the project grotta azzurra - over the blue: hypothesis of ... · title: the project grotta azzurra...

Endolithic eukaryote and prokaryote microorganisms produce micro- galleries through biochemical dissolution due to the production of acidic or chelating substances.

Sandra Ricci and Barbara Davidde Istituto Superiore per la Conservazione e il Restauro, Via di San Michele 23, 00153 Roma sandra.ricci@beniculturali.it; barbara.davidde@beniculturali.it Filomena Lucci Architect specializing in restoration of monuments and landscapes, Bacoli (Napoli) filomenalucci@tiscali.it

The Project Grotta Azzurra - Over the blue: hypothesis of valorisation and study of the state of conservation of the marble statues

Sandra Ricci, Filomena Lucci and Barbara Davidde

The cave used by Emperor Tiberius as nymphaeum has been observed only in Dec 1975 and Jan 1976 during the resounding recovery of the statues lying on the seabed. The statues were part of the sculptural furniture and among them there was probably an underwater Thyasos.

The project •Architectural-urban study of the Nymphaeum correlated to the sea area of the imperial maritime villa •Archaeological study of statues for the political and religious interpretation •Biological study of the damage of the artefacts due to a typical cave environment •Geological study of the submersion phases of the cavity via the observation of wave erosion and possible spring waters that could carry water to the Nymphaeum

The multidisciplinary project includes the study of the state of conservation of the marble statues recovered underwater in the 60s from the Grotta Azzurra.

The research is focused on the characterisation of the various forms of degradation, using different analytical methods. The examined submerged artefacts showed various degrees of damage to very serious alterations caused by the direct action of epilithic, chasmolithic and euendolithic organisms.

Biological study

Bivalve molluscs play an essential role in the bioerosion processes creating cavities of various length and width, according to the shell or body size.

The genera known for rock boring are Lithophaga, Gastrochaena, Petricola and Coralliophaga.

The most frequent type of bioerosion is the pitting, caused by different species of endolithic sponges which create galleries and chambers.

Euendolithic organisms are the most dangerous because they dig cavities or tunnels into the rock through chemical and physical mechanisms.

The bioerosion is very significant because the artefacts were exposed to the biological agents in the same position for a long period of time, and it was verified that the combined action of sponges and bivalves can lead, over time, to the destruction of large portions of the artefacts.

International Scientific Colloquium on Factors impacting Underwater Cultural Heritage 13 December and 14 December 2011 in Brussels (Belgium)