#02 2023

Taming the Agulhas Current: An offshore capacity building experience for South Africa’s emerging researchers

By Juan-Jacques Forgus, Safiyya Sedick and Lara Atkinson, Egagasini Node, NRF-SAEON

South Africa’s south coast is affectionately termed the ‘Cape of Storms’. With strong westerly winds, heaving swells and a fast-moving current, the physical offshore environment can often be unpredictable, leaving many unable to brave its waters. 

It is here where a group of passionate young marine scientists would spend two weeks enwrapped in a flurry of scientific activity on board the R/V Observer. The cruise comprised daily seagoing trips out of East London harbour to build capacity in sampling techniques and contribute to deep sea research in South Africa.

The cruise was funded by the One Ocean Hub programme, supported and facilitated by the South African Institute for Aquatic Biodiversity (SAIAB), the South African National Biodiversity Institute (SANBI) as well as SeaMap, the FBIP (Foundational Biodiversity Information Programme) large grant project.

The chief scientists (Luther Adams and Prof. Kerry Sink) and emerging researchers including SAEON science technician JJ Forgus (R) gather on board the R/V Observer in the last leg of the trip. (Photo: Prof. Kerry Sink)

With a view to conquering the Agulhas Current and the inevitable seasickness, a wide variety of benthic sampling techniques were used during the cruise:

Remote operated vehicle (ROV) dives provided live views of the seabed and the diversity of fauna present at different sampling sites. Those eager enough were given the opportunity to operate the ROV camera and manipulator arm to capture images and collect invertebrate samples and JJ Forgus (SAEON’s newly appointed biodiversity technician) discovered scientific application for his well-developed gaming skills.

The ROV was equipped with sensors to measure water parameters (salinity, temperature and depth) and Niskin bottles to collect water samples for environmental DNA (eDNA) processing.

The ROV ready for deployment is equipped with a robotic arm and Niskin bottles to collect specimens as well as water samples at depth for analysis. Captured camera footage provides valuable biodiversity data on benthic habitats.

Benthic landers with a baited remote underwater video (BRUV) system captured footage of species inquisitive enough to investigate the equipment, with some of these deployments capturing imagery from depths greater than 1 000 metres.  

Rosette samplers with conductivity, temperature and depth (CTD) sensors were deployed for collecting water samples at various depths within the water column (using Niskin bottles), while simultaneously capturing the associated water parameter data using flow-through sensors.

Benthic lander deployment prep (left) and retrieval off the stern of the R/V Observer before the researchers steam to their next sampling station.

Part of the cruise included sampling seafloor invertebrates as part of the SeaMap project. This involved using a benthic dredge for collecting invertebrates and a cone dredge for collecting seafloor sediment samples. These invertebrates were collected to improve biodiversity data spatial coverage and conduct genetic sampling, forming part of the overarching objective to provide foundational information that can be translated into governance and policy.

The young scientists sort through the samples to find the diversity of organisms which includes sponges, sea squirts, corals and crustaceans (left and centre). Dredge sample before sorting and identifying (right).

More information on the SeaMap project can be found here: https://enews.saeon.ac.za/issue-01-2022/seamap-mapping-marine-biodiversity-to-detect-change-and-support-south-africas-ocean-economy/

The cruise provided the ideal opportunity to observe and participate in all aspects of the sampling process. This involved setting up the equipment, deploying the instruments, extracting and cleaning up data and sorting, identifying and preserving the specimens. This provided a holistic capacity development experience where networks were formed and questions were answered, with everyone free to assist and learn about whichever techniques were most relevant to them, their projects and their work.

Further details about the cruise can be found here:

Seafloor specimens collected from 83m depth using a benthic dredge.