Our experiment began 20 days ago with dry clothes and warm hands. Our final sampling days are now upon us and we have learned to deal with numb limbs and wet clothes. Most of us can hardly believe that only 20 days ago our knowledge of mesocosm studies was diminutive. Now as the experiment draws to a close we find ourselves engaged in conversations planning additional mesocosm experiments, commenting on ways to improve our protocol, and saying farewell to our international colleagues. The apprenticeship provided critical training in experimental design, best practices in ocean acidification research and interdisciplinary collaboration with experts in the ocean acidification field.
As we launch into May we were eager to start the analysis and piece together our story. Most of our time will be spent getting caught up on processing samples, comparing our data for statistical differences, and composing the first draft of our manuscripts (coming soon to the new Ocean Acidification Journal!). Throughout the experiment we were aware of the daily chemical trends (i.e., chlorophyll, pCO2, alkalinity, nutrients) taking place within each treatment. However, after spending the past 3 weeks hidden away in a dark room illuminated only by a small night light I am excited to see if any changes have taken place among the biological communities. Soon I will be able to determine if high CO2 has an effect on the abundance and biomass of the microzooplankton. Continue reading
Happy Earth Day! Our second week of sampling has come to an end and today we start T13. The week was full of exciting discoveries, data collection, interactive paper discussions, and additional media interviews (new article to come out Friday…stay tuned!). The team has mastered the sampling procedures and is efficiently processing the samples. Our efficient sampling has allowed us to carefully monitor our pCO2 levels daily. As a result, we have successfully maintained the dissolved CO2 within each mesocosm to the desired treatment levels. Daily maintenance of our pCO2 levels is critical to identifying the effects of low pH on the biomass of the phyto and microzooplankton communities. Past mesocosm studies have let the CO2 levels decline throughout the various phases of the plankton bloom masking the effects of high CO2 conditions. Continue reading
Week one of sampling is complete! The week started by setting up the 9 mesocosms with the desired experimental carbon dioxide (CO2) concentrations. Our experimental design consists of three mesocosms that are being held at 650 ppm of CO2. These will be our controls since the water at Friday Harbor is influenced by strong upwelling and is already high in dissolved CO2. Another three mesocosms are “drift” replicates. The “drift” replicates started with the same CO2 concentration as the controls but we are not making efforts to keep the dissolved CO2 elevated. Finally, we have three mesocosms that are our high CO2 treatment (1200 ppm).
Since the CO2 gradually declines within the controls and high replicates (due to biological activity from planktonic organisms) we analyze our water chemistry samples immediately so that we can inject additional CO2 in an attempt to keep the same pCO2 throughout the experiment.
We spent most of Monday setting up the experiment. Data collection started bright and early Tuesday morning and we are fast approaching our 7th day of sampling. The week was fully of exciting science, data collection, and paper discussions for all the students involved in the apprenticeship. Continue reading