by Elena Romano
A PROJECT FOCUSED ON SCIENTIFIC GOALS
We are in Cala Gonone Bay, East Sardinia, where several underwater caves have already been explored and mapped by local and foreigner cave divers but with low work on scientific aspects; the elements that could help in understanding the evolution of these caves and how they have and continue to interact with the open sea are still missing. Besides, most of these caves were in the past the preferred location of the Mediterranean monk seal (Monachus monachus), a species now in danger of extinction, and for this reason included in the IUCN (International Union for Conservation of Nature) Red List of Threatened Species, the most comprehensive inventory of endangered species on a global scale. The monk seal used to live nearby the caves during the reproductive period or to protect themselves from potential enemy and evidences of their presence were testified by several bones found in 2004, in Bel Torrente cave.
The project was focused on the study of the ecological aspect of cave environment, specifically Bel Torrente and Bue Marino caves, characterizing the sediment on the bottom by a physical and chemical point of view and studying the association of some very small organisms, benthic foraminifera, which live in the sediment and that are considered important environmental indicators because as they are very sensitive adapting sometime to environmental conditions and variation.
Superficial sediments (0-2 cm) and water have been collected from the entrance to 450 m distance in each cave, to analyze the variation of environmental condition from the marine area going inside the cave and checking the passage from marine to aquifer influence.
Initially, the guideline was re-surveyed in order to have a georeferred position of each station in the cave, starting from GPS position of the open water primary station; sediment collected at each station will be analyzed by researchers for living benthic foraminifera (stained with Rose Bengal solution), grain-size, C/N ratio and 13 Corg while water samples will be used to determine physical-chemical parameters (pH, redox, dissolved oxygen, temperature and conductivity) and the link existing between sediment and foraminifera associations.
On the other hand, the Mediterranean monk seal bones inside Bel Torrente cave have been surveyed, mapped and documented by means of photomosaic and detailed pictures, taking in particular account the lateral/ventral way of the skull and lateral/upper jaw view; the photomosaic was carried out to visually census the location of all the bone fragments, previously identified by numbered identification markers, to recognize their position in the detailed pictures. Also in this case was necessary to re-survey the specific cave section to georeference the bones in the cave.
GUE divers which participated to the project are from Belgium, Portugal, Germany, The Netherlands and Italy: Andrea Marassich, Claudio Provenzani, Elena Romano, Ricardo Constantino, Peter Brandt, Onno van Eijk, Jan Duikt, Jonas Patteet, Dorota Czerny, Marco Colman, Matthias Trappeniers, Ineke Van Daele, Katja Muermans, Anton van Rosmalen and Sander Jansson. During the first days of the project also the GUE divers from MY Pacific Provider gave support during the underwater activity.
As the logistic base was used Dimensione Mare diving center, by Fabio Sagheddu.