Reactive oxygen shown to impact carbon cycling in tidal sands
Reactive oxygen species—very reactive molecules containing oxygen—have a great impact on mineralization processes in tidal sandflats, finds a study now published in Nature Communications. Their investigation is thus important for understanding marine carbon cycling.
The Wadden Sea, stretching along 500 kilometers of the North Sea shore along the coasts of Denmark, Germany and the Netherlands, mostly consists of so-called intertidal permeable sediments—i.e. seafloor that is flushed by seawater in the change of tides. It is frequently visited by seabirds, marine mammals and recreationists.
But this highly dynamic habitat is also home to a plethora of microbes. They process carbon and nutrients from the seawater and fluvial inflows, making the sand a crucial site for organic matter remineralization and transforming it into an enormous purifying filter.
A perfect spot for ROS production
The frequent fluctuation between oxic and anoxic conditions (at high tide and low tide, respectively) in the sediments makes them a perfect spot for the production of reactive oxygen species (ROS). ROS are molecules that contain oxygen and are chemically very active. Their environmental role is multifaceted: ROS can be dangerous to organisms and damage cell components, but they can also be beneficial for microbial growth.
Because of their high activity, ROS are very important agents in the transformation and cycling of carbon and other substances in the environment and can thus have a great impact on the functioning of ecosystems. Nevertheless, they remain poorly studied in many habitats—amongst them the sandy flats of the Wadden Sea.
A group of scientists from the Max Planck Institute for Marine Microbiology in Bremen now took a closer look at ROS in a sandflat called Janssand in the German Wadden Sea off the island of Spiekeroog. Olivia Bourceau, Marit van Erk and their colleagues from the Microsensor Group investigated the ROS hydrogen peroxide.
“We wanted to know if there is any detectable hydrogen peroxide in the intertidal sands,” says Bourceau. “And if so, we wanted to know how this hydrogen peroxide impacts the mineralization processes, the recycling of organic matter, in these sands.”
Hydrogen peroxide impacts microbial activity
Indeed, the team around Bourceau and van Erk detected high concentrations of hydrogen peroxide in the intertidal sands. “We found that there is a fine balance between the production and degradation of hydrogen peroxide,” says co-author van Erk.
When the scientists changed the input of oxygen or removed hydrogen peroxide in experiments, that massively impacted the sand-dwelling microbes. ROS inhibited the microorganisms in the sand, thus its removal boosted microbial activity. “The amount of ROS naturally present in the sands reduced the rates of the main mineralization processes, both aerobic respiration and sulfate reduction, substantially.”
Important for carbon and nutrient cycling
Elevated ROS levels can be expected particularly during disturbance events and at oxic–anoxic interfaces—both frequently occurring in intertidal permeable sediments. The high rates of carbon and nitrogen remineralization make these sediments into huge biocatalytic filters. Any changes in ROS concentrations thus have the potential to directly impact the effectiveness of sands as such filters and the functioning of shallow water ecosystems.
Consequently, ROS may play an important and yet unappreciated role in the biogeochemistry of dynamic coastal sediments. “From our findings, we can conclude that ROS have the potential to substantially impact carbon cycling in the sediments. Understanding the controls on carbon cycling is very important for studying eutrophication and the impact of human activity on coastal systems,” Bourceau concludes.
Marit R. van Erk et al, Reactive oxygen species affect the potential for mineralization processes in permeable intertidal flats, Nature Communications (2023). DOI: 10.1038/s41467-023-35818-4
Max Planck Society
Reactive oxygen shown to impact carbon cycling in tidal sands (2023, March 14)
retrieved 14 March 2023
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CME storm effect! Sun sparks auroras without even hitting Earth – HT Tech
CME is one of the most influential drivers of solar storms and leads to powerful Geomagnetic storms on Earth. According to NASA, they are huge bubbles of coronal plasma threaded by intense magnetic field lines that are ejected from the Sun over the course of several hours. Although CMEs usually occur with solar flares, they can occur on their own too, and have the potential to disrupt sensitive electronics on Earth, as well as affect power grids. Surprisingly, a CME doesn’t need to strike Earth to have an effect.
Just a couple of days ago, a CME passed close by Earth and this caused, what is known as a, ‘Ripple Effect’. According to a report by spaceweather.com, the interplanetary magnetic field near Earth suddenly rotated by almost 180 degrees. This usually occurs when a CME passes by closely. Despite the CME not striking Earth, it still had a spectacular effect on our planet. Auroras were seen and captured over the Arctic Circle.
The spaceweather.com report said, “Yesterday, March 20th, the interplanetary magnetic field (IMF) near Earth suddenly rotated by almost 180 degrees. This kind of magnetic ripple is a typical sign of a CME passing nearby. The “ripple effect” ignited colorful lights inside the Arctic Circle.”
What happens when solar particles hit the Earth?
As the particles erupted during the CME reach Earth, they interact with Earth’s magnetic field and cause the formation of Geomagnetic storms. When solar particles hit Earth, the radio communications and the power grid is affected when it hits the planet’s magnetic field. It can cause power and radio blackouts for several hours or even days. However, electricity grid problems occur only if the solar flare is extremely large.
Auroras form because of the Coronal Mass Ejection (CME) from the Sun which sends solar fares hurtling towards Earth. Geomagnetic storms are often the precursor to stunning streaks of green light across the sky known as Northern Lights or Aurora Borealis.
How NASA monitors solar activity
Among many satellites and telescopes observing the Sun currently, one is the NASA Solar Dynamics Observatory (SDO). The SDO carries a full suite of instruments to observe the Sun and has been doing so since 2010. It uses three very crucial instruments to collect data from various solar activities.
They include Helioseismic and Magnetic Imager (HMI) which takes high-resolution measurements of the longitudinal and vector magnetic field over the entire visible solar disk, Extreme Ultraviolet Variability Experiment (EVE) which measures the Sun’s extreme ultraviolet irradiance and Atmospheric Imaging Assembly (AIA) which provides continuous full-disk observations of the solar chromosphere and corona in seven extreme ultraviolet (EUV) channels.
Uracil Has Been Found In Asteroid Ryugu Samples
Researchers have analyzed samples of asteroid Ryugu collected by the Japanese Space Agency’s Hayabusa2 spacecraft and found uracil—one of the informational units that make up RNA, the molecules that contain the instructions for how to build and operate living organisms. Nicotinic acid, also known as Vitamin B3 or niacin, which is an important cofactor for metabolism in living organisms, was also detected in the same samples.
This discovery by an international team, led by Associate Professor Yasuhiro Oba at Hokkaido University, adds to the evidence that important building blocks for life are created in space and could have been delivered to Earth by meteorites. The findings were published in the journal Nature Communications.
“Scientists have previously found nucleobases and vitamins in certain carbon-rich meteorites, but there was always the question of contamination by exposure to the Earth’s environment,” Oba explained. “Since the Hayabusa2 spacecraft collected two samples directly from asteroid Ryugu and delivered them to Earth in sealed capsules, contamination can be ruled out.”
The researchers extracted these molecules by soaking the Ryugu particles in hot water, followed by analyses using liquid chromatography coupled with high-resolution mass spectrometry. This revealed the presence of uracil and nicotinic acid, as well as other nitrogen-containing organic compounds.
“We found uracil in the samples in small amounts, in the range of 6–32 parts per billion (ppb), while vitamin B3 was more abundant, in the range of 49–99 ppb,” Oba elaborated. “Other biological molecules were found in the sample as well, including a selection of amino acids, amines and carboxylic acids, which are found in proteins and metabolism, respectively.” The compounds detected are similar but not identical to those previously discovered in carbon-rich meteorites.
The team hypothesizes that the difference in concentrations in the two samples, collected from different locations on Ryugu, is likely due to the exposure to the extreme environments of space. They also hypothesized that the nitrogen-containing compounds were, at least in part, formed from the simpler molecules such as ammonia, formaldehyde and hydrogen cyanide. While these were not detected in the Ryugu samples, they are known to be present in cometary ice—and Ryugu could have originated as a comet or another parent body which had been present in low temperature environments.
“The discovery of uracil in the samples from Ryugu lends strength to current theories regarding the source of nucleobases in the early Earth,” Oba concludes. “The OSIRIS-REx mission by NASA will be returning samples from asteroid Bennu this year, and a comparative study of the composition of these asteroids will provide further data to build on these theories.”
Associate Professor Yasuhiro Oba
Institute of Low Temperature Science
Sohail Keegan Pinto (International Public Relations Specialist)
Public Relations Division
Yasuhiro Oba, et al. Uracil in the carbonaceous asteroid (162173) Ryugu. Nature Communications. March 21, 2023.
The Hayabusa2 project has been led by JAXA (Japan Aerospace Exploration Agency) in collaboration with DLR (German Space Center) and CNES (French Space Center) and supported by NASA (National Aeronautics and Space Administration) and ASA (Australian Space Agency). This research is partly supported by the Japan Society for the Promotion of Science (JSPS) under KAKENHI (21H04501, 21H05414, 21J00504, 21KK0062, 20H00202); the Consortium for Hayabusa2 Analysis of Organic Solubles, supported by NASA. This study was partly conducted by the official collaboration agreement through the joint research project with JAMSTEC, Keio University and HMT Inc. This study was conducted in accordance with the Joint Research Promotion Project at the Institute of Low Temperature Science, Hokkaido University (21G008, 22G008).
How to Break the Universe and Other Adventures in UMass Astronomy
A team of astronomers, including assistant professor Kate Whitaker, recently published research in the journal Nature that many popular publications have said “breaks the universe.” While not literally true, the team, which used the newest trove of data retrieved from the James Webb Space Telescope (JWST), discovered that very old, very massive galaxies seem to exist on the fringes of the universe—which, according to current astronomical theory, shouldn’t be possible.
“Do I think we broke the universe? Well, no”, says Whitaker, “but this puzzling discovery tells us that something isn’t quite right in our models. This discovery is a learning opportunity, opening completely unexplored parameters in space and impacting our understanding of galaxy formation and evolution at the most fundamental level.”
These six galaxies are about 13.5 billion light-years away, which means that the light the team saw was emitted 13.5 billion years ago. Put another way, the team was able to look back in time 13.5 billion years. This is exciting because the universe itself is only about 14 billion years old, which means that the team was able to observe the universe’s infancy.
It has long been thought that only very young, small galaxies would have existed 13 billion years ago because not enough time would have elapsed since the Big Bang for cosmic dust and gas to accrete into massive galaxies.
And yet, this is exactly what the team seems to have found.
“These galaxies are impossibly massive for their epochs, suggesting an accelerated growth very early on. It would be like seeing a picture of a toddler, when we expected to find infants.”
This upends what many astronomers considered to be largely settled matters. All that extra mass at the fringes of the universe means either the current cosmological models need significant altering or our scientific understanding of galaxy formation in the early universe is incorrect. Both options require rethinking what we know about the universe’s earliest days.
“The revelation that massive galaxy formation began extremely early in the history of the universe upends what many of us had thought was settled science,” said Joel Leja assistant professor of astronomy and astrophysics at Pennyslvania State University and one of the paper’s co-authors. “We’ve been informally calling these objects ‘universe breakers’—and they have been living up to their name so far.”
But before throwing out the old astronomy textbooks, the team needs to follow up on their initial observation with more sensitive measurements that can confirm distance and size, and whether or not all of the objects are actually galaxies.
CME storm effect! Sun sparks auroras without even hitting Earth – HT Tech
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