RRS DISCOVERY

THE EXPEDITION:
WHERE TO & WHY



VIDEO


 Ploughing through bad seas in the North Atlantic

Satellite Images

A slideshow of satellite images taken during the expedition

Marine Snow at 4800 meters - how, when and why

COMING SOON:

Under Pressure -
or what happens at 301 atmospheres

    

From the editor:

Welcome aboard …

In 1995 for the first time I walked on the dock at the National Oceanography Centre in Southampton as a wide-eyed student, I was faced by two elegant ships ‘Challenger’ and ‘Discovery’. The names rung bells in my head as the ships stood proud on the dock boasting a long history of ocean charting and explorations. Even NASA felt inspired in the 1960’s and borrowed their names for two of their ships charting that other final frontier. In today’s space age, we have all heard the clichés reminding us that the oceans are often less well known than the lunar surface, but why should that be?

Over the next 3 weeks National Oceanography Centre, Southampton and www.sinia-planeta.com invite you to virtually climb aboard the UK’s oceanographic flag ship DISCOVERY and find out for yourself what is it really like exploring our blue and watery frontier, what life is like at sea and the challenges and rewards of ocean exploration.

And now lets see what the crew is up to (Ivo Grigorov, Sinia Planeta)

Daily Entries: 4 July, 5 July, 6 July, 7 July, 8 July, 10 July, 11 July, 12 July, 13 July

Porcupine Abyssal Plain Observatory

11^th July 2005

The deep-sea camera sled (SHRIMP) tow was broadly successful last night and it was pleasing to get about 20 minutes bottom time which proved all parts of the system work. We did have a slight problem with the cable during recovery, however, which delayed recovery back onboard by about an hour meaning that the pre-dawn CTD rosette cast was also delayed (image).

Following recovery of the CTD rosette, it was time to locate and recover the 2 “PELAGRA” floating traps, a task made more difficult by the fact that neither appeared to be transmitting their location. We were fortunate to sight one quite quickly and this was back onboard by 07:00; however the other proved to be more elusive. We therefore started an expanding box pattern search of its estimated position while we awaited a further scheduled transmission at 08:50. This came and went though without any sign of a signal and although we had about 10 people on the bridge scanning for any sign of it, we unfortunately had to abandon the search at 10:00 and commence passage towards Ireland. Hopefully it will make its location known so it can be recovered on the next cruise. The rest of the day has therefore been spent squaring the decks away after the last couple of days of frantic activity, while the AUTOSUB team made some last adjustments before their final trial on the continental shelf tomorrow.

Geraint West, Cruise Chief Scientist, RRS Discovery
 

10^th July 2005

This morning picked up pretty much where last evening left off with the CTD rosette cast (image) being aborted when the cable jumped off the sheave resulting in it needing re-termination. With mooring operations not scheduled to recommence until after first light, the night-time hours were therefore unproductive. This was more than made up for during the day though, as the moorings team worked hard to try and complete all remaining moorings work before our scheduled departure from Porcupine Abyssal Plain at 10:00 tomorrow.

First to be deployed was the new PAP2 mooring during the morning, followed by the re-deployment of McLane Moored Profiler and 2 sediment traps in the afternoon; all were completed without any problems – something of a relief after the last few days. Meanwhile the rest of the team fixed the wire for the CTD rosette in the morning. This meant that on completion of the moorings work there were still a couple of hours spare before the deep tow would be ready for use. Consequently the science party took the decision to undertake a trial deployment of the 2 “PELAGRA” floating traps (essentially programmable and independently floating dust bins that trap falling marine snow at a pre-determined depth).

This is a fairly far-reaching decision though, since their expected time of surfacing in the morning combined with the estimated time to locate and recover them, means that we will not have enough time to do the final recovery of other equipment deployed last year – a bit of a disappointment having worked so hard to put ourselves in a position to make this feasible.

Nevertheless, despite some last minute programming problems, the 2 “PELAGRA” floating traps were deployed just in time to enable deployment of the deep-sea camera sled SHRIMP at 23:00. SHRIMP is now on its way down towards the seabed, 4800m below our feet and so far all cameras and lights appear to be functioning correctly.

Geraint West, Cruise Chief Scientist, RRS Discovery
 

8^th July 2005
49^o North 16 ^o 15’ West

Setbacks - part of the job

The first action on reaching the site yesterday was to take predawn water samples using the CTD rosette of 10 liter bottles (image). The water samples are to be used for on-deck primary production incubations. The experiments aim to determine the growth rate of plankton in the surface of the North Atlantic.

In addition, using a radioactive isotope of thorium (²³⁴Th) as a sophisticated rain gage, Sandy Thomalla will be calculating the rate at which biogenic particles rain out of the surface waters and deliver organic carbon to the depths of the ocean. Although sampling is going well the results will not be known for a few weeks.

One of the major tasks of the cruise was to recover the PAP#1 mooring which we deployed a year ago. This mooring had a full suite of biogeochemical sensors which monitored temperature, nutrients, chlorophyll and dissolved CO₂ as well as local currents. The aim of such moorings is to build up a detailed long term record of surface productivity and the factors that affect it. But problems from the previous day persist. In spite of their being substantial backup in the design of the mooring with two release systems to free the mooring from the seabed and an automatic emergency beacon should it come to the surface prematurely, there was no sign of the mooring and after several hours of attempting to make contact, it has to be assumed to be lost.

This is a major blow to the program and although occasionally part of the job, still a difficult pill to swallow. It’s all gloom however. Rob McLachlan and Chris Crowe deployed two other mooring with the usual highly level of professional skill. The first was PAP#2 which carries an array of CTDs (Microcats) over the top 1000m and a satellite system to relay the data to shore in real time. This gives information on temporal changes in the depth of mixing which is of course of considerable importance in studies of upper ocean biogeochemistry as well as being of great interest from the perspective of physical oceanography.

The second (PAP#4) carried the McLane Moored Profiler (MMP) (photo). This will profile the upper 1000m of the water column once per day for the coming year measuring as it does so temperature, salinity, chlorophyll and ambient water currents (see photo of MMP on afterdeck. Of particular interest is the development of the subsurface chlorophyll maximum which occurs as surface nutrients become exhausted. We expect to make a specific study of this next summer so to have a time series of its development will be of enormous value.

Richard Lampitt, Cruise Chief Scientist, RRS Discovery
 

7^th July 2005

On site

“Discovery arrived in the vicinity of the PAP site soon after midnight and the CTD was prepared for a pre-dawn shallow deployment. This was completed without incident – the first event to really go to plan of the cruise so far. The mooring team then readied themselves for what promised to be a very busy day and were ready to recover the first mooring (PAP1) at first light. Unfortunately our frustrations continued as it became clear that we could not communicate with the mooring’s releases which means they are still anchored to the seabed. By breakfast we had abandoned attempts to recover this mooring. The impact was doubly serious since several component pieces of instrumentation were required for re-deployment and we will now have to consider whether the replacement mooring deployment is even viable. Fortunately our second mooring activity of the day; deployment of the new PAP 2 mooring was successfully completed by early afternoon, although we again had problems when it came to deployment of the new PAP 4 McLane Moored Profiler which oscillates though the water column like a yo-yo recording water parameters. This was the result of approaching a high relief submerged feature before we could deploy the mooring, but fortunately as gentle alteration of course took us back out over the flat abyssal plain where the mooring was finally deployed. As the day draws to a close, we are currently deploying a CTD to 4,800m to measure water temperature, salinity, dissolved oxygen and chlorophyll partly for the science party, but also to test some of the new Remote Operated Vehicle navigation transponders which have been fitted to the frame.”

Geraint West, Cruise Chief Scientist, RRS Discovery
 

6^th July 2005
Under way to the Porcupine Abyssal Plane, West of the English Channel

The calm before the storm

”The crew of the RRS Discovery is using the transit time to the Porcupine Abyssal Plane (PAP) to prepare equipment for the busy two weeks of sampling that lie ahead. The weather has not been particularly good so headway to PAP has been slow but we expect to reach the site at about 0100h on Thursday at which time we will collect water samples to 300m to sample for surface primary productivity and levels of chlorophyll in the water.

A wide variety of instruments (measuring nutrients, chlorophyll and water properties) are being calibrated to be attached to a mooring which will send us data continuously over the next 12 months. Soon after arrival at PAP, the mooring deployed this time last year will be replaced.“
 
Richard Lampitt, Cruise Co-Chief Scientist, RRS Discovery

“As soon as the ship reached the 1000m contour in the early hours, streaming of the deep tow cable was commenced.  The main purpose of doing this is to ensure that the cable is properly tensioned and scrolling properly onto the drum.  Unfortunately though the depth did not increase as quickly as anticipated and with over 2500m of cable streamed, the depth was still only 1100m.  Consequently to make sure we were ready to commence Autosub trials after breakfast the cable was recovered and we’ll have to try again later in the trip to complete this. Autosub was made ready for deployment after breakfast; however the vehicle only made it as far as being extended out over the stern before it became clear that there were problems with initialising the GPS receiver.  Further attempts to correct this proved fruitless and after a couple of hours it was decided to abort the day’s Autosub trials and to push on to reach the PAP site for first light the next morning. All in all a very frustrating day with little to show for our labours.”

Geraint West, Cruise Chief Scientist, RRS Discovery
 

5^th July 2005
West of the English Channel

Under Way

”Unfortunately, the weather overnight had steadily deteriorated, and although conditions would have been OK to deploy AUTOSUB, the threat of further deterioration lead to a decision to abort any attempt to conduct AUTOSUB trials today. Although conditions would have been acceptable if Autosub had been fully worked up, the combination of weather and the fact that this is the first-time that Autosub operations have been conducted from RRS Discovery, made it too risky to ‘baptise’ the vehicle today. We therefore continued our passage West towards the Porcupine Abyssal Plain with just a short break to conduct some initial communications checks of a new USBL positioning system for the deep sea remote operated vehicle ISIS. Most people therefore continued their preparations ready for arrival at Porcupine Abyssal Plain later in the week.”

Geraint West, Cruise Chief Scientist, RRS Discovery



4^th July 2005
Falmouth, UK
50^o 09’ North, 5^o 04 West

Engines Full Ahead

“Having completed a very busy mobilisation which included embarking all the equipment required for the next 3 cruises on the RRS Discovery, we managed to sail from Falmouth at 16:00.  Final departure from Falmouth Bay however was slightly later though as we had to wait for the ship’s Second Officer to arrive following a delay in his travel (or was because someone was hoping for another evening in our mobilisation ‘local’ the ‘Chain Locker’?)  With a fine evening to send us on our way, we commenced a fast overnight passage towards Porcupine Abyssal Plain making use of the benign conditions to complete final equipment preps and conduct briefings for the upcoming work.”

Geraint West
Cruise Chief Scientist
RRS Discovery