published on 22 September 2015 in ecosystems
An artificial paradise under the sea
In the blue
If we were to go scuba diving in the waters of the Atlantic Ocean we could meet old warships, planes, tanks or train or underground carriages. All these means of transport, in fact, have been “deliberately” thrown into the ocean, but this time it is not an act of vandalism, but a work designed to foster the marine ecosystem! These relics, in fact, have become a paradise for scuba divers and marine organisms. They are important and very popular artificial reefs on the ocean floor, and play an important role: protecting the coasts, increasing marine biodiversity, attracting scuba divers and creating a new habitat for marine organisms. Therefore, throwing this type of scrap metal into the sea to promote marine life is not an extravagant idea or a contradiction, but works perfectly and especially marine species appreciate it!
Artificial reefs are submerged man-made structures fostering marine biodiversity which, for example, hinder illegal trawling, increase shelters for fish nurseries and restocking, increase the substrate suitable for sessile marine organisms, facilitate the reproduction of fish species of economic importance, etc. Laying an artificial reef on a sandy or muddy bottom serves to recreate a natural rocky habitat that can attract fish. The effects are therefore both an increase in the overall wealth of the environment thanks to protection of the most sensitive biological stages of certain species, as well as the increase and diversification of the trophic component. To increase production nutrition must increase, feeding must be fostered, there must be shelters against predators and a favourable habitat for fry. Reefs are therefore very important for the nutrition of fish in protected areas, spawning grounds and nurseries.
Artificial reefs can be of two different types depending on the objectives for which that are designed.
- Protection reefs
- Fish production reefs
Protection reefs are constructions used to preserve fish stocks, forming veritable dams arranged in a row or in isolated spots that prevent the passage of towing gear. These structures are built precisely to prevent bottom trawling. Trawling is a technique consisting of towing a fishing netseabedsea grass on the fishing netseabedsea grass, which is why it is very invasive. Trawl nets, in fact, destroy or remove anything they encounter on the seabed – fish, invertebrates, corals, algae, fishing netseabedsea grass – and leave a devastated environment where the original biotic communities can only replant after a very long time. In particular, Posidonia oceanica meadows can be totally destroyed with a single pass. By preventing the destruction of the meadows, the spawning areas important for fishing and the areas in which trawling is prohibited are therefore protected. These works are much smaller than those designed to produce fish stocks and have no cavities.
Fish production reefs
Fish production reefs are built to increase fish stocks of species of commercial interest. The shapes of these structures are much more complex, full of holes and gaps and are bulky and large. The openings are adjusted depending on the species to be accommodated. The lower part can accommodate benthic species, i.e. that live on the seabed, such as shellfish.
The construction materials of artificial reefs can be the most varied: car carcasses, metal structures, decommissioned ships, stone or concrete, the material certainly most widely used. Also the size, structures and appearance vary significantly. Generally they are modular structures consisting of several elementary units of limited dimensions, easier to transport and install. Exceptions are barriers consisting of shipwrecks or oil platforms. These modules can be put together in an orderly fashion, often in pyramids, or randomly scattered on the seabed. The modules usually have complex shapes, full of cavities and protrusions that create hiding places, dens or supports for marine organisms. Artificial reefs can be also arranged in groups, randomly or in regular lattices. The distance between one group and another varies according to the purpose for which the structure is designed. In the case, for example, of reefs that need to prevent illegal trawling near the coast, the distance must be less than the minimum size of the fishing gear to be discouraged.
Here are some examples of artificial reefs in the world.
The second life of an oil tanker: the Haven
In 1991 as a result of an accident, the oil tanker Haven sank off Arenzano in Liguria. The wreck of the Haven rests on a sandy bottom on which, before it sank, there was nothing. Currently the wreck of the oil tanker Haven is the largest and most beautiful scuba diving site in the Mediterranean. Since 2008, after the end of the reclamation and safety works on the wreck, scuba diving began to visit the wreck.
An underwater art museum
The artist Jason de Caires Taylor is a sculptor of international renown, a graduate of the London Institute of Arts; he is also a qualified diving instructor and award-winning underwater photographer. Taylor creates permanent submarine installations that function as artificial reefs, designed to increase marine life. The sculptures constantly change over time due to the effects of the marine environment in which they are situated and this gives a living appearance to the works, changes that would be impossible to reproduce artificially. Over time the sculptures develop biological growth that redefines the submarine landscape and creates a perfect habitat for marine species. In 2006, Taylor created the first submarine sculpture park in the world. It is situated off the west coast of Grenada, in the Caribbean, and the National Geographic defines it as one of the 25 wonders of the world. In 2009, the sculptor founded MUSA, Museo de Arte Subacuatico, a monumental museum with a collection of more than 500 life-size sculptures, submerged off the coast of Cancun in Mexico. The museum aims to combine art and ecology in a complex artificial barrier that becomes a substrate for marine life, shelter and spawning ground for many underwater organisms. All the sculptures are made of pH neutral cement material, in order to allow colonisation by corals, and serves as a fish restocking area. The marine park of Cancun is visited each year by more than 750,000 tourists. If you want to see this spectacular museum for yourself go to: http://www.underwatersculpture.com/
When the underground ends up under water
Since 2001, 2,580 decommissioned underground carriages have been sunk in the sea off the East Coast of the United States to create an artificial reef and provide a new habitat for ocean inhabitants. The project was documented by photographer Stephen Mallonche for two years in every detail, step by step, from the cleaning of the carriages until their launch into the sea off the coasts of Virginia, Georgia, South Carolina, Delaware, New Jersey and Maryland. The carriages perfectly adapt to the ocean floor and quickly become dens and nurseries for fish and marine invertebrates. Desert marine areas thus begin to repopulate with life: mussels attach themselves to the ceilings, fish find crevices in which to hide and breed undisturbed and sponges grow on the surfaces.
Marine life after terrestrial life
To commemorate their dead some Americans must wear wetsuits and scuba diving equipment! In fact, in Florida, at about 5 km off the coast of Miami at a depth of 14 metres, the company Neptune, the largest cremation service company in the United States, has built a new “final resting place”: the Neptune Memorial Reef, revolutionary both for marine life and as a memorial for the deceased. You read right: the company Neptune has built an underwater cemetery that recreates the legendary lost city of Atlantis, complete with installation on the ocean floor of statues, vases, columns, streets and benches, to rebuild the submarine landscape. The Neptune Memorial Reef covers approx. 6 hectares of ocean floor and not only offers rest for the departed, but an ideal habitat for marine species. In fact, the motto of the cremation company is “Creating life…after life”! It is the largest artificial reef ever built and was designed by a marine biologist to create an ideal ecosystem for marine organisms: tall columns to support corals, horizontal surfaces for benthic species, metal mesh structures that allow prey find shelter, blocking predators. The Neptune Memorial Reef does not offer, for legal reasons, a true and proper burial, but allows the deceased to become a part of the marine ecosystem: the ashes of the cremated body are mixed with cement to create a commemorative plaque in the name of the deceased on the ocean floor. You can choose the form in which your loved one will be part of the reef: as a column, if you think in life he/she was a mainstay of the family or in the shape of starfish or shell or if he/she had a more sensitive soul! To find out more visit http://www.nmreef.com/index.html
The Paguro resurrected
In 1965, the Paguro platform sank following an accident in the waters off Ravenna. The highest part of the platform is situated at a depth of 10 metres, while the lowest at 35 m. Since that day the Paguro began its metamorphosis and has had an explosion of flora and fauna, so much so that today the site has become a popular destination for many scuba divers. In 1991, other structures of ferrous material coming from the disposal of other platforms in the Adriatic were sunk near the wreck, increasing the submarine area of this marine sanctuary. In 1995, the site was declared a “biological protected area” and the following year the “Paguro Association” was formed that deals with management of the area; the promoters are fishermen, diving clubs, biologists and the harbour master of Ravenna. Since 1997, the Paguro Association organises and manages scuba diving visits in the area. In 2010, the biological protected area became a site of community interest. Today, the area occupied by the Paguro wreck is approx.15,000 square metres and can provide opportunities for scientific research and great interest for divers due to its particular location in the northern Adriatic and to the incredible life that has colonised the structures, offering spectacles of unparalleled splendour and charm, not easily found in other marine areas of Italy. In the highest part of the wreck, from 9 to 12 metres deep, the metal structures are completely covered by mussels, oysters and other sessile organisms, such as sponges. The invertebrates include urchins, sea cucumbers and starfish, but also lobsters and crabs. Fish living in the vicinity of the wreck are those typical of rocky bottoms, hard to find in other parts of the north west Adriatic that notoriously has a sandy bottom. To date it is estimated that approx. 4,000 divers a year visit the Paguro platform, providing job opportunities to 7 boats and several diving centres and diving clubs. In 10 years, 40,000 dives have been made and 50% of scuba divers come from other Italian regions and 12% from other countries, notably Austria and Germany. To take a dive on the Paguro while remaining dry, watch this video: https://www.youtube.com/watch?v=7vQk_L23JJQ
We hope that researchers and the entire scientific and environmental world support the opportunities offered by these artificial reefs that intervene on the marine environment to repopulate desert areas marine, understanding the ecological and economic significance.
by Tiziana Bosco
To find out more…
https://www.youtube.com/watch?v=9DoqV54ju5M documentary on artificial marine parks in the Adriatic