Lorenza Raimondi

Time: 0757 UTC

Longitude: 56 44.45 W

Latitude: 67 03.62 N

Conditions: Snow/Rain mix, 18 kt winds (Not enough snow for a snowman though, darn!)

Hi Everyone,

My name is Lorenza and today I will be writing for Andrew’s blog. I am originally from Napoli (Italy) but one and a half years ago I moved to Halifax to start my PhD in Chemical Oceanography under the supervision of Dr. Kumiko Azetsu-Scott (BIO) and Dr. Doug Wallace (Dalhousie University). I am currently on board of the RV Atlantis collecting samples across the Davis Strait.

Lorenza Raimondi running Winkler titration samples in the lab aboard 

the R/V Atlantis (See Lorenza run Winkler titration on YouTube)

My PhD project focuses on CO2 and O2 exchanges between ocean and atmosphere along the Labrador Sea, so this cruise is not really part of my PhD project but it’s indirectly linked with it since the Labrador Sea and the Davis Strait are adjacent areas strictly connected through water mass circulation. 

Why are we specifically observing the Labrador Sea area? As you may well know, there are areas in our oceans where deep waters are formed, triggering the entire ocean circulation known as Ocean Conveyor Belt. The Labrador Sea is one of these areas and contributes as a source to the North Atlantic Deep Water through deep convection. 

Our main goal is therefore to understand how winter convection affects the carbon chemistry in this key region. Do they serve as a source of carbon dioxide, releasing CO₂ produced by remineralization at depth to the atmosphere, or as a sink, enhancing surface uptake and storage at depth?

During my PhD I will also focus on the anthropogenic fraction of carbon stored in the Labrador Sea. The anthropogenic carbon signal is very small compared to the natural background and different indirect estimates have been developed during last 20 years. So we would like to apply several methods and compare them to gain a clearer understanding of how human activities are affecting this important region.

Last but not least, we are also interested in dissolved oxygen trends during last decade. Are the concentrations changing over time? If yes, why is this happening?

Lorenza collects water samples aboard the
CCGS Hudson in April of 2014.

So now you are wondering, how can we measure these changes? Well, this is the reason why researchers need to conduct fieldwork and go at sea for weeks: to sample and measure the water column along transects and obtain data that will hopefully describe patterns and trends of different parameters. 

To characterize the carbon cycle we use 4 parameters, that we are currently sampling on board of the Atlantis: Total Alaklinity (TA), Dissolved Inorganic Carbon (DIC), pH and Partial Pressure of CO2 (pCO2). We also collect samples for Dissolved Oxygen and analyze them on board using the Winkler Titration method. 

Once back home, the data obtained will be processed and then, after hours and hours spent in front of the computer, will be used to present our results to the scientific community and open discussion on whether these results are comparable in similar regions or they completely disagree from previous works. Finally, this information will be “translated” for the general public in an effort to increase public awareness of anthropogenic impacts on the environment. 

Certainly this last part of our job does not sound very exciting compared to the adventures at sea, the time spent among whales, icebergs and astonishing northern lights but it’s the real target of our work. It’s the reason why we are doing all this: produce knowledge and share it with decision makers and the general public to shape future policies.

CTD Rosette bottles, ready for action (Photo by L. Raimondi)

Personally, I have contrasting feelings about the different steps that a scientist has to go through. When I spend days in my laboratory or office I feel like I'd rather be at-sea with the smell of sea in my lungs; however, if all that time pouring over data in a cramped space results in an idea or conclusion that can change public perception or policy for the better, then the hours of toil will be worth the effort!