RV Poseidon cruise 332. Chasing Saharan Dust Storms: winter, 26 January-26 February 2006

The Poseidon P332 cruise in the Cape Verde Island region was undertaken as part of the UK-SOLAS project (Surface-Ocean /Lower-Atmosphere Study, websites: www.solas-int.org and www.nerc.ac.uk/funding/thematics/solas/) to improve understanding of the atmospheric transport, cycling and deposition of dust and nutrients into the North Atlantic. The cruise was funded by NERC. The objectives of the cruise were: 1) Obtain an improved temporal and spatial estimate of atmospheric dust input to the Tropical N Atlantic. 2) Obtain an improved estimate of the seawater dissolution of N, P and Fe species from aerosol dust. 3) Determine the influence dust exerts on phytoplankton carbon fixation, species diversity and nutrient cycling in surface waters. 4) Determine the impact of atmospheric dust derived micronutrients on microbial community production and species diversity in the surface microlayer and underlying waters. In particular this cruise aimed to combine in-situ aircraft measurements of the atmosphere (DODO, University of Reading, www.met.rdg.ac.uk/ˊaer/dodo/dodo.html) with in situ sampling of the lower atmosphere and the water column (University of East Anglia, University of Southampton, National Oceanography Centre Southampton and University of Birmingham) around the Cape Verde islands. However, the Poseidon did not meet up with the aircraft due to a lack of dust in the atmosphere. The main sampling and data-gathering activities comprised 21 stations for CTD and GoFlo profiles, 175 underway samples from the towed Fish and 6 samples of the surface microlayer. Stand Alone Pumps (SAPS) were deployed 4 times but without success. One dust event was encountered at 4-8 Feb. The transect sailed at 3-4 Feb. during the dust event was again sampled a week later to investigate changes in nutrients, trace-metals and the microbial community. The Cape Verde Time Series Station was sampled at 9 Feb.