Experimental Design: It can be a Crabshoot
Hello again, readers! June is over, and summer is starting in earnest! This marks the end of the second week in the REU program here at OIMB. This week was filled primarily with deciding on and designing our projects for the rest of the term. There are so many ways to approach the subject of trophic ecology; essentially the “who-eats-who” of an ecosystem. One of the common questions is: how do energy and nutrients get from the place where they enter the ecosystem all the way up to the higher levels of the food web? In terrestrial ecosystems, the trend can be a bit more straightforward; plants capture sunlight, and use carbon dioxide gas and water to produce sugars and other molecules which they use to build their bodies. Primary consumers (herbivores) such as bugs, deer, birds, or other herbivorous animals eat those plants, and are then eaten by secondary consumers, and so on up the food web.
In marine ecosystems, this pattern tends to vary somewhat, though follows the same general pattern. In coastal ecosystems, energy enters as sunlight and is captured primarily by algae and photosynthetic plankton. How this energy gets distributed may follow a similar pattern as mentioned before, though can become a bit more convoluted. Many types of marine animals eat algae, but also eat each other; there tend to be a lot of opportunistic behaviors, especially when the presence of algae or other primary production is low. Some animals, such as the purple sea urchin Strongylocentrotus purpuratus, consume algae but tend to be “messy eaters” meaning they shred the food particles into small pieces, which are much more accessible to small animals such as snails or developing crabs. Their waste might also be enriched in nutrients such as nitrogen or phosphorous. Thus, the waste from urchins (primarily their poop), and perhaps even the algae itself, might be an important food source for young crabs, providing some of the essentials needed for growth in their juvenile stages until they are large enough to eat other things. I plan to study how different diets- such as different types of meat, algae, and sea urchin waste- affect growth rates in juvenile Dungeness crabs (Cancer magister).
This week we also attended a seminar on the synthesis of art and science, exploring topics such as science communication, biological illustration, and the ways that science inspires art, and vice versa. The week also included a LOT of tidepools; searching for and collecting some specimens for projects, learning about the ways that the structure and location of tidepools influence what is there, and just exploring the beautiful places the Oregon coast has to offer, such as the Cape Arago Lighthouse (below), Sunset Bay, and Bastendorff Beach. Several students were able to find an octopus, though I wasn’t there for that (sad day).
Now, at the end of the week, I’m preparing to begin the six-week experiment collecting data on Dungeness crab growth. The question has become: how do I fit 75 crabs in containers in a small water table while making sure they all have adequate water flow, oxygen, and space, without any cross-contamination? More on that to come.
Thanks for reading!
Hey, readers! My name is Zade Clark-Henry. I'm from Salem, Oregon, and I'm an undergraduate student majoring in Natural Resources at Oregon State University, with an emphasis ecological studies, specifically forest ecosystems and ecological restoration. I'm interested in all types of science, but especially life sciences, and within that I'm most interested in ecological interactions between organisms. My non-academic interests include playing music, hiking, camping, exploring, kayaking, reading, and drinking tasty espresso.