Thursday, 8 April 2004
Scrutiny on the Bounty Trough
Careful what you wish for; you might just get it. We’ve had the extreme winds that gave us the high gas exchange we’d hoped for, putting folk on their backs, instruments on the deck and the ship hove to for a day. Then high mixing and rapid spreading, resulting in a highly mobile patch that led us a merry dance around an eddy. Now we need the biology to play ball.
Things here are looking positive, with the biological indicators moving in the right direction following the 4th iron addition two nights ago.
Wednesday, 7 April 2004
A plankton brew
It was a late night. We had our first and probably only opportunity to run Go-flow bottles for trace metal chemistry tonight. I was assisting Mike Elwood with this sampling, which he estimated would take about 3 hours but it ended up taking us around 6 hours.
Tuesday, 6 April 2004
A sign of things to come?
It’s a clear, calm, low-flux day here in the patch, though we are hardly aware of that in our lab down in the bowels of the ship. The CO2 lab is below the water line – a nice stable place in the ship, though we can’t tell if it’s day or night, sunny or cloudy. Twice a day we emerge to take water samples from the CTD casts (in-patch and out-patch stations) then it’s back below to analyze the water for pH and alkalinity, from which we calculate total inorganic carbon concentration.
Monday, 5 April 2004
Science on the high seas
Today was very much like others – high winds, intervals of sun, and some rain showers. There was swell of few metres running for most of the day. The routine of mapping the patch continues, with CTDs both inside and outside the fertilized area. With the passage of time it has become apparent that the patch is moving clockwise around an eddy.
Sunday, 4 April 2004
Dawn at dusk
As was previously mentioned, we took another stab at trying to buff up the phytoplankton by, as Peter Minnet so eloquently put it, "pumping iron" into the patch yesterday. We are now waiting to see if the phytoplankton respond to this.
I am involved in the atmospheric chemistry group (along with Mike Harvey, Jill Cainey, and Murray Smith), specifically looking at aerosol chemistry.
Saturday, 3 April 2004
It’s on our radar
After a night of winds reaching 50 knots, the weather settled today, and towards evening we had a short period when there was none discernible. There is still a 2–3 m swell remaining. Today we re-infused the patch with more iron, to maintain the enhanced biological activity.
I spend most of my time looking after the ocean remote-sensing radar. This consists of an antenna, bolted to the starboard railing below the bridge, connected to the signal processing electronics and associated computers in the science area on the bridge.
Friday, 2 April 2004
Dissolved dimethylsulphide (DMS) is being determined onboard by Associate Professor Graham Jones (Southern Cross University, Australia), Mike Harvey and John McGregor (NIWA), and Hilton Swan (Australian Government Analytical Laboratories, Sydney). A measurement is being made every 14 minutes and this data with sea surface temperature and wind speed measurements will be used to calculate the flux of DMS as Tangaroa samples in and out of the patch.
Thursday, 1 April 2004
No fooling around
It’s been a good couple of days. A break in the weather after we rejuvenated the patch with iron and tracer has enabled us to play catch-up with a couple of sampling techniques. This is an important period as the reduced wind enables near-surface waters to stratify, forming layers near the surface. The stratification affects how nutrients and phytoplankton are circulated as well as mediating rates of mixing due to breaking waves.
Wednesday, 31 March 2004
It’s déjà vu time
As Mike Harvey mentioned in the previous weblog, we had decided to re-infuse what remains of our patch with more iron and tracers. This started last night.
Complicated procedures often seem to go more smoothly the second time around, and the second iron/tracers infusion was no exception. Unlike the first time, where it took many days (and a detour) to have a working GC/TCD (gas chromatograph/thermo conductivity detector), Andrew Marriner and Peter Hill were able to get the GC/TCD up and running after less than one hour.
Tuesday, 30 March 2004
Time to stir things up again
Looking back at my diary notes, I see that the comment "Day dawns grey as usual" is my most common remark about our Southern Ocean environment. You will have gathered from other web entries that it has also often been windy with periods around 40 to 45 knots, and this has limited the range of activities. Altogether, it has been a very challenging environment to operate a very complex experiment in which we need to keep track of a patch of water labelled with inert tracers.
Monday, 29 March 2004
With the tempest somewhat appeased, early this morning we returned to SF6 mapping. The patch was originally released as a hexagon approximately 7 km across, and as recently as Saturday apparently a single well-defined blob. The question now is whether it has been stretched, distorted and broken into filaments by the variable relative motion of the surface ocean currents, particularly in response to the recent storm. It could also have been forced down upon meeting a slightly less dense, warmer layer of surface water.
Sunday, 28 March 2004
What a breeze!
Before I even left the comfort of my bunk I knew we were in for a rough day. As the Tangaroa pitched downwards I was thrown from my pillow almost crashing my head on the bunk above. Outside tremendous waves broke on the bow and their white caps tailed off in a fine mist. High wind speeds (around 50 knots) were going to prevent us from doing many of the things planned for the day. In these conditions it is impossible to do a CTD cast because of the risk of cracking the cage against the hull, or snapping the steel cable.
Saturday, 27 March 2004
Another calm day in the Southern Ocean, but rumour has it, that we will be facing 50-knot southerly winds by tonight, so everyone is frantically getting in some good work before the going becomes too difficult.
I am part of the atmospheric group, working in a cramped container laboratory on the forecastle deck. This laboratory is crammed full of gear and we are high above the poor souls scrambling for seawater from the CTD.
Friday, 26 March 2004
Getting into the swing of things
Close to midnight last night the injection of iron and tracer gases was completed. Overnight mapping confirmed the creation of a patch. Measured iron concentrations in the patch were, as expected, up to 3 nM. This morning brought the beginning of our routine sampling schedule with two CTDs. The gas cast, which is always a circus, led the two casts this morning. On each of these CTD casts, we collect water for our respective experiments.
Thursday, 25 March 2004
Tracer and iron release day
This is the day we have all been waiting for, release day. The day dawned fine with only a moderate swell making it an ideal day to carryout the iron and tracer gas release. But before the release, two buoys were deployed. One of the buoys deployed is to mark the centre of the patch and the other is a Carioca buoy. This buoy makes numerous measurements that include seawater fCO2, sea surface temperature, and salinity.
Wednesday, 24 March 2004
The day dawned dark and gray, and while not particularly foreboding, it was not particularly promising either. The strong winds of yesterday had abated somewhat during the evening and night, but the swell had persisted, rendering attempts at sleep very difficult – more an exercise in trying to wedge yourself in the bunk between naps than getting a refreshing sleep. However, as the morning wore on conditions improved as the winds and swell subsided and eventually sunlight broke through.
Tuesday, 23 March 2004
This morning at 7.00am we arrived at Taiaroa Heads off Dunedin to meet a ship’s pilot to take Tangaroa into Port Chalmers. We have had to come into port as an instrument critical to our experiment has broken down and we have had to pick up a replacement from the University of Otago. I think quite a few of the scientific crew are pleased to be in port as it was pretty rough at sea yesterday a quite a few people were sea sick and stayed in their bunks most of the day. Today the weather is even worse so it is a good day to have to spend time in port.
Monday, 22 March 2004
Finding the spot.
We spent the last day and night running a transect south through the site where we hope to make the release. This survey will last for a few days, as we determine what is going on in the surface ocean. Initial results confirm that the iron in the seawater is low, and that there are enough of the other nutrients needed for a bloom to form. It is also important for us to find a place where the currents are relatively weak, so that the fertilised patch doesn't get swept away. The figure shows sea surface temperature along the ships path.
Sunday, 21 March 2004
Today we began the big task of preparing the iron fertilizer solution in two large tanks. The first half of the tanks are filled with seawater, then acid, and iron sulfate. Over one tonne of iron sulphate is being sieved and loaded into the tanks from a hopper, then the tanks topped up with seawater. Large pumps mix the solution around to dissolve the iron sulfate.
At the same time a start was made on preparing the tracer tanks.
Obviously a complex voyage like this requires a lot of coordination.
Saturday, 20 March 2004
We left Wellington at 14:00 and are currently sailing towards the experimental site centered at approximately 48°S, 173°E. The weather couldn't be better.
There is still much work to be done to prepare everything for the experiment, so there is still much activity on board.
As the captain, Roger Goodison, surveyed the back of the ship with all the containers, tanks, and scaffolding, he was heard to remark that it was like sailing a building site!
Brian Ward, WHOI
View of the aft deck from outside the bridge before any of the tanks or containers are loaded.
Tuesday, 16 March 2004
SOLAS/SAGE voyage mobilisation is underway as a warehouse full of science equipment that has been coming in from all corners of the globe is moved aboard Tangaroa for departure later this week. Some of the larger items include 8 tonnes of iron sulfate fertiliser, two 9000 L tanks for mixing the fertiliser.
Most collaborators are here, some even escaping from the Hamilton fog.
As time permitted, scientists on the SAGE voyage posted descriptions of their daily activities and images of the work they were doing. The voyage track shows the position of RV Tangaroa as the experiment progressed.
Thursday, 15 April 2004
The final day
As the SAGE voyage comes to an end, it is only fitting that we have the best weather of the month. After all, we did ask for strong wind conditions to assist in giving high gas exchange, and we certainly got it.
Tasks & Teams
This experiment combines seven main research objectives considering:
Quantification of gas transfer fluxes and velocities
Physical processes affecting gas transfer
Ecosystem interactions controlling dissolved DMS concentration and CO2 removal
Impact of iron availability upon phytoplankton productivity and its influence upon dissolved gas concentration
Impact of photochemistry in the surface ocean on dissolved gas concentration and air–sea exchange
Fate of DMS in the atmosphere and aerosol c
1. How do I get a copy of the MEC?
Ministry for the Environment (MfE) has distributed copies of the MEC to all levels of national and local government, as well as to government departments and agencies. If you work for one of those agencies, then you will have a copy; check with your IT department. Otherwise, copies of the DVD can be obtained from Kirsty Johnston at MfE (email@example.com).
2. What are the system requirements for the MEC?
The MEC is delivered as GIS layers in ESRI shapefile and grid format.
The Marine Environment Classification (MEC), a GIS-based environmental classification of the marine environment of the New Zealand region, is an ecosystem-based spatial framework designed for marine management purposes.