Sherry Tamone is a crustacean physiologist at the University of Alaska Southeast in Juneau who recently started studying the affects of OA on shrimp.
I recently received funding from Alaska Sea Grant to study the potential effects of ocean acidification and warming temperatures on the physiology of the Northern spot shrimp (Pandalus platyceros). My lab is interested the physiology of molting (growth) and we know that molting is an energetically expensive process. We think that living in a warming an increasingly acidic environment will have a metabolic cost to growing animals. We will test this hypothesis using juvenile spot shrimp that may be most susceptible since they need to molt more often.
Q: How do you run this type of experiment?
This is a great question because in order to run this experiment you need to have newly settled juvenile shrimp. We actually collect females with embryos with the help of the Alaska Department of Fish and Game in late November and keep them fed in our seawater laboratory at the University of Alaska Southeast. When the embryos hatch, we spend about 60 days caring for them through their planktonic larval stages until they undergo a metamorphosis and settle to the bottom of their tanks. At this point, they are quite small, but ready for the experiments. The experiments require that that the juvenile shrimp be exposed to normal seawater, warmed seawater, acidified seawater, and warmed acidified seawater. After exposures, the metabolic rates of all shrimp will be measured to see if any of the treatments have effects on their metabolic physiology.
Q: We know you’re putting together a flow-through system to simulate changes in temperature and pH and these are challenging to build. What have you found so far, and do you have any tips for people trying to replicate this process?
Yes, because we have a limited budget we had to build our own pH control systems. We are collaborating with Dr. Kirt Onthank at Walla Walla University who has experience in building low cost pH stat systems for monitoring and controlling the carbon dioxide chemistry of the seawater tanks. The challenge to these experiments is adding CO2 into the flow-through system at just the correct concentration to maintain conditions of ocean acidification. This does require one to measure the chemistry of the seawater regularly to make certain that the desired environmental conditions are remaining stable. While the cost of the controllers is reasonable, the time required to build these units is significant! Be prepared to become an expert at soldering, working with computer boards, cutting PVC pipes and plumbing!
I am a crustacean physiologist (endocrinologist) who has spent my adult years studying growth and reproduction in crabs, shrimps, and lobsters. I was always fascinated by the complex physiology of molting of crustaceans in graduate school in California. When I moved to Alaska, I learned more about cold-water physiology and how it impacted the coordination of molting and reproduction (two energetically demanding processes) in the crabs that I was studying. The reality is that invertebrate animals have an energy budget that allows for specific physiological processes and when an external stress (ocean acidification or increased temperature) imposes a metabolic cost, then some physiology will be compromised. As a physiologist, I have been interested in how organisms respond to stress including environmental change and it is difficult to assess change if you do not have data concerning the “normal” or baseline physiology.
Q: I know you work closely with students. How have you involved students in your projects and what advice do you have for students interested in ocean acidification or ocean change?
I have a great lab that includes undergraduate and graduate students. Undergraduates begin in my lab learning about shrimp husbandry and helping one another keep the animals healthy. Some students take on specific projects and learn scientific techniques that allow them to perform experiments to test their hypotheses. All of my students read scientific papers to understand the current knowledge of ocean acidification. There are so many avenues for a student to study marine science related to ocean acidification that they should discover what area is most interesting to them. They could be very interested in oceanography or organismal physiology. Those are very different areas of study that both relate to ocean acidification. Students should be prepared to be interdisciplinary in their studies in marine science. My graduate students are required to take courses in biological and chemical oceanography as well as physiology and statistics.
Q: Please tell us about a memorable moment from working with shrimp or marine biology in Southeast Alaska
One of the most rewarding aspects of working with shrimp in Southeast Alaska is getting out in the field, on the ocean to collect the research animals. I can remember setting pots near a small island near Juneau on a warm summer day with humpback whales nearby. Pulling the pots, we would often get more than just our target species and would sometimes have a giant Pacific octopus and beautiful basket stars in the pot. It can be a lot of physical work but very rewarding.