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ASCA and the perfect storm

By Tamaryn Morris, Lucienne Human, Phumlile Cotiyane, Rudzani Silima, Zonke Gumede, Gustav Rautenbach, Tommy Bornman and Juliet Hermes, SAEON
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Research vessels within South Africa are so oversubscribed that it is often difficult, and expensive, to secure time for dedicated research on these vessels.

So, when the opportunity came around to sail on the brand new Dr. Fridtjof Nansen (hereafter called the Nansen), owned by the Norwegian Agency for Development Cooperation (Norad), to do a shortened survey along the ASCA transect, there was no shortage of scientists, interns and students to take on the challenge.

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The full scientific complement on the deck of the Nansen in a blustery Durban on Wednesday 24 January 2018 (Photo: Magne Olsen)

The Science Manager for the Department of Environmental Affairs’ Ocean and Coasts branch, Mr Mthu Gulekana, kindly suggested at the Nansen Western Indian Ocean planning meeting in Mauritius late in 2017 that the vessel be used to undertake a survey of the ASCA transect on its transit between Cape Town and Durban. The science planning team at the Norwegian Institute of Marine Research in Bergen, Norway, agreed to a 36-hour window to undertake stations, resulting in about half the transect (10 stations) being completed.

This provided a golden opportunity for the biogeochemical and biological teams to get valuable summer data along the transect which have not yet been obtained in the project, and furthermore providing a somewhat synoptic survey of the inshore waters through the Agulhas Current without having to break the survey to service moorings.

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Painting of the second (left) and third (right) Nansen research vessels (Photo: Tamaryn Morris)

SAEON student Rudzani Silima sampling dissolved oxygen from the CTD rosette Niskin bottles (Photo: Tamaryn Morris)

Sunset adjacent to the Port St. Johns coastline (Photo: Tamaryn Morris)                    

The Nansen Programme

The current Nansen is the third vessel of that name. The Nansen Programme was initiated to support developing countries in assessing their fisheries stocks and ecosystem challenges. The initiative initially focused primarily on the Indian Ocean as the most understudied ocean by the 1960s, but later included the west coast of Africa.

The programme has gone through four phases - exploratory surveys from 1975-1980; detailed mapping of resources within countries’ specific exclusive economic zones (EEZs) from 1980-1990; monitoring, management and capacity development from 1990-2006; and the implementation of an ecosystem approach to fisheries from 2006-2016. The first Nansen operated from 1975-1993, the second from 1993-2016, with this new Nansen beginning her journey from the shipyard in Spain in 2016*.

And so out to sea!

Our six-day voyage left Cape Town on Friday 19 January 2018 in gale force conditions, with the port being closed directly after we left at 6 pm that evening. Due to the ferocious southeaster, the vessel initially held position in Table Bay in order to lash down all new equipment and stores and prepare the scientific complement in terms of safety drills and laboratory preparations before beginning the transit around Cape Point and on to the east coast.

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Vertical bongo nets being deployed on the starboard side of the vessel (Photo: Tamaryn Morris)                                                               

The Conductivity, Temperature and Depth (CTD) instrument being deployed over the starboard side of the vessel (Photo: Tamaryn Morris)

SAEON student Zonke Gumede sampling dissolved oxygen from the CTD rosette Niskin bottles (Photo: Tamaryn Morris)                        

With gale force winds peaking at 70 knots, there remained only a few brave souls on the four-hourly underway stations for biogeochemistry, collecting samples for microplastics, total chlorophyll a, size fractionation chlorophyll a, phytoplankton identification and nutrients, and the monitoring of seabirds and cetaceans from Cape Town to the ASCA transect 50 hours away.

Eventually we reached the start of ASCA on Monday morning, to comparatively pleasant conditions, and began the survey from the coast moving offshore. We achieved seven of our requested ten stations in ever-worsening conditions, until finally we were sampling in 46 knots winds, thus ending all hope of stations further offshore.

Nevertheless, we achieved a brilliant survey in arguably unworkable conditions, while training 13 students and interns in physical, chemical and biological oceanography data collection techniques at sea. At least seven of these students will continue working directly with the data collected for their BTech projects in collaboration with SAEON.

Naturally, the following day and a half of steaming to Durban from the end of the transect took place in stunning conditions, with a fairly festive sunset deck session on the Tuesday night as the vessel steamed past Port St. Johns.

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Some of the scientific staff and students departing the vessel on Thursday 25 January 2018 (Photo: Tamaryn Morris)

A five-star learning experience in stormy conditions

The Nansen is a world-class research vessel, equipped with the latest technologies and winch systems able to compensate for the swell of the ocean to deliver incredible profile data. Her dynamic positioning system, high-tech transducers and relative stability, allowed the nearly impossible task of CTD and vertical bongo casts through horrendous weather conditions.

We hope to be a permanent feature of the Nansen Programme whenever the vessel transits between the east and west coasts of Africa, given the collaboration, capacity development and skills transfer both the Nansen and ASCA projects would benefit from.

The cruise would not have been possible without the support of Norad, the Food and Agriculture Organization (FAO) of the United Nations (who manage the vessel), the Norwegian Institute for Marine Research, the Nansen Programme, and the captain, officers and crew of the Nansen.

The work undertaken on this cruise is an ongoing collaboration between the Egagasini and Elwandle Nodes of SAEON, the Cape Peninsula University of Technology, the University of Cape Town, and the Department of Environmental Affairs’ Ocean and Coasts branch.

* For further information on the work undertaken by the Nansen Programme, please refer to: The RV Dr Fridtjof Nansen in the Western Indian Ocean: Voyages of marine research and capacity development. Edited by Groeneveld, J.C. and Koranteng, K.A. FAO, 2017.

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