Institute of Marine Science (ICM-CSIC). Ocean Sampling Day, Summer Solstice 2012 (20th June).

Sampling was carried out at Blanes Bay Microbial Observatory (BBMO; http://www.icm.csic.es/bio/projects/icmicrobis/bbmo/). BBMO is located at the NorthWestern Mediterranean and it is a good example of an oligotrophic (relatively nutrient-poor) coastal ecosystem which is relatively unaffected by human and terrestrial influences. Furthermore, it is one of the sites for which more information exists on the ecology of the Mediterranean planktonic environment, with papers dating back to the 1950's. Finally, it happens to be very close to one marine research laboratory (the CEAB-CSIC in Blanes itself) and not far away from the Institut de Ciències del Mar (ICM-CSIC;http://www.icm.csic.es/en/content/institute-marine-sciences ) in Barcelona.

We left the ICM in Barcelona at 9 a.m. on June 20 2012. We arrived at BBMO at 10.30 a.m. The first thing we did was to deploy the CTD to record temperature and salinity profiles and the radiometer to measure light in the water column. We also put the Secchi disc in the water to check the water turbidity. The Secchi disc is a circular and white disc of 30 cm that is mounted on a line, and lowered slowly down in the water. The depth at which the disc is no longer visible is taken as a measure of the transparency of the water. The day was sunny and warm, the sea was flat calm and the temperature of the water was 20 ºC. While we were sampling a couple of friendly jellyfish (Rhizostoma sp.) came to see us.

Regarding to the water samples we collected them from the surface. The seawater was pre-filtered through a 200 µm mesh into 20 liters carboys. These big bottles were transported in the dark, and cold in the case of the samples for RNA, to the ICM in Barcelona. Back in the lab we took samples for chlorophyll a measurements; pigments analysis by HPLC; and inorganic nutrients, organic matter and organic carbon analysis. We also took samples for phytoplankton, picoeukaryotes, bacteria and virus recounts. We measured primary production and bacterial production to study activity of the microorganisms. We extracted DNA and RNA from the picoeukaryote and the bacteria fractions to study the diversity of the microbial population.

Sunrise at BBMO