AMT Blog

Following the article on the BBC World website we have recieved and answered questions from the general public. I have added a selection of them below.

The Bridge is the command centre of the ship. The officers on watch have responsibility for driving the ship, navigation and keeping track of deck operations. The day is split into 6 shifts, with each officer taking two of them. Chief officer Richard works the 4-8, 2nd officer Malcolm works 12-4, and Euan 3rd officer is on watch between 8-12. This is a 24 hour operation, with the Master, Peter, on the bridge when necessary, normally during busy periods such as CTD operations.

Earlier this week I was sticking up the blog in the corridor outside the labs. When asked ‘What are you doing?’ I simply replied ‘putting the blog on the wall’ to which I got ‘there are no walls on ships!’ hollered at me! Walls are in fact called bulkheads on ships. So it got me thinking, what are the other terms out there with a maritime alternative. One coffee break later with the deck crew and engineers I was well on my way learning the maritime lingo!

Today we have a very special blog entry. I hold great pleasure in handing over to the Master of RRS James Cook, Peter Sarjeant. As the Master, or Captain, Peter holds a positon of great responsibility, overseeing all the operations on board the ship. It is because of him, and his fantastic team that we are here in the middle of the South Atlantic. I will now hand over…

Monday 15th November 2010, I will start at the beginning of the day.

T’was a Friday, and all was calm. Breakfast was unusually quiet, what was wrong!? The science technicians on the other hand had been having a busy morning. We had reached the site of the South Atlantic Gyre (SAG) mooring site. This meant no pre-dawn CTD, but a hectic day on the aft deck.

Thursday 11th November, just two weeks until we reach Punta, and science is back in full flow. An early start for all; now we only have one pre-dawn CTD at 4.30am, so no more 6am lie ins to sample the second one!

Satellites are part of our everyday life, for mobile phone conversations, sat nav, weather forecasts… the list is endless really. Out here we receive three sets of images a week for sea surface temperature (SST) and chlorophyll from the National Earth Observation Data Archive and Analysis Service (NEODAAS) at Plymouth Marine Laboratories. The SST image is awash with colour, painting the Atlantic Ocean as a rainbow. However, the chlorophyll is a complete contrast, making the ocean look like a blue desert. If that’s really the case then why are we spending 6 weeks, sampling for biology in a desert!?

A month ago AMT20 mobilisation started in Southampton. Labs were barren, the deck resembled a storage facility and the ship was full of contractors. In just a few days we had the ship converted into a state of the art research facility for biological, chemical and physical studies of the ocean. Laboratories had been plumbed in, electrics and internet access sorted and 31 cabins belonging to scientists and technicians had been converted into homes. Computers, printers, instruments, boxes, fridges and freezers had all been tied or screwed in place for a safe passage over the coming 46days. For some this was a voyage of the unknown, having never been to sea before, and for others this was an annual reunion of researchers and Atlantic marine science.  

AMT20 occupied sampling stations. Courtesy of Rob Thomas, created with Ocean Data View

As I write this, sat in the library, the ship now feels like home. There are no longer any strangers on board, the labs and decks are frequented with banter and a buzz of hard work. Corridors and decks are now easily navigated, with short cuts to various locations now found. Routines are set, experiments are in full flow and data analysis has been pouring out of the library over the last few days. The rumble of the ships thrusters and winch room are a frequent indicator of being on station. To wake up without such sounds indicates problems! The problems we have incurred have all been overcome. A team of highly skilled engineers and technicians work around the clock to ensure that everything runs smoothly for the science. Equipment and experiments have been adapted for efficiency, enabling more samples to be run. The unfortunate detour to Ascension Island has meant that we don’t have as much time for science as expected. However, with a small amount of tweaking very few samples will be lost from this. AMT has developed substantially over the years, involving more scientists, climate studies and experiments. In comparison to AMT in the early days we are still achieving a great deal out here, even with the time restrictions.  

By taking vertical depth profiles with the CTD, we have been observing the vast changes in the water column properties from the English Channel, to the middle of the North Atlantic gyre, and recently the equator.  

Vertical depth temperature profile. Purple= N.Atlantic, Brown= Gyre, Green= Equatorial. Courtesy of Rob Thomas, created using Ocean Data View

Vertical Salinity profile, surface-300m deep. Purple= N.Atlantic, Brown= gyre, Green= equatorial. Courtesy of Rob Thomas, created using Ocean Data View.

By taking three CTD casts a day each day we build a picture of what is going on throughout the Atlantic basins. We then interpolate between the points, to gauge an estimate of what’s in between. The processes that we are focussing on here operate on large scales, hence we can do this. If the processes were taking place and changing every few kilometres we would need to sample much closer together to be able to accurately observe what’s going on.  

Temperature section plot of data from surface t0 300m depth from data collected up to 7th November 2010 from stainless steel CTD casts. Courtesy of Rob Thomas, created using Ocean Data View.

Since leaving Southampton we have observed a 100% temperature increase at the surface, from 15degC to 30degC. However, we could have also seen this from a satellite image, which we can easily see back at home. What we are really interested in out here is what is going on beneath the surface. A deepening of the thermocline is present coinciding with travelling south; this is the depth at which temperature rapidly decreases, separating the upper mixed surface layer, with the cooler layer below. This is indicative of increased solar radiation, which obviously increases towards the equator. However, between 35degN and 15degN in the North Atlantic gyre the warm waters extend right the way down to 300m. At 15degN we see an upwelling of cold water in the deeper layers. By taking water and plankton net samples in these regions, we are able to identify what species are living where, and how their composition changes with the progression of this meridional transect. This is something that satellite observations are unable to see, making in-situ sampling vital in the oceanographic research field.  

Salinity section plot of data from surface t0 300m depth from data collected up to 7th November 2010 from stainless steel CTD casts. Courtesy of Rob Thomas, created using Ocean Data View.

Corresponding with temperature, the warmest regions of the section are also the most saline, a result of increased evaporation. This is especially apparent in the North Atlantic gyre. From 15degN to the equator, upwelling brings cold, less saline water up from the deep. This has a counteractive effect on evaporation, so the equator is not as hot and saline as you might expect!   

To save bombarding you with too much data the biology review will be tomorrow.  

What an eventful week- Halloween, three birthdays, crossing the equator and a detour to Ascension Island. With all of this going on, it has certainly felt like a long week as we reach the middle of the cruise. Although not ideal, the lack of sampling has provided a much needed breather and rest bite for many. Today there was a lazy start to the day, with everyone savouring the late start! The underway sampling was turned off early in the day since we would be entering the Exclusive Economic Zone of Ascension Island. Once that was done, no one had any samples to analyse. So back to data processing and thoughts going towards the cruise report. Others have embarked on Scrabble and Lord of the Rings marathons!

Gavin and Viv modifying equipment

Paola and I had a tour of the winches and cranes from deck engineer, Viv. He looks after all of the kit that deploys scientific equipment… more on this once the pictures are sorted!

Mid-afternoon had us offshore of Ascension. We took in the views of stunning, gleaming white beaches, standing in contrast with the vivid black mountains. This tiny, isolated volcanic island has an area of only 91km² (Plymouth= 80km², Isle of Wight= 380km², Malta = 300km², and Boothbay Maine = 120km²). Ascension Island is politically organized and governed by the British Overseas Territory of Saint Helena, Ascension and Tristan da Cunha. The island boasts 40km (25miles) of roads and white sandy beaches which turtles use as a nesting ground. In 2010, 880 people were recorded to live there, 696 from St Helena (British citizens), 106 British citizens from the UK, 70 citizens of USA and 12 of other nationalities.

Johanna and others looking across to Ascension

There is substantial history surrounding the island. It has been vital to mariners over the years, offering a safe haven and coaling station. During WWII it was a vital naval air station, providing anti-submarine warfare bases in the Battle of the Atlantic. Now it is predominantly known for the Wideawake airfield, a joint Royal Air Force and United States Air Force facility. Those of us on the ship who have been there have visited on the RAF operated flight between Brize Norton, UK and the Falkland Islands, since it is used as a re-fuelling stop. As well as a military base, Ascension Island hosts a BBC World Service Relay station. It also hosts one of 5 ground antennas globally which assist in the operation of Global Positioning Systems (GPS). The islands economy is fuelled by the military and the BBC. However, the greatest income behind these is selling the .ac internet domain! This is popular with educational institutes who wish to shorten the .ac.uk they are provided with in the UK.

View of the sandy beaches on Ascension

After the boat transfer of personnel we were on our way. Itching to get back to sampling we have realised that marine scientists would make possibly some of the worst cruise ship tourists! What would you do with all that time? Realising that there is far more entertainment on cruise ships, we’d still prefer to be here, just with some water to sample and filter! Crazy- after working long days most people would appreciate a day off. But days off are not part of life out here, and actually become quite a challenge when you live in such confined space. CTD’s and nets are back in play tomorrow once we’re out of the 200mile EEZ.