Shelf Sea Biogeochemistry blog

Monday, 10 November 2014

Salp soup

The weather deteriorated a bit after the first CTD cast. Wind reached about 40 knots, so we had to stop working as the motion of the ship was putting too much stress on some of the equipment hanging over the side. However, things have calmed down nicely for the afternoon. A group of 6 or so dolphins has been hanging around the ship, probably feeding on the fish that often congregate underneath us if we stay in one place for a while.

zooplankton net

Sari Giering (University of Aberdeen) has started her sampling of the zooplankton – the tiny animals that feed on the microbial plants (and on each other). There is general surprise that there is so much biological stuff in the water, given the time of year. The zooplankton net, which is hauled vertically upward through the water to catch any zooplankton on a mesh at the end of the net, has come back with all sorts of stuff. The latest haul had a large colonial salp – a gelatinous filer feeder about the size of your finger, but that lives in long connected ribbons of several dozen clones.
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bucket full of sulps

The first data

Right on schedule, at 0500 our main set of instruments hit the water to collect the first data. This package of instruments (the "CTD") is made up of several sensors that measure water temperature, saltiness, oxygen concentration, and also how many of the microscopic ocean plants there are. The long grey tubes around the outside are used to trap water (20 litres at a time) from depths where the scientists want samples for their experiments.

CTD into sea

The first data is exactly what I was hoping for. Throughout the summer this part of the sea would have had a warm, sunlit layer above deeper, colder water. As autumn and winter approach this surface layer cools and starts to get thicker, until eventually the whole of the water from the surface to the seabed (140 metres deep here) reaches the same temperature. The red lines in the left panel of the computer screen show the temperature. It’s about 14 deg C in the upper 40 metres, then drops to 12 deg C in the deeper water. In summer it would have been about 18 deg C in the upper 30 metres, and 11 deg C below. So, we’ve got here just in time to see the change in conditions towards winter.
These early morning "CTD casts" are sampled a lot by the scientists. There was a big meeting last night to discuss who required how much water from what depths. Also the order in which the samples are taken is really important (samples for dissolved gases need to be taken first, while samples for salt can wait until the end).

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orderly queue


Sunday, 9 November 2014

Leaving Falmouth

Bang on time we left Falmouth Docks at 0830. The ship is so quiet many of us didn’t realise we’d started moving. We dropped the pilot off once clear of the docks. Ship pilots work for the port, rather than they ship. They know the sea in and around the port very well, so ships use them to guide into and out of the docks. Once we were clear of Falmouth, a fast boat came alongside us to pick up the pilot and take him back to shore.
The weather is remarkably sunny and calm. In fact we have some spare time as our first planned work is to start at 0500 tomorrow, and it’s about 15 hours to get to the work site. So, the ship’s crew have been testing one of the lifeboats – making sure that the davits (or cranes) that are used to lower it into the water work, and that the lifeboat’s engine is fine.
 

lifeboat recovery


Preparation of the laboratories continues, with the lab space gradually becoming clearer. Note in the picture below the typical fashion of the scientist at sea: lab coat, hard hat, lab groves, and also stell-toecapped boots. This is Matthew Bone (from the University of East Anglia); he will be working on how nutrients are released from the seabed at the start of winter.

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Matthew Bone

Saturday, 8 November 2014

Everyone aboard

Everyone has made it aboard now. We had our safety briefing this afternoon, learning about where to go if there were to be an emergency, how to operate the watertight doors, as well as other practical information such as where the laundry is and what time meals are served.

Snowcatcher Discussion


The scientists have continued getting the gear ready, and then all strapped down so that once we get to sea things don’t start rolling around the deck. We have two enormous "marine snow catchers" on the aft deck. These are used to capture 400 litres of water from key depths, which is then brought back onto the ship and sampled to see what particles are in it. For instance tiny animals (zooplankton), or bits of sediment from the seabed, or – very importanly – bits of zooplankton poo. Particles in the ocean sink, taking with them lots of carbon which ultimately was removed from the atmosphere. It’s what happens to these particles, and the carbon that they carry, that forms the basis of a large component of our work. One of the mooring components was also completed and strapped down, ready to take out into the middle of the Celtic Sea and dropped onto the seabed. This seabed lander has two devices for measuring the water currents using pulses of sound. It will sit on the seabed measuring currents until March next year.

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adcp bedframe

Friday, 7 November 2014

Preparation continues

Things are gradually finding their place inside the ship. Everything is now aboard, and slowly being put together or stored. Jo Hopkins (from the National Oceanography Centre in Liverpool) is putting together the wirewalker mooring. This is a device that uses wave action to crawl up and down a wire between the seabed and the sea surface. As it does this, instruments on it measure the water temperature, saltiness, and the amount of the microbial plants (the phytoplankton) in the water. The wirewalker doesn’t work if the sea is flat calm, which we suspect won’t be a problem on this cruise.

jo assembling wirewalker

 Malcolm Woodward (nutrient chemist from Plymouth Marine Laboratory) has, perhaps a little early, got into the Christmas spirit. His nutrient autoanalyser and its control computer are festooned with flashing coloured lights.
We are all keeping a wary eye on the weather forecast. Looks to be fairly good still for the first day, which will at least allow us to get out to the first sampling site in the middle of the Celtic Sea. After that the wind is forecast to pick up, but it doesn’t look like it’ll be strong enough to worry us for a few days.

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Well lit autoanalyser

Changes in BODC personnel for SSB

Sean Gaffney from the British Oceanographic Data Centre here. Up until now, I have been the Data Manager for Shelf Sea Biogeochemistry Work Package 1 and Work Package 4. Unfortunately, I am no longer going to be involved with SSB, having just taken on a new role within BODC as the Marine Environmental Data and Information Network (MEDIN) Standards Officer.

I’m saddened that I’m leaving SSB at this time, just as the data collection is beginning to start in earnest, but I know that I leave you in the capable hands of my colleague Louise Darroch, who will be responsible for all five work packages from now on.

I want to wish you all good luck for the remainder of the programme and hope that the science outputs from the research match the enthusiasm of all the SSB participants. I’ve thoroughly enjoyed my time working with you all and look forward to meeting you all again in the future.

Sean Gaffney,
(Ex) Data Manager for Work Package 1 and Work Package 4

Thursday, 6 November 2014

Loading the ship begins….

The various groups of scientists gradually began to arrive in Falmouth today. People have travelled from Plymouth, Norwich, Oban, Aberdeen, Southampton, and of course Liverpool. Each van load of equipment was loaded onto the ship, and stacked in the ship’s laboratories. Tomorrow the hard work starts, sorting all the boxes of stuff into the correct labs, setting up all of the equipment and beginning to see if it all works OK after the journey here. The plan is to sail 0830 Sunday morning.


Disco Loading

I met the captain to chat about the plans for the next few days. This is her first cruise as captain on this ship. Before this she worked for several years with the British Antarctic Survey on their research vessel. It’s interesting to see how things have changed since my first cruise way back in 1989. Then the crew was entirely male, and the scientists tended to be predominantly male. This is my first cruise where there are more women scientists on board than men, and the ship has several women, including the captain, one of the engineering officers and the head chef.

Disco Laoding