More than two months after the first expedition of PRIMUS-related project e-IMPACT, Prof. Javier Arístegui (ULPGC) and Prof. Xosé A. Álvarez-Salgado (IIM-CSIC) returned on RV Sarmiento de Gamboa (from 7 November to 7 December) to look for more clues on the impact of eddy-related processes on plankton variability in the Canary Current EBUS, including net primary production (NPP).
This second expedition was planned to continue monitoring the structure and dynamics of the same eddies from July-August, but now assessing their oceanographic and ecological characteristics at a more mature state of “life history”. According to Javier, the area of the main anticyclonic eddy in the region – named Eddy Bentayga by the e-IMPACT team – has already multiplied its extension more than 10 times since it was formed in the south of Gran Canaria, about 4-5 months ago. Throughout this period, the eddy evolved through entraining water from its surroundings, including waters from the coastal upwelling and other eddies, reaching an area larger than the islands of Tenerife and Gran Canaria combined.
Pictures of plankton communities living in the Canary Current EBUS taken by Javier Aristegui during the e-IMPACT expedition.
PRIMUS-members and e-IMPACT leaders Javier Arístegui (ULPGC) and Xosé A. Álvarez-Salgado (IIM-CSIC) (left), and the scientific team of e-IMPACT-2 expedition on-board RV Sarmiento de Gamboa.
The e-IMPACT-2 team’s observational strategy, to gain a high-resolution perspective of the structure and dynamics of Eddy Bentayga, combined traditional oceanographic sampling – including the in-situ collection of samples for the study of NPP and the composition of plankton communities living in this highly dynamic EBUS region - with novel instrumentation (e.g., buoys and gliders).
The collected data will be used to assess the importance of the formation and dynamics of oceanic subtropical mesoscale eddies for the functioning of the Biological Carbon Pump in the Canary Current EBUS, i.e., the biologically-mediated fixation of atmospheric CO2 to produce carbon-enriched particulate organic material, and its subsequent export and sequestration to the deep ocean. In addition to contributing for unravelling the complex interplay of processes governing marine productivity in this important EBUS, the NPP data sampled during the expedition will add to PRIMUS database.
Above you can see two images illustrating the high submesoscale variability of anticyclonic Eddy Bentayga during November 2022, as tracked and measured by satellite remotely sensed sea surface temperature (SST, on the left) and Chlorophyll-a concentrations (on the right), using NOAA-VIIRS (JPSS1 and SNPP) and ESA Sentinel 3 data, respectively. Satellite data were used in synergy with intensive in-situ surveys with SeaSoar, ADCP and XBTs, complemented with a glider survey.
For more information about the expedition and Project e-IMPACT (“Biogeochemical impact of mesoscale and sub-mesoscale processes along the life history of cyclonic and anticyclonic eddies: plankton variability and productivity”) check the cruise blog.