Posted by: adorsk | September 25, 2008

Iron

Note: I originally wrote this post on 2008-08-07.

I’m back on board the Oceanus. The ship left from Barbados for a 28-day zig-zag across the Atlantic to Cape Verde.

Iron Crew

I flew down to meet the ship in Barbados on Monday the 4th. The plan was to sail on Wednesday morning. I wasn’t expecting any trouble. Barbados had seemed fine to me when I met the Knorr there last year. People were generally helpful, the buses ran on time, and the streets seemed safe. But this recent port stop dashed my first impressions.

On Monday night our captain, captain B, got mugged on his way back from town. He was beaten up badly and had to fly home the next day. This was both unfair and unfortunate. Captain B was about to retire after sailing for twenty-eight years on the Oceanus. This was going to be his last set of cruises. I am sorry that his career ended this way.

Then on Tuesday L, our most experienced deckhand, ruptured his bicep tendon. He had to fly home.

In a crew of twelve the loss of one member is hard. The loss of two can be crippling. Fortunately the rest of the crew buckled down to get through the chaos. E the first mate became the Captain and M the second mate moved up to first mate. WHOI was able to fly in in a new second mate, L. C the bosun worked 18-hour days to get the deck set-up. The engineers helped out on deck to fill in for L. The Oceanus crew is made of iron.

We finally sailed on Wednesday night. It’s a testament to the quality of the crew and WHOI’s shore-side support that we only had to delay sailing for a few hours. I think we were all glad to head out to sea.

Oceanus in Barbados

Oceanus in Barbados

Barbados harbor, good riddance

Barbados harbor, good riddance

Iron Science

The main scientific goal of this cruise is to survey sub-surface iron concentrations. We care about iron because it is an essential nutrient for oceanic life. When there’s no iron there’s no growth.

Some time ago oceanographers found that concentrations of iron to the West of Africa seemed to be greater than in other parts of the world. Where does this iron come from? The Sahara? from other parts of the Ocean? No one really knows. During this cruise we hope to find out more.

There are 10 people in the science party from 4 main groups. The largest group, led by Chief scientist E, is from MIT.

One of the sampling methods which E’s group uses is ‘Vane Sampling’. A vane is a bottle with fins that is programmed to close after a certain period of time. It looks like a virus that has been strapped to a giant letter ‘Y’. It’s called a vane because it aligns itself with the current, just as a weather vane would turn into the wind. E’s team sends the vanes down to various depths and waits for them to close. In this way they can iron at specific depths without getting contamination from the ship’s metal.

RF, E, and R deploy a vane

RF, E, and R deploy a vane

Contamination is one of the biggest challenges in sampling for iron. Seawater normally has trace amounts of iron. Iron from metallic sampling gear or a ship hull can easily mask natural base levels. The most common strategy to avoid contamination is what a quarterback thinks about in the check-out line: use plastic and go deep. Thus the vane samplers.

The second group of scientists consists of of P & S, from WHOI. they are also working on iron sampling, though with some different techniques. They use pumps to filter water samples at specific depths. Then they put their filters in ‘the bubble’, a make-shift clean room that they built in the main lab. It looks a bit like the hospital scene from ‘E.T.’.

S, R, C, & RF deploying a pump

S, R, C, & RF deploying a pump

P & S building the bubble

P & S building the bubble

The third group, consisting of M & Y, is from Rutgers. They are testing a new type of fluorometer. A fluorometer is a sensor which measures biological activity by looking at how much light critters in the water generate.

M & Y, analyzing data (photo by JA)

M & Y, analyzing data (photo by JA)

M & Y's fluorometer.  Shiny... (photo by JA)

M & Y's fluorometer...shiny... (photo by JA)

And the fourth group is just one person, T, from the University of Washington. He is measuring the saturation of noble gases at various depths in order to determine how the ocean mixes water at various depths.

T sampling from the CTD

T sampling from the CTD

And do you know what an iron scientist’s favorite carnival ride is? The ‘ferrus’ wheel.

Iron Stomach ?

It feels good to be back out to sea now that things have calmed down. We have been fortunate to have good weather. Hot sunny days and small seas. I was surprised that I haven’t been seasick. Perhaps the sea is turning my stomach to iron?

It’s been nice to be back to work, too. For me there is definitely such thing as too much vacation. (we’ll see what I say in five months).

*Forging Ahead*

Now we’re forging on towards Cape Verde. Check back in a couple weeks to see how it goes.

Various Pictures

S filtering water in the wetlab

S filtering water in the wetlab

Let me out!

P says: Let me out!

M at the winch during a vane cast

M at the winch during a vane cast

R uses Jedi skills to fend off a vane

R uses Jedi skills to fend off a vane

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  1. […] Iron (cruising from Barbados to Cape Verde) […]


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