropical beaches with fresh sand.
I’ve explained to you the general way coral reefs are formed; now I would like to show you what they need to flourish.
Triumphant In The Tropics
Coral reefs are most abundant in the warm waters of the tropics and subtropics. In fact, they are not able to grow in waters below 64.4 degrees Fahrenheit (18 degrees Celsius). For this reason, stony corals become fewer in numbers as they approach 30 degrees latitude north and south. Beyond these latitudes they are usually not found. One interesting exception is located in the waters off of Bermuda, which are located at latitude 32 degrees north. The reason for this is that this location receives the warm waters that come from the Gulf of Mexico called the Gulf Stream.
Corals also require very clear water in order to receive the maximum amount of sunlight. This is why you will find them mainly in the euphotic zone. This level of the ocean spans from the surface to the maximum depth where the sunlight is able to reach.
It’s obvious that coral reefs need salt water since they are only found in the world’s oceans and seas. However, the water they need has to have a salt content between 32 and 42 parts per thousand (NOAA) – this means very salty water.
The water must also be free of suspended sediment; otherwise the coral’s mouth will become clogged making it impossible to eat. Turbid water will be a double edge sword for the coral; it will interfere with their ability to capture and swallow food as well as with their capacity to receive much-needed sunlight. As a result, coral reefs do best in clear tropical and subtropical waters. For this reason they are a main destination for snorkelers visiting the tropical waters of the world.
These underwater paradises grow into three general shapes. One is closer to the shore while the other two are farther out to sea.
Around And Under
All coral reefs are an awesome display of what life can be when left untouched by humankind. Depending on its location in relation to a given landmass, coral reefs can grow into one of three general forms: fringe reef, barrier reef and atoll.
The last time you visited a beach and gazed at the waves, it is likely that just beneath the surf there was fringe reef – if for example you happen to be visiting the eastern United States or the Caribbean. This variety extends from the coastline out into the sea. They form borders along the coastline and also around islands – making them the most popular type of reef.
The barrier reef occurs even farther out to sea; It is usually separated from the land mass by a deep body of water such as a lagoon.
A fringing reef becomes an atoll when the land mass sinks below the water while the reef continues to grow upward. This specific type of reef has a circular shape which surrounds a large body of water.
Regardless of its shape, coral reefs are a haven showcasing life’s splendor. Nevertheless, these invaluable habitats face numerous threats.
With Great Power Comes Great Responsibility
As critically important as coral reefs are to the world’s oceans, they still have to contend with many dangers. Let’s begin with those that arise from nature herself.
As you may have guessed, powerful waves pose a significant danger to the physical structure of these ecosystems. It seems a bit ironic that coral reefs thrive in the part of the world (tropics) which generate the most powerful storms in the world known as hurricanes and cyclones. The force of the waves can break and scatter large parts of the coral leaving wide areas flattened. This undoubtedly will affect many other members of the reef as well, as many species depend on them for their own survival.
Another threat is longer than usual low tide; being exposed to the sun for long periods of time can cause the coral to become stressed and succumb to bleaching and even death.
In 1997 – 1998, El Nino was responsible for higher ocean surface temperature, lower sea levels ( due to unusually low rainfall) and an increase in water salinity. This situation resulted in the death of up to 80% of the shallow-water coral in many parts of the Indo-Pacific.
Coral reefs are also targeted by a variety of predators, including crabs, snails, sea stars, fish, barnacles and marine worms. Although it is unusual, entire coral reefs can be devastated by predators. There have been times, although rare, when a whole reef has be devastated by predators.
As tough as it may be, corals can bounce back from natural assaults. However, when the threat is exacerbated by human-made global warming and/or pollution these ecosystems are pushed to the brink.
Among the many ways we harm these majestic ecosystems include: pollution, over fishing, catastrophic fishing tactics that make use of cyanide or dynamite, mining the coral to extract building material and removing live coral to be sold to the aquarium market (NOAA).
Other human – made hazards include industrial chemical, and sewage runoff into the ocean, as well as deep water trawling which can dislodge corals from their base.
The sad reality is that we pose a far greater danger to coral reefs than nature ever could. Yet, this means that it’s up to all of us to make sure, through our choices of consumption, that these majestic marine cities will be there for our children in the future.
On The Brink
Coral polyps begin their lives as free-swimming larvae in search for a suitable hard surface on which to settle for life. The few that manage to avoid being eaten become part of a new or existing coral. By extracting calcium from the sea water they produce calcium carbonate, which they use to build the foundation of the coral structure.
Coral reefs are mainly found in tropical and subtropical oceans; there the waters are warm, clean and clear. This is very important since corals can’t tolerate water temperatures below 64.4 degrees Fahrenheit; in addition, the water must be very salty and clear of sediment. Clear water allows them to obtain nutrients and absorb the needed sunlight.
Depending on the reef’s position in relation to land they can grow to form a fringing reef, barrier reef or an atoll. A fringing reef extends from the coast out into the sea, while a barrier reef is formed farther out to sea allowing a body of water, such as lagoon, to be between the reef and the coastline. An atoll is formed when the land is submerged under water while the coral reef continues to grow upward; this type of reef has a circular shape. Regardless of the type of reef, they are all a marvel of nature.
Both nature and humanity pose many threats to these marine habitats. Events like prolonged low tide and predators are some natural threats the reef can bounce back from. However, when it comes to human originated dangers such as global warming, pollution and harmful fishing practices, to name a few, the world’s corals reefs are being pushed to the brink.
On the bright side, the fact that we represent the most serious threat to the world’s coral reefs means that we can, if we choose to, bring these essential habitats back from the edge of calamity. We must first realize that we have to live in harmony with nature, rather than simply profit off or it.
It has been said that what one does for another one does for one self. If we don’t care for the world’s coral reefs then we are not caring for our selves. If, however, we decide to protect them, then we will be further ensuring our own survival.
Today humanity is a lot more aware of how our actions affect the environment. Only time will tell if we follow that awareness with concrete action in time to save the planet and in turn ourselves.
What do think we can do to protect the world’s coral reefs? Have you ever seen a coral reef at low tide? Would you like to see one some day? Please leave your comment below.
Thanks for stopping by,