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!

Well first of all, happy belated Fourth of July! This past week I spent time further analyzing the data from the first run through of the experiment, while also doing all the preparation necessary to start it up again. Interestingly, a test used to more accurately measure chlorophyll (a different test from the initial results) showed less confidence in our data set. As a consequence we have decided to add another replicate to each treatment. For those keeping track at home, the math now changes to 4 x 4 x4 or 64 bottles floating around in our little mesocosms. I won’t bore you with the details, but this significantly adds to the work involved in running the experiment.

I promised last week to discuss the consequences of nutrient limitations in estuaries, so lets delve into that a bit. Nutrient limitations of phytoplankton are an interesting topic of discussion. You may have heard about two relatively popular topics in the media related to these ideas. These are iron fertilization and the dreaded “dead zones.” These topics show the potential benefits of understanding nutrient limitation, and also the potential for havoc. They are two sides of the same coin. Iron fertilization seeks to enhance phytoplankton blooms in an under productive area of the ocean in an attempt to remove carbon dioxide levels in the atmosphere. In these areas, iron is largely seen as the limiting nutrient. “Dead zones” in contrast to the less productive open ocean, usually occur in the productive areas and result in eutrophication. Eutrophication is the direct result of an abundance of the nutrients in a system. These nutrients may come from natural processes like upwelling events and nitrogen fixers, but also from human wastes. These nutrients, in contrast with the iron limited open ocean, are largely nitrogen and phosphorous. Eutrophication decreases the available dissolved oxygen in the water as an abundance of phytoplankton bloom and ultimately die like all life on earth. This decrease in available oxygen is the reason for the term “dead zone.” As you can imagine, a decrease in available oxygen is undesirable for marine ecosystems.

So what does all this mean for Oregon’s estuaries? Well, if out of our 64 bottles a treatment shows a significant response for say phosphorous or “P”, we know that region is phosphorous limited. For an agency like the EPA, this directly translates into tools for management and policy. My advisor is  working on tools for scientists from states throughout the country to be able to identify conditions in which nutrient limitations may be a factor. Regulations may also be crafted to prevent phosphorous wastes in fertilizers and other sources from polluting aquatic systems and ultimately harming species by depleting the available oxygen.  And so, while I spend my hours of the day pulling bottles out of a tank and doing science on them, I can take pride in knowing that yes, this matters. Alrighty, that’s all for this week. Stay tuned for next week in which I may have some more results from the experiment! Here’s hoping for clarity!

The Mesocosm or "Tank 1"

Monday arrived this past week, and with it came the dawn of the project I will be working on this summer. I collected 35 liters of water  from 4 sites throughout Yaquina Bay. One of the sites, “OSU Dock” as the EPA calls it, is right outside the Hatfield Marine Science Center Visitor’s Center. The other sites are further up river around the city of Toledo, with one site being labeled as “Toledo” and the other sites “Cannon Quarry” and “Elk City.” So why on earth am I collecting 35 liters of water and lugging it back to the EPA labs? Excellent question. Let me explain.

The purpose of collecting these 140 liters of water combined is to examine the nutrient limitations of phytoplankton throughout the estuary. After these samples were collected, we divided them up into 48 two liter bottles. We measured the initial nutrient concentrations as well as the chlorophyll a concentrations, and then proceeded to “spike” them. Along with a control of plain water, these spikes consisted of treatments in which a Nitrogen spike, or “N”, was added as well as Phosphorous, or “P” spike. To further confirm whether a given spike had an effect an “N+P” spike was also a treatment. The result is 3 replicates of each treatment for each site, or 3 x 4 x 4, totaling 48 bottles. Complicated, I know, and they proved to be a little difficult to manage as the experiment progressed.

Once these bottles were spiked according to the given treatment, they were randomly placed in a mesocosm or in this case two tanks with pumped sea water and UV lights. These tanks produce the environmental conditions found throughout the estuary, so they are quite useful in conducting experiments. They were placed in these tanks starting Monday night, and there they remained till Friday morning. Every day, I measured the temperature of the water in the tanks, and the photosynthetically active radiation (PAR). More interestingly though, I also measured the relative fluorescence of each bottle, to get a sense of whether any given spike was having an effect. The result? The OSU Dock, or the site closest to the ocean, had a significant response for the “+N” and “N+P” treatments, suggesting that there wasn’t very strong upwelling prior to the sampling resulting in Nitrogen limitation. This may change as the summer progresses. The results further up river suggested “P” limitation, as the Toledo and Cannon Quarry sites showed significant results for the “+P” and “N+P” treatments. Elk City showed a significant response for the “+P” treatments, but mixed results for the “N+P” treatments. We believe that if given more time, the “N+P” treatments might further reflect the results from other sites. We will replicate this experiment several more times of the course of the summer so we will see how the results change as summer progresses. Regardless, from this week of the experiment it is evident that further up river phytoplankton appears to be limited by phosphorous concentrations. Keeping with my themes of leaving you hanging, I’ll get more into what this means next week! But I will say that I really enjoyed this week. Performing science at a high level, with the means and ability to conduct an experiment in a week is amazing, and I consider myself to be very, very lucky. Furthermore, it is a terrific feeling to know that the science you are doing is extremely pertinent to the state and the country in which I have largely spent my entire life. Alright, before I get too sentimental, I will say goodbye and remind you to look for next week’s post to learn more about what the results of my summer experiment mean for Oregon’s estuaries!

Wow, what a week! After Thursday and Friday finals, moving out and cleaning out Saturday, and a Sunday afternoon graduation featuring First Lady Michelle Obama, Monday arrived with orientation with Sea Grant and the PCEB of the EPA at HMSC! That would be the Pacific Coastal Ecology Branch of the Environmental Protection Agency, located at the Hatfield Marine Science Center, and yes, this is only the beginning of the dizzying array of acronyms I would encounter this week.

In turns out, working for the federal government involves some fairly extensive training. The EPA requires employees to undergo 24 hours of Safety, Health and Environmental Management training (SHEM). Once those 24 hours were completed, I was able to move on to the science paperwork and the Standard Operating Procedures (SOPs)! Believe me, while not sounding incredibly interesting, these documents were a relief from the SHEM training. It was in these documents that I was able to see a glimpse of the future science I would be performing. Despite the endless amounts of paperwork that came through my door and unto my desk Tuesday, Wednesday, and into Thursday, I remained incredibly excited about the opportunity that I had received, and that excitement was rewarded on Friday.

On Friday I got my first taste of fieldwork with the EPA. We took the boat out with our personal flotation devices (PFDs) securely fastened and collected samples showing the effects of different nutrient solutions on the growth of periphyton. While this project was not the one I will be working on, it was an important opportunity to get familiar with some of the procedures and equipment that I will be using in my own project. My project will examine nutrient limitations on phytoplankton, and it begins next week! So stay tuned for next week’s post where I will have exciting descriptions of my experimental design, and hopefully some super cool pictures of my laboratory work! Believe me, this lab is neat. Think mesocosm. I have said too much! See you next week!