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Extreme species deficit of nitrogen-converting microbes in European lakes

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Sampling of Lake Constance water from 85 m depth, in which ammonia-oxidizing archaea make up as much as 40% of all microorganisms

Dr. David Kamanda Ngugi, environmental microbiologist at the Leibniz Institute DSMZ

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Leibniz Institute DSMZ

 

An international team of researchers led by microbiologists from the Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures GmbH in Braunschweig, Germany, shows that in the depths of European lakes, the detoxification of ammonium is ensured by an extremely low biodiversity of archaea. The researchers recently published their findings in the prestigious international journal Science Advances. The team led by environmental microbiologists from the Leibniz Institute DSMZ has now shown that the species diversity of these archaea in lakes around the world ranges from 1 to 15 species. This is of particularly concern in the context of global biodiversity loss and the UN Biodiversity Conference held in Montreal, Canada, in December 2022. Lakes play an important role in providing freshwater for drinking, inland fisheries, and recreation. These ecosystem services would be at danger from ammonium enrichment. Ammonium is an essential component of agricultural fertilizers and contributes to its remarkable increase in environmental concentrations and the overall im-balance of the global nitrogen cycle. Nutrient-poor lakes with large water masses (such as Lake Constance and many other pre-alpine lakes) harbor enormously large populations of archaea, a unique class of microorganisms. In sediments and other low-oxygen environments, these archaea convert ammonium to nitrate, which is then converted to inert dinitrogen gas, an essential component of the air. In this way, they contribute to the detoxification of ammonium in the aquatic environment. In fact, the species predominant in European lakes is even clonal and shows low genetic microdiversity between different lakes. This low species diversity contrasts with marine ecosystems where this group of microorganisms predominates with much greater species richness, making the stability of ecosystem function provided by these nitrogen-converting archaea potentially vulnerable to environmental change.

Maintenance of drinking water quality
Although there is a lot of water on our planet, only 2.5% of it is fresh water. Since much of this fresh water is stored in glaciers and polar ice caps, only about 80% of it is even accessible to us humans. About 36% of drinking water in the European Union is obtained from surface waters. It is therefore crucial to understand how environmental processes such as microbial nitrification maintain this ecosystem service. The rate-determining phase of nitrification is the oxidation of ammonia, which prevents the accumulation of ammonium and converts it to nitrate via nitrite. In this way, ammonium is prevented from contaminating water sources and is necessary for its final conversion to the harmless dinitrogen gas. In this study, deep lakes on five different continents were investigated to assess the richness and evolutionary history of ammonia-oxidizing archaea. Organisms from marine habitats have traditionally colonized freshwater ecosystems. However, these archaea have had to make significant changes in their cell composition, possible only a few times during evolution, when they moved from marine habitats to freshwaters with much lower salt concentrations. The researchers identified this selection pressure as the major barrier to greater diversity of ammonia-oxidizing archaea colonizing freshwaters. The researchers were also able to determine when the few freshwater archaea first appeared. Ac-cording to the study, the dominant archaeal species in European lakes emerged only about 13 million years ago, which is quite consistent with the evolutionary history of the European lakes studied.

Slowed evolution of freshwater archaea
The major freshwater species in Europe changed relatively little over the 13 million years and spread almost clonally across Europe and Asia, which puzzled the researchers. Currently, there are not many examples of such an evolutionary break over such long time periods and over large intercontinental ranges. The authors suggest that the main factor slowing the rapid growth rates and associated evolutionary changes is the low temperatures (4 °C) at the bottom of the lakes studied. As a result, these archaea are restricted to a state of low genetic diversity. It is unclear how the extremely species-poor and evolutionarily static freshwater archaea will respond to changes induced by global climate warming and eutrophication of nearby agricultur-al lands, as the effects of climate change are more pronounced in freshwater than in marine habitats, which is associated with a loss of biodiversity.

Publication: Ngugi DK, Salcher MM, Andre A-S, Ghai R., Klotz F, Chiriac M-C, Ionescu D, Büsing P, Grossart H-S, Xing P, Priscu JC, Alymkulov S, Pester M. 2022. Postglacial adaptations enabled coloniza-tion and quasi-clonal dispersal of ammonia oxidizing archaea in modern European large lakes. Science Advances: https://www.science.org/doi/10.1126/sciadv.adc9392

Press contact:
PhDr. Sven-David Müller, Head of Public Relations, Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures GmbH
Phone: ++49 (0)531/2616-300
Mail: press@dsmz.de

About the Leibniz Institute DSMZ
The Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures is the world’s most diverse collection of biological resources (bacteria, archaea, protists, yeasts, fungi, bacteriophages, plant viruses, genomic bacterial DNA as well as human and animal cell lines). Microorganisms and cell cultures are collected, investigated and archived at the DSMZ. As an institution of the Leibniz Association, the DSMZ with its extensive scientific services and biological resources has been a global partner for research, science and industry since 1969. The DSMZ was the first registered collection in Europe (Regulation (EU) No. 511/2014) and is certified according to the quality standard ISO 9001:2015. As a patent depository, it offers the only possibility in Germany to deposit biological material in accordance with the requirements of the Budapest Treaty. In addition to scientific services, research is the second pillar of the DSMZ. The institute, located on the Science Campus Braunschweig-Süd, accommodates more than 82,000 cultures and biomaterials and has around 200 employees. www.dsmz.de

PhDr. Sven David Mueller, M.Sc.
Leibniz-Institut DSMZ
+49 531 2616300
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Solar Storm That Caused Dazzling Auroral Display Could Linger

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(Bloomberg) — A brilliant display of northern lights touched off by a massive geomagnetic storm was visible to a wide swath of the world Friday, and the aurora could linger through Saturday in many places if the weather is clear.

Red, purple and green streamers of the aurora borealis dazzled viewers in North America on Friday and were seen much farther south than normal, with people in California, Arizona and Texas reporting they could see it, according to AccuWeather, Inc. Typically, the spectacular display is only visible in northern locales like Alaska, North Dakota, Canada and Iceland.

The display was touched off by a severe geomagnetic storm that peaked about 12:04 a.m. Friday, according to the US Space Weather Prediction Center, and if the weather is clear, more could be in store on Saturday.

A coronal mass ejection, an explosion of magnetic fields and plasma from the sun’s atmosphere, hit Earth early Friday with more force than initially forecast. These events can disrupt Earth’s magnetic field causing auroral displays, as well as disrupting satellites, communication and electric grids.

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Read more: A Swedish Resort Lets You See the Northern Lights From Your Room

The US Space Weather Prediction Center had originally expected a G2 level storm Friday on its five-step scale, the event measured in at G4, one of the strongest triggered on Earth since 2017.

In addition to the dazzling auroral displays, a G4 storm can cause headaches for power grid operators and force spacecraft to adjust their orbits. The storm can also degrade satellite navigation, radio broadcasts and even cause pipelines to build up an electric charge. In early 2022, Elon Musk’s SpaceX lost 40 Starlink satellites because of a solar storm.

The impacts from the coronal mass ejection have trailed off, but energy coming from what scientists call a “coronal hole” will continue at least through Saturday and that could mean the aurora could be seen by viewers across Europe, Asia and North America through Sunday, the UK Met Office said on its website.

There are currently eight sunspot clusters visible on the side of the sun facing Earth, however another coronal mass ejection blasting toward us isn’t forecast, the UK Met Office said.

 

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An airplane-sized asteroid will pass between the Earth and moon’s orbits Saturday

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An asteroid dubbed “city killer” for its size will pass harmlessly between the moon and the Earth Saturday evening.

The asteroid 2023 DZ2 will pass at a distance of over 100,000 miles, less than half the distance between the Earth and the moon. It’s about 160 feet long — about the size of an airliner. An asteroid that size could cause significant damage if it hit a populated area, hence its nickname.

“While close approaches are a regular occurrence, one by an asteroid of this size (140-310 ft) happens only about once per decade, providing a unique opportunity for science,” NASA Asteroid Watch tweeted.

Astronomers from the International Asteroid Warning Network, established about 10 years ago to coordinate international responses to potential near-Earth object impact threats, will be monitoring and learning from this asteroid.

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NASA Asteroid Watch called the opportunity “good practice” in case “a potential asteroid threat were ever discovered.”

Near-Earth objects are asteroids or comets that pass close to the Earth’s orbit, and they generally come from objects that are affected by other planets’ gravity, moving them into orbits that push them close to Earth, according to the United Nations Office for Outer Space Affairs.

The European Space Agency maintains a risk list of 1,460 objects, which catalogs every object with a non-zero chance of hitting Earth over the next 100 years. Asteroid 2023 DZ2, which is in orbit around the sun, is not on the risk list.

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Large asteroid to zoom between Earth and Moon

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On Saturday, the 2023DZ2 will come within a third of the distance from the Earth to the Moon.

A large asteroid will safely zoom between Earth and the Moon on Saturday, a once-in-a-decade event that will be used as a training exercise for planetary defence efforts, according to the European Space Agency.

The asteroid, named 2023 DZ2, is estimated to be 40 to 70 metres (130 to 230 feet) wide, roughly the size of the Parthenon, and big enough to wipe out a large city if it hit our planet.

At 19:49 GMT on Saturday, it will come within a third of the distance from the Earth to the Moon, said Richard Moissl, the head of the ESA’s planetary defence office.

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Though that is “very close”, there is nothing to worry about, he told AFP news agency.

Small asteroids fly past every day, but one of this size coming so close to Earth only happens about once every 10 years, he added.

The asteroid will pass 175,000km (109,000 miles) from Earth at a speed of 28,000 kilometres per hour (17,400 miles per hour). The Moon is roughly 385,000km (239,228 miles) away.

An observatory in La Palma, one of Spain’s Canary Islands, first spotted the asteroid on February 27.

Last week, the United Nations-endorsed International Asteroid Warning Network decided it would take advantage of the close look, carrying out a “rapid characterisation” of 2023 DZ2, Moissl said. That means astronomers around the world will analyse the asteroid with a range of instruments such as spectrometers and radars.

The goal is to find out just how much we can learn about such an asteroid in only a week, Moissl said. It will also serve as training for how the network “would react to a threat” possibly heading our way in the future, he added.

The asteroid will again swing past Earth in 2026, but poses no threat of impact for at least the next 100 years – which is how far out its trajectory has been calculated.

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