Transatlantic expedition JC134: the beginning of DUSTCO!

The scientific team and the ship crew posing together at the back of the ship at the end of the expedition.

It all started in the spring of 2016, when the dusty-team decided to cross the tropical North Atlantic for the fourth and last time. On the 19th of March we sailed from St. Johns (Antigua) on board of the British research vessel James Cook, heading to Sta. Cruz, Tenerife, where we would arrive one month later. The expedition was dedicated to recover the transatlantic array of instruments that had been collecting Saharan dust in the ocean between Africa and the Caribbean since 2012, in the context of TRAFFIC and DUSTTRAFFIC projects.

This is Jan-Berend Stuut (left), our chief scientist and the PI of TRAFFIC and DUSTTRAFFIC projects; and Laura Korte (middle) and Michelle van der Does (right), both doing their PhD on material retrieved from the transatlantic array of sediment traps.

Our team preparing the sediment trap carrousels to be redeployed on station M1 (12ºN, 23ºW).

Sailors John and Marc resting during one of the few quiet moments at the deck of the ship.

In addition to the recovery and redeployment of the sediment trap moorings, we also sampled the upper ocean for all kinds of marine life, including viruses, phytoplankton and zooplankton, while also sampling the atmosphere for mineral dust. We even carried out a shipboard incubation experiment to test the bioavailability of dust-born nutrients via dry- vs. wet dust deposition!

Monica Martens, Laura Schreuder, Franziska Pausch and Laura Korte working on Laura's incubation experiment at the lab.

Our CTD team carefully monitoring vertical variations in the temperature, salinity and fluorescence in the photic layer of the ocean.

Amongst the phytoplankton communities, we were especially interested in calibrating our recent findings regarding the coccolith export production across the transatlantic array (see Guerreiro et al., 2017) with new observations of the modern coccolithophore communities thriving in the photic layer of this region. To that aim, we collected seawater samples between the surface and 250m and measured vertical water profiles if temperature, sanity and fluorescence at each sampling station between the Caribbean Sea (Antigua) and the region offshore Cape Blanc (Mauritania).

Catarina collecting plankton samples from the NISKIN bottles of the CTD-rosette. Each sample was filtered using a water jet pump for further taxonomic analysis of the coccolithophore communities at the microscope.

At the end of our transatlantic expedition, we were surprised to find that buoy Carmen, which had been deployed perfectly clean offshore Cape Blanc (NW Africa) in November 2015, was now completely covered by gigantic barnacles - in Portuguese the so-called "percebes", most likely reflecting the spring bloom off this highly productive upwelling region.

Besides all the exciting data and sample material that we collected from the expedition, and of the interesting and multidisciplinary discussions onboard..., the truth is... we had lots of fun too! And when you're lucky enough to be part of a really friendly and cooperative scientific team and ship crew, this is the kind of happy atmosphere that you get! :)