The overall effect of aerosols (tiny particles suspended in the air) on climate change remains highly uncertain. One of the most complex aspects of the oceanic emissions/cloud interactions is the dynamic evolution of the size and composition of the marine aerosol population which ultimately controls the number of cloud condensation nuclei (CCN). Unlike over land, the mechanisms of aerosol formation in the pristine air over the oceans (50% of the surface of our planet) only recently are beginning to be elucidated. The following national and international projects are used during the research vessel BIO Hesperides between 20th October 2015 and 12th February 2015.
PEGASO (Plankton-derived Emission of trace Gases and Aerosols in the Southern Ocean, Spanish State grant), BIO-NUC (BIOgenic Marine Aerosol: from NUcleations to Clouds, Spanish State grant) and MANU (Marine Aerosol NUcleations, EU Marie Curie project). The projects are led by Dr Rafel Simo and Dr Manuel Dall´Osto, both researchers at the Institut de Ciencies del Mar of the CSIC (ICM-CSIC) in Barcelona and members of the Research Group on Marine Biogeochemistry and Global Change funded by Generalitat de Catalunya (Catalan Government).
The projects aim to fill crucial knowledge gaps presently existing in the timely subject of marine aerosol sources as well as the main aerosol chemical, physical and biological processes responsible for aerosol formation and transformation in open ocean regions.
This is important because little information is available about aerosol levels prior to the industrial era, and obtaining this level as a reference is crucial to estimating the radiative forcing of aerosol. Aerosols, depending on their properties, can dramatically alter clouds, either increasing or decreasing the sun-reflecting effect.
The quality of the projects raised by the ICM-CSIC, along with the excellent platform provided by the research vessel BIO Hesperides, has attracted a number of international institutions from several countries, including the National University of Ireland, in Galway (Ireland), the University of Birmingham (UK), the Plymouth Marine Laboratory (UK), the Institute of Instrumental Analytical Chemistry (Italy), the University of Mainz (Germany), the Instituto de Investigación en Biodiversidad y Medio Ambiente (Argentina), the Finnish Meteorological Institute (Finland), as weel as the technological company Aerodyne Research (USA).
The BIO Hesperides has been modified to allocate state-of-the-art instruments (worth more than 1.5 million euro altogether) that have never been deployed before in the Southern Ocean and Antarctica. These instruments include mass spectrometers designed to elucidate the chemical composition of gases in seawater and particles in the air. A special lab has been closed in the interior of the ship’s bow, air conditioned and connected to the atmosphere with a sampling line 8m long. This will allow real-time atmospheric measurements that will be compared and combined with measurements of the biology and chemistry of seawater.
This is a truly multidisciplinary and international initiative that makes a synergic use of cutting edge expertise in plankton ecology, ocean-atmosphere biogeochemistry and atmospheric chemistry. The project, without precedent in Spain, will elucidate the influence of marine aerosols on cloud droplet formation and the radiative budget, thus contributing to reduce current uncertainties in climate projections.