Run Crustaceans, Run!
When humans fall ill, we can go to the doctor to receive a diagnosis and treatment. We have a form of communication, and our body has good indicators that can help the doctor diagnose the problem. But what happens when we are trying to diagnose organisms that have no way to tell us what is wrong, and no way of knowing how badly they are affected? For instance, in the case of many marine organisms, illness is being caused by humans. We have used our oceans such that they now contain areas with little to no oxygen, where life is barely sustainable. How does this, combined with ongoing pollution and human activities, stress marine life?
Researchers at the College of Charleston recently faced this problem, and have developed a method of “talking” to crustaceans such as shrimp and blue crabs through motor physiology. Karen and Louis Burnett have created an underwater treadmill to determine vital signs as a measure of stress. The study organisms are infected with bacteria, and water conditions on the treadmill can be regulated to encompass various oxygen levels, pH, and other water quality characteristics. Vital signs such as heart rate and blood pressure from the infected animals can then be compared to those of uninfected animals in the same water conditions (the same vital signs that are used in human stress tests). The studies are also looking at muscle physiology to examine the use of aerobic and anaerobic respiration to molecularly determine how stressed animals are affected. How are abilities necessary for their lives, such as walking and swimming, affected by bacterial infections and water oxygen levels? The Burnetts have found that uninfected animals perform better on the treadmill, and that infected animals have a hard time taking up oxygen due to immune responses. Additionally, the animals’ ability to fight infection is negatively affected by a low oxygen supply in the water. Continual study to answer questions such as these will help assess what we can change in our use of natural resources.
See an interview with the Burnetts here.
And just for fun…here’s shrimp on a treadmill!
Energy metabolism and metabolic depression during exercise in Callinectes sapidus,
the Atlantic blue crab: effects of the bacterial pathogen Vibrio campbellii – The Journal of Experimental Biology