Tag Archives: Coastal

The Methane Ocean on Saturn’s Moon Titan is Causing Coastal Erosion

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Titan's liquid hydrocarbon ocean may have waves

NASA/JPL-Caltech/University of Arizona/University of Idaho

Saturn's largest moon, Titan, has rocky coastlines around its methane seas and lakes that appear to have been carved out by waves, and a NASA mission launching in 2028 may be able to get a closer look.

Titan is the only body in the solar system other than Earth that has liquid on its surface. It has lakes and oceans made of hydrocarbons such as liquid methane, ethane, and other organic molecules. Scientists think that winds in Titan's thick, nitrogen-rich atmosphere drive the waves in these lakes, but this has never been observed directly because Titan's atmosphere is too hazy to see through.

now, Rose Palermo Researchers from the U.S. Geological Survey in Florida and their colleagues found that the shape of Titan's coastline is best explained by the presence of waves that have eroded the ocean surface over eons.

Palermo and his team looked at the shorelines around Titan's largest oceans and lakes, including Kraken Mare and Ligeia Mare, and compared them to coastlines on Earth with known origins, such as Lake Rotoef in New Zealand, which initially formed by floods and later was eroded by waves. The team then created different simulations of Titan's oceans, including those in which the shores were eroded by waves or by dissolving their edges.

Photographed by NASA's Cassini spacecraft, Ligeia Mare on Saturn's moon Titan has a variety of edges that appear to have been carved by waves.

NASA/JPL-Caltech/ASI/Cornell

The researchers found that images of Titan's coastline, best depicted by wave simulations, resemble Earth's wave-eroded coastlines.

“It's still tentative, but I'm very excited about it.” Ingo Muller-Vodarg The Imperial College London researchers say that although the study did not observe waves themselves, it is very strong evidence that waves exist. Dune-like structures.

The only way to truly verify that waves exist is to send a spacecraft to the surface, like NASA's Dragonfly drone mission, scheduled to launch in 2028, Mueller-Vaudergues said.

Studying Titan's coastlines may also help us understand how the first coasts on Earth formed, Palermo says: “Titan is a unique laboratory for studying coastal processes because it is not influenced by humans or plants. It's a place where we can study coasts only as physical processes.”

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Source: www.newscientist.com

After Hurricane Hits, Majority of Coastal Town’s Residents Abandon Rebuilding Efforts

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According to NASA’s estimates, Louisiana has lost about 750 square miles of coastal wetlands since 1984. Check out the report for more details. In a recent paper published in February, researchers have predicted that three-quarters of Louisiana’s wetlands could be submerged by 2070.

In various coastal cities across the United States, the land is gradually sinking due to fossil fuel and water extraction, exacerbating sea level rise. By 2050, the sinking phenomenon could potentially put over half a million more people at risk of severe flooding.

Raising resilient children

Anna Dupont, 21, is one of the few young residents left in Cameron Parish. She cherishes her parents’ stories about the vibrant community of Cameron.

Anna Dupont, 21, is one of the few young people left in Cameron after a series of devastating hurricanes.
Michael Gemelli/NBC News

Before Hurricane Rita, Cameron Parish was a thriving, close-knit community that enjoyed festivities like crawfish boils and barbecues, with residents being proud supporters of the high school football team.

Dupont recalls nostalgic memories of fishing and birdwatching in the expansive wetlands surrounding her former home. She laments the loss of her favorite hangout spot, T-Boy’s Cajun Grill, which now stands as an empty lot.

Cameron is considered ground zero for climate change by Dupont, who witnessed her home being destroyed twice by storms before she even graduated from high school. Hurricane Laura’s impact forced her and her family to evacuate, leading to a sense of loss and emptiness upon their return.

Despite a joyful upbringing, Dupont saw her peers struggle with disrupted childhoods due to unstable living conditions post-hurricanes, leading to mental health challenges and substance abuse in some cases.

While many residents departed Cameron Parish after Hurricane Rita in 2005, others chose to remain resilient despite subsequent natural calamities. However, the proposed expansion of Venture Global LNG’s CP2 LNG terminal construction has stirred concern among the remaining residents.

Source: www.nbcnews.com

Coastal Cities in the US Facing Increased Flooding Risk Due to Rising Sea Levels by 2050

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New Orleans is at risk of more flooding than expected due to land subsidence

William A. Morgan/Shutterstock

Sea levels are rising faster than expected in U.S. coastal cities, primarily due to land subsidence from groundwater and fossil fuel extraction. This means up to 518,000 additional people living in these areas could be at risk of major flooding by 2050 if adequate protection is not in place.

Coastal cities often experience subsidence, where the land gradually sinks over time. One of the biggest factors causing this is the compaction of the earth by extracting resources such as water and fossil fuels from the ground.

To investigate how land subsidence and sea level rise will impact coastal communities. leonard owenhen The Virginia Tech researchers created a model based on land elevation changes in 32 major coastal cities, including Boston and San Francisco, and sea level rise projections through 2050.

Researchers found that cities on the Atlantic and Gulf coasts, such as New Orleans, have lower elevations and are sinking faster. It is sinking at least two millimeters more per year than other cities in the region, increasing the risk of future flooding. . Urban areas along the Pacific coast are better protected from rising sea levels because of their higher elevations.

“We were surprised to see that Biloxi, Mississippi, experienced the most rapid subsidence,” Owenhen says.

They also found that existing flood risk assessments in the United States do not take into account the combined effects of land subsidence, underestimating its threat. Researchers have found that nearly 1,400 square kilometers more land will be at risk of flooding by 2050 than current estimates. That means, in total, 1 in 50 people and 1 in 35 homes in 32 cities are at risk. .

This would put an additional 518,000 people and more than 288,000 homes at risk of flooding.

The study looked at flood risk for dozens of coastal U.S. cities by 2050.

Image courtesy of Leonard Owenhen

These findings highlight the urgent need to strengthen U.S. flood protection now, team members say Manuchel Shirzai, also at Virginia Tech. “Individual cities will need to adapt differently. New Orleans will need to strengthen city-wide flood protection, while San Francisco will probably only need to protect its critical infrastructure.”

Other things could be done to reduce the threat. “If land subsidence is being caused by groundwater extraction, oil and gas development, or other human-induced stresses, we need to do everything we can to reverse these trends before it’s too late.” he says. Simon Anisfeld At Yale University.

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Source: www.newscientist.com

Rivers’ Inability to Preserve Coastal Wetlands: A Problematic Situation

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Salt marshes in Barnstable, Massachusetts show signs of erosion and submergence as sea levels rise (December 2, 2022).Credit: Erin Peck

Creating wetlands, which are being submerged by rising sea levels, remains a challenge, but scientists are now one step closer to identifying a solution.

Amid climate change, large-scale dam removal projects are gaining traction as a solution to the loss of coastal wetlands that reduce flooding, filter water, and provide habitat for wildlife. However, in a recently published paper, scienceresearchers concluded that this strategy does not work in most rivers in the United States.

Limited sediment supply hinders wetland recovery

The reason is that there is not enough sediment. Of the nearly 5,000 rivers analyzed, nearly three out of four were unable to transport enough sediment to keep up with sea level rise in the coastal regions they connect to. Nearly half were at least 10 times short of the required amount of sediment.

This is the first national study to examine how much watershed sediment can be deposited in coastal areas by rivers. So far, research has focused on a few very large rivers. mississippi,and, Elfa In Washington, they are not representative of most other areas of the continental United States.

Most watersheds in the United States are small and are not major sources of sediment buildup in wetlands, researchers said. It is on these small rivers that most dams are located.

Expert insights on dam removal and sediment supply

The study was led by Dr. Scott Ensign, a research scientist at the Stroud Water Research Center, a nonprofit organization that studies freshwater streams and rivers around the world. He said: “Elfa is the poster child for dam removal projects that restore coastal sediment, and for good reason: it liberated vast amounts of sediment and sand.

“However, rivers along the East and Gulf coasts are not as steep as the West Coast and there is less sediment that can reach the wetlands, so the wetlands are wider and require more sediment to keep them above the rising ocean.” is required.Basically, the numbers don’t add up.”

Dr. Christopher Craft, an Indiana University professor who focuses on wetland restoration and climate change, said, “The extensive and comprehensive spatial analysis conducted by the authors shows that sediment supply in most coastal basins is This strongly suggests that this is insufficient.” As sea levels rise, tidal wetlands appear. In other words, sediment cannot save them. ”

Methodology and findings

Ensign and her co-authors, Joanne Halls of the University of North Carolina Wilmington and Erin Peck of the University of Massachusetts, used publicly available data from the U.S. Geological Survey and the National Oceanic and Atmospheric Administration to map watersheds to coastal wetlands. Sediment supply was modeled. Uses Esri’s ArcGIS Pro technology. They then compared their projections to previously reported rates of change for tidal wetlands across the United States.

“By and large, the sediment that saves most wetlands from drowning doesn’t come from upstream rivers. In many places on the East Coast, removing dams won’t help. You’ll have to look elsewhere.” explained the lieutenant.

Impact on wetland conservation

Dr. James Pizzuto, a professor of geological sciences who specializes in river science at the University of Delaware, said the researchers deftly addressed a complex problem. “These results, and the local variations documented by mapping the entire U.S. coastline, provide important guidance to managers and scientists, and future efforts to investigate other processes beyond basin sediments. “We are documenting where we should focus our efforts,” he said.

Such efforts include finding ways to retain more mineral deposits, plant material and organic carbon in wetland soils, said Donald F. Boesch, professor emeritus at the University of Maryland Center for Environmental Science. He explained that it was possible. “This is true both where sediment is being depleted and where it is being diverted to construct and maintain wetlands with relatively high rates of sea level rise, such as the Mississippi Delta,” he said. ” he said.

Future research and conservation strategies

Future research is needed to measure how much sediment is trapped behind a particular dam and accurately predict the impact on downstream tidal wetlands.

“In general, the most important action to protect tidal wetlands is to allow them to move up slopes. In some areas, we need to restore natural hydrology and protect lowlands,” said Ensign. Direct application of deposits and other engineering approaches may also be helpful at very local scales.”

References: Scott H. Ensign, Joanne N. Halls, and Erin K. Peck, “Catchment Sediments Cannot Offset Sea Level Rise in Most U.S. Tidal Wetlands,” December 7, 2023. science.
DOI: 10.1126/science.adj0513

The National Science Foundation funded the research.

Source: scitechdaily.com