It is a beautiful night and you decide to walk by the coast get energised by the light breeze and sound of waves, as they beautifully break at the shore. In the distance you notice a magnificent yacht lit with colours that illuminates its most prominent features and surroundings. You find yourself lost at the sight.
This is one of the primary reasons yachts are equipped with underwater lights, to attract the attention of a large audience. Yet their allure expands further, as it transforms the sea into a natural, live aquarium, amusing their guests and passers-by in the marinas. And in the end how can one miss the opportunity of a night swim, the most relaxing experience after a lovely party?
All of the aforementioned have made underwater lights an integral feature.
Decorative light is only one category of underwater lighting, as there is also lighting for submersibles and submarines. Humans need to explore and this drive takes us now to the depths of the oceans. Although most would like to visit what oceanographers call the photic zone, deeper than 1000m, the area is only for naval submarines at this point. Nonetheless most leisure submersibles can decent easily to the euphoric zone, i.e. beyond the 100 m and their popularity is growing. Those that can pay the price don’t miss the opportunity.
It is a great opportunity for the yachtsmen. For a moment though, let’s stand from the viewpoint of the fish or crustaceans, what is their perspective? We see the light turning the sea into an aquarium yet turn a blind eye, as we laterally support predators continuing to get their prey through the night as well. Zooplankton and smaller fish could found refuge in the darkness, rest and grow. That is all gone now. Our lighting habits change all that and our entertainment is sourcing a top down regulation of the aquatic population.
We ought to understand that these lights are quite strong. One of the prominent brands in the segment propositions that they have the brightest light at 13000 fixture lumens, as another market leader suggest that the optimum design requires a fixture at every 2m. Can you estimate the lumen per m2? Then compare the result with the standard lighting in the supermarket of 750lumens output per m2. We have to factor in the percentage loss between the fixture and the output and that water has different transmission characteristics than air, the effect still is quite strong. There is no way one can miss the invasion on the marine environment.
Let’s look at another phenomenon, of photosynthesis, that is happening during daytime and scientists are estimating that it requires approximately 70lux (lumens per m2) to materialise. The aforementioned luminosity surpasses this level and can upset the norm to actually reach to a point that we can have nocturnal photosynthesis. The ongoing research hasn’t confirmed that possibility yet, but in the event it is confirmed, we are practically have the algae, cyanobacteria and plankton growing 24/7. Considering the finding on land based plants, who’s growth has been disproportional, we know that nutritional wise this process is producing negative result.
We have touched upon the fish and plankton near the surface, but the fish in deeper seas are subjected to a most unfortunate effect when coming across the lights of a submersible, as they are completely unfamiliar to bright lights. In the smallest case, this lights is damaging their photoreceptors and causing photobleaching. In the most severe cases, it affects their retina tissues and leads to permanent blindness.
Some weeks ago I was reading about a group of parkour athletes that goes in the night and switches off the signages light of luxury brands in Paris. Doing the same for a ship would be very dangerous but wouldn’t have a sound cause behind it? Yuval Noah Hariri names three massacres caused by us in his book “Homo Sapiens”, with the last during our present time, which is ironically the only one also affecting the marine life.
Although he have affected our environment quite extensively, it is possible to make sounder choices and limit the impact. We shouldn’t stop exploring and reaching greater depth, just moderate our invasion.
Going back to that initial walk from the beginning of this text, stand by the sea and look in the background the beautiful yacht lit only by the stars. Its silhouette is more illusive and less definitive, letting our fantasy fill the details. It is still a very beautiful image.