The subject of algae growth is likely one of the most frequently discussed among the freshwater and saltwater aquarium hobbies. Although we know that light and nutrients are key factors affecting the growth of unwanted algae, new research on the purpose of seasnake coloration can now help us better understand why algae grows in some places but not others. For a decade, I have personally noticed that new marine aquariums almost always grow algae on the plastic surfaces of the tank: the pumps, the overflow, the locline and most other plastic surfaces. Concurrently, Justin Credabel has noticed that algae prefers to grow on dark surfaces before lighter ones and in retrospect, I now realize that my observation of algae growth pioneering plastic surfaces also happened to all be black or dark gray. Scientist investigating the coloration of Sea snakes have shown pretty clearly that algae prefers to grow on black and dark surfaces over light ones, and that sea snakes balance the amount of dark color on their bodies. Keep reading to find out how seasnake researchers made this discovery and how this affects marine aquairum know-how.
Some populations of certain seasnake species have a banded pattern which ranges from very light to very dark and all patterns in between. Evolutionary researchers Rick Shine and Dr Adele Pile from the School of Biological Sciences at the University of Sydney wanted to know why there was such a variation in color pattern. Shine and Pile knew that some seasnakes experienced a degree of biofouling from algae growth so they made seasnake models with very light, very dark and banded patterns. The researcher placed these sea snake mimics in midwater for two weeks to see how algae would grow differently on the different patterns. The differently colored sea snake models showed that algae preferentially settled onto the darker snakes, and darker parts of the half colored snakes over the light colored areas. Like all reptiles, Seasnakes are cold blooded animals who must gain body heat from their environment. Since sea snakes live in water which wicks heat away 25 times faster than air, they frequently swim near the surface to absorb heat from the sun. The dark color of seasnake skin helps it to absorb heat but it also encourages algae growth that reduces it’s swimming speed. because of the interplay between heat and algae, many seasnakes split the difference and go half white and half dark.
So what does this mean for out tanks? The first conclusion that I draw from the research is that all of our powerheads, Streams, Korallias and Vortechs, are all colored black and the perfect color to attract algae spores and increasing biofouling of these devices. I like to keep my flow devices free and clear to keep flowrates high but I don’t exactly want to have to clean them any more than I have to. I am not advocating for white powerheads and flow devices but if submerged parts could be light to mid gray to reduce biofouling, what a simple change that would be. If you have frag racks, your white eggcrate will reduce algae growth while the black ones will encourage it. Who knows, maybe you want to grow coralline algae in which case you ought to be using black surfaces. What you do with this new found knowledge about colroation and algae growth is up to you and this research really underscores the need for reef aquarists to be interdisciplinary learners from all fields of science. Thanks to Justin Credabel for suggesting this post-worthy topic and bringing this study to our attention, more of which can be read in this Science Daily article.