Ocean acidification
Ocean acidification and a continual decline in the ocean’s pH will likely have drastic consequences for hermit crabs such as "Calcinus elegans". The shells of hermit crabs, primarily composed of calcium carbonate, are easily susceptible to a decline in pH. Low pH environments degrade calcium carbonate rapidly, creating a large amount of structural instability within the hermit crab’s primary defense system. Without proper protection from sturdy shells and a decline in the number of suitable shells within the environment, the population of "Calcinus elegans", and other hermit crabs may begin to drop. Studies have also been performed that indicate that the resulting stress of ocean acidification could be impacting the hermit crabs’ sense of smell. Insufficient sensory stimuli were found to reduce both feeding behavior and even the rate of shell exchange. As stated before, the sense of smell is key to the survival of "Calcinus elegans". If inhibited, many individuals may have difficulty sensing predators, and as such, populations could decline.