For the second year on a row, the DUSTCO team, funded by the EU-project PORTWIMS, is taking part on the Atlantic Meridional Transect (AMT29) for exploring the effects of atmospheric dust on biological processes across the Atlantic, with special focus on the coccolithophore communities.
This was the track of the AMT28, the first meridional transect in which our DUSCTO team has participated 1 year ago. Together with the material currently being collected in the course of AMT29, we will have a 2-yr time-series for exploring links between Saharan dust deposition and coccolithophore production across the Atlantic Ocean.
This year, the expedition will be on board the RRV Discovery heading from Southampton (UK) to Punta Arenas (Chile) (13 October 2019 - 23 November 2019). Over these six weeks, a team of international researchers leaded by the Dr. Giorgio Dall’Olmo (Plymouth Marine Laboratory – PML) will perform observations of biological and chemical processes occurring in the waters of the Atlantic Ocean, and reporting on CO2 concentrations in the water and atmosphere. The AMT is an interdisciplinary scientific programme that has been performed annually for the last 24 years, funded by the Natural Environment Research Council's National Capability. In addition to in situ collection of a wide range of environmental parameters and samples, the team on board will be also reporting back to the European Space Agency (ESA) to validate measurements made by remote-sensing satellites. You can check their online blog here!
Here is our DUSTCO/MARE dream-team posing in front of RRV Discovery (from left to right): Andreia Tracana, Giulia Sent and Carolina Sá (picture from http://www.mare-centre.pt/en/node/1202) (Photo credit: Polina Lobanov).
Our DUSTCO/PORTWIMS team includes the marine biologists Andreia Tracana, Giulia Sent and Carolina Sá all working as scientists at MARE/University of Lisbon. In addition to collecting samples across the photic zone for investigating the distribution of coccolithophore communities along gradients of light and nutrient conditions, they are also collecting daily dust samples for further comparison with the biological communities. Their participation on the expedition is part of a training program funded by the EU-project PORTWIMS (Portugal Twinning for Innovation and Excellence in Marine Science and Earth Observation) currently ongoing at MARE/Uni-Lisbon, of which we are also team members.
This is Andreia collecting water that has been collected from the upper part of the ocean with these Niskin bottles attached to the CTD-Rosette. Each bottle has collected water from a specific and pre-defined water depth, allowing us to understand how different species are distributed vertically along the phobic zone of the ocean (i.e. between 5m and 250 m depth) (Photo credit: Carolina Sá).
Here, Andreia is working on the wet lab of the ship. She is filtering the same water samples that she brought from the Niskin bottles. Each resulting filter will be further analysed at the microscope for the taxonomic identification of the coccolithophore communities (Photo credit: Carolina Sá).
Above, you can see Giulia (left) and Andreia (right) placing a filter inside the dust collector. The plan is to track whether such dust, which is deposited from the atmosphere into the upper ocean, acts or not as a fertiliser for phytoplankton in general, and on coccolithophores in particular. We also want to know whether dust-born nutrients are mostly consumed at the surface, or whether they also benefit species thriving at lower light conditions below the surface.
On the 2nd of November, at around 15ºN near Cape Verde, our team found a lot of Saharan dust on the dust collector filters, coinciding with a period of high concentrations in Chlorophyll-a at the surface of the ocean, as seen from remote sensing. According to recent updates from Carolina, this dramatic increase in Chl-a at the surface of the ocean appears to reflects an ecological response of marine cyanobacteria Trichodesmium to dust-iron iron during this period (Photo credit: Giulia Sent; MT4OceanSatFlux @AMT4SatFlux).
The dust samples will be further analysed for nutrient concentrations by Alex Baker (East Anglia University) and for particle bulk composition and size by Jan-Berend Stuut (University of Utrecht and Royal Netherlands Institute for Sea Research).
This is Alex Baker preparing the dust samples collected during last year’s AMT28 in his super-clean laboratory of trace metals analysis, at East Anglia University. This picture was taken in August 2019 when we visited Alex to discuss the next steps of our DUSTCO collaboration.
Apart from the hard work, being part of such an expedition also means lots of fun! This is how Carolina, Andreia and their teammates dressed up for Halloween on board of the RRV Discovery: as a bloom of Emiliania huxleyi! :)
This is Giulia, dressed as a satellite for Halloween! :)
As a final message, we wish Andreia, Giulia, Carolina and to the entire AMT29 team, the best time ever during this amazing Atlantic journey! And we look forward to know what news they will bring about the Atlantic Ocean! :)