Google Play icon

Every grain of sand is a met­ro­polis for bac­teria

Posted December 5, 2017

Just ima­gine, you are sit­ting on a sunny beach, con­ten­tedly let­ting the warm sand trickle through your fin­gers. Mil­lions of sand grains. What you prob­ably can’t ima­gine: at the same time, bil­lions upon bil­lions of bac­teria are also trick­ling through your fin­gers. Between 10,000 and 100,000 mi­croor­gan­isms live on each single grain of sand, as re­vealed in a study by researchers from the Max Planck Institute for Marine Microbiology in Bremen. This means that an in­di­vidual grain of sand can have twice as many res­id­ents as, say, the city of Fairb­anks, Alaska.

View of a sand grain under a fluorescence microscope: The green spots are stained bacteria, which have mainly colonized depressions on the grain. Credit: MPIMM/CC-SA BY 4.0

It has long been known that sand is a densely pop­u­lated and act­ive hab­itat. Now David Probandt and his col­leagues have de­scribed the mi­cro­bial com­munity on a single grain of sand us­ing mod­ern mo­lecu­lar meth­ods. To do this, they used samples taken from the south­ern North Sea, near the is­land of Hel­go­land, off the Ger­man coast.

The bac­teria do not col­on­ize the sand grains uni­formly. While ex­posed areas are prac­tic­ally un­col­on­ized, the bac­teria bustle in cracks and de­pres­sions. “They are well pro­tec­ted there”, ex­plains Probandt. < “When wa­ter flows around the grains of sand and they are swirled around, rub­bing against each other, the bac­teria are safe within these de­pres­sions.” These sites may also act as hid­ing grounds from pred­at­ors, who comb the sur­face of the sand grains in search of food.

Impressive diversity

However, the di­versity of the bac­teria, and not just their num­bers, is im­press­ive. “We found thou­sands of dif­fer­ent spe­cies of bac­teria on each in­di­vidual grain of sand”, says Probandt.

Some bac­teria spe­cies and groups can be found on all in­vest­ig­ated sand grains, oth­ers only here and there. “More than half of the in­hab­it­ants on all grains are the same. We as­sume that this core com­munity on all sand grains dis­plays a sim­ilar func­tion”, ex­plains Probandt. “In prin­ciple, each grain has the same fun­da­mental pop­u­la­tion and in­fra­struc­ture.” We can there­fore really dis­cover a great deal about the bac­terial di­versity of sand in gen­eral from in­vest­ig­at­ing a single grain of sand.

Sandy coasts are enormous filters

Sand-dwell­ing bac­teria play an im­port­ant role in the mar­ine eco­sys­tem and global ma­ter­ial cycles. Be­cause these bac­teria pro­cess, for ex­ample, car­bon and ni­tro­gen com­pounds from sea­wa­ter and flu­vial in­flows, the sand acts as an enorm­ous puri­fy­ing fil­ter. Much of what is flushed into the seabed by sea­wa­ter does­n’t come back out.

“Every grain of sand func­tions like a small bac­terial pantry”, ex­plains Probandt. They de­liver the ne­ces­sary sup­plies to keep the car­bon, ni­tro­gen and sul­phur cycles run­ning. “Whatever the con­di­tions may be that the bac­terial com­munity on a grain of sand is ex­posed to – thanks to the great di­versity of the core com­munity there is al­ways someone to pro­cess the sub­stances from the sur­round­ing wa­ter.”

Source: MPG

Featured news from related categories:

Technology Org App
Google Play icon
86,172 science & technology articles

Most Popular Articles

  1. NASA Scientists Confirm Water Vapor on Europa (November 19, 2019)
  2. Scientists Reverse Dementia in Mice with Anti Inflammatory Drugs (December 5, 2019)
  3. How Do We Colonize Ceres? (November 21, 2019)
  4. Universe is a Sphere and Not Flat After All According to a New Research (November 7, 2019)
  5. Scientists created a wireless battery free computer input device (December 1, 2019)

Follow us

Facebook   Twitter   Pinterest   Tumblr   RSS   Newsletter via Email