Octopus is a seafood delicacy that can help prevent heart disease, lower cholesterol and regulate blood sugar levels. It also contains the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which may reduce depression symptoms in some people. However, it is high in sodium and should be eaten in moderation, especially by pregnant women.
Marine biologists Lloyd Trueblood, associate biology professor at La Sierra University, and Kirt Onthank, associate biology professor at Walla Walla University, recently analyzed the East Pacific ruby octopus (Octopus rubescens) in one- and five-week studies at WWU’s collaborative Rosario Beach Marine Laboratory. Their analysis was the first to look at an animal’s natural behavior in short-term ocean acidification, caused by the rapid increase of carbon dioxide into the atmosphere from burning fossil fuels.
The research aimed to find out whether octopuses can camouflage themselves by mimicking their surroundings, and how the animals cope with a changing environment. To do this, the scientists placed octopuses in tanks with clear water and then added varying amounts of turbidity (cloudiness) to the tank. They then measured the octopuses’ skin spectra against the spectra of green algae, brown algae and orange sponges that they typically live among.
They found that octopuses with clear water were able to match their skin spectra with the algae, brown algae and sponges to some extent, but this ability declined in the presence of more turbidity. They also found that octopuses are able to distinguish their own color from the background, but only within a limited range. In addition, the octopuses’ camouflage was more effective in clear water than in deeper, darker waters where colour-matching would be harder.
In the future, the researchers hope to examine the ways that octopuses deal with changes in the acidity of their ocean home. This change happens when CO2 from burning fossil fuels dissolves in the seawater, lowering its pH level and causing it to become more acidic. This process, known as ocean acidification, is expected to occur across the globe by the end of this century if human emissions continue at current rates.
To help protect themselves from the effects of ocean acidification, octopuses may be adjusting their behaviour by editing RNA, changing gill transport proteins and modifying blood oxygen-carrying proteins to adapt to a new reality. The researchers also plan to study the octopuses’ ability to cope with other stresses, including temperature extremes and decreased oxygen supply. Their work could lead to ways to improve the health of our own planet’s oceans by reducing the amount of CO2 released into the air from human activity. This is vital for sustaining life on earth, because a more acidic ocean means less food for marine animals. This is a big problem because many species of fish and shellfish are threatened by ocean acidification, making it even more important to reduce our environmental footprints. A diet low in carbon dioxide and high in plant-based foods is the best way to reduce our carbon footprint.