Episode 1: The Charlie-Gibbs Fracture Zone
On the 6th June 2017, an international team of scientists led by Dr. Ewan Wakefield departed Southampton on the Royal Research Ship Discovery. Their cruise number was DY080 and their aim was to gather multiple data from an area in the mid-Atlantic where the Charlie-Gibbs Fracture Zone (CGFZ) interrupts the mid-Atlantic ridge between the Azores and Iceland. In this area, polar and southern waters meet and form a perennial but moving front. Major fronts of the world’s oceans support relatively high levels of primary and secondary production and tend to be important foraging hotspots for wide-ranging higher predators, such as pelagic seabirds. Ewan and colleagues observed that tracking data highlighted the sub-Polar Front of the North Atlantic as a potentially important area for both migratory and locally-breeding seabirds. In particular, the complex region of the sub-polar front south of the CGFZ, where the North Atlantic Current crosses the mid-Atlantic ridge, is targeted by seabirds from multiple populations. In addition, a small but growing body of evidence suggests that other wide-ranging taxa, including cetaceans, tuna and marine turtles, also aggregate south of the CGFZ. As evidence from tracking data mounts, Bird Life International is preparing to submit a proposal to OSPAR to designate this area as an Important Bird Area.
The cruise route (yellow), with the North Atlantic Current (green). The proposed Important Bird Area (pink). The Scientific Team (bottom right). From left to right: Igor Belkin, Vladimir Laptikhovsky, Paulo Catry, Ali Al-Hashem, Holly Hogan, Simon Pinder, Julie Miller, Ewan Wakefield, Paloma Carvalho, Laura Thompson, Nadya Ramirez-Martinez, Marguerite Tarzia, Guilherme Bortolotto de Oliveira, Claire Lacey, and Tom Browning.
Despite these advances in tracking data, very few direct observations have been made of higher predators in the CGFZ. As a result there is a lack of information on predator distribution, abundance and diet – information that is necessary for effective management and protection. Observational evidence would also serve to address fundamental ecological questions, such as how oceanic higher predators partition niches, how they connect disparate ecosystems and how these processes are affected by climate change.
In this episode, we hear from PSO (Principal Scientific Officer) Dr. Ewan Wakefield and Marguerite Tarzia representing Birdlife International on the cruise. Together, they explain the motivation behind the research and how a multi-disciplinary team ended up on a ship heading off to the middle of the ocean…
The NERC flag catching the ‘breeze’ on the RRS Discovery (Photo: Julie Miller)
Cruise DY080 forms part of a UK Natural Environment Research Council (NERC)-funded project Seabirds and wind – the consequences of extreme prey taxis in a changing climate, which aims to quantify the past and future distributions and ecosystem roles of pelagic seabirds in the CGFZ and similar areas.
This podcast series was designed, recorded and narrated by Julie Miller, and edited by Martina Quaggiotto and Taya Forde.
Feature image: Royal Research Ship Discovery, courtesy of Julie Miller.
Music during the podcast from “(Another) Swan Song” by The New Mystikal Troubadours, accessed from freemusicarchive.org.