Why smell the sea?

A beach trip means sand in your feet, salt water in your mouth and cool air in your nose. But what brought the sea something so pleasant and unmistakable? Now the veil of secret has been lifted.

When dying, plankton and marine plants, such as algae, produce a gas called Dimethylsulfoniopropionate (DMSP). Scientists have long known that bacteria can use DMPS as food and produce dimethyl sulfide gas (DMS). Dimethyl sulfide makes the ocean's air more fragrant, said Andrew Johnston, a researcher at the University of East Anglia.

"Although it is known that bacteria can produce dimethyl sulfide, no one has ever figured out how they make this gas before," Andrew said. " I and my colleagues decided to do that ."

The team took samples of mud from mangrove swamps along the coast of England to isolate a previously unknown strain of bacteria. Following its genetic arrangement and comparing it to the genetic structure of many known human bacteria, experts discovered that the gene is involved in the mechanism of DMPS conversion into dimethyl sulfide .

Unexpected

Experts used to think that just one simple enzyme could break the molecular structure of DMSP, turning it into dimethyl sulfide . But in fact, this process turns out to be much more complicated because DMPS is very hard to break.

Bacteria apply a very clever strategy: Only to find decaying marine creatures. For example, when a population of plankton is attacked by a virus, the bacteria will come to seek opportunities."They only start genes to break up DMSP if they encounter a rotting plankton , " Andrew said.

Andrew and his colleagues succeeded in cloning the genes of the strange bacteria and introducing it to other strains of bacteria, such as E. Coli (living in the stomach). After receiving the gene, these bacteria were able to produce dimethyl sulfide gas.

Scientists estimate that bacteria have broken about 1 billion tons of DMPS in the ocean. But that would not make sense if they did not find that dimethyl sulfide could affect the formation of clouds above the ocean - one of the processes that affected the Earth's climate.

Some seabirds rely on dimethyl sulfide to find food. On one of the mud sampling samples in the mangrove lagoon, a member of Andrew's group opened a dimethyl sulfide gas container . Immediately, they were attacked by a flock of seabirds.

Viet Linh