title: The spectral and spatial distribution of light pollution in the waters of the northern Gulf of Aqaba (Eilat).
abstract: The urbanization of the shores of the Gulf of Aqaba has exposed the marine environment there, including unique fringing coral reefs, to strong anthropogenic light sources. Here we present the first in situ measurements of artificial nighttime light under water in such an ecosystem, with irradiance measured in 12 wavelength bands, at 19 measurement stations spread over 44 square km, and at 30 depths down to 30-m depth. At 1-m depth, we find downwelling irradiance values that vary from 4.6 × 10-4μW cm-2nm-1500 m from the city to 1 × 10-6μW cm-2nm-1in the center of the gulf (9.5 km from the city) in the yellow channel (589-nm wavelength) and from 1.3 × 10-4μW cm-2nm-1to 4.3 × 10-5μW cm-2nm-1in the blue channel (443-nm wavelength). Down to 10-m depth, we find downwelling irradiance values that vary from 1 × 10-6μW cm-2nm-1to 4.6 × 10-4μW cm-2nm-1in the yellow channel and from 2.6 × 10-5μW cm-2nm-1to 1.3 × 10-4μW cm-2nm-1in the blue channel, and we even detected a signal at 30-m depth. This irradiance could influence such biological processes as the tuning of circadian clocks, the synchronization of coral spawning, recruitment and competition, vertical migration of demersal plankton, feeding patterns, and prey/predator visual interactions.
authors.affiliation: The Mina &Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel.|The Interuniversity Institute for Marine Sciences of Eilat, Eilat, Israel.
authors.forename: Raz
authors.initials: R
authors.lastname: Tamir
authors.affiliation: Ocean BioOptics and Vision (OBOV) Laboratory, National Institute of Oceanography, Oceanographic and Limnological Research, Tel-Shikmona, P.O.B. 8030, Haifa, Israel.
authors.forename: Amit
authors.initials: A
authors.lastname: Lerner
authors.affiliation: Fredy and Nadine Herrmann Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.
authors.forename: Carynelisa
authors.initials: C
authors.lastname: Haspel
authors.affiliation: The Mina &Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel.
authors.forename: Zvy
authors.initials: Z
authors.lastname: Dubinsky
authors.affiliation: The Mina &Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel.|School of Agriculture and Environmental Studies, Beit Berl College, Kfar Saba, Israel.
authors.forename: David
authors.initials: D
authors.lastname: Iluz