| Type |
Oceanographic cruise |
| Ship |
Archipelago |
| Ship owner |
Divers Prive |
| Dates |
03/11/2005 - 05/11/2005 |
| Chief scientist(s) |
COLACO Ana |
|
DOP/IMAR (DEPT. DE OCEANOGRAFIA E PESCAS) University of Azores Rua Prof. Dr. Frederico Machado 9901-862 HORTA 351.292.292944 |
| Objective |
The objective was to recover a Test mooring (Archipelago vessel), the MOB0 set there during the EXOMAR cruise. MOB0 is made of an aluminium structure (re-used from a Prosper fishery science mooring), 2 acoustic releases (AR391 n° 24 and 25) and an ASSEM power pack. Photos are taken with a Hytech camera developed for Victor with local photo storage fitted with a pilot card (OSEAN). The camera's porthole has an antifouling system (ERT/IC, Micrel). Two LED (Dynasub) projectors supply needed lighting and are controlled by the OSEAN card. One of the projectors has the antifouling system. Since the latter didn't work in the laboratory, it was disconnected before mooring was deployed. The mooring is also equipped with an Argos beacon (25843), a radiogoniometer (channel 73, 156.675 MHz) and a flash attached to the lens on the syntactic foam float. In the framework of the MoMAR programme, our objective was to install this module (and its replicates) on vent mussel beds in the Lucky Strike hydrothermal fields (Mid-Atlantic Ridge) in order to obtain the first temporal data on these communities' dynamics.
There was significant corrosion on the structure (not far from releases), on the stainless steel clips of the camera and the flashes. The anodes on the releases were almost completely gone. The camera's porthole was very clean (SnO2 coating + polarization 5mn ON / 5mn OFF). The porthole of projector N°1 (SnO2 coating, but not polarized) displayed some very slight deposits. The porthole of projector N°2 (without protection) was clean. Thus it seemed that biofouling did not develop much during the 3 months of exposure. The antifouling system worked properly. The unpolarized SnO2 coating provides a rougher surface than the "uncoated" porthole. In the case of a breakdown, this becomes a disadvantage. 97 photos were unloaded, and they clearly show the sedimentation of particles on the test target without any appreciable change in their quality. The chlorination unit was reset (only 17 measurements dated 1/1/2003) most likely by a power cut. Likewise, after four days of normal operation, the dating of photos was reset (date: 1/1/2000 at 00:00) and this applied to each shot. This problem must be addressed and solved before the next deployment.
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