25 October 2022
Intense activity in Aldabra
A look back at 5 days of intense activity in Aldabra
Arriving in Aldabra on 19 October on board the S.A. Agulhas II, the scientific teams continued the operations started on the first day. On 20 October, one of the scientists, a member of the English-speaking research team, suffered a head injury. In order to take all health precautions and in consultation with the ship’s doctor Brendan Quinn, the ship’s captain Knowledge Bengu and the scientific project leaders, the head of expedition Gilles Bessero decided to go to Grande Comores Island, the nearest destination, to carry out additional examinations at Kenia in Nairobi and then have the injured person repatriated to England. These reassuring examinations confirmed that the patient was out of danger. In the early hours of 22 October, the S.A. Agulhas II was back at work in Aldabra. Meanwhile, the teams that had already disembarked on 19 October had continued their work on the atoll and the others resumed their normal activities as soon as the ship returned.
The circulation of currents around Aldabra causes dense accumulations of plastic waste on the atoll. In order to determine the origin of this waste, Gwennaïs Fustemberg and Vyctoria Marillac Fernandes Da Costa carried out 11 transects on land during which they collected about 20kg of plastic samples. At sea, they carried out 12 traicts with the manta net to collect microplastics, potentially carrying pathogenic germs, particularly for the reefs.
World Coral Conservatory
During their days of underwater work, the World Coral Conservatory team collected 60 colonies of live corals, no larger than 15 cm, representing 21 species, during seven dives between 19 and 24 October 2022. These colonies, packed on deck 3 of the ship in storage tanks, will be transported to Mahé in the Seychelles, where they will be flown to several aquariums, including the Oceanographic Museum in Monaco and Océanopolis in Brest.
Nick D’Adamo, a member of the expedition’s advisory committee and a researcher at the University of Western Australia, has deployed nine surface drifters since the mission’s departure in Mauritius. Their function: to acquire temperature and salinity data to model these currents accurately and to study their influence on the distribution of biological biodiversity in the region. This data is also valuable for other projects. Students from the onboard school were also involved in the deployment of the buoys. A further 10 buoys will be deployed on the second Malha Saya leg.
On-board School: D-day
D-day for the students of the on-board school! The teachers asked the students to present a concrete expedition case, i.e. a project with figures from A to Z, including the scientific and logistical aspects, before an audience made up of the mission’s scientific project leaders and members of the Advisory Committee. This was a very instructive exercise and a great challenge for this young generation of researchers.
Since the beginning of the mission, CTD Rosette operations and Argo float deployments have followed each other at a good pace. 11 floats deployed out of a total of 29, 5 CTD Rosettes to a depth of 2000 metres with collection of water samples at different depths. As part of the Adopt a float educational programme, one buoy was adopted by a class in Reunion Island and another one is to be adopted by a class in the Seychelles and deployed on the second part of the expedition.
Other scientific operations in pictures
The team from the Royal Zoological Society of London, in collaboration with the Seychelles Islands Foundation, collected coral samples for DNA analysis, carried out video inventories of the underwater fauna and flora and implemented the ROV to a depth of 700 metres, a first here in Aldabra. The Ifremer GECOS and 4Sea teams, who remained on the atoll for these 5 days, carried out studies of turtle populations and mapping of the shallow waters and inventories of the atoll’s biodiversity using connected boards and also by drone. These were intense and productive days that will see further developments and descriptions in the days to come.