I’ve done – and still do – a lot of diving in the Netherlands and abroad. I just love being under water and watch fish and other marine creatures do whatever they do and not taking any notice of me at all.
As I’m really passionate about my diving, I always tell people that “I had an incredible dive here” and “a beautiful dive there”. And every time I tell people, they start asking questions: “what is it like to dive in lakes” and “do you see anything” are all questions I’ve heard many a time.
I tell them that there is a lot to see, as well as that most of the lakes I dive in – and basically most of the dive sites I’ve been to, including tropical waters – contain at least one or more artificial structures.
Artificial dive sites like reef balls, ships or boats, caravans and trucks, all in different sizes and people usually start laughing and tell me how funny and weird that sounds.
Funny as it may sound, artificial structures and artificial reefs are really important for the marine environment.
Just like natural reefs, they provide hard surfaces for algae, barnacles, coral and oysters to attach to. They create an intricate structure containing cracks, crevices, overhangs and other places for prey to hide from predators; or for predators to sit and wait for prey to come by so they can have a lovely dinner.
What are artificial dive sites and what is their purpose
Artificial reefs are man-made underwater structures and can be built on purpose, such as reef balls. Other types of artificial reefs include ships and oil rigs that are sunk, either on purpose or not.
As mentioned above, most artificial reefs provide food and shelter. But they can also serve as sanctuaries, stabilise shorelines and serve as an alternative dive site.
Most of the artificial structures and dive sites I have seen are blooming with life. They create an oasis in areas that otherwise seem barren (even though there is often lots to see in what appears to be a sandy and bare area).
They can also serve as an additional dive site to the normal dive sites visited by dive schools.
One great example is the island of Koh Tao. Every year, thousands of backpackers come and visit this tiny little island in the Gulf of Thailand to learn how to dive and to “Get their PADI”.
With many new divers diving the beautiful coral reefs all around the island, not all of them are able to master their buoyancy skills, so an enormous amount of reef resilience is required.
As coral reefs have a very small range of biotic factors in which they thrive, this can cause a huge strain on the coral reef.
Long-lasting pressure, such as divers touching the coral in addition to natural causes of stress such as, increasing water temperatures and more and more extreme weather conditions, causes the reefs to degenerate.
Around the island of Koh Tao, there are multiple artificial reefs which have been built/ deployed. These sites, ranging from an in-house artificial reef ‘Junkyard’ to an old navy-ship (HTMS Sattakut) at a depth of 30m.
They all offer something different to see and are therefore are very popular artificial dive sites, taking pressure away from the natural reefs all around the island and with that offering the reefs some respite from diving pressure. Artificial dive sites here really do make a difference!
Coral reefs are struggling to survive due to natural and anthropogenic threats such as pollution, run-off and tourism, leading to an overall decline in live coral cover all over the world.
With all these causes of stress, creating artificial reefs to take pressure away from the natural reefs is, in my opinion, becoming more and more important. Especially because coral reefs being one of the oldest, most diverse and most productive ecosystems on Earth, play a vital role in global ecosystem health and in many human economies.
They provide habitat and act as nurseries for fish and aquatic invertebrates, provide barriers from storms and waves to protect sea coasts, breakdown excess nutrients and compounds, and help to regulate atmospheric gases.
In order to offer natural coral reefs assistance, as well as to be able to increase knowledge and understanding about the complex systems of coral reefs, some artificial reefs are built solely for scientific purposes.
The structures deployed for these purposes for instance serve as coral nurseries. Coral fragments can be obtained by collecting the ones laying on the sea floor and subsequently transplanting them onto these structures.
In some cases, after growing big enough, the coral fragments are taken off the artificial structures and are then transplanted onto the natural reef. This way an attempt is done to help a degenerated natural reef to regenerate and thrive.
In other situations, the coral fragments remain on the coral nurseries and eventually take over the structure and create a new “natural reef”. An example of this type of artificial reef where coral fragments eventually take over the artificial structure is BiorockTM.
Coral grows by building a calcium carbonate skeleton. BiorockTM uses small electric pulses that stimulate the excretion of this calcium carbonate and therefore increases coral growth rates.
The above is very useful and necessary in tropical waters. However, cold water dive sites have lower water temperatures and a visibility that is half of the visibility in tropical waters and do not attract hundreds of divers a day.
These coral reefs need help and have the same natural and anthropogenic issues threatening these marine environments.
At these dive sites, artificial structures usually offer divers something to see on their dives. The lake I dive in on a weekly basis during summer time, contains several artificial structures, with a tiny boat, caravan, hang glider and a minivan being some of them. There even is a concrete waste pipe (not in use) that has a residential eel. Whenever I dive this lake I always go and check it out, hence really adding to my dive experience.
Actually, some of the most beautiful dives I’ve done in the Netherlands are actually at dive sites containing artificial structures. One of them is a shell fish farm containing mussel long lines.
At these long lines, cultivated mussels are kept for a maximum of two years after which they are harvested. As these mussels and oysters are filter feeders, clear water is extracted so the water around this dive site is very clear and therefore visibility is pretty awesome!
In addition, oysters and mussels have hard shells, providing a substrate for organisms to grow on; hence the site blooms with life! As mussels and oysters would naturally not grow this way – they usually create the very famous mussel banks – this dive site can also be called an artificial dive site.
There is one final type of artificial dive site that is not, in the first place, extremely beneficial for the marine environment, but is nonetheless very useful and totally worth creating: the diver training site.
These open water training sites contain different structures and obstacles where divers can practice their buoyancy skills, for example buoyancy squares and triangles.
There will still be enough to see for divers: the structures will attract algae and therefore also other marine animals. And divers kicking up the sand (which obviously happens when training your skills) will also attract fish keen for an easy meal.
In the end, every diver that masters his or her buoyancy skills will be a better diver and do less damage to the natural marine environment, which is one less stress factor for the marine environment to deal with.
As you might have noticed by now, I am quite fond of artificial dive sites, and I think more of them could – and maybe should – be created to help marine environments as they increase biodiversity, provide hiding- and foraging places, take pressure off natural reefs, serve for scientific purposes and act as diver training sites.
All these purposes are beneficial for the short or long term for the marine environment and should therefore be promoted.
Artificial structures and dive sites only work if they are in addition to the natural marine environment and should not be used as an easy and quick way to dispose of old junk that’s laying on the beach or in your garage.
If you plan on creating an artificial dive site, be aware of local laws and legislation, as this might differ in each country.
If you’re planning on deploying a boat, bus or other type of vehicle or structure that contains or contained oils and other harmful materials, make sure that you legally dispose of this and be very sure the structure is clean before deploying.
Otherwise, you will do more harm to the marine environment than doing any good.
Also, be aware that most of the artificial dive sites need a lot of attention and maintenance. It’s not just a case of “dumping stuff in the ocean and you’ve created an artificial reef”.
If, for example, a boat is deployed, it needs regular checking to see whether it is safe to dive or penetrate. And when you deploy a coral nursery, the nursery needs regular cleaning as well as data collection.
In any case, make sure that you use the information available about artificial reefs before you start, and at best have experienced scientists and organizations to help you!
Keep on diving and explore those artificial dive sites!
Eco Koh Tao Intern | Crystal Dive Koh Tao Divemaster