New research indicates that one possible source for the decline in Atlantic sea-surface temperature in 2006 may have been dust from the Sahara Desert. The image at left shows a dust plume being blown westward off the coast of Mauritania.

William Lau and Kyu-Myong Kim of NASA's Goddard Space Flight Center have concluded that airborne Saharan dust over the Atlantic was likely responsible for low temperatures because it effectively blocked sunlight from reaching the ocean's surface. Their research was published in EOS and the International Journal of Climatology.

In 2005, when the Atlantic was warmer, there were 15 hurricanes (including Katrina and Rita). In 2006, many people were expecting similar numbers and strengths of storms. However, there were only five that year due to lower sea-surface temperatures. Lau and Kim estimate that the dust was responsible for 30%-40% of the cooling effect.

Read more about it here and here.

Meanwhile, another team of researchers has found that these well-traveled dust particles may be a potential vector of disease. In the current issue of Environmental Microbiology, Anna Gorbushina and William Broughton (of the University of Geneva) report that germs can "hitchhike" on dust particles, allowing them to spread from continent to continent. The researchers used geochemical analyses to determine that samples of dust originally collected by Charles Darwin in Barbados actually originated in Africa. Furthermore, bacteria and tiny fungi were found stuck to the dust grains. The species found were not pathogenic (disease-causing), and the researchers note that most pathogens are not hardy enough to survive a long voyage on the Dust Express.

Read more about it here.

Labels: disease, dust, global warming, hurricanes, satellite imagery, silt