|Saharan dust storm in 2003. We are just south of the frame of this picture|
|Aerosol samplers on the flying bridge with lots of dust!|
Some scientists on board from University of Alaska, Fairbanks and from Florida State University, are studying these dust storms and other "aerosols" in the marine environment. Aerosols are tiny particles that are generally made up of some kind of dust or sea salt, and water. They are called aerosols because they are a mixture between a liquid and a solid, and are found floating in the air. Aerosols are comprised of many things, and oceanographers often distinguish between anthropogenic aerosols (aerosols that are human-derived, often forms of smoke/smog and other pollution) and natural aerosols (like those from the Sahara). By measuring the sizes of the aerosols, and the different metals and nutrients in the aerosols, scientists can often distinguish where these particles originated from and how far they have traveled. This is just what scientists on our ship have been doing everyday of the cruise since we left. They have large aerosol samplers on the "flying bridge" of the ship, which is the highest desk on the ship above everything else so that the samples don't get contaminated by any pollution coming from the ship itself.
|Red/orange Sahara dust in the medium size range|
|Black/gray anthropogenic dust in the small size fraction|
|Sahara dust on the aerosol filters|
For example, dust from the Sahara usually has high levels of iron, an important nutrient for phytoplankton, so a dust storm could mean an increase in nutrients that the phytoplankton need. On the other hand, anthropogenic dust from industrialized areas has high levels of toxins such as lead and sometimes mercury, which can be potentially harmful to phytoplankton and other organisms.