Day 6: Helen's water.....


Todays blog is written by Helen Findlay from Plymouth Marine Lab.

As another sun rises into view through the porthole of the chemical lab, I count how many samples I have left to analyse (40), and not for the first time on this trip, wonder why oh why I collected so many samples.
Why am I sat here at 4 am, watching two machines slowly pipette acid into a small bottle of seawater? Why do I do this for over 12 hours a day while at sea? My job on this research trip is to collect and analyse seawater samples for carbon chemistry and other oceanographic parameters, like temperature, salinity, and chlorophyll. This sort of general environmental information allows us to know what the conditions are like in the water column above the reef, which the rest of the people on the cruise are interested in studying. Without knowing what the organisms and reef critters actually experience (especially in the context of ocean acidification), its difficult to put results from laboratory studies into any sort of context. Also, there are some interesting tidal dynamics around the Mingulay Reef and I’m interested to know of these have an impact on the carbon cycle – for example to investigate whether these dynamics effect how the ocean can take up carbon dioxide (CO2) from the atmosphere. This all makes my job seem quite important, and that make sitting in a lab for over 12 hours a day seem worthwhile!

During the “night” shift (midnight to midday) it’s pretty quiet in the chemistry lab. Every ten minutes or so I hear a soft beeping of my machine, telling me it’s ready for a new sample – talk about Pavlov’s dogs! After just a few days, whenever I hear a beep, I was trained to jump up and look for a new bottle of seawater! The rest of the time I sit with my laptop doing other work, watching the sun get higher in the sky through the port-hole, the waves roll by, listening to some music, and having a chat with whoever sticks their head around the door on their way past. This morning’s calm was punctuated with a few nervous moments when I came in the lab to find the plug for one of the machines had broken! This would have meant certain disaster for any sort of analysis to continue to take place for the rest of the cruise. Luckily this ship is full of practical people, and several with some electrical skills too. Today, Nigel came to my rescue and managed to fix the plug so that I could get back on my way through my analysis. Only 36 more to go…
The seawater I’m analysing is collected from different depths through the water column. We use the CTD and Nisken rosette to collect the water. So far we have carried out 10 water profiles and sampling sessions. We try to sample every day at 11am, which marks the last event of our shift. As well as sometimes sampling more frequently to capture changes through time as well as in different locations. Each day I collect more samples, prepare them and then the following night I’m back in the lab, analysing them on my two machines… and there’s that beep again, off I go…