Happy September! While summer isn’t officially over yet (there’s still time to beach and enjoy summer produce!), the start of a new semester is a good time to reflect on the last few months of work.
It was an eventful summer for me – I deployed and repeatedly sampled two field experiments for my master’s thesis, mentored an awesome intern, and spent some time traveling to see family and present at ESA.
It’s a bit too much for one blog post to dive into both experiments, so I’ll highlight one.
One of the experiments I deployed this summer examines what drives intertidal eastern oyster distributions in the Northeastern United States. Up here in New Hampshire’s intertidal zone, a macroalgae called rockweed covers much of the shoreline.
Here, it seems that when eastern oysters occur in the intertidal zone, they occur primarily under rockweed as individuals, or in small aggregations – nothing like the huge intertidal oyster reefs that you might see in the Mid-Atlantic. Why might this be? Does rockweed reduce extreme temperatures, thus improving survival prospects? Does rockweed protect young oysters from predation by, for example, invasive green crabs?
To answer these questions, I designed a full factorial experiment, with rockweed cover as one of the variables (covered or uncovered) and predator exclusion cage as the other variable (caged, not caged, or partially caged). Excluding predators to varying degrees will help us see whether predation affects oysters in general, and whether predators interact with rockweed in some way.
Setting up the experiment took quite a bit of time. I settled on using concrete pavers as the basis for each treatment “plot” because they’re heavy enough to stay put, and they provide a nice standard unit to sample. I spent most of May drilling and drilling and drilling so I could easily affix some additional sampling units to the pavers. Then my labmates kindly helped me haul these pavers into the field (each one is 17 lbs!), where they’ve been sitting ever since.
I had an amazing team of interns, labmates, and friends helping me sample this experiment each month.
Together, we’ve measured lengths and widths of 240 oysters 4 times over! That’s 1,920 caliper measurements...phew! Of course, it’s not just all about the oysters in the field. We’ve seen a lot of beautiful wildlife in New Hampshire’s Great Bay. Horseshoe crabs, great blue herons, other egrets (I’m not so good at bird ID), and eels, among other animals!
Now, I’m still working through the data to figure out what’s going on. So far, < 7% of total oysters have died even after the hottest months of the year, so it might be that winter is a more stressful time for oysters instead of summer. I’m going to keep checking on these pavers monthly until April 2026, so we’ll see how the winter goes...stay tuned!
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