Bacteria Mats May be Good For Fishing

Photo courtesy: Teske Lab

For the past decade, one of the largest collaborations to investigate marine biodiversity, the Census of Marine Life has trolled the oceans to identify, catalogue and examine all oceanic life. This collaboration was carried out by 2,000 scientists from more than 80 countries.

During this intensive, global study, 5,000 new species have been identified. Some species thought to have gone extinct have been rediscovered; and, one study looked at an area of the deep ocean that was no bigger than the size of a small bathroom and discovered 700 new species of crustaceans.

The study officially concludes in October; but, preliminary results were released this month.

Probably the largest and most significant discovery was a giant mat of string-like bacteria deep in the ocean off the coasts of Chile and Peru. This huge mat is the size of Uruguay or the US state of Alabama.

The fact that this mat of bacteria has been discovered in prime fishing waters has not escaped the notice of the researchers. They are now speculating whether this mat may contribute to the rich, thriving fisheries found in these waters.

"Some 50 percent of the world's fish catch comes from fisheries off the west coast of South America, where the biggest of these bacterial mats are found," said Dr Víctor Ariel Gallardo, vice-chair of the Census of Marine Life Scientific Steering Committee.

The megabacterium Thioploca spp. is string-like in appearance and measures about 2-7 cm (.8-2.8 in) making it visible to the naked eye. The mat discovered off the South American coast measures an astounding 130,000 sq km (80,778 sq mi).

Flourishing under oxygen-deficient conditions, the bacteria feed off toxic hydrogen sulphide. Hydrogen sulphide is produced when organic matter degrades without oxygen. Where there is no oxygen, large whitish mats of Thioploca spp. can be found at 50 to 200 metres deep. Scientists believe that Thioploca spp. is ancient - at least 2.5 billion years old - and most likely covered the oceans' surface back then when there was no oxygen at all.

"There are fossils of bacteria from that time that are very similar to what we find now," said Gallardo.

Scientists now hypothesize that these mats may now exist in many of the oceans' deeper, oxygen-poor zones and may extend along vast tracts of ocean floor, covering thousands of kilometers.

Other smaller mats have been found living on sulphide chimneys near Galápagos Archipelago, Ecuador, off the Pacific coasts of Mexico, Panamá, Costa Rica and near Namibia, which is also known for its abundant fisheries. The mats have also been found in "dead zones" created by agricultural run-off and salmon farms.

"Fishermen sometimes can't lift nets from the bottom because they have more bacteria than shrimp," said Gallardo. "We've measured them up to a kilo (2.2 lbs) per square meter."

While the link between the bacterial mats boosting fish populations is not totally clear yet, what is clear is that microbes - which make up 50 to 90 percent of all marine biomass - are crucial in regulating the planet's atmosphere, climate, nutrient recycling and decomposition. According to Census estimates, there may be a "nonillion" individual microbes in the seas - that's 1,000,000,000,000,000,000,000,000,000,000 (with 30 zeroes) and weighing the equivalent of 240 billion African elephants. Who would've thought such small critters could be so hefty?

Via TreeHugger and InterPress Service