Bacterioplankton responses to desert dust in the (sub)tropical northeast Atlantic

June 2, 2010
Saharan dust settles on the deck of the RRS Discovery during a research cruise in the eastern (sub)tropical North Atlantic Ocean. Credit: Ross Holland, NOC

Inputs of dust from the Sahara desert could change the composition of microbial communities in the (sub)tropical eastern North Atlantic say Southampton researchers writing this month in the journal FEMS Microbiology Letters.

When high winds blow over the Sahara, consisting of are lifted high into the atmosphere, blown over the sea, and then deposited on the ocean surface.

"Desert dust particles contain nutrients such as iron that can boost the production of tiny planktonic plants called phytoplankton as well as in some oceanic regions," explained researcher Polly Hill, a PhD student at the University of Southampton's School of Ocean and Earth Science (SOES) based at the National Oceanography Centre (NOC) in Southampton.

The new research was conducted aboard the Royal Research Ship Discovery in the eastern (sub)tropical North Atlantic Ocean during January-February 2008.

"During the voyage a huge cloud of Saharan dust came over, turning the sky brown and covering the ship in a layer of red-brown dust. The dust cloud was clearly visible in satellite images," recalled Hill.

Hill and her colleagues Mike Zubkov and Duncan Purdie experimentally assessed the affect of oceanic dust deposition on the metabolic activity of (bacterioplankton) contained in seawater samples collected at a depth of 20 metres. They focused on two types of bacteria, Prochlorococcus and SAR11.

"Prochlorococcus bacteria are the dominant phytoplankton group in the subtropical and tropical ocean and are responsible for a large proportion of carbon dioxide fixation in those regions. Conversely, SAR11 bacteria respire organic carbon and release carbon dioxide," said Hill.

The researchers' experiments aboard ship showed that dust inputs generally advantaged SAR11 over Prochlorococcus, for which these inputs may even be detrimental.

"This means that large inputs of Saharan dust has the potential to change the composition of the bacterioplankton community in the (sub)tropical North Atlantic, as has been shown previously for some other oceanic regions," concluded Hill.

Explore further: Climate monitor to sample African dust

More information: Hill, P. G., Zubkov, M. V. & Purdie, D. A. Differential responses of Prochlorococcus and SAR11-dominated bacterioplankton groups to atmospheric dust inputs in the tropical Northeast Atlantic Ocean. FEMS Microbiology Letters 306, 82-89 (2010).

Related Stories

Study ties hurricanes to Sahara

April 3, 2007

A U.S. government study suggests that the relatively tame 2006 hurricane season may have been tied to activity in Africa's Sahara desert.

Bacterial 'food supplements' for small algae

March 29, 2010

To boost their diet of mineral nutrients and sunlight, small algae also feast on bacteria in order to grow and fix carbon dioxide (CO2). Understanding more about the lifestyle of small algae - which are major players in CO2 ...

Recommended for you

Plant light sensors came from ancient algae

July 28, 2015

The light-sensing molecules that tell plants whether to germinate, when to flower and which direction to grow were inherited millions of years ago from ancient algae, finds a new study from Duke University.

Head and body lice read DNA differently

July 28, 2015

What makes head lice different from body lice had scientists scratching their heads as previous genetic studies failed to find any substantial differences between the two types of lice.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.