Underwater Cultural Heritage Notes

Underwater Cultural Heritage

Underwater Cultural Heritage (UCH) is defined as:

• "All traces of human existence having a cultural, historical or archaeological character which have been partially or totally under water, periodically or continuously, for at least 100 years" (Convention on the Protection of the Underwater Cultural Heritage, UNESCO, 2001).

Such traces include:

• Sites, structures, buildings, human remains, together with their archaeological and natural context.

• Vessels, aircraft, other vehicles or any part thereof, their cargo or other contents, together with their archaeological and natural context.

• Objects of prehistoric character.

Historical Context and Significance

• Over centuries, vessels traversed seas and rivers, carrying merchandise and people.

• Relics are found worldwide in both freshwater and saltwater.

• Famous sites include Port Royal in Jamaica and the Lighthouse of Alexandria.

• An estimated 3 million shipwrecks exist, some containing valuable items.

• Underwater excavations risk being associated with treasure hunting.

• These remains represent human history, and modern diving techniques increase accessibility and risk.

Core Elements of UCH

The definition of UCH includes two core elements:

• Age: Remains must have existed underwater for at least 100 years.

• Conditions of the deposit

Archaeological material can be further defined by:

• Time period.

• Region.

• Typology (e.g., pottery, animal bone, stone).

Discovery of Underwater Archaeological Sites

• Most UCH sites are located by individuals whose work or recreation is sea-related such as sport divers, free divers, naval staff, oil and gas workers, fishing industry workers and coastguards.

• UNESCO's 2001 Code of Ethics for Divers recommends:

  • Documenting the location and state of a wreck or ruin using photos, drawings, or notes.

  • Reporting the discovery to authorities.

  • Reporting recovered objects to the competent national authority.

• Specialists also discover UCH sites through research, guided by historical sources and associated archaeology.

• Examples include the Pharos Lighthouse in Egypt and Neapolis in Tunisia, rediscovered through strategic underwater surveys.

• New technologies, like remote sensing, facilitate the discovery and documentation of UCH sites.

• Surveys occur in areas likely to contain submerged sites, such as ancient harbors, trade routes, and hazardous navigation zones.

• Countries like Bulgaria, Greece, Italy, Malta, Norway, Spain, and Turkey have discovered UCH sites using remote sensing.

• Many countries now combine remote sensing with traditional archaeological surveys to document and preserve UCH in situ.

Special Characteristics of Underwater Cultural Heritage

• The value of archaeological sites lies in what they teach about past cultures and technologies.

• UCH sites, especially shipwrecks, have unique characteristics.

• The underwater environment preserves organic materials like wood, leather, bone, and textile due to the lack of oxygen, slowing oxidation.

• Underwater sites commonly contain well-preserved wooden wrecks and contents that are hundreds or thousands of years old.

• UCH sites often result from unintentional events, such as shipwrecks or natural disasters.

• UCH sites, particularly shipwrecks, can capture specific moments in time, representing a "closed context".

• A "closed context" means the ship, its contents, and crew remain unaltered from the moment of wrecking to rediscovery (except for environmental or human disturbance).

• Shipwrecks are often described as time capsules, providing a snapshot of a vessel's last voyage and the lives of those on board.

Case Studies

The Pharos Lighthouse (Alexandria, Egypt)

• Alexandria held a distinct position among world cities, founded by Alexander the Great in 331 BC.

• For nearly a millennium, it was Egypt's capital and cultural center.

• The port of Alexandria was one of Alexander’s first projects.

• A 1.2 km causeway linked the island of Pharos to the mainland, forming the Eastern and Western Ports.

• The Eastern Port (Great Port) was the main center for maritime activity, including commercial, military, and private harbors.

• The Pharos Lighthouse, completed around 280 BC, marked the port entrance, reaching approximately 110 m in height.

• Damaged by natural disasters, it was destroyed by an earthquake in the 14th century AD.

• The submerged remains cover over 25,000
  ewline m^2, containing over 3,000 objects, including statues, sphinxes, columns, obelisk parts, and building blocks.

• 36 pieces are displayed across Alexandria's city center.

• Most items remain submerged, accessible only to divers.

The SS Thistlegorm (Egypt)

• Located in the Red Sea near Ras Mohamed, it is a famous diving site.

• The SS Thistlegorm was a British merchant steam vessel built in Sunderland in 1940.

• The ship was 128 m long with a gross tonnage of 4,898 tons.

• It completed three voyages before being sunk in 1941 en route to Alexandria with supplies for the Allied war effort.

• Its hold contained ammunition, trucks, motorbikes, trains, and aircraft parts.

• The ship was sunk by the German air force on October 6, 1941.

• The wreck lies at a depth of 32 m.

• During the summer, an average of 8-10 diving boats visit daily, with 300-600 dives conducted per day.

The Submerged Town of Neapolis (Tunisia)

• Since 2010, archaeologists have explored the Gulf of Hammamet for the ancient Roman town of Neapolis.

• The town was partly submerged by a tsunami following an earthquake in 365 AD and later completely submerged due to tectonic activity.

• In 2017, underwater archaeologists discovered the remains extending over 50 hectares off the coast of Nabeul.

• Neapolis was an industrial and commercial center known for producing fish sauce (garum).

• Remains found included streets, monuments, and around 100 tanks used for making garum.

• The discovery indicates Neapolis was among the largest centers for garum and salted fish production in the Roman world.

Threats to Underwater Cultural Heritage

Natural Threats

• The marine environment is complex and dynamic, with factors adversely affecting UCH sites.

• Waves and currents can scatter artifacts and destroy weak organic materials.

• They can also change site features by moving sand and sediments.

• The growth of living organisms can damage archaeological artifacts.

• Organic material is at risk from bacteria, algae, and fungi, causing decomposition.

• Shipworms can penetrate the timbers of shipwrecks, causing wood erosion and damage.

• Micro-organisms need oxygen to survive, protecting vessels buried under sediments.

• Metal artifacts can be damaged by rust or corrosion from chemical reactions with seawater.

Human Threats

Pillages

• Pillage is the theft of historical artifacts, facilitated by modern equipment.

• Communities involved range from sport divers to specialized treasure-hunt enterprises.

• The 2001 Convention provides measures to prevent pillaging, including direct site protection, prohibition of trafficking, port closure, seizure, and international cooperation.

Commercial and Tourist Exploitation

• Coastal construction projects, such as marinas and tourist resorts, can destroy undiscovered sites.

• Land reclamation projects are problematic for submerged landscapes if protective measures are not implemented.

Trawling and Fishing

• Bottom trawling can pick up and displace archaeological material and cause damage to submerged sites.

• Nets can reach depths of over 500 m.

Economic activities

• Infrastructural projects in coastal areas can significantly impact underwater archaeological heritage.

Industrial Work

• Harbor extensions, bridge construction, and pipeline laying can impact submerged archaeological heritage.

• These activities can increase pollution.

Oil and Gas Industry

• The oil and gas industry may threaten UCH through exploratory drilling and the development of oil rigs and pipelines.

• Companies should conduct thorough surveys with qualified archaeologists.

Underwater Cultural Heritage Management

• Features include exploration, research, conservation, presentation, public awareness, and education.

• The key objective is to preserve UCH within sustainable development.

• Management balances preservation with access and use.

• Sites may be closed to visitors but accessible via museums, footage, and online resources.

• Disciplines involved include archaeology, tourism, restoration, economics, and law.

The Protection of Underwater Cultural Heritage

• The remote nature and fragility of UCH require robust protective measures.

• Methods are divided into legal and physical protection.

Legal Protection

• Developing law at local, national, and international levels is vital.

• Laws, implementation methods, and protection levels vary widely.

• Some nations have specific laws for UCH, while others include UCH in general antiquities laws.

• Many European countries, the USA, Canada, and Australia have detailed laws on regulating and monitoring UCH protection.

• Laws made by sovereign states focus on territorial waters.

• Problems arise in international waters, where UCH can be exploited by treasure hunting companies.

• In 1997, UNESCO agreed that UCH protection must be overseen internationally through a dedicated convention.

• The 2001 Agreement on the Protection of the Underwater Cultural Heritage was approved on November 2, 2001, and came into force in 2009.

Physical Protection

• In addition to legal protections, there are physical methods for protecting UCH sites in situ.

• Possible actions include:

  • Leaving the site undisturbed.

  • Preserving the site in its original condition.

  • Conducting limited, non-intrusive activities.

  • Preserving the site until an archaeological excavation can occur.

  • Carrying out partial or complete archaeological excavations.

• Methods for in situ preservation vary by site nature, material, and threats.

• Reburial is a common means of preservation using sandbags or artificial coverings.

• Reburial prevents biological damage, minimizes damage from currents and waves, and reduces interference from divers.

• Sand and sediments accumulate over protective layers, resembling the seafloor and protecting the buried heritage.

• These techniques are effective in protecting UCH sites worldwide.