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Sailing the seas as scientific explorers of the ocean

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“A research cruise is a special experience, linked with the feeling that you are doing something that will increase our understanding of an entity so important and beautiful, as well as enjoying the fun of sailing the seas.” - Isabelle Giddy (Picture: James Campbell)

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During the cruise 50 CTD (Conductivity Temperature Depth) casts were deployed -- to depths that ranged from 60 m at the coast to 4600 m about 300 km offshore (Picture: James Campbell)

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The aim of this specific cruise was to recover and deploy moorings along a line extending SE from 34S (Picture: James Campbell)

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Staring out into the vast ocean (Picture: James Campbell)

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During a career now in its fourth decade, the RV Melville has cruised over almost all the World's oceans in the pursuit of scientific knowledge (Picture: James Campbell)

- Isabelle Giddy, Student, UCT

Going on an oceanographic research cruise is not quite like becoming a character in the movie Pirates of the Caribbean, but it can be close.

The romanticisms of life on a ship, gazing at the stars in the dark of night, staring out into the vast ocean, gliding with the swoop of the albatross ... are all truths that one experiences, although we never did quite meet Poseidon, the Greek god of the sea.

As the ship steams through the blue-gray swell, with naught but the expanse of ocean visible to all the horizons, and keeping in mind that the average depth is 4 km, one comes to the realisation that our oceans are incredibly huge. But all we see is gray-blue bumps of water passing by -- leaving a huge space of unknown. That is where oceanographers come in -- sailing the seas as explorers of the ocean.

Recovering moorings from the dark depths of the ocean

The main aim of the Agulhas Current Time Series Project that this cruise is a part of, is to get a realistic idea of the mean volume transport of Agulhas Current water. This has implications for the ocean’s heat and salt budget, and thus climate change. The aim of this specific cruise was to recover and deploy moorings along a line extending SE from 34S.

When dealing with the ocean, one is in a constant state of being out of control. Off the coast of South Africa, the storms from the Southern Ocean creep up with vengeance, stirring up the waves. If the wind happens to be in contradiction with the flow of the fast south-westward flowing Agulhas Current, the ocean becomes a force to reckon with. That is what we were in the middle of at the beginning of the cruise. We were stressfully looking out amongst the churning ocean for a little orange buoy that Robert Jones, a mooring technician from Miami had released. Once spotted, it had to be recovered onto the ship.

Mooring operations in conditions such as those that we experienced initially were difficult and dangerous. Mooring operators were standing on the edge of the ship, being sprayed by waves and rocked to and fro as the mooring was being recovered after spending its due in the company of the dark depths of the ocean for a year and a half. But all in all, six out of the seven moorings were successfully recovered, bar a couple of missing instruments that the current had taken for itself.

Learning to problem solve effectively

Apart from mooring work, 50 CTD (Conductivity Temperature Depth) casts were deployed. The depths that they went down to ranged from 60 m at the coast, to 4600 m about 300 km offshore. Long casts such as these generally take about four hours to complete. As with all research cruises things can go wrong. What one learns to do is to problem solve effectively, using what is available in the situation to make a new plan that will help you reach the goal.

On two occasions the winch that lowers the CTD into the ocean failed. This meant that the whole CTD rosette had to be moved from one part of the ship to another, where a different winch could be utilised. This always seemed to happen in the dark of night while the ship rolled with the swell, making the transfer no easy task.

Increasing our understanding of the oceans

When placed into such situations in a confined space with 30 odd people, everyone works together and a companionship grows that rarely happens in normal life within 25 days. It is a special experience, linked with the feeling that you are doing something that will increase our understanding of an entity so important and beautiful, as well as enjoying the fun of ”sailing the seas”.

Among all hardships, including weird working hours (waking up at 3:30am for a month is not as much fun as it sounds), 25 days after leaving Port Elizabeth we sailed into port in Durban, successfully gaining more knowledge on the unseen movements and properties of the water off the east coast of our country.

Isabelle was funded to participate in the cruise with support from SAEON, UNDP GEF and ASCLME.

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