ANTARES is a project leading towards the construction and deployment of a neutrino telescope in the deep Mediterranean Sea .
The telescope will use an array of photomultiplier tubes to detect the Cherenkov light emitted by muons resulting from the interaction with matter of high energy neutrinos .
In the vicinity of the deployment site the ANTARES collaboration has performed a series of in-situ measurements to study the change in light transmission through glass surfaces during immersions of several months .
The average loss of light transmission is estimated to be only \sim 2 % at the equator of a glass sphere one year after deployment .
It decreases with increasing zenith angle , and tends to saturate with time .
The transmission loss , therefore , is expected to remain small for the several year lifetime of the ANTARES detector whose optical modules are oriented downwards .
The measurements were complemented by the analysis of the ^ { 210 } Pb activity profile in sediment cores and the study of biofouling on glass plates .
Despite a significant sedimentation rate at the site , in the 0.02 – 0.05 cm \cdot yr ^ { -1 } range , the sediments adhere loosely to the glass surfaces and can be washed off by water currents .
Further , fouling by deposits of light-absorbing particulates is only significant for surfaces facing upwards .