The potential influence of bioluminescence from marine animals on a deep-sea underwater neutrino telescope array in the Mediterranean Sea

The density of bioluminescent organisms in the water column was measured using a vertically descending impact screen technique at experimental underwater neutrino telescope sites in the Eastern Mediterranean (Ionian Sea NESTOR 36°37′N 21°21′E) and in the Western Mediterranean Sea (Ligurian Sea ANTARES 42°25′N 6°11′E). The mean density at depths >1500 m in the Ligurian Sea was 0.622 m−3 and at 1500–2500 m in the Ionian Sea it was 0.068 m−3. At greater depths in the Ionian Sea, density decreased to 0.043 m−3 at 2500–3500 m and 0.018 m−3 at >3500 m. At these densities it is predicted that the effect of natural background bioluminescence would be negligible in its effect on the telescope. Modelling encounter of bioluminescent organisms carried in deep-sea currents impinging on a telescope photo-detector predicts bioluminescent flashes, 16.59 h−1 at ANTARES and at NESTOR 1.84 h−1 at 1500–2500 m depth, 1.16 h−1 at 2500–3500 m and 0.49 h−1 at >3500 m.