- Javier Arístegui
Deciphering Eddy Bentayga
At the base of Roque Bentayga, in Gran Canaria, rock art impressions are preserved in the libyco-berber alphabet, indicating the origin and close relationship with the Saharan-Berber culture of the Canarian aborigines. Similarly, our Bentayga eddy maintains a close connection to the Saharan heritage. We have followed it from its origin to its current state, using both satellite images and Copernicus models. In order to understand the physical dynamics and biogeochemical processes associated with its structure, we have designed a very detailed study at high-resolution spatial and temporal scales. We use state-of-the-art technology approach including oceanographic probes, acoustic and optical profilers, underwater vehicles, and Lagrangian buoys.
SeaSoar (left) and rosette sampler with CTD and optic profilers (right)
We have discovered that Bentayga keeps inside secrets from his recent past. It originated in the south of Gran Canaria more than five months ago, but during its life cycle it approached the Saharan upwelling on several occasions embedding its waters. Interestingly, it is characterised by a bag of low salinity and low oxygen trapped in its upper core, a marked identity sign that will transport to the open ocean. Around its periphery, water rich in plankton circulates from the African coast, which contributes to fixing carbon dioxide, and which may sink into the deep ocean or feed higher trophic levels, such as fish.
Satellite images of the eddy showing chlorophyll-a (left) and temperature (right)
Now that our cruise is coming to an end, we can say we know a little more about the properties of the Canary eddies and their connection with the waters of the Saharan upwelling. But this eddy like many others that preceded it, holds secrets that probably we will never be able to unravel. Perhaps in the past some Berbers reached the islands in boats at the mercy of the currents generated by eddies such as Bentayga, just as today Saharan and sub-Saharan habitants arrive in search of a better future.