Sinhue Torres-Valdes - Nitrogen, phosphorus, silicon and carbon are elements essential for life that exist dissolved in seawater. Phytoplankton use them to produce organic matter and oxygen (that we eventually breathe, by the way) through photosynthesis (i.e., primary production). A proportion of organic matter (and the energy it contains) is transferred up the food webs. Another proportion is lost as biogenic particles that sink to depth, and yet, another proportion is converted to dissolved organic matter (DOM). Some of the DOM and sinking organic matter are then used by bacteria, which in turn transform it back into nutrients and dissolved CO2. Particles and DOM escaping bacterial degradation end up locking carbon for hundreds or thousands of years. This way, life is sustained in the ocean and in the process, Earth’s Climate is regulated. Amazing!
The transformations described above are known as “Biogeochemical Cycles” and occur within large masses of water circulating around the world´s oceans. “Physical processes”, for example, changes in temperature, fresh water content, formation and melting of ice, evaporation/precipitation and interaction with other water masses also exert control on how and where nutrients and CO2 are distributed in the ocean, which has implications for primary and bacterial production and CO2 uptake by the ocean.
In order to understand how such biogeochemical cycles function, I make observations, ranging from shipboard and on-ice observations (via the collection of seawater samples and subsequent chemical analyses) to observations generated via the deployment of state-of-the-art and emerging techno- logies (sensors, remote access samplers). I then use the information to diagnose the imprint of biogeochemical processes in the ocean and how these might be affected by climate change.