Phytoplankton play a key role in the global carbon cycle. These organisms take CO2 of the environment and release O2, by a process called oxygenic photosynthesis, that affects the gas composition in the ocean, and therefore in the atmosphere. Primary production is essential to understand and predict the biogenic flux of CO2 into the oceans. So, it is necessary to know the behaviour of phytoplankton in a future scenario of high CO2 levels. The BIOACID project, through the experiment KOSMOS GC 2.0, gives us the opportunity to take a look forward into the future of phytoplankton.
Estimating primary production in the oceans is a complex issue. Many methodological approaches are used, but no one is exempt of criticism. Here we are measuring primary production with the most common approach: the incorporation of the radioactive isotope C14. We want to see how the different size fractions of phytoplankton (>20 µm, 2-20 µm, <2 µm) respond, in terms of particulate and dissolved production (i.e. exudation), to different CO2 treatments and nutrient enrichment, along the life of the experiment (2 months). To avoid daily variability that could mask the response (like changes in light irradiance due to cloudiness), we incubate our samples under controlled temperature and irradiance (close to in situ average conditions), inside a culture chamber.
The experiment start early in the morning like Alice tells us in his blog entry (http://www.oceanblogs.org/kosmos2014gc/2014/10/21/samplingday/). We leave the Taliarte´s harbour heading to Gando´s Bay, where we start the sampling. Sampling is like go to gym, pulling up and down the samplers. It is a tough task, but it becomes easy and pleasant when sharing the boat with so many wonderful colleagues. During samplings you have the opportunity to exchange scientific opinions and talk about life with your “boat-mates”, while practicing new languages and watching amazing seascapes (some of them portrayed in other KOSMOS BLOG entries).
Reaching the end of the experiment, I´m sure that I will miss the pleasure of sampling, and the exitation of to know more about the future of primary production.