Some of you will have noticed from my moblog and lab notebook that I’ve been at sea for the past few days. I’m sailing on the CEFAS Endeavour, currently around the Eastern North Sea but from tomorrow through the English Channel and out to the Western Approaches (the bit of shelf sea west and southwest of Cornwall. We were supposed to sail on Saturday morning but a strong cross wind prevented the Endeavour, who is quite a big ship (~85m long and 15m wide at a guess) getting through the narrow swing bridge at the mouth of Lowestoft Harbour. Eventually we got away on Monday morning. Since then it has been completely full on! I’m on board doing my own science, which hopefully I’ll get a chance to write about some time before the end of the cruise – it’s panning out quite well at the moment – but also helping with the general scientific duties – mainly centred around taking regular water samples from the ship’s underway supply (a pumped inlet in the hull of the ship which is supplied to the on board labs) and bottle (CTD – will explain later) casts for key ocean parameters which are measured routinely or are of particular interest to scientists on this cruise. The ‘core’ ones, which oceanographers have been measuring for hundreds of years are temperature and salinity, which tell us about ocean circulation and water mass patterns (and here in the coastal North Sea about where river plumes are spreading and mixing through the sea). Also chlorophyll (sampled on filters, extracted with acetone and analysed by measuring its fluorescence), which tells us about the algal productivity; and a core measurement in the Shelf Seas particularly – suspended load, which is about amount of particulate matter- particularly and and silt which is transported from the rivers running into the North Sea. We’re also sampling for dissolved inorganic carbon and alkalinity, which is part of the NERC Ocean Acidification Program, which CEFAS are involved in along with Andy Watson’s group at UEA.
The cruise is run by CEFAS (Centre for Environment, FIsheries and Aquaculture Science, in Lowestoft) and has various purposes. CEFAS maintain a fantastic array or moored instruments around English waters, including the SMARTBuoy nutrient monitoring network, the data and samples from which I’m working with in collaboration with Dave and Naomi who run the project; and the ‘waverider’ wave obervation buoys. These get pretty clagged up pretty quickly in the North sea so every month or so they are recovered and clean serviced ones are redeployed. That isn’t always done from a big ship like the Endeavour, but we can get through quite a few of them relatively efficiently.
There have also been lander recoveries and deployments today – these are rigs which sit on the sea bottom making measurements (in this case current measurements) and when commanded to, some months later, float back to the surface for recovery. Or at least that’s the the theory. One didn’t come back today so we had to trawl for it with wires off the back of the ship. That didn’t work either. Such is life when you leave things at the bottom of the North Sea for two months! Also, there are a couple of guys on board who are using the brand new manta net to scour the sea surface for particles of microplastics and other man made saolid contaminants. They’re making some of the first such measurements in the world as I understand. Thomas, the guy in charge of this, told me some pretty scary stuff about plastic particulate pollution – I’d heard about it before before, but not the potential magnitude of it or the indirect dangers. But that’s not my story to tell…
What about me? I’m measuring various nitrogen species (ammonium, nitrate, nitrite, organic nitrogen) from various types of samples and doing various experiments, which I’ll try to find time to talk a little about tomorrow. Other than a few hours sleep, mealtimes and half an hour a day to find a quiet spot and have a strum on the banjo I’ve been working full tilt all the time until now. Just having a bit of quiet time after dinner this evening before being back on shift at 8pm.
btw, CTD casts are a set of instruments winched down to near the sea floor (and back up again), collecting data all the way, to create a profile of physical and biological/ biogeochemical properties. The sampling bottles are actually open tubes with covers which snap sut at either end to capture water when instructed to from the scientist in control on the surface. They are 10L in volume and you can fit 20 of them on the big size of CTD frame like the one in the picture below, but as we’re only sampling top and bottom mostly, we only have 6 (2 + 1 backup for each depth).