Three, two, one … go! .... Welcome to the Central Celtic Sea!

Chata Seguro, PhD student,  University of East Anglia

It is 4^th of April, 10 am and we have just finished almost all of the work for the day. Many of the SSB (Shelf Sea Biochemistry) scientists had a very early morning, rising at 2:30am for the first pre-dawn CTD of the cruise. 

Why we are doing all the work so early in the morning? 

Because we need to catch the phytoplankton while they are not fully active, so that we can start our measurements and experiments early and follow their activity throughout the day. There was a bit  of confusion and “moving in slow motion" at the first CTD, but  the usual pre-dawn rhythm quickly set in, followed by two glider deployments, and then another CTD after that. 

The last rays of sunlight disappear behind the clouds the night before the first pre-dawn.
Sunset was quickly followed by many scientists disappearing as well to rest a few hours
 before the early CTD. Photo: Chata Seguro

The deployment of the sea-gliders later in the morning, appeared to act as a big colourful toy for the local dolphins as a large school of them, including baby dolphins, appeared on the horizon just after the glider deployment. They remained around during breakfast, but unfortunately, I did not manage to take any photos. Soon after breakfast, I decided to try a  trick that worked well one night during the cruise last November - to whistle to them! And .... they came! But once the large yellow toy disappeared under the waves, the dolphins  couldn't find anything interesting to play with, so they left as fast as they came. To my disappointment, no photos, but still great to see them coming after just a few whistles! It is thanks to Charlotte Williams, a physical oceanographer, that I am able to post a picture of dolphins playing around during the glider deployment (picture below)

 

Dophins playing around the Seaglider and ship. Photo by: Charlotte Williams.

Dophins playing around the RRS Discovery. Photo by: Charlotte Williams.

Apart from seeing the playful dolphins, it is always great to see scientists in action. James Fox and myself (both PhD students) enjoy comparing how our daily peaks of photosynthesis and oxygen production match on our instruments, which are set up next to one another in the main laboratory of the ship.

A few minutes ago, there was another call for another CTD and scientists were already queuing to sample the CTD. Suddenly, Robin (our NMF technician) shouted: "three, two, one … go!" It is the Central Celtic Sea and we were ready!

Picking up the marine glider

Louis Byrne, British Oceanographic Data Centre, NOC

We arrived at CANDYFLOSS early Monday morning and immediately got into the swing of things with some early morning CTD casts and then NIOZ coring. Between the two we briefly left the site to pick up a marine glider, an instrument which is one of the latest developments in marine research.

Marine glider shortly before being picked up after three months at sea.

Once released into the water, marine gliders are controlled remotely by scientists working for Marine Autonomous Robotics Services (MARS) based in Southampton. They are capable of gliding around the ocean for months at a time and thus are very useful for gaining valuable long term data. They can move up and down the water column by changing their volume and are steered either using rudders or by shifting their mass to one side or the other.

Gliders are useful because they can stay out for a lot longer than your average research cruise, and because they transmit their data remotely to land every time they surface the scientists at MARS can inspect the data almost immediately and find areas of the ocean which are of interest, such as the locations of fronts. Gliders can then be programmed to stay in these scientifically interesting areas gathering useful data. They are also able to work in all conditions, whereas ship based research cannot be performed during times when the weather conditions are too rough to be able to safely deploy instruments over the side of the ship. Autonomous instruments such as gliders are not going to replace ship based research, but the hope is that they will be able to further the capabilities of ocean science and remove some ship based tasks from current research programmes.

Dolphin watching on the RRS Discovery

 

As well as having sensors measuring chlorophyll, salinity, temperature and oxygen, these gliders also have acoustic monitoring devices used to listen for calls made by whales or dolphins, with the acoustic data being sent back to scientists at St. Andrews University to analyse. This particular glider appears to have been sent to an excellent location to listen for cetaceans, as we had only been at CANDYFLOSS for a few hours when the ship was surrounded by a pod of 8-16 (uneducated guess) common dolphins. This pod stayed around the ship most of the day, and seemed in their element racing the bow as we moved between stations.

Dolphins! (photo by Malcolm Woodward)