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What new methods can be used to help predict glacier melt patterns as climate change continues to ravage the planet? This is what a recent study published in GIScience & Remote Sensing hopes to address as a pair of researchers from The Ohio State University investigated changing glacier heights that could provide insights into future melting patterns. This study has the potential to help researchers, climate scientists, and the public better understand the threat of glacier melting and the steps that can be taken to predict and mitigate them.

For the study, the researchers used a combination of satellite imagery and 3D elevation models to analyze glacier melting patterns for the La Perouse Glacier in North America, the Viedma Glacier in South America and the Skamri Glacier located in Central Asia between 2019 and 2023. The goal of the study was to ascertain differences between seasonal melting and melting caused by climate change. In the end, the researchers discovered that while the Viedma Glacier (Argentina) and the La Perouse Glacier (Alaska) exhibited regular intervals of melting, the Skamri Glacier (Pakistan) exhibited glacier ice increases.

“This is something that we’ve been thinking about for a long time, because existing glacier studies have such sparse seasonal observations since it’s difficult to get data out of remote areas,” said Dr. Rongjun Qin, who is an associate professor of civil, environmental and geodetic engineering at The Ohio State University and a co-author on the study. “What we wanted to do is to use medium-to-high resolution data to broaden those capabilities and improve the accuracy of the 3D models generated from that data.”

Going forward, the researchers note that improvements in their methodology, specifically modeling, will enable more accurate predictions and disaster preparedness.

What new methods for predicting glacier melting will researchers make in the coming years and decades? Only time will tell, and this is why we science!

As always, keep doing science & keep looking up!

Sources: GIScience & Remote Sensing, EurekAlert!

Ancient Romans were known for creating delicious sauces, including garum—a famous fish-based condiment. Scientists studying ancient DNA from a Roman-era salting plant in Spain have found that European sardines were the key ingredient.

Fish was an important part of the ancient Roman diet, and Romans processed their catch for long-term preservation in coastal fish-salting plants called cetariae. There, they crushed and fermented small fish into pastes and sauces such as the iconic umami-flavored garum. Today, fermented fish-based sauces remain popular, whether in the form of classic Worcestershire sauce or the many fish sauces produced in Southeast Asia.

Analyzing the fish used in Roman condiments could provide insight into the diets and culture of ancient people as well as information on fish populations of the time, but the intense processing that took place at the salting plants, among other things, makes it almost impossible to visually identify species from their remains.

To overcome this limitation, an international team of researchers tested a different approach: DNA analysis. Despite the fact that grinding and fermentation accelerate genetic degradation, they were able to sequence DNA from fish remains found in a fish-salting vat at a cetaria in northwest Spain. This achievement sheds light on Roman-era sardines and opens the door for future research on archaeological fish remains.

“The bottoms of fish-salting vats offer a myriad of remains, yet one of the biggest challenges to studying pelagic fish from these contexts is the small size of the bone material,” the researchers wrote in a study published today in Antiquity. “To our knowledge, genomic studies have yet to take advantage of the vast potential of this data source for elucidating past fish consumption and the population dynamics of commercially relevant fish species.”

To test the validity of genetic analysis within this context, the team successfully extracted and sequenced DNA from the small bone remains of previously identified European sardines discovered at an ancient Roman fish-salting plant in the Spanish archaeological site of Adro Vello. Co-author Paula Campos—a researcher at the University of Porto specializing in ancient DNA—and her colleagues then compared the ancient DNA sequences with genetic data from contemporary sardines. They concluded that ancient sardines were genetically similar to their modern-day counterparts in the same region. This is notable, given that the species is known for its dispersal capabilities.

“Here, the authors demonstrate that, despite being crushed and exposed to acidic conditions, usable DNA can be recovered from ichthyological [fish] residues at the bottom of fish-salting vats,” the researchers explained. “Analysis of these data has the potential to open a new research avenue into the subsistence economies, cultures, and diets of past human populations and provide information on fish populations that cannot be obtained from fishery catch data or modern specimens alone.”

Ultimately, the study highlights a successful way of accessing an overlooked archaeological resource. It also confirms that in ancient Rome, fish weren’t friends—they were very much food.

Impact craters exist on every continent on Earth. While many have eroded away or been buried by geologic activity, some remain visible from the ground and from above. This week, we revisit stories featuring some of our most captivating satellite images of impact sites around the planet. The images and text on this page were originally published on September 1, 2018.

About two billion years ago, an asteroid measuring at least 10 kilometers across hurtled toward Earth. The impact occurred southwest of what is now Johannesburg, South Africa, and temporarily made a 40-kilometer-deep and 100-kilometer-wide dent in the surface. Almost immediately after impact, the crater widened and shallowed as the rock below started to rebound and the walls collapsed. The world’s oldest and largest known impact structure was formed.

Scientists estimate that when the rebound and collapse ceased, Vredefort Crater measured somewhere between 180 and 300 kilometers wide. But more than 2 billion years of erosion has made the exact size hard to pin down.

“If you consider that the original impact crater was a shallow bowl like you would serve food in, and you were able to slice horizontally through the bowl progressively, you would see that the bowl’s diameter will decrease with each slice you take off,” said Roger Gibson of University of the Witwatersrand and an expert on impact processes. “For this reason, we are unable to categorically fix where the edge now lies.”

According to Gibson, the uplift at the center of the impact was so strong that a 25-kilometer section of Earth’s crust was turned on end. The various layers of upturned rock eroded at different rates and produced the concentric pattern still visible today. Vredefort Dome, which measures about 90 kilometers across, was observed on June 27, 2018, by the Operational Land Imager (OLI) on Landsat 8.

Notice that only part of the ring is visible. That’s because areas to the south have been paved over by rock formations that are less than 300 million years old. The young rock formations have begotten fertile soils that are intensely cultivated.

The darker ring in the center of this image, known as the Vredefort Mountainland, has shallow soils with steep terrain not suitable for farming, so the area remains naturally forested. Along the ridges in the Mountainland you can see white lines: these are the hardest layers of rock, such as quartzite, which resist erosion. The outer part of Mountainland has exposed rocks that are roughly 2.8 billion years old; this is the Central Rand Group, the source of more than one-third of all gold mined on Earth.

Visitors to the impact site today can witness geologic time by traversing just 50 kilometers from Potchefstroom toward Vredefort. The journey would take you from shallow crustal sedimentary rocks deposited between 2.5 and 2.1 billion years ago, ending with 3.1- to 3.5-billion-year-old granites and remnants of ocean crust that were once about 25 kilometers below Earth’s surface.

“Such exposed crustal sections are incredibly rare on Earth,” Gibson said. “The added bonus here is that the rocks preserve an almost continuous record spanning almost one-third of Earth’s history.”

NASA Earth Observatory image by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Kathryn Hansen.