- Ronmel Rugama-Montenegro
Vitamins in Eddies
B-vitamins you may find in your vitamin supplements (cobalamin B12, biotin B7, pyridoxin B6, riboflavin B2, thiamin B1) are important for our health and for the growth of phytoplankton and bacteria in the ocean. They are important as coenzymes for phytoplankton metabolic processes. Some phytoplankton in the ocean cannot synthesize B-vitamins themselves, so they source them from their surroundings. These B-vitamins in the ocean have been found at very low concentrations (picomolar). These low ambient levels have been found to be too low for what some phytoplankton species require for growth. Despite how important we know B-vitamins are for phytoplankton in the ocean, we do not have many studies quantifying them in the ocean.
My studies on the e-IMPACT cruises will be the first of its kind to quantify B-vitamins in mesoscale and submesoscale eddies. We do not know much about B-vitamin cycling in the ocean and this study will be one of the few trying to understand how mesoscale/ submesoscale eddies may impact their availability in the ocean.
To measure vitamins in the study site we have been collecting 1 liter of filtered sea water from our sites at different depths. This filtered water is frozen to be taken to the lab where it will be dethawed, preconcentrated, and analyzed. Preconcentration is necessary, because as previously mentioned vitamins are found at very low/near limit of detection levels. We are then able to measure concentrated samples on a Liquid Chromatography Mass Spectrometer (LCMS). In the preconcentration step we pour our sample over C18 resin-packed columns to trap the vitamins, elute it with methanol, and evaporate away that methanol. This leaves us with less than 1 mL of water that now has 1000 times the concentration of vitamins from our original sample.
Ronmel collecting the filtered water for aminoacids
Ronmel filtering the water collected from the rosette sampler
B-vitamins are a requirement for phytoplankton that are not capable of synthesizing them de novo. In previous studies the availability of B-vitamins may have influenced the taxonomic composition of phytoplankton communities, rates of primary production, and carbon sequestration. We are eager to see if the availability or lack of B-vitamins is impacting phytoplankton dynamics and carbon fluxes in the eddies.