Credit: Curt L. Ontank
As the impact of climate change increases day by day, scientists are studying the ways in which human behavior contributes to harm. A recent study at Walla Walla University, through the collaboration of researchers from Walla Walla University and the University of La Sierra, examined the effects of acidic water on octopuses, which may provide new insight into how our activities affect the world around us, and the way the world adapts in response.
The study, “The effect of short and long-term exposure to high seawater PCO.”2 On the metabolic rate and tolerance of hypoxia in Octopus rubescens, “Focus on the metabolic rate of octopuses exposed to carbon dioxide acidified water, and the changes they have introduced in animals.2 It is a leading indicator of the increasing acidity of our oceans because much of the gas that humans release into the air dissolves into seawater.
Initial work in this area focused on the negative effects of ocean acidity: impaired growth of infected species such as hermit crabs, for example, or reduced survival rates of certain fish species over time. However, resilience has not received as much attention, especially when it comes to octopuses and other cephalopods. Studies have shown conflicting results, especially when it comes to the short term versus the short term. Long-term exposure to increased ocean acidity (OA).
For example, studies on cuttlefish showed no significant change in metabolism after exposure to increased OA, while cuttlefish exposed to the same conditions showed a decrease in aerobic metabolism, indicating reduced oxygen circulation in the subjects.
For the purposes of this experiment, the researchers used octopus rubescens, a small, easy-to-preserve octopus common on the west coast of North America. Subjects were exposed to increased carbon dioxide2Acidity formed for 5 weeks. The researchers measured routine metabolic rate (RMR) without prior acclimatization to acidic water, and then again after 1 week and 5 weeks. Critical oxygen pressure for people was measured at 5 weeks as well.
Metabolic rates are very expressive in such conditions because most physiological changes – such as smaller organs or reduced growth – are reflected in the metabolism shift. (Changes in physiology are basically changes in energy use, which can be observed by monitoring metabolism.)
The results showed an amazing amount of adaptability in the subjects, as well as possible reasons for the variation in the data in the other trials. Subjects experienced high levels of metabolic change during the first 24 hours of exposure to increased acidity: a departure from previous studies on various cephalopods, which showed a decrease in metabolic change.
However, when the same subjects were evaluated after 1 week, RMR returned to normal. The normal readings remained after 5 weeks as well, although her ability to function with low oxygen levels was affected by the increased acidity.
The results suggest that octopuses may be better able to tolerate changes in ocean acidity levels, which may have a long-term impact on our understanding of climate change. It is also the first study to compare the long-term and short-term effects of increased exposure to acids. More research is needed to elucidate the mechanism that drives change in RMR, but the experimental parameters – and the use of octopus rubiensis as test subjects – provide an excellent model system for studying the effects of OA on cephalopods.