Bull kelp, Temperature, and Snails! Oh my!

Forgive the terrible pun, a perhaps too far departure from the iconic “Lions, tigers, and bears! Oh my!” line spoken by Judy Garland in the classic, the Wizard of Oz. Unfortunately, this post has little to do with the Wizard of Oz or lions, tigers, and bears – no more than what was just mentioned in fact. However, what follows is a brief story about snails and their food.

Chlorostoma funebralis, better known as the black turban snail, is about the diameter of a nickel or quarter and calls the coastal waters from British Columbia to California home. This type of snail commonly feeds on kelp and other seaweeds, though diligent scientists have discovered that it really likes kelp best. Bull kelp, less well known as Nereocystis leutkeana, is one such kelp that is found throughout its entire range. Bull kelp can grow at an amazing rate, up to 61 cm in a single day!


The black turban snail: Chlorostoma funebralis. (image: http://m0.i.pbase.com/o3/01/ 618801/1/116646180.9w59ZASC.turbansnail.jpg)

As scientists do, we set about an experiment in the laboratory – no white lab coats, goggles, or gloves in this instance, I’m afraid. We aimed to gain a better understanding the relationship between temperature and the black turban snail. In particular, we wanted to see if temperature would affect the amount of kelp that snails consume. We predicted that snails would eat more at higher temperatures. This marked the first exciting milestone in our grand experiment with snails.

So, how to figure out how much kelp snails consume? To do this, we set up four seawater-filled containers: two with kelp but no snails and two with kelp and two snails in each. For a total of 48 hours, one of each type of container was kept at room temperature or at about 10 degrees Celcius. We then measured the change in kelp mass that took place over 48 hours, and you have officially done science!

What we found was that higher temperature caused a decrease in kelp mass. While at first this doesn’t seem to make sense, remember this is a single detached blade of kelp. Like with flowers put in vase, they die and degrade over time. The kelp does the same in the water, only much faster. Higher temperature caused faster degradation and so more mass was lost. We also found that, not surprisingly, the snails decreased the amount of kelp after 48 hours. They ate it! Lastly, we didn’t find that temperature affected the amount of kelp the snails ate. This could have been because our experiment was too small or too short-lived to tell. Or, it could be true! Repeating the experiment is the only way to know for sure.

This is important since it helps us understand how changes to temperature could affect populations of the black turban snail and bull kelp!

For more information about black turban snails and bull kelp, see the links below:

Cool bull kelp facts!


Or, if you are feeling ambitious, this very interesting and relevant paper about Chlorostoma:



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