Does artificial high intensity light damage permanently dark ecosystems?

Question

Popular science features on wildlife typically capture camera images using natural light, or high-speed exposures. This is not possible where the ambient light is extremely poor. E.g. Caves, Undersea

For beings accustomed to the stygian dark, the high illumination for a video camera and/or the flash of a still camera could both be the equivalent of a 1" spanner wallop on the head or worse. Do we, inadvertently, injure the local ecosystem this way?

Answer 1

I don't know how harmful the exposure to a camera flash could be to organisms that live in complete darkness. However, since the animals that live in this conditions are usually blind, and the time of exposure is quite short, it's reasonable to assume that the damage produced should be minimal.

In the case of caves, permanent artificial illumination is very destructive to the environment, but the effect is due mainly to temperature changes and the introduction of organisms coming from more illuminated parts of the cave (cave organisms are usually slow and react poorly to light, so they are an easy prey if they're under light). In fact, for tourist activity, the use of lanterns or miner helmets is highly recommended.

In the case of abyssal ecosystems, ecological invasions are less likely, since there still exist a vertical barrier based in temperature, oxygen and carbon dioxide concentration and pressure. However, in this ecosystems there exist many animals which are very sensitive to light, due to the prominence of bioluminescence. Some of this animals could be damaged by the kind of light you describe. However, it's very unlikely that the main functioning of this ecosystems could be affected because of its extensive size. Moreover, the low population densities it has implies that even very long submersions would encounter only a few samples (with the exception of volcanic vents and some other geological curiosities which, in fact, are even more isolated from the rest of the biosphere by physical and chemical barriers), so the global effect should be negligible.

Answer 2

Yes, it's possible to damage dark-adapted ecosystems this way, and there are at least a few examples of it happening:

• Deep sea Norwegian Lobsters were blinded by being brought to the surface as bycatch by fishermen (or by scientists tagging them). The original paper is Loew 1976, a more recent paper (Chapman et al. 2000) suggests that even a <1 minute light exposure could cause significant harm, which suggests a camera flash could certainly have an effect.
• There is evidence that shrimp that live by deep-sea hydrothermal vents have been blinded by the floodlights of exploratory vehicles (Herring et al. 1999).

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Chapman, CJ et al. (2000). Survival and growth of the Norway lobster Nephrops norvegicus in relation to light-induced eye damage. Marine Biology 136:233-241 doi:10.1007/s002270050681

Herring, PJ et al. (1999). Are vent shrimps blinded by science? Nature 398:116 doi:10.1038/18142

Loew, ER (1976). Light, and Photoreceptor Degeneration in the Norway Lobster, Nephrops norvegicus (L.) Proceedings of the Royal Society of London. Series B, Biological Sciences 193:31-44