It has been a while since we last post here, and a lot has changed in the course of this strange past year of 2020. The project DUSTCO ended in March, giving rise to the start of a new “dusty project”. We present you CHASE (CHASing the environmental Effects of dust deposition across the Atlantic and Southern Ocean: a coccolithophore perspective), a project funded by the Portuguese Science Foundation that is closely intertwined with EU-project PORTWIMS and a follow-up study from the recently completed EU-H2020 DUSTCO. CHASE has started in September 2020 at MARE-ULisbon in close collaboration with Instituto Dom Luiz (IDL), Plymouth Marine Laboratory (PML), Royal Netherlands Institute for Sea Research (NIOZ) and East Anglia University (EAU).
With CHASE, we want to expand existing knowledge on the transatlantic export productivity of coccolithophores gained from DUSTCO towards an environmentally broader perspective, spanning tropical, subtropical, temperate, subpolar and polar waters across the entire Atlantic Ocean and Southern Ocean. We also want to explore the potential effects from other sources of dust besides the Saharan desert and the Sahel region.
CHASE is based on biological, sedimentological and hydrological data that were collected and measured along a meridional transect approximately between 50ºN and 62ºS, collected during the Meridional Atlantic Transect on board the RRV James Clark (AMT28 - boreal fall 2018) and the RRV Discovery (AMT29 - boreal fall 2019), and during two Antarctic expeditions on board the Polar Ship Admiral Maximiano (OPERANTAR-37 and OPERANTAR-38), during the austral summers of 2019 and 2020. Plankton and dust samples were collected by a team of young researchers from MARE-UL who embarked on RRV James Clark and RRV Discovery to be part of these expeditions, in the context of a training program funded by PORTWIMS. Amongst other assignments, Andreia Tracana, Afonso Ferreira, Giulia Sent and Carolina Sá were in charge of daily sampling atmospheric dust and plankton samples for the study of coccolithophores (calcifying phytoplankton) thriving along the entire photic zone. The goal is to further explore the link between dust-born nutrient deposition in the Atlantic Ocean and the productivity, composition and distribution of the biogeochemically important coccolithophores. To that aim, we will work closely with Prof. Dr. Alex Baker (EAU) and with Dr. Jan-Berend Stuut (NIOZ) who are in charge of analyzing the dust samples for nutrient concentrations and for particle-size/bulk composition, respectively.
Here are some images of the beautiful coccolithophore species diversity found along the northernmost part of AMT28 (50º – 30ºN). Pictures taken at Nanolab.
Andreia Tracana, Giulia Sent and Carolina Sá in front of RRV Discovery just before embarking on the AMT29 expedition (top, letf), Giulia and Andreia preparing the atmospheric dust collector on the deck of the ship (top, right). All dressed up as a bloom of Emiliania huxleyi for Halloween (bottom, left). Andreia filtering seawater for the study of coccolithophore communities (bottom, right),
We are now excited to share that the sample collected by them during AMT28 have already started to be analyzed. The microscope analysis for the taxonomic identification of coccolithophores living in northernmost part of the AMT28 is now completed, thanks to Catarina Pinto, an MSc student from the University of Aveiro (Portugal) who is working with us since early September 2020. Catarina is doing her MSc research on “Coccolithophores (Haptophyte) living in the North Atlantic (50º – 30ºN): results from the AMT28”, supervised by Prof. Dr. Henrique Queiroga (University of Aveiro) and Catarina Guerreiro (PI of CHASE). So far, she has done a terrific job at learning the taxonomy of the group during such strange pandemic times, providing the first pictures of some of the beautiful coccospheres that we found on the plankton samples (see above). While this part of her work was mostly done at the Laboratory of Calcareous Nannofossils (IDL-FCUL), coordinated by Prof. Dr. Mário Cachão, her next step will be undertaking a detailed multi-proxy exploration of all the gathered ecological data in synergy with a wide range of remote-sensing time-series observations.
Catarina Pinto and Catarina Guerreiro in front of the Laboratory of Calcareous Nannofossils at the Faculty of Sciences of the University of Lisbon (righ).