Once again I find myself in classrooms at Kodiak Middle School talking about ocean acidification. The causes and background, the chemistry, and the effects on shell building animals and why it all matters for us in Kodiak are topics we discuss and explore with lectures and hands-on experiments. Due to a curriculum change I get to teach about ocean acidification in two grade levels this year; last year we learned about ecosystems in the ocean.
While those of you who read this column regularly are well familiar with the topic, and it certainly is no longer new to science, there are still many people uneducated about the connection between the burning of fossil fuels and the chemical changes affecting our ocean and fisheries. Because fisheries and any long lasting and large changes to the fisheries are so important for all Alaskans, a push to teach ocean acidification in the school curriculum is making waves. In March, I am invited to a workshop in Juneau to share with other teachers how I approach the topic of ocean acidification in the classroom.
One of the things I always show the kids is a website called virtualurchin, which is created by the University of Stanford. Among a number of great online resources, there is a virtual laboratory where you can learn how sea urchin development gets affected by an increase in ocean acidity. Several weeks ago a team of four 8th grade students contacted me and asked if they could replicate something like that virtual sea urchin experiment in the Kodiak Fisheries Research Laboratory. Making sure the team understood that any experiment you do for the first time carries the risk of not yielding any data, because there may be numerous things that can go wrong, we set out to study the larval development of green sea urchins under different acidification scenarios.
First, the students read a paper about a similar study. Then, they developed their experimental design and hypothesis, while I talked to one of the divers at the Kodiak Research Laboratory about getting a few urchins. When all was set, the team learned how to prepare a solution of potassium chloride and how to perform a volumetric measurement to determine how much solution to inject into each urchin to initiate spawning without causing harm to the animal. Since each student had watched the steps on the virtual lab they were able to perform the real life injections like a group of professionals.
Nature has a way of messing with science experiments. There is no way to tell from the outside whether a green sea urchin is a he or she. Out of the 8 urchins we had available, four were not ready to spawn and the other four were all males, which dutyfully released copious amounts of sperm into the test beakers. Referring to a study about when sea urchins around Kodiak get ready to spawn we knew that the males are a little sooner than the females. Determined not to give up that fast, we tried again 4 days later. This time we were in luck. Two females laid eggs and three males provided the sperm, so that the students were able to mix the gametes in beakers and add them to the three beakers with different degrees of acidification.
If we had had the time to check the eggs every few hours we could have studied early egg development. Realistically, the students could only come once a day to check on their experiment. After only a couple of days it became evident, that the urchin larvae in the more acidified water were developing slower. On days 3 and four the students took random samples from each beaker and counted the proportions of fully developed, dead, and not fully developed larvae. Then, they had to translate their numbers into proportions to account for the fact that we did not start with the same amount of eggs in each treatment.
I continued the incubation over the next weekend and 10 days after the initial fertilization I took one last look at the larvae. In the most acidified water dead urchin lavae were getting consumed by a host of microbial organisms. In the control treatment beautiful sea urchin larvae with long spines were floating serenely through the water. In the less acidified water I found live sea urchin larvae, however their spines were stunted and shorter.
The hardest part of science is that the real work comes after the fun of discovery. Now, the students have to write a research paper and present their results. The paper is supposed to get submitted to an ecybermission science competition. If the team does an awesome job, they might be in the running for a $1,000 prize per student. That prize money may be a good motivator to do the work, but
besides learning a lot about how to design an experiment, conduct it, use the lab equipment and record and analyse data, the students and I enjoyed watching the miracle of life starting on a microscope slide in front of our eyes. What an amazing experience!
Kodiak Middle School 8th grade students Josala and Stephanie use a pipet to sample sea urchin larvae from their experiment.