Week 4: Phytoplankton Limitation Experiment 2

Ahhh another week, another experiment! The joys of science! This past week we again collected water from our same four sites throughout the estuary. Having mastered, or at least improved, our procedures and techniques for the experiment we were looking to clarify some of the results from our first run through. As you may or may not recall, our first week suggested that the OSU had a significant response to the “+N” and “N+P” treatments, suggesting nitrogen limitation. While the sites further upstream tended to show “P” limitation, with Elk City showing some variability. These are all results we were looking to clarify. Would OSU still be nitrogen limited? Or had we sampled during a period of weak upwelling? Would Elk City and the sites up river have a clearer response?

As we progressed through the week, and hadn’t had many answers to these questions, we began to grow a little nervous. 3-4 days of results from the mesocosms weren’t providing many answers. This seems to be how these nutrient limitation experiments go, as often times there are fews signs that point to limitation, and then all of a sudden a huge response. This is difficult to account for as the week comes to a close, and the difficult decision of whether working on a weekend will produce results needs to made, as it could be that no response is the actual result. This week we decided to go for it and see if Saturday would give us the breakthrough we were hoping for.

It turned out that Saturday was largely a success. We determined that there was in fact a significant “P” and “N+P” at Elk City. Cannon Quarry showed similar results, but with more variability in the “N+P” treatments. Toledo also showed significant responses for these two treatments. As for OSU? Less clarity than had been hoped for. The week’s data trends point to “P” limitation as opposed to the “N” limitation that initially occurred, perhaps indicating stronger summer upwelling. However, there is fairly large variability in the “P” and “N+P” treatments, meaning the statistics are throwing a wrench in our quest for results! There may be bright spot though, as  our chlorophyll extractions could provide clearer, more accurate results. This is a big maybe though. We seemed to have some problems with severe degradation in our samples during the first run through, so hopefully those problems magically disappeared! We were quite puzzled as to how it could have happened. And so with that sense of bewilderment fresh in your mind, I will again leave you in suspense! Tune in next week for the results of the chlorophyll extractions! Will the mysterious source of degradation strike again? Or will the chlorophyll respond to my careful, sweet nurturing? Until then! Good night and good luck!



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1 thought on “Week 4: Phytoplankton Limitation Experiment 2

  1. How will it end?! I can’t wait to find out! Thanks for the great presentation on Friday, too.

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