Latest news with #JournalofGeophysicalResearch
Saba Yemen
6 days ago
- Science
- Saba Yemen
Scientists Reveal South Africa Is Floating on Ocean
Washington - (Saba): As climate change intensifies, South Africa is not only becoming hotter and drier; it is also warming by up to 2 millimeters per year, according to a new study. Scientists knew this rise was occurring, but the prevailing explanation was that it was caused by mantle flow within the Earth's crust. The new study, published in the Journal of Geophysical Research, suggests that this rise is due to the recent drought and the resulting water loss, a trend linked to global climate change. This discovery was made possible thanks to a network of Global Navigation Satellite System (GNSS) stations in South Africa. This network is used primarily for atmospheric research and provides accurate elevation data for various locations across the country. "These data showed an average rise of 6 millimeters between 2012 and 2020," says geodesist McCann Carrigar of the University of Bonn. Experts have attributed this phenomenon to the Kwathlamba hotspot. A localized bulge in the Earth's crust likely resulted from the upwelling of material from a mantle plume suspected of lying beneath the region, which triggered the recent uplift. However, we have now tested another hypothesis, says Karigar. "We believe that the loss of groundwater and surface water is also likely responsible for the land-level rise." To explore this possibility, Karigar and his colleagues analyzed Global Positioning System (GNSS) elevation data along with rainfall patterns and other hydrological variables across southern Africa. A strong correlation emerged. Areas that had experienced severe drought in recent years experienced significant land-level rise. The rise was most pronounced during the drought that lasted from 2015 to 2019, a period when Cape Town faced the imminent threat of "Day Zero"—a day without water. The study also examined data from the GRACE satellite mission, a joint effort between NASA and the German Aerospace Center to measure Earth's gravity field and changes in water distribution. 'These results can be used to calculate, among other things, the change in the total mass of the water reserve, including the sum of surface water, soil moisture, and groundwater,' says Christian Mielke, a geodesist at the University of Bonn. 'However, the spatial resolution of these measurements is very low, only a few hundred kilometers.' Despite this low resolution, the GRACE satellite data supported the hypothesis: places with less water mass had higher elevations at nearby GNSS stations. The team used hydrological models to gain a more accurate view of how drought affects the water cycle. 'These data also showed that the uplift of the land can be primarily explained by drought and the associated loss of water mass,' says Mielke. The researchers suggest that, in addition to upward pressure from the mantle plume, the loss of moisture in the Earth's crust may also be causing it to bulge. Given the serious threat posed by droughts in South Africa, as well as many other parts of the world, this discovery may provide a valuable insight into water availability. Whatsapp Telegram Email Print
Forbes
25-05-2025
- Science
- Forbes
Subsurface Sea Mud Is The Unsung Hero In The Climate War
Old growth forests usually get a lion's share of the credit for their role in sequestering Earth's atmospheric carbon. But subsurface sea mud is finally coming into its own as the potential unsung hero in the climate change wars. Trouble is, oceanographers don't really have a full handle on when and how these important mud deposits formed, much less how they can be fully protected. To answer such questions, researchers from the U.K. are focusing on three subsurface sea mud sites that date back thousands of years. All lie on what is known as the Northwest European Shelf, a shallow continental shelf area in the Northeast Atlantic. Continental shelf sediments are really important for storing organic carbon over an enormous area, Zoe Roseby, a sedimentologist at the U.K.'s University of Exeter in Penryn, tells me at the European Geosciences Union General Assembly 2025 in Vienna. We've produced a model that has the capacity to predict the location of muddy deposits and consider how they've evolved over time, she says. We can then can identify potential hotspots of carbon storage, says Roseby. In fact, in a recent paper published in the Journal of Geophysical Research: Oceans, the authors note that three mud centers in the northwest European shelf seas are all effectively sequestering carbon. There are potentially hundreds of kilometers of such mud at depths of tens of meters, which is effectively helping sequester carbon, says Roseby, one of the paper's co-authors. They're a really important part of our global carbon cycle, she says. The Celtic Deep is in what we call the Celtic Sea, and that is offshore southeast of Ireland and southwest of Cornwall in the U.K., Sophie Ward, the paper's lead author and an oceanographer at Bangor University in the U.K., tells me at the European Geosciences Union General Assembly 2025 in Vienna. The Western Irish Sea mud belt is in the northwestern Irish Sea, which is in a semi enclosed body of water between mainland of the Republic of Ireland, Northern Ireland, and Great Britain, she says. In the Celtic Deep, most mud accumulation has occurred in the past 10,000 years, with earlier tidal conditions too energetic for fine sediment deposition, the authors write. The Fladen Ground --- located some 160 km north of Aberdeen, Scotland, appears to have been tidally quiescent since the region was fully submerged some 17,000 years ago, they note. Muds are important because they have a greater capacity to store organic carbon than sands and gravels, says Roseby. But here's where there is an important distinction. The formation of organic carbon in the marine environment has the potential to draw down carbon dioxide from Earth's atmosphere (a carbon sink), says Ward. The same cannot be said for inorganic carbon. Organic carbon on the seafloor is derived from both terrestrial and marine sources of living (or once living) matter, whereas the inorganic carbon in the sedimentary environment is largely made up of broken shells and skeletons. The latter (mostly calcium carbonate) can have a very negative impact on the ecosphere by releasing CO2 from the marine environment back into our atmosphere. This is why these precious sea muds are so important. But what is subsurface sea mud? Mud is any sediment that's less than 63 microns; the scientific cut off between mud and sand, says Roseby. Sand grains larger than 63 microns is what you're seeing on the beach, she says. How does this mud build up over time? Muds have this capacity to form very thick deposits which can then store quite large volumes of carbon, says Roseby. It's a combination of the surface area of the muds, but there's also a tendency to form thick deposits that makes them important for carbon storage, she says. Thousands of years ago, when the shelf seas were a lot shallower because so much water was locked into ice sheets in some areas, the tidal dynamics were very different to what they are now, says Ward. Over time, the water depth has changed and the configuration of the land, the shapes of the shelf seas have changed massively, she says. It's important that we know where these muddy deposits are, so that we can quantify carbon stocks, says Ward. But going out and sampling these muddy deposits can be a very expensive research campaign; expensive ships and large coring equipment is required, with lots of post-sampling analysis in the labs, she says. As for the biggest threat to this subsurface mud? That's probably trawling for shrimp on the sea bottom, says Ward. So, it's really important that we understand exactly what's going on when these muddy deposits are trawled and the potential effects for carbon that is stored and locked up in these muddy deposits, she says. Like most mud deposits around the U.K., the Celtic Deep is intensively trawled for Nephrops prawns in a fishery that grew rapidly from the 1970s, the authors note. The Fladen Ground, a heavily trawled and organic carbon‐rich area, was highlighted as experiencing relatively high losses of organic carbon, the authors write. The shrimp burrow into the mud which they use as a habitat, but the act of trawling itself causes significant amounts of the sequestered carbon to be released. In the future, we hope that sediments considered worthy of protection will go hand in hand with protecting subsurface habitat and living marine biology, says Roseby.
IOL News
11-05-2025
- Science
- IOL News
Drought reveals rising land: South Africa's surprising connection to water loss
As climate change continues to escalate, South African coastal cities such as Cape Town and Durban are already under siege from rising sea levels, eroding shorelines, and increasingly severe flooding. Researchers at the University of Bonn, Germany, have uncovered that certain regions in South Africa are gradually lifting, by as much as two millimetres a year, due to a phenomenon far removed from the hot mantle plumes previously thought to be responsible for such changes. Instead of deep-earth forces driving this uplift, the legs of science have turned to the immediate and pressing culprit: drought. The groundbreaking study employs data accumulated through a vast network of Global Navigation Satellite System (GNSS) base stations known as TrigNet, which has been observing subtle land movements across South Africa for over two decades. Current analyses indicate that when surface and underground water evaporate or deplete, the Earth's crust can rebound in a manner akin to a sponge expanding after being squeezed. This newly revealed elasticity of the land — a response to water loss — could have lasting implications for how scientists monitor and manage water in a warming world. Detailed findings published in the Journal of Geophysical Research: Solid Earth illustrate a compelling correlation between drought-stricken regions and measurable land uplift. Between 2012 and 2020, an average uplift of six millimetres was recorded, consistent with declining water mass, particularly in areas experiencing severe drought. This pivotal research challenges long-held beliefs that attributed regional uplift predominantly to tectonic activity tied to mantle hotspots. Dr. Makan Karegar, a key researcher in this study, alongside hydrologists and geodesists, matched the GPS data with climate records and findings from the GRACE satellite mission, which monitors changes in gravity caused by shifting water masses, to make their discovery. 'Groundwater adds weight to the land,' Karegar said. His research team found that as groundwater and surface water significantly diminished during prolonged dry spells, the land naturally lifted in response. Further exploring this phenomenon, Dr. Christian Mielke from the same research team pointed out the potential applications of their findings: 'By measuring how much the land lifts during droughts, we can estimate how much water has been lost. This gives us a unique, independent method to track vital water resources, particularly underground reserves.' The implications for countries like South Africa, where much of the water supply relies on underground aquifers, are profound. The urgent need for accurate water resource management has grown, especially following Cape Town's harrowing experience with 'Day Zero' in 2015, when the city faced the prospect of running entirely dry. By utilising existing GNSS data to monitor vertical land motion, the research indeed offers a cost-effective approach to preemptively manage water crisis. As climate change continues to escalate, South African coastal cities such as Cape Town and Durban are already under siege from rising sea levels, eroding shorelines, and increasingly severe flooding. The study's findings highlight a complex interaction between drought and rising ground — while some areas may be somewhat shielded from rising sea levels, the diminishing water reserves remain a tantalising yet alarming dilemma. 'If I had to choose between a decreasing sea level rise at the coast versus drought in the interior, I would choose sea level as the least-worst option,' said Jasper Knight, a geoscientist at the University of Witwatersrand who reviewed the study. This research not only reshapes perceptions surrounding South Africa's land dynamics but also underscores an urgent message: the land is responding to our choices regarding water use. As researchers continue to elucidate the nuances of changing climates, citizen awareness and policy integration concerning climate and ocean discussions, as highlighted by ocean governance policy researcher David Willima, become imperative. Properly linking these concerns could enable effective responses to one of the biggest challenges facing South Africa today — the disappearance of its water resources.
IOL News
10-05-2025
- Science
- IOL News
Drought reveals rising land: South Africa's surprising connection to water loss
As climate change continues to escalate, South African coastal cities such as Cape Town and Durban are already under siege from rising sea levels, eroding shorelines, and increasingly severe flooding. Researchers at the University of Bonn, Germany, have uncovered that certain regions in South Africa are gradually lifting, by as much as two millimetres a year, due to a phenomenon far removed from the hot mantle plumes previously thought to be responsible for such changes. Instead of deep-earth forces driving this uplift, the legs of science have turned to the immediate and pressing culprit: drought. The groundbreaking study employs data accumulated through a vast network of Global Navigation Satellite System (GNSS) base stations known as TrigNet, which has been observing subtle land movements across South Africa for over two decades. Current analyses indicate that when surface and underground water evaporate or deplete, the Earth's crust can rebound in a manner akin to a sponge expanding after being squeezed. This newly revealed elasticity of the land — a response to water loss — could have lasting implications for how scientists monitor and manage water in a warming world. Detailed findings published in the Journal of Geophysical Research: Solid Earth illustrate a compelling correlation between drought-stricken regions and measurable land uplift. Between 2012 and 2020, an average uplift of six millimetres was recorded, consistent with declining water mass, particularly in areas experiencing severe drought. This pivotal research challenges long-held beliefs that attributed regional uplift predominantly to tectonic activity tied to mantle hotspots. Dr. Makan Karegar, a key researcher in this study, alongside hydrologists and geodesists, matched the GPS data with climate records and findings from the GRACE satellite mission, which monitors changes in gravity caused by shifting water masses, to make their discovery. 'Groundwater adds weight to the land,' Karegar said. His research team found that as groundwater and surface water significantly diminished during prolonged dry spells, the land naturally lifted in response. Further exploring this phenomenon, Dr. Christian Mielke from the same research team pointed out the potential applications of their findings: 'By measuring how much the land lifts during droughts, we can estimate how much water has been lost. This gives us a unique, independent method to track vital water resources, particularly underground reserves.' The implications for countries like South Africa, where much of the water supply relies on underground aquifers, are profound. The urgent need for accurate water resource management has grown, especially following Cape Town's harrowing experience with 'Day Zero' in 2015, when the city faced the prospect of running entirely dry. By utilising existing GNSS data to monitor vertical land motion, the research indeed offers a cost-effective approach to preemptively manage water crisis. As climate change continues to escalate, South African coastal cities such as Cape Town and Durban are already under siege from rising sea levels, eroding shorelines, and increasingly severe flooding. The study's findings highlight a complex interaction between drought and rising ground — while some areas may be somewhat shielded from rising sea levels, the diminishing water reserves remain a tantalising yet alarming dilemma. 'If I had to choose between a decreasing sea level rise at the coast versus drought in the interior, I would choose sea level as the least-worst option,' said Jasper Knight, a geoscientist at the University of Witwatersrand who reviewed the study. This research not only reshapes perceptions surrounding South Africa's land dynamics but also underscores an urgent message: the land is responding to our choices regarding water use. As researchers continue to elucidate the nuances of changing climates, citizen awareness and policy integration concerning climate and ocean discussions, as highlighted by ocean governance policy researcher David Willima, become imperative. Properly linking these concerns could enable effective responses to one of the biggest challenges facing South Africa today — the disappearance of its water resources.
Yahoo
24-04-2025
- Science
- Yahoo
Scientists Spotted Signs of a Hidden Structure Inside Earth's Core
While most of us take the ground beneath our feet for granted, written within its complex layers, like the pages of a book, is Earth's history. Our history. Research shows there are little-known chapters in that history, deep within Earth's past. In fact, Earth's inner core appears to have another even more inner core within it. "Traditionally we've been taught the Earth has four main layers: the crust, the mantle, the outer core and the inner core," Australian National University geophysicist Joanne Stephenson explained in 2021. Our knowledge of what lies beneath Earth's crust has been inferred mostly from what volcanoes have divulged and what seismic waves have whispered. From these indirect observations, scientists have calculated that the scorchingly hot inner core, with temperatures surpassing 5,000 degrees Celsius (9,000 Fahrenheit), makes up only 1 percent of Earth's total volume. But a few years ago, Stephenson and colleagues found evidence Earth's inner core may actually have two distinct layers. "It's very exciting – and might mean we have to re-write the textbooks!" Stephenson explained at the time. The team used a search algorithm to trawl through and match thousands of models of the inner core with observed data across many decades about how long seismic waves take to travel through Earth, gathered by the International Seismological Centre. Differences in seismic wave paths through layers of Earth. (Stephenson et al., Journal of Geophysical Research: Solid Earth, 2021) So what's down there? The team looked at some models of the inner core's anisotropy – how differences in the make-up of its material alters the properties of seismic waves – and found some were more likely than others. While some models suggest the material of the inner core channels seismic waves faster parallel to the equator, others indicate the mix of materials allows for faster waves more parallel to Earth's rotational axis. Even then, there are arguments about the exact degree of difference at certain angles. The study here didn't show much variation with depth in the inner core, but it did find there was a change in the slow direction to a 54-degree angle, with the faster direction of waves running parallel to the axis. "We found evidence that may indicate a change in the structure of iron, which suggests perhaps two separate cooling events in Earth's history," Stephenson said. "The details of this big event are still a bit of a mystery, but we've added another piece of the puzzle when it comes to our knowledge of the Earth's inner core." These findings may explain why some experimental evidence has been inconsistent with our current models of Earth's structure. The presence of an innermost layer has been suspected before, with hints that iron crystals that compose the inner core have different structural alignments. "We are limited by the distribution of global earthquakes and receivers, especially at polar antipodes," the team writes in their paper, explaining the missing data decreases the certainty of their conclusions. But their conclusions align with other studies on the anisotropy of the innermost inner core. Future research may fill in some of these data gaps and allow scientists to corroborate or contradict their findings, and hopefully translate more stories written within this early layer of Earth's history. This research was published in the Journal of Geophysical Research. An earlier version of this article was published in March 2021. 'Bone Collector' Caterpillar Wears Dead Bugs to Steal Prey From Spiders 113 Million-Year-Old 'Hell Ant' Discovery Is Oldest Ever Found Most Bees Nest in The Ground. Offering Rocks And Gravel Is a Simple Way to Help Them Thrive.
