[IIOE2-EP57] The role of the Agulhas Current on the Coastal Environment
Lead Investigator :
- Tamaryn Morris, South African Environmental Observation Network (SAEON), Egagasini Node, 5th floor, Foretrust Building, Martin Hammerschlag Way Foreshore, Cape Town, South Africa
t[dot]morris[at]saeon[dot]nrf[dot]ac[dot]za
Other Key participants:
- Shaun Deyzel, Co-PI, SAEON, Elwandle Node, South Africa
hp[dot]deyzel[at]saeon[dot]nrf[dot]ac[dot]za - Jenny Huggett, Co-PI, DFFE Ocean and Coasts, South Africa
jenny[dot]huggett[at]gmail[dot]com - Juliet Hermes,Co-PI, SAEON, Egagasini Node, South Africa
jc[dot]hermes[at]saeon[dot]nrf[dot]ac[dot]za - Tommy Bornman, Co-PI, SAEON, Elwandle Node, South Africa
tg[dot]bornman[at]saeon[dot]nrf[dot]ac[dot]za - Jethan D’Hotman,Co-PI, SAEON, Egagasini Node, South Africa
js[dot]dhotman[at]saeon[dot]nrf[dot]ac[dot]za
Period of Project: April 2024 - March 2027
Brief description of the Project:
The Agulhas, a fast-flowing and powerful western boundary current, is incredibly difficult to monitor. Previous expeditions have deployed full-depth water column moorings from the shelf edge across the Agulhas Current core using large, state-of-the-art research vessels. The costs associated with the installation and subsequent maintenance of full-depth moorings is very high, and the logistics incredibly timeconsuming. The value of such data is important for climate dynamics, especially if a program of this nature can be maintained for several years. However, in today’s economic climate such a program cannot be supported solely from a South African perspective. The objectives also may not represent the needs of the South African coastal communities, likely focusing instead on the understanding of the global climate and the impacts the Agulhas Current has on this. As a current that drives significant changes globally, but also locally, very little is understood of the Agulhas Current itself. As an ocean science community, few studies have looked at the relationship between the Agulhas Current and the local climate, on the influence on local subsistence fisheries, on tourism, safe shipping and efficient port operations. While these issues are not in themselves simple, we know that only through a multi-disciplinary approach can we begin to address some of these ideas.
For this proposal, we refer to anomalies as unusual physical circumstances within the Agulhas Current that may potentially drive changes in the biogeochemical and biological processes along the shelf edge and coastal ecosystems adjacent to the Agulhas Current and the anomalies themselves. These anomalies can be trapped cyclonic eddies propagating south-westwards inshore of the Agulhas Current from the KwaZuluNatal region. From anecdotal knowledge, we know that trapped cyclonic eddies allow for cooler northwestward flowing waters along the east coast, and when well timed, can assist ships with safer passage northwards and influence such phenomena as the Sardine Run. What maybe is not as well understood, is Hyderabad India Node Indian National Centre for Ocean Information Services (INCOIS) Pragathi Nagar, Hyderabad, Telangana 500 090, India. Phone: +91-40-2388 6038 E-mail: iioe-2@incois.gov.in IIOE-2 Project Office (PO) what nutrients and biodiversity is trapped and transported with those cyclonic eddies. We also refer in this proposal to unusually warming events along the inshore region potentially linked to marine heatwaves, and in reverse, intensive or prolonged cooling events, such as the Port Alfred upwelling cell, and understanding these dynamics and the impacts on coastal ecosystems. Filaments of enriched productive waters carved off of the Agulhas Current as it bifurcates off the shelf south of Port Alfred, particularly where the filament impacts Algoa Bay, is another physical mechanism that warrants further investigation.
This proposal looks to develop a monitoring program that will study these processes and anomalies within and inshore of the Agulhas Current and relate these back to coastal ecosystems. The focus initially will be on the southern Agulhas Current – off of the Port Alfred region and southwards – and work to establish a second monitoring program of anomalies south of Durban when funding and opportunity arises. The value of surveying a trapped cyclonic eddy south of Durban, and again once it reaches Port Alfred or Algoa Bay would be incredibly beneficial in terms of structural changes of the eddy, biogeochemical and biological changes and the potential transport these anomalies have for nutrients, larvae, and even pollutants.
Region(s) of study:
The project is based in Algoa Bay, South Africa, undertaking surveys from inshore to off the shelf and slope and impacting with the Agulhas Current.