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The Common Octopus is Facing Even More Common Problems, and It’s Our Fault

Authors: Piper Evans, Agostina Galluzzo, Marissa Hernandez, Taylor Hauenstein

Octopus vulgaris, better known as the common octopus, is part of the class Cephalopoda. These octopuses are abundant in Mediterranean waters, as well as in the East Atlantic coasts. Like other octopus, they have 8 arms and lack an internal skeleton, reaching a length of 1-3 feet, including their arms, and a mass of 180-874 grams. They sustain themselves off small fish and crabs [1] [2], and live in depths ranging from 0-200 meters, decreasing in abundance with depth [3]. However, the common octopus is not “common” in the slightest; with extreme intelligence and no skeletal structure, the octopus has been known to be able to squeeze through any opening larger than its beak [4]. Their brain contains two enlarged areas that are specialized for memory storage. Stories have been recorded of octopuses in captivity being able to dismantle plumbing, escape their tanks, and even exhibit playful behavior, like squirt water to turn off lights [5]. As intelligent as they are, octopuses are in serious threat as we continuously expose them to the aftermath of human activity.

Most recently, with the issue of ocean warming and toxic pollution becoming more prominent, research has been focused on how increasing temperature and chemical waste affects this intelligent species both directly and indirectly. More specifically, how does this impact the unique life of a common octopus? There have been a few different studies on this subject that shows how changes in temperature and pollution could potentially alter the O. vulgaris way of life in immense ways. 

A warming ocean can have detrimental effects on an octopus starting from the moment they are laid as eggs. A 2013 study by Repolho et al. has shown that an increase in water temperature by only 3°C will negatively affect a developing octopus by enabling it to hatch prematurely, decreasing its chance of survival. In this way, an increase in temperature can be a direct cause of the decrease in abundance of our octopus friend.

Temperature will still be affecting O. vulgaris once the octopus reaches maturity as well. A study conducted in 2004 by researchers Katsanevakis et al. looked at how temperature might be affecting the metabolic rates of the common octopus. The metabolic rate is the amount of energy it uses per unit of time. Metabolic rates have a huge impact on animals, determining if and how they grow among other important biological aspects. Comparing octopuses living at 20°C and 28°C, the researchers found that octopuses living at higher temperatures had a significantly higher standard metabolic rate than those living at the lower temperature. This means that at higher temperatures, the octopus is having to expend a lot more energy on a day to day basis, limiting their overall growth.  

Not only are ocean temperatures on the rise due to climate change, it’s also being heavily polluted and acidifying faster than ever before. As humans continue to dump waste into the ocean, there have been numerous side effects found that can potentially destroy marine life. For Octopus vulgaris this means that they are having to deal with different metals and chemicals entering their habitat and severely affecting their ability to survive and thrive. It was shown in a study by Nicosia et al. that chemicals such as cadmium have negative effects on both growth rate and mortality rate of the common octopus. Cadmium is a chemical found in plastics, glass, batteries, and many other common ocean pollutants. The study found that after being exposed to cadmium, octopuses synthesize a heat shock protein called hsp70 that is used to prevent damage and is a general response to stress for the octopus. Because this protein was made by the octopus at such high levels when exposed to even small amounts of cadmium, it was concluded that the presence of cadmium is a major source of stress. In order to have enough energy be put into making these protective proteins needed for survival means that the octopus is forced to inhibit its own growth and decrease its chance of survival. 

Pollution determines the fate of the common octopus in more ways than one. As humanity continues to dump cosmetics and other man-made materials into the ocean, the immune system of the octopus is forced to fight off the chemical bombardment that comes with it. Immune systems are what allows animals to fight off potentially life-threatening diseases. If it is overworked or dysfunctional, then the animal is more likely to suffer from sickness or other related ailments much worse than the common cold. Titanium dioxide nanoparticles (nTiO2) are one of the lethal byproducts of human pollution that is affecting this species. This chemical is commonly found in cosmetics, sunscreens, and toothpaste, and is generally considered safe in terms of animal welfare according to the F.D.A. However, one study has shown that it may not be as safe as once thought. In 2013, researchers Grimaldi et al. performed experiments in order to see if nTiO2 would trigger a response in the immune system of the common octopus, and it did! The response showed an increase in lysozyme activity, hemocytes, and nitric oxide, the

main elements that enable an octopus to fend off diseases and foreign substances and keep them from deteriorating. The fact that they are responding to titanium dioxide shows that their immune system is being overworked and can potentially lead to more complications and even death. 

While this information is useful, more questions have arisen from these studies than answers. One thing is clear: these anthropogenic effects are taking their toll on this clever creature. From external morphological growth down to protein synthesis, warming temperatures and toxic pollution are negatively affecting one of the most abundant octopus species. However, this evidence doesn’t mean all hope is lost for our tentacled friend. Looking forward, scientists can continue research to find out which pollutants being dumped are harming marine animals the most. The same can be done to find solutions for the effects of rising temperatures. But there’s even smaller steps that we can all do to help; it may seem small, but being mindful of what we wash down our drains can make a huge difference. Try to avoid products with titanium dioxide nanoparticles and look for “non-nano” kinds (like sunscreen) instead! Even simple things like limiting your plastic waste and using natural cosmetics and home goods can make a huge difference. That way, our ocean friends like the common octopus can look forward to a healthy future full of play.




Citations

[1]  Nicosia, A., Salamone, M., Mazzola, S., Cuttitta, A. (2014).Transcriptional and Biochemical Effects of Cadmium and Manganese on the Defense System of Octopus vulgaris Paralarvae. BioMed Research International, 2015:1–11

[2]  Grimaldi, A. M., Belcari, P., Pagano, E., Cacialli, F., Locatello, L. (2013). Immune responses of Octopus vulgaris (Mollusca: Cephalopoda) exposed to titanium dioxide nanoparticles. Journal of Experimental Marine Biology and Ecology, 447:123–127

[3] Katsanevakis, S., Protopapas, N., Milou, H., Verriopoulos, G. (2004). Effect of temperature on specific dynamic action in the common octopus, Octopus vulgaris (Cephalopoda). Marine Biology, 146:733-738.

[4] https://www.scientificamerican.com/article/are-octopuses-smart/

[5] https://www.npr.org/templates/story/story.php?storyId=96476905?storyId=96476905

[6] Repolho, T., Baptista, M., Pimentel, M. S., Dionısio, G., Trubenbach, K., Lopes, V. M., Rita A. L., Calado R., Diniz M., Rosa R. (2013). Developmental and physiological challenges of octopus (Octopus vulgaris) early life stages under ocean warming. Journal of Comparative Biology 2014, 184:55-64. 

 [7] Sobrino, I., Silva, L., Bellido, J. M., & Ramos, F. (2002). Rainfall, river discharges and sea

temperature as factors affecting abundance of two coastal benthic cephalopod species in the

Gulf of Cadiz (SW Spain). Bulletin of Marine Science, 71(2), 851-865.



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