Showing posts with label Earth Science. Show all posts
Showing posts with label Earth Science. Show all posts

Thursday, September 23, 2021

Vampire bats may coordinate with ‘friends’ over a bite to eat

 

Photo: Sherri and Brock Fenton
Vampire bats that form bonds in captivity and continue those “friendships” in the wild also hunt together, meeting up over a meal after independent departures from the roost, according to a new study.

Researchers attached tiny “backpack” computers to 50 vampire bats – some that had previously been in captivity together and others that had lived only in the wild – to track their movement during their nightly foraging outings. By day, the bats shared a hollow tree in Panama, and at night they obtained their meals by drinking blood from wounds they made on cows in nearby pastures.

Tracking data showed that vampire bats set out to forage separately rather than as a group – and those that had established social relationships would reunite during the hunt for what the researchers speculated was some sort of coordination over food.

The findings suggest “making friends” in the roost could create more interdependence among socially bonded vampire bats – meaning they could benefit from each other’s success at obtaining blood meals and join forces when competing with other groups of bats for food resources.

“Everything we’ve been studying with vampire bats has looked at what they’re doing inside of a roost. What nobody has really known up until now is whether these social relationships serve any function outside the roost,” said study co-author Gerald Carter, assistant professor of evolution, ecology and organismal biology at The Ohio State University.

“Understanding their interactions with a completely different group of bats out on the pasture can help us understand what’s going on inside the colony. If every time they leave the roost they’re getting into battles, that can increase the amount of cooperation within the colony.”

Co-author Simon Ripperger, a former postdoctoral researcher in Carter’s lab, later supplemented the tracking data by capturing video and audio of foraging vampire bats. He observed bats clustered together on one cow and others atop separate cows, some drinking from different wounds and some fighting over food access. He also made what are likely the first audio recordings of a specific type of vampire bat vocalization associated with foraging.

Tuesday, September 21, 2021

Electric Bees

 
Image: Pexels
New research has found that the electrical charge created by visiting bumblebees stimulates some flowers to release more of their sweet-smelling scent. This is the first time a plant has been shown to use the presence of pollinators as a cue to emit more of its attractive perfume - increasing its chances of being visited.

The tiny electrical charge carried by bees is thought to help pollen stick to them during flight but the team of researchers from the University of Bristol, Rothamsted Research, and Cardiff University found that it can also announce their presence to the flowers they visit. 

According to lead author, Dr Clara Montgomery, who was funded by the BBSRC, the trait possibly evolved in plants to maximize the effectiveness of the attractive chemicals they release. 

“Flowers have a limited supply of these scents, so it makes sense they only release them when their pollinators are around.  Essentially, it is only worth advertising when you know you have an audience. Other cues they might use, such as daylight or temperature can be unreliable, as it might also be windy or raining, which would reduce pollinator presence. 

“These scents are also used by insects that want to eat or lay eggs on the plant, so increasing their chances of only attracting pollinators is vital.”  

Monday, September 20, 2021

Coral reef biodiversity predicted to shift as climate changes

 

Experimental set up at HIMB with mesocosms. (Photo credit: Chris Jury)
Coral reefs are among the most biologically diverse, complex and productive ecosystems on the planet. Most of coral reef biodiversity consists of tiny organisms living deep within the three-dimensional reef matrix. Although largely unseen, this diversity is essential to the survival and function of coral reef ecosystems, and many have worried that climate change will lead to dramatic loss of this diversity.

New research led by scientists at the University of Hawaiʻi at Mānoa reveals that the species which dominate experimental coral reef communities shift due to climate change, but the total biodiversity does not decline under future ocean conditions of warming and acidification predicted by the end of the century.

The study was published in the Proceedings of the National Academy of Science.

“Rather than the predicted collapse of biodiversity under ocean warming and acidification, we found significant changes in the relative abundance, but not the occurrence of species, resulting in a shuffling of coral reef community structure,” said Molly Timmers, lead author who conducted this study during her doctoral research at the Hawaiʻi Institute of Marine Biology (HIMB) at UH Mānoa’s School of Ocean and Earth Science and Technology (SOEST).

Important but overlooked organisms

“The tiny organisms living in the reef structure are known as the cryptobiota, which are analogous to the insects in a rainforest,” said Timmers. “They play essential roles in reef processes such as nutrient cycling, cementation and food web dynamics—they are an important diet of many of the fishes and invertebrates that make coral reef ecosystems so dynamic.”

Despite their critical importance to coral reef ecosystems, these cryptobiota are often overlooked in climate change research due to the challenges associated with surveying them using visual census and in identifying this highly diverse and understudied community.

“As a result, our perceptions of coral reef biodiversity across marine gradients and how biodiversity will respond to climatic change has been primarily based on a handful of observable surface-dwelling taxa, such as corals and fish,” said Timmers.

Experimental designs

To assess the responses of the understudied cryptobiota to future ocean conditions, Timmers and colleagues at HIMB devised an experiment wherein tiered settlement plates were placed in experimental flow-through tanks. These mesocosms received unfiltered seawater from a nearby reef slope off the shore of HIMB and were treated with end-of-the-century predicted ocean warming and/or ocean acidification conditions. After two years of exposure, the team examined the organismal groups that had developed on the settlement plates using DNA metabarcoding techniques.

“This two-year experimental mesocosm study is unprecedented for climate change research and is the first one to examine the diversity of the entire coral reef community from microbes and algae to the corals and fishes,” said Chris Jury, the author who developed and maintained the mesocosm system.

Source/Credit: University of Hawaiʻi

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Friday, September 17, 2021

Reforestation could help save coral reefs from catastrophe

Increasing reforestation efforts in coastal regions could substantially reduce the amount of sediment run-off reaching coral reefs and improve their resilience, a University of Queensland-led study has found.

The study analyzed more than 5,500 coastal areas from around the world and found that nearly 85 per cent of them leached sediment to coral reefs, the second most serious threat facing the world’s reefs behind climate change.

Dr Andrés Suárez-Castro from UQ’s Centre for Biodiversity and Conservation Science said it was important to address the issue of sediment runoff if efforts to reduce the human impact on reefs were to be successful.

“Increased sedimentation can cause aquatic ecosystems to be more sensitive to heat stress, which decreases the resilience of corals to pressures caused by climate change,” Dr Suárez-Castro said.

“If the link between the land and sea is not recognized and managed separately, any future efforts to conserve marine habitats and species are likely to be ineffective.”

Excess sediment runoff from land clearing and agrichemical pollution along coastlines can increase sediment transport to coastal waters.

Dr Suárez-Castro said one of the impacts of sediment runoff on coral reefs is a massive reduction in light levels that were key for coral and sea grass growth and reproduction.

Image credit: Diego Correa Gomez
One solution proposed by Dr Suárez-Castro and his team is for countries to commit to land and forest restoration in coastal regions, which will help reduce the amount of sediment runoff.

“Reforestation is hugely important as it maintains the stability of soils that are vital in limiting erosion risk – it also helps to trap more sediments and prevent them from reaching aquatic systems,” he said.

“Building coral resilience through reducing sediment and pollution is also key to improving a coral reef’s potential for recovery.

“If land management to reduce sediment runoff does not become a global priority, it will become increasingly challenging, if not impossible, to protect marine ecosystems in the face of climate change.”

The researchers said that while the benefits of land restoration activities were clear, it would be a challenge to get countries and governments to commit to restoration activities.

“It’s encouraging to see many countries with high coral diversity committing large areas to land restoration, however the cost of reforestation, as well as political and social barriers may make it difficult to achieve these ambitious goals,” Dr Suárez-Castro said.

“If an average of 1000 hectares of forest was restored per coastal basin, land-based sediments reaching coral reefs could be cut by an average of 8.5 per cent among 63,000 square kilometers of reefs.”

Dr Suárez-Castro and his team hope that local authorities can use their results to identify areas where reforestation can have the highest benefit on coral reefs.

“Our approach can be adapted with local data to identify optimal actions for preserving ‘win-wins’ for multiple ecosystems spanning the land and sea,” Dr Suárez-Castro said.

“Several global initiatives such as the Paris Climate Agreement are bringing forest restoration to the forefront of global conservation discussions and our hope is that our study can facilitate more informed and educated conversations around the importance of a more integrated land-sea approach.”

The research has been published in Global Change Biology

Source/Credit: University of Queensland

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Wednesday, September 15, 2021

Region of 'Super Corals' Discovered

Corals found in an area of the ocean with extremely high levels of
Carbon Dioxide in the Verde Island Passage in the Philippines.
 In 2019, a hydrology professor at The University of Texas at Austin set out on a research project to see if he could identify harmful nutrients flowing through groundwater into a delicate coral reef sanctuary in the Philippines. He achieved this goal, but following the long history of accidental scientific discoveries, he instead stumbled upon something completely unexpected: a region of possible “super corals” that are thriving despite high levels of carbon dioxide.

The findings based on the 2019 field work were published in August in the journal ACS ES&T Water.

For the first time, the UT Austin professor, Bayani Cardenas, and a team of international researchers were able to attribute the source of CO2 and other gases and nutrients in seawater at this location to groundwater, a finding that the researchers believe shows how the undersea reef environment can be vulnerable to the way communities discharge wastewater, agricultural runoff and other byproducts into the sea.

“This is an unseen vulnerability,” said Cardenas, a professor in the Department of Geological Sciences at the UT Jackson School of Geosciences. “We’ve been able to show with this site that groundwater is part of these delicate coral reef environments. There is a connection, and that’s still not as accepted in science and in many parts of the world.”

More than that, Cardenas said the research has led to new questions — and new research proposals — about the super corals they found that could be replicated elsewhere in the coming years as global CO2 levels are expected to rise.

Coral reefs have long been suffering due to climate change, most notably during a global coral bleaching event from 2014 to 2017 that caused heat stress to 75% of the world’s reefs, according to the American Meteorological Society. Yet the coral-filled area Cardenas studied in the Verde Island Passage in the Philippines, a region so vibrant and diverse that he refers to it as the “Amazon of the ocean,” is thriving despite the vast amounts of CO2 being pumped in from groundwater.

Lead author Rogger E. Correa, a researcher at Southern Cross University in Australia, estimated that groundwater is pumping about 989 grams of CO2 per square meter per year into the area they studied, which is known as “Twin Rocks” and borders a chain of volcanoes. That’s the equivalent of parking two cars on the seabed and letting them emit carbon dioxide for a full year on every hectare of reef.

To distinguish groundwater from seawater, the scientists submerged devices that measure the levels of CO2 and radon 222, a naturally occurring radioactive isotope that is found in local groundwater but not in open ocean water. The measurement technique was developed by co-author Isaac Santos, a professor at the University of Gothenburg in Sweden.

This work follows a 2020 study conducted by Cardenas where he discovered CO2 bubbling up from the seafloor off an area of the Philippine coast so dramatically that he dubbed it “Soda Springs.”

The end result from the latest investigation is an entire region of coral reefs that must be studied more closely, said Cardenas, who is a geoscientist and not a coral researcher.

Adina Paytan, a research scientist at the Institute of Marine Sciences at the University of California, Santa Cruz, who was not associated with the study, warned that other human-made stressors, including sedimentation, overfishing and pollution, can still doom coral reefs. But she was heartened that Cardenas’ team showed corals can grow in high-carbon environments, a finding that “provides some hope for the future of corals.”

Study co-authors included researchers from the Leibniz Centre for Tropical Marine Research (ZMT) in Germany; the State Office for Mining, Energy and Geology in Germany; and the following institutions in the Philippines: Ateneo de Manila University, Agricultural Sustainability Initiatives for Nature Inc., and Planet Dive Resort.

Source/Credit: University of Texas at Austin

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Troubled waters

Dr Katrina Davis
Associate Professor of Conservation Biology

New research led by the University of Oxford, published in Conservation Letters, has examined the conflict between small-scale fisheries and marine mammals, using the experience of fisheries on the west coast of South America to highlight a worldwide issue.

Globally, conflict between recovering seal and sea lion populations and fishing communities has been escalating. This new research presents a unique overview of this conflict, particularly from the fishers’ perspective, and proposes solutions that will be relevant to many fishing communities around the world. 

In this part of South America, specifically Peru and Chile, marine mammals have been protected since the mid-20th century. Conservation policies have mostly been successful and over the last thirty years marine mammal populations - specifically those of sea lions and seals - have recovered. The study found:

• Nearly 9 out of 10 fishers have a negative impression of sea lions.

• Fishers report that on average sea lions reduce their catch and income by over 50%. 

• Whilst it’s illegal for sea lions and seals to be killed, this is happening regularly with over 70% of fishers admitting that sea lions are being killed to defend catches.

• Fishers’ overwhelming concern is that sea lion populations are now too large. 

To manage this conflict, there’s a need to balance the competing objectives of wildlife conservation with protection for local communities. There’s still concern about sea lion and seal populations because of how recently they’ve recovered, but small-scale fisheries are struggling, and fishers are often earning less than the minimum wage.

The international community needs to incorporate the needs and opinions of fishers in the global dialogue, including considering if protecting human welfare could involve reducing protection for marine mammals. 

‘If the global community is committed to a post-2020 deal for nature and people where improvements to people's wellbeing and nature conservation are both fulfilled - the elusive ‘win-win’ - then governments and scientists must engage with these “messy” local conflicts that repeat across the globe but resist high-level simplification.’ Professor Katrina Davis

'The recovery of marine mammals means that there’s a much higher likelihood that these animals will come into conflict with local fishers.'  Professor Katrina Davis

Sea lions and seals eat the same fish targeted by fisheries, so they’re in competition for resources, and it’s not uncommon for fishers to catch fish that have already been ‘nibbled’ by the marine mammals. They can also be accidentally caught in fishing nets and break them, meaning that the fisheries must pay to replace equipment.  

By understanding fishers’ motivations and perceptions we can develop more effective managerial solutions to the fisheries. Including managing sea lion populations, providing financial compensation for catch losses and gear damage, training programs, and shifting focusing from fishing to eco-tourism. 

Lead author Professor Katrina Davis says, 'A tricky balance must be met between ensuring the future viability of marine mammal populations and ensuring that the livelihoods of small-scale fishers are protected. Fishers perceive that they are suffering large catch and income losses because of sea lions—and it’s these perceptions that we have to manage when we’re developing policy solutions.'

Moving forward, researchers plan to investigate the impact of culls on these interactions, whether this would be viable without harming population levels, and whether it would curb aggression towards marine mammals. 

Source/Credit: University of Oxford

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Tuesday, September 14, 2021

Weather Extremes by 2060

In this visualization, based on weather and climate observations from NASA's MERRA dataset, the northern hemisphere's polar jet stream is seen as a meandering, fast-moving belt of westerly winds traversing the lower layers of the atmosphere. Credit: NASA

 New research provides insights into how the position and intensity of the North Atlantic jet stream has changed during the past 1,250 years. The findings suggest that the position of the jet stream could migrate outside of the range of natural variability by as early as the year 2060 under unabated greenhouse gas emissions, with potentially drastic weather-related consequences for societies on both sides of the Atlantic.

Matthew Osman steadies an ice core
drilling barrel into the Greenland Ice Sheet
Credit: Sarah Das/Woods Hole Oceanographic Institution
Led by Matthew Osman, a postdoctoral research associate at the University of Arizona Climate Systems Center, the study is published in Proceedings of the National Academy of Sciences.

Familiar to air travelers flying between North America and Europe, the North Atlantic jet stream is the ribbon of prevailing westerly winds circling the Arctic. Often called the "polar jet," these high-altitude winds impact weather and climate across eastern North America and western Europe, accounting for between 10% and 50% of variance in annual precipitation and temperature in both regions. However, little is known about how the jet stream varied during the past, or how it might change in the future.  

Osman's research team collected glacial ice core samples from nearly 50 sites spanning the Greenland ice sheet to reconstruct changes in windiness across the North Atlantic dating back to the eighth century.  The reconstructions suggest that natural variability has thus far masked the effect of human-caused warming on mid-latitude atmospheric dynamics across annual and longer timescales.

"For most places on Earth, direct climate observations typically do not span more than a few decades," Osman said. "So, we haven't had a great sense of how or why the jet stream changes over longer periods of time. What we do know is that extraordinary variations in the jet stream can have severe societal implications, such as floods and droughts, due to its impacts on weather patterns and so, in terms of thinking about the future, we can now begin to use the past as a sort of a prologue."

The work reveals that although natural variability has largely controlled the position of the North Atlantic jet stream, continued warming could cause significant deviations from the norm. In particular, model projections forecast a northward migration of the North Atlantic jet stream under 21st-century warming scenarios. Such migration could render the jet stream significantly different within a matter of decades.

Although the polar jet stream blows most swiftly near the typical cruising altitudes of planes, the band of winds actually extends all the way to the ground. While of lesser intensity, Osman explained, near the ground the winds are often referred to as storm tracks. Storm tracks impact weather and climate across Greenland, affecting the island's precipitation and temperature changes. By analyzing year-to-year variations in the amount of

snowfall archived in Greenland ice cores, as well as the chemical makeup of the water molecules comprising those annual snow layers, the researchers were able to extract centuries-old clues into how the jet stream changed.

"These layers tell us about how much precipitation fell in a given year and also about the temperatures that air masses were exposed to," Osman said.

Weather events like this summer's heat wave in the Pacific Northwest and the floods in Europe are some recent examples of how the jet stream affects weather patterns based on its intensity or location in the short term, Osman said. But societally significant changes also occur across longer time scales; reconstructing the jet stream's past revealed that in some years, it could be far north, only to venture more than 10 degrees farther south a few years later.

"Such variations have huge implications on the types of weather that people might experience at a given place," Osman said. "For example, when the jet stream is situated farther south, the normally dry Iberian Peninsula tends to experience milder, moister conditions. But, as the jet stream migrates northward, much of that moisture also moves away from Iberia towards already-wet regions of Scandinavia. A poleward-shifted jet stream in the future thus might have similar, but more permanent, consequences."

The team was able to match certain changes in wind speed and geographical shifts to historical weather-related calamities. For example, during a famine that gripped the Iberian Peninsula in 1374, the jet stream was situated unusually far north. Similarly, two famine events in the British Isles and Ireland in 1728 and 1740 coincided with years that winds blew at nearly half their usual intensity, dramatically cooling temperatures and reducing precipitation. The latter of these events, in 1740, is estimated to have cost the lives of nearly half a million people.

Osman and his co-authors expect that any future shifts in the North Atlantic jet stream would also have dramatic implications on day-to-day weather and ecosystems, with trickle-down effects impacting national economies and societies.

"Our results serve as a warning: Although pushing the jet stream beyond its natural range would be problematic, its ultimate trajectory is still largely in our control," he said.

Source/Credit: University of Arizona/Daniel Stolte

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Flipping the “genetic paradox of invasions”

A close-up look at a green crab. Image credit: Ted Grosholz

The green crab, Carcinus maenas, is considered a globally distributed invasive species, an organism introduced by humans that eventually becomes overpopulated, with increased potential to negatively alter its new environment. Traditionally, it’s been assumed that successful populations contain high genetic diversity, or a variety of characteristics allowing them to adapt and thrive. On the contrary, the green crab - like many successful invasive populations - has low genetic diversity, while still spreading rapidly in a new part of the world.

A new study led by Carolyn Tepolt, an associate scientist of biology at Woods Hole Oceanographic Institution, is investigating the adaptive mechanisms of the green crab along the west coast of North America, where it has shown extensive dispersal in the last decade despite minimal genetic diversity. The study was published recently in Molecular Ecology and is a collaboration between WHOI, the University of California at Davis, Portland State University, and the Smithsonian Environmental Research Center.

“Invasive species like these are generally unwelcome. Green crabs can compete with native species, rip up eelgrass ‘nurseries’, and eat small shellfish before they have a chance to be harvested. Green crabs can be an ecological menace and an economic burden,” Tepolt said. “In this study, we found that one of the world's most serious marine invasive species has evolved specific genetic variation that likely helps it adapt to new environments really quickly, even when it's lost a lot of genetic diversity overall.”

Genetic diversity refers to small individual-to-individual differences in DNA, and often translates into a range of different inherited traits within a species. A population with high genetic diversity is more likely to include individuals with a wide range of different traits. In order for a population to adjust to changing environments, this variation can be crucial - or so scientists have often thought. Invasive species often challenge this assumption, successfully spreading in new regions despite low genetic diversity caused by descending from a small number of initial colonists.

This study focuses on a northwest Pacific population of green crab that has spread within the last 35 years from a single source. High-profile marine invasive species, such as green crabs, often live across thousands of kilometers of ocean, spanning countless environmental differences, both small and large. Using six U.S. west coast locations spanning over 900 miles from central California to British Columbia, Tepolt and her team examined the species’ genetic structure at thousands of places across its genome. While this population has lost a large amount of overall genetic diversity relative to its European source, a piece of DNA associated with cold tolerance in a prior study appears to be under strong selection from north to south across its invasive West Coast range.

This may represent a type of genetic feature - a balanced polymorphism - that evolved to promote rapid adaptation in variable environments despite high gene flow, and which now contributes to successful invasion and spread in a novel environment. Researchers do occasionally find incredibly successful populations that have passed through severe bottlenecks, dramatically decreasing their genetic diversity relative to their source. This study is amplifying the need to consider that diversity at specific parts of the genome (rather than genome-wide diversity) may play a critical role in resilience in new or changing environments.

“This is exciting for two main reasons. First, the study tests a partial resolution to ‘the genetic paradox of invasions’, demonstrating that variation at key parts of the genome permits rapid adaptation even in a population with low overall genetic diversity. Second, it suggests that high gene flow in a widespread species’ native range may generate evolutionary mechanisms, like this one, which provide that species with the substrate for rapid adaptive change as it spreads across new environments,” Tepolt explained.

Identifying invasive species spread can also be a job for non-scientists. As the climate changes and as humans get better and better at moving stuff around the globe, there’s more potential for species to come along for the ride and expand into new environments. Tepolt says it’s important to keep an eye out for cues, changes in the environment and possible new species in places they haven’t been before. She recommends seizing the opportunity to tell officials and researchers if there is something unusual at the coastline. There may be signs at beaches and boat ramps asking people to keep a lookout for particular species and giving contact information. If there are suddenly green crabs in an area for the first time, for example, on the West Coast in the Salish Sea and in Alaska, they likely should not be there and should be reported.

Source/Credit: Woods Hole Oceanographic Institution

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Monday, September 13, 2021

Crop-eating moths will flourish as climate warms

 
The top map shows the distribution of diamondback moths as of 2016. Overwintering regions are shown in red. The bottom map shows regions where the diamondback moth’s range has expanded in the past 50 years, based on a climate change model in which mean global temperatures will increase 2 degrees Celsius this century. Darker colors indicate a greater chance for overwinter survival.
(Image courtesy of V. Rudolf/Rice University)

Climate change in this century will allow one of the world’s costliest agricultural pests, the diamondback moth, to both thrive year-round and rapidly evolve resistance to pesticides in large parts of the United States, Europe and China where it previously died each winter, according to a study by U.S. and Chinese researchers.

The moth, Plutella xylostella, which is also known as the cabbage moth, already causes more than $4 billion in damage worldwide each year to broccoli, cauliflower, cabbage, kale, mustard, radishes, turnips, watercress, Brussels sprouts and other crops. It is also one the world’s most pesticide-resistant species, with a documented resistance to at least 97 insecticides.

In a first-of-its-kind study published in the open-access journal Nature Communications, researchers from Rice University and the Chinese Academy of Agricultural Sciences combined results from years of laboratory and field experiments, computer simulations of future climate warming scenarios and a meta-analysis of decades of prior moth research.

“It’s well-documented that climate change is shifting the distribution and ranges of species, but the challenge is trying to predict where species will go,” said study co-author Volker Rudolf, an ecologist, evolutionary biologist and professor of biosciences at Rice University.

Rudolf said the team, which was led by co-lead authors Chun-Sen Ma and Wei Zhang, began with laboratory experiments aimed at isolating a specific mechanism that could be used to accurately predict how the range of diamondback moths would evolve in response to climate change. Previous experiments had found the coldest temperature individual moths could survive, but it was also well-known the moths died out each winter in places where temperatures were considerably higher. Rudolf said the lab studies allowed the team to predict where the moths can “overwinter,” or survive year-round, based on the daily accumulated low temperatures below a critical threshold in winter, a metric they dubbed “low temperature degree days.”

“That variable alone predicts over 90% of mortality, which is pretty nuts,” Rudolf said. “You don’t normally get correlations that strong.”

That gave the researchers “a simple variable that was both mechanistically linked to the survival of the species and really easy to calculate from either past climate data or future-climate models,” he said.

Diamondback moth
(This work, “Plutella.xylostella.7383,” by of Olaf Leillinger
is used and provided under
CC BY SA 2.5 courtesy of Wikimedia Commons)
The researchers found climate change over the past 50 years has increased the overwintering range of the diamondback moth by more than 925,000 square miles. They also showed each increase in mean global temperature of 1 degree Celsius will allow the moth’s overwintering range to expand by about 850,000 square miles. Current climate models predict mean global temperatures will increase by 2-6 degrees Celsius during the coming 100-150 years, the study said.

Rudolf said the overwintering data combined with a meta-analysis of decades of previous studies of diamondback moth pesticide resistance allowed the team to show how climate change could dramatically worsen the problem of evolved pesticide resistance in parts of the U.S., China, Japan and the Mediterranean that are currently “marginal” overwintering regions for the moth.

“We care about overwintering because if they survive winters and stay year-round that allows for rapid evolution of pesticide resistance,” Rudolf said.

Diamondback moths and many other crop pests like armyworms, planthoppers, leafrollers and some species of aphids overwinter in warm regions and migrate annually, causing significant damage to crops in regions where they cannot overwinter. Where these species cannot overwinter, they are slower to evolve pesticide resistance, Rudolf said.

“Because they always come from somewhere else to recolonize a particular site, the individuals are most likely coming from different ancestors every year,” he said. “So, you can have within-season selection for pesticide resistance, but selection across-seasons gets interrupted.”

The researchers’ global meta-analysis of pesticide resistance in diamondback moths illustrated the critical difference between these two types of evolutionary processes: Mean pesticide resistance was 158 times higher at overwintering sites compared to non-overwintering sites, the research showed.

The double whammy of an expanded year-round range and more rapid evolution of pesticide resistance could severely impede control efforts and allow diamondback moths to cause greater economic losses for farmers, the study found.

But the study’s authors said the research also presents an opportunity, both as a template for studying similar crop pests and as a guide to designing and coordinating more effective control efforts.

The findings could be used to “develop proactive pest management in a changing world, reduce costs of control efforts and assure food security while minimizing impacts on natural enemies and other aspects of the ecosystem,” they wrote in the study. “In practice, our results emphasize the importance of adjusting pest management strategies to adapt to differences in winter survival across regions and how this will change under future climate scenarios.”

Study co-authors include Yu Peng, Liang Zhu and Gang Ma of the Chinese Academy of Agricultural Sciences in Beijing, Fei Zhao and Kun Xing of both the Chinese Academy of Agricultural Sciences and Shanxi Agricultural University in Shanxi, Xiang-Qian Chang of both the Chinese Academy of Agricultural Sciences and Hubei Academy of Agricultural Sciences in Wuhan, and He-Ping Yang of the National Meteorological Information Centre in Beijing.

The research was supported by the National Natural Science Foundation of China (31471764, 31620103914, 31501630), the National Key R&D Program of China (2018YFD0201400, 2019YFD1002100), the Chinese Academy of Agricultural Sciences’ Fundamental Research Fund (Y2017LM10) and the Chinese Academy of Agricultural Sciences’ Innovation Program (CAAS-ZDRW202012).

Source/Credit: Rice University

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Friday, September 10, 2021

Mapping project completed, helping to save world’s reefs

 
Ailinginae Atoll - Ailinginae Atoll in the Marshall Islands.
Photo credit: Greg Asner
All of the world’s shallow coral reefs have been digitally mapped, thanks to a three-year project combining two million satellite images, enormous amounts of field data and University of Queensland-developed mapping techniques.

The Allen Coral Atlas project has officially launched its high-resolution maps of the world’s reefs which, together with the Atlas’s coral monitoring tool launched in May, will revolutionize reef management.

The project is an international research collaboration led by Arizona State University in partnership with UQ, Planet Ltd, National Geographic and Vulcan Inc.

UQ’s Remote Sensing Research Centre researcher Dr Chris Roelfsema said the digital atlas is a comprehensive and continually updated tool, perfect for scientists, policy makers and planners.

“To manage environmental assets like the world’s reefs, you need to know what’s happening at any given time,” Dr Roelfsema said.

“The Allen Coral Atlas provides maps that accurately describe the composition and extent of our reefs globally, and at a level of detail not seen before.

“These maps are connecting people with the data they need to save our reefs – it’s momentous.”

The Allen Coral Atlas, now available online, has been a global effort with UQ scientists playing the leading role in gathering verification data, developing and implementing the mapping approach for the world’s coral reefs.

“The verification and mapping approaches we’ve developed are based on 20 years of experience UQ has in combining reef knowledge, field data and earth observation processes to map and monitor coral reefs,” Dr Roelfsema said.

“This work combined 450 field data sets from global collaborators with machine learning and automated contextual-editing approaches, which helps us achieve the highest spatial and thematic resolution of coral reefs anyone has ever seen.”

The data is needed now more than ever, with models predicting 70 to 90 per cent of coral reefs will be lost by 2050, because of warming, polluted and acidic oceans.

Professor Greg Asner, Director of Arizona State University's Center for Global Discovery and Conservation Science and Managing Director of the Atlas project, said he was thrilled to announce the platform.

“It is a gratifying milestone after years of dedicated non-stop teamwork to bring this global map to fruition,” Dr Asner said.

“But the true value of the work will come when coral conservationists are able to better protect coral reefs based on the high-resolution maps and monitoring system.

“We must double down and use this tool as we work to save coral reefs from the impacts of our climate crisis and other threats.”

The Allen Coral Atlas is named for the late Microsoft co-founder Paul G. Allen, and founder of Vulcan Inc.

Source/Credit: University of Queensland

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Thursday, September 9, 2021

Mystery of icy plumes that may foretell deadly supercell storms

 

An Above Anvil Cirrus Plume emanates from the top of a storm.
(Image credit: NASA)
The most devastating tornadoes are often preceded by a cloudy plume of ice and water vapor billowing above a severe thunderstorm. New research reveals the mechanism for these plumes could be tied to “hydraulic jumps” – a phenomenon Leonardo Da Vinci observed more than 500 years ago.

When a cloudy plume of ice and water vapor billows up above the top of a severe thunderstorm, there’s a good chance a violent tornado, high winds or hailstones bigger than golf balls will soon pelt the Earth below.

A new Stanford University-led study, published Sept. 10 in Science, reveals the physical mechanism for these plumes, which form above most of the world’s most damaging tornadoes.

Previous research has shown they’re easy to spot in satellite imagery, often 30 minutes or more before severe weather reaches the ground. “The question is, why is this plume associated with the worst conditions, and how does it exist in the first place? That’s the gap that we are starting to fill,” said atmospheric scientist Morgan O’Neill, lead author of the new study.

The research comes just over a week after supercell thunderstorms and tornadoes spun up among the remnants of Hurricane Ida as they barreled into the U.S. Northeast, compounding devastation wrought across the region by record-breaking rainfall and flash floods.

Understanding how and why plumes take shape above powerful thunderstorms could help forecasters recognize similar impending dangers and issue more accurate warnings without relying on Doppler radar systems, which can be knocked out by wind and hail – and have blind spots even on good days. In many parts of the world, Doppler radar coverage is nonexistent.

“If there’s going to be a terrible hurricane, we can see it from space. We can’t see tornadoes because they’re hidden below thunderstorm tops. We need to understand the tops better,” said O’Neill, who is an assistant professor of Earth system science at Stanford’s School of Earth, Energy & Environmental Sciences (Stanford Earth).

Supercell storms and exploding turbulence

The thunderstorms that spawn most tornadoes are known as supercells, a rare breed of storm with a rotating updraft that can hurtle skyward at speeds faster than 150 miles an hour, with enough power to punch through the usual lid on Earth’s troposphere, the lowest layer of our atmosphere.

In weaker thunderstorms, rising currents of moist air tend to flatten and spread out upon reaching this lid, called the tropopause, forming an anvil-shaped cloud. A supercell thunderstorm’s intense updraft presses the tropopause upward into the next layer of the atmosphere, creating what scientists call an overshooting top. “It’s like a fountain pushing up against the next layer of our atmosphere,” O’Neill said.

As winds in the upper atmosphere race over and around the protruding storm top, they sometimes kick up streams of water vapor and ice, which shoot into the stratosphere to form the tell-tale plume, technically called an Above-Anvil Cirrus Plume, or AACP.

The rising air of the overshooting top soon speeds back toward the troposphere, like a ball that accelerates downward after cresting aloft. At the same time, air is flowing over the dome in the stratosphere and then racing down the sheltered side.

Using computer simulations of idealized supercell thunderstorms, O’Neill and colleagues discovered that this excites a downslope windstorm at the tropopause, where wind speeds exceed 240 miles per hour. “Dry air descending from the stratosphere and moist air rising from the troposphere join in this very narrow, crazy-fast jet. The jet becomes unstable and the whole thing mixes and explodes in turbulence,” O’Neill said. “These speeds at the storm top have never been observed or hypothesized before.”

Hydraulic jump

Scientists have long recognized that overshooting storm tops of moist air rising into the upper atmosphere can act like solid obstacles that block or redirect airflow. And it’s been proposed that waves of moist air flowing over these tops can break and loft water into the stratosphere. But no research to date has explained how all the pieces fit together.

The new modeling suggests the explosion of turbulence in the atmosphere that accompanies plumed storms unfolds through a phenomenon called a hydraulic jump. The same mechanism is at play when rushing winds tumble over mountains and generate turbulence on the downslope side, or when water speeding smoothly down a dam’s spillway abruptly bursts into froth upon joining slower-moving water below.

Leonardo DaVinci observed the phenomenon in flowing water as early as the 1500s, and ancient Romans may have sought to limit hydraulic jumps in aqueduct designs. But until now atmospheric scientists have only seen the dynamic induced by solid topography. The new modeling suggests a hydraulic jump can also be triggered by fluid obstacles in the atmosphere made almost entirely of air and which are changing shape every second, miles above the Earth’s surface.

The simulations suggest the onset of the jump coincides with a surprisingly rapid injection of water vapor into the stratosphere, upwards of 7000 kilograms per second. That’s two to four times higher than previous estimates. Once it reaches the overworld, water may stay there for days or weeks, potentially influencing the amount and quality of sunlight that reaches Earth via destruction of ozone in the stratosphere and warming the planet’s surface. “In our simulations that exhibit plumes, water reaches deep into the stratosphere, where it possibly could have more of a long-term climate impact,” said co-author Leigh Orf, an atmospheric scientist at the University of Wisconsin-Madison.

According to O’Neill, high-altitude NASA research aircraft have only recently gained the ability to observe the three-dimensional winds at the tops of thunderstorms, and have not yet observed AACP production at close range. “We have the technology now to go verify our modeling results to see if they’re realistic,” O’Neill said. “That’s really a sweet spot in science.”

This research was supported by the National Science Foundation and the NASA Precipitation Measurement Mission and Ground Validation program.

Source/Credit: Stanford University/Josie Garthwaite

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Ancient sea ice core sheds light on modern climate change

 


A 170 m record of marine sediment cores extracted from Adélie Land in Antarctica by the Integrated Ocean Drilling Program is yielding new insights into the complicated relationship between sea ice and climate change.

In a new study published in Nature Geoscience, researchers at the University of Birmingham, have collaborated in an international project to identify how fluctuations in sea ice levels have interconnected with both algae blooms and weather events linked to El Nino over the past 12,000 years.

They found that Antarctic winds strongly affect the break-out and melting of sea ice, which in turn affects the levels of algae which can grow rapidly in surface waters when sea ice is reduced. Changes in the levels of algae growth in the waters surrounding the Antarctic are important enough to affect the global carbon cycle.

The researchers used techniques such as CT scan (computed tomography) imaging and analysis of microfossils and organic biomarkers, to examine the relationship between sea ice and large algae growth “bloom” events at annual timescales. The findings, produced in partnership with research institutes in New Zealand, Japan, France, Spain and the USA, span the entire Holocene period and have yielded a highly detailed picture of these relationships that can help predict future sea ice, climate and biological interactions.

The researchers found that algal bloom events occurred nearly every year before 4,500 years ago. However, a baseline shift to less frequent algal blooms and the type of algal production after 4.5 thousand years ago, saw bloom events responding to the El Nino Southern Oscillation (ENSO) and other climate cycles as sea-ice levels rapidly increased. Recent work by many of the same team links the expansion of sea ice at this time to glacial retreat and the development of the Ross Ice Shelf, which acts to cool Antarctic surface waters to create a “sea-ice factory”.

Dr James Bendle, of the University of Birmingham’s School of Geography, Earth and Environmental Science, is a co-author on the paper. He said: “While there’s a clear relationship between temperatures rising in the Arctic over recent decades and sea ice melting, the picture is more complex in the Antarctic. That’s because some areas of the Antarctic are warming, but in some areas sea ice has been increasing. Since sea ice reflects incoming sunlight, not only is the warming effect slowed down, but algae are unable to photosynthesize as easily. Climate models currently struggle to predict observed changes in sea ice for the Antarctic, and our findings will help climate researchers build more robust and detailed models.”

He added: “The relationship we have observed with these changing conditions and the ENSO wind fields is particularly significant. We know that El Nino amplifies the effects of climate change in some regions, so any insights linking this with Antarctic Sea ice is fascinating and has implications for how future long-term loss of sea ice may affect food webs in Antarctic waters, as well as carbon cycling processes within this globally important region.”


Dr Katelyn Johnson, of GNS Science, in New Zealand, is the lead author on the paper. She said: “While sea ice that persists from year to year can prevent these large algal blooms from occurring, sea ice that breaks out and melts creates a favorable environment for these algae to grow. These large algae ‘bloom events’ occur around the continent, form the base of the food webs and act as a carbon sink”.

“Unlike the Arctic where rising temperatures have led to reduced sea ice, the relationship in the Antarctic is less clear, as is the subsequent impact on primary productivity. Our new record provides a longer-term view of how sea ice and climate models like ENSO impact the frequency of these bloom events, allowing climate modelers to build more robust models.”

Source/Credit: University of Birmingham

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Coral cryopreservation for breeding key to survival

 

Fragment of endangered Caribbean elkhorn coral grown from cryopreserved sperm.
(Photo credit: Chris Page)
Flash-frozen sperm collected from corals in Florida and Puerto Rico was used to fertilize coral eggs from hundreds of miles away in Curaçao. The juvenile corals raised from this trans-Caribbean coupling demonstrate the reproductive compatibility of coral colonies that would otherwise be too far apart to produce offspring in the wild and they represent the largest wildlife population ever raised from cryopreserved material.

A paper describing this study, by an international team of researchers, including Mary Hagedorn at the University of Hawaiʻi at Mānoa School of Ocean and Earth Science and Technology (SOEST), was published in the Proceedings of the National Academy of Sciences.

The technique could be used as a conservation tool by introducing genetic variation into endangered corals and potentially accelerating their adaptation to climate change.

“Most corals only attempt sexual reproduction once a year and the eggs and sperm are only viable for a short time period,” said Hagedorn, a research biologist at the Smithsonian Conservation Biology Institute and UH Mānoa’s Hawaiʻi Institute of Marine Biology. She is the lead author of this study, and has developed the technique to cryopreserve coral sperm in her laboratory at UH. “Cryopreservation allows us to breed corals with parentage from hundreds of miles apart.”

Assisted gene flow

“Corals are a vital foundation species for reef ecosystems,” said Iliana Baums, professor of biology at Penn State and one of the leaders of the research team. “Reefs provide habitat for astonishing species diversity, protect shorelines and are economically important for fisheries, but they are suffering in many places due to warming ocean waters. Without intervention, we will continue to lose corals to climate change with potentially disastrous consequences.”

Genetic diversity is the fuel for species adaptation. One of the main sources of genetic diversity is sexual reproduction—new combinations of genes are created when a sperm fertilizes an egg. However, sexual reproduction by Caribbean corals in the wild is now vanishingly rare. Worse yet, because corals are sessile creatures (fixed in one place), they have a limited ability to gain new genetic diversity through gene flow, the evolutionary force that increases genetic diversity when distant populations come together, each bringing with them their own unique versions of genes.

“To increase genetic diversity in corals, we can use ‘assisted gene flow’ by bringing corals together that are physically distant in the wild, but this is logistically incredibly difficult,” said Baums.

Cryopreservation

Most corals reproduce by broadcasting bundles of eggs and sperm into the sea water in a spectacular spawning event timed with the full moon. The researchers collected these bundles from corals in Florida and Puerto Rico, separated the eggs and sperm, and then quickly froze the sperm cells using a liquid nitrogen cryopreservation technique.

“Because these corals only produce eggs and sperm once per year, frozen sperm collected in Florida and Puerto Rico needed to be cryopreserved in advance and stored for over a year until it could be used for a spawning event in Curaçao,” said Baums.

Some of the sperm were kept frozen at the USDA National Animal Germplasm Program’s gene bank for up to 10 years. The frozen sperm was transported to Curaçao where it was thawed and used to fertilize fresh eggs collected locally. The fertilized eggs developed into larvae that were then transported to Mote Marine Laboratory and The Florida Aquarium in Florida, where they were allowed to develop into adults.

Source/Credit: University of Hawaiʻi

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A source of hope for coral reefs

 

A healthy coral reef in the Phoenix Islands Protected Area in 2018.
Photo credit: Michael Fox
Some coral communities are becoming more heat tolerant as ocean temperatures rise, offering hope for corals in a changing climate.

After a series of marine heatwaves hit the Phoenix Islands Protected Area (PIPA) in the central Pacific Ocean, a new study finds the impact of heat stress on the coral communities lessened over time.

While a 2002-2003 heatwave devastated coral communities in PIPA, the reefs recovered and experienced minimal losses during a similar event in 2009-2010. Then, in 2015-2016, a massive heatwave put twice as much heat stress on the corals, yet the die-off was much less severe than expected, according to new research published in Geophysical Research Letters, AGU’s journal for high-impact reports with immediate implications spanning all Earth and space sciences.

The authors of the new study suspect heat-tolerant offspring from the surviving corals are repopulating the reefs, allowing the community to keep pace with warming seas, at least for the time being.

The new study could help coral reef managers identify coral communities most likely to survive in the warming ocean, improving conservation and restoration outcomes.

“It’s easy to lose faith in coral reefs,” said first author Michael Fox, a postdoctoral scientist and coral reef ecologist at the Woods Hole Oceanographic Institution (WHOI). “But in PIPA, which is protected from local stressors, and where reefs have enough time to recover between heatwaves, the coral populations are doing better than expected.”

Underwater heatwaves

Just like on land, heatwaves underwater are becoming more frequent and intense as the world warms, putting stress on ocean ecosystems. High temperatures hit coral reefs especially hard by causing widespread bleaching events, where corals eject the symbiotic algae in their tissues, further weakening the animals. With continued ocean warming, coral reefs face a dim future.

In the new study, researchers monitored coral communities at four islands within PIPA, an area encompassing over 400,000-square-kilometers of coral reef and deep-sea habitat. The Republic of Kiribati established the reserve in 2008, and the United Nations Educational, Scientific and Cultural Organization (UNESCO) designated PIPA as a World Heritage Site in 2010. “The protected area gives us a rare opportunity to study pristine and isolated coral reef ecosystems, a privilege for which we thank the people of Kiribati,” said co-author Anne Cohen, a marine scientist at WHOI.

The team used daily satellite data and temperature loggers to examine how each heatwave impacted the corals. They ruled out 11 environmental factors that might explain the higher-than-expected survival following the 2009-2010 and 2015-2016 heatwaves, such as greater cloud cover or more gradual warming.

After the 2002-2003 heatwave, the surveyed sites lost more than three-quarters of their coral cover. The reef was beginning to recover when the 2009-2010 heatwave hit, sparking fears of widespread bleaching, but two years later, coral cover had increased by more than 5%. Following the “Super El Niño” in 2015-2016, which raised ocean temperatures by 3 degrees Celsius (5.4 degrees Fahrenheit), the loss of coral cover was 40%— about half of the 2002 losses, despite causing twice the level of thermal stress.

A source of hope for coral reefs

Many of the reef-building species survived the heatwaves. “We’re seeing areas that were devoid of corals after 2002-2003 that are now flourishing with most of the original species,” Fox said.

At other reefs worldwide, sometimes only a handful of especially hardy or fast-growing species recover after a bleaching event. Coral larvae can float long distances on ocean currents, but due to PIPA’s isolation, the researchers hypothesize that local heat-tolerant individuals are repopulating the reefs.

Now that the researchers have shown that some coral communities have the potential to keep up with ocean warming, their next step is to figure out how they are doing it.

The findings are “important for giving us hope for the future of coral reefs, and also for helping to maintain support for protecting reefs, including efforts to reduce local threats, like pollution, sedimentation and overfishing that undermine the reefs’ ability to adapt,” said Lizzie McLeod, the Global Reef Systems Lead at the Nature Conservancy, who was not involved in the study.

She recommends reef conservationists prioritize the conservation of heat-tolerant reefs, because they can act as climate refuges that repopulate other sites decimated by heatwaves.

The study’s authors caution that even these remarkable corals have their limits and reversing climate change remains paramount. As heatwaves become more frequent or intense, even heat-tolerant communities could die out.

“We’re in a race against time, so anything that increases the chances that corals are going to make it is really good news,” said Nancy Knowlton, the Sant Chair in Marine Science Emerita at the Smithsonian National Museum of Natural History, who was not part of the study. “The corals are doing their part,” she said. “We have to do ours.”

Source/Credit: Woods Hole Oceanographic Institution

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Tuesday, September 7, 2021

Nature’s archive reveals Atlantic tempests through time

 
The North Atlantic network of sites that preserve records of hurricanes stretches along the coast from Canada to Central America, but with significant gaps. A new study led by scientists at Rice University shows filling those gaps with data from the mid-Atlantic states will help improve the historical record of storms over the past several thousand years and could aid in predictions of future storms in a time of climate change. Illustration by Elizabeth Wallace

Atlantic hurricanes don’t just come and go. They leave clues to their passage through the landscape that last centuries or more. Rice University scientists are using these natural archives to find signs of storms hundreds of years before satellites allowed us to watch them in real time.

Elizabeth Wallace.
(Credit: Abby Llona)
Postdoctoral fellow Elizabeth Wallace, a paleotempestologist who joined the lab of Rice climate scientist Sylvia Dee this year, is building upon techniques that reveal the frequency of hurricanes in the Atlantic basin over millennia.

The North Atlantic network of sites that preserve records of hurricanes stretches along the coast from Canada to Central America, but with significant gaps. A new study led by scientists at Rice University shows filling those gaps with data from the mid-Atlantic states will help improve the historical record of storms over the past several thousand years and could aid in predictions of future storms in a time of climate change. Illustration by Elizabeth Wallace

Paleoclimate hurricane data (or ‘proxy’ data) is found in archives like tree rings that retain signs of short-term flooding, sediments in blue holes (marine caverns) and coastal ponds that preserve evidence of sand washed inland by storm surges. These natural archives give researchers a rough idea of when and where hurricanes have come ashore.

In a new paper in Geophysical Research Letters, Wallace, Dee and co-author Kerry Emanuel, a climate scientist at the Massachusetts Institute of Technology, take hundreds of thousands of “synthetic” storms spun up from global climate model simulations of the past 1,000 years and examine whether or not they are captured by the vast network of Atlantic paleohurricane proxies.

Reconstructing the past will help scientists understand the ebb and flow of Atlantic hurricanes over time. Previous studies by Wallace and others have demonstrated that a single site capturing past storms cannot be used to reconstruct hurricane climate changes; however, a network of proxies might help refine models of how these storms are likely to be affected by climate change going forward.

Sylvia Dee.
(Credit: Rice University)
“These paleo hurricane proxies allow us to reconstruct storms into the past, and we’re using them to figure out how basin-wide storm activity has changed,” said Wallace, a Virginia native who earned her doctorate at MIT and the Woods Hole Oceanographic Institution last year and connected with Dee when the professor spoke there in 2017.

“If I have a sediment core from Florida, it’s only capturing storms that hit Florida,” she said. “I wanted to see if we can use the full collection of records collected from the Bahamas, the East Coast and the Gulf of Mexico over the past few decades to accurately reconstruct basin-wide storm activity over the last few centuries.”

The synthetic storms they built helped illustrate what Wallace already knew: There’s a bias toward the Caribbean and Gulf of Mexico, and a need for more proxies along the east coasts of North and Central America. The Rice team’s quest going forward will be to refine their climate simulations and add more sites to the networks to better reconstruct past hurricane activity.

“In particular, there aren’t really any sites from the Southeast U.S., places like the Carolinas,” she said. “One of the goals of this work is to highlight where scientists should go to core next.”

Wallace has first-hand experience drilling cores. “During a storm event, you get high winds and waves that take the sand from the beach and essentially just throw it back into a coastal pond,” she said. “Only during storm events do these sand layers get deposited in the pond, and in the sediment cores you can see them interspersed with the fine mud that’s typically there. We can date these sand layers and know when a hurricane struck the site.”

She noted there has not yet been an “intensive” effort to compare sediment and tree ring records. “The tree record is still an uncertain proxy,” Wallace said. “We’re looking for tree ring records with rainfall signatures that correspond to storms going over the past 200 or 300 years that match the sediment records for that same interval.”

Dee said the work is fundamentally different from the paleoclimate models she most often studies. “Here we’re taking climate models and generating hundreds of pseudo-tropical storms,” she said. “We’re ‘playing Gaia’ by making a plausible version of reality and combining it with our knowledge of available proxy sites.

“This tells us how many records from how many places we realistically need to capture a climate signal,” Dee said. “It’s really expensive to go out and drill cores, and this helps give us a way to prioritize where to drill.

“This research is crucial as we accelerate into a climate mean state with ever-warmer Atlantic Ocean temperatures,” she said. “Understanding how these storms have evolved over time provides a baseline against which to evaluate tropical cyclones with and without human impacts on the climate system.”

A Pan Postdoctoral Research Fellowship and Rice Academy Fellowship to Wallace and a Gulf Research Program grant to Dee supported the study. Dee is an assistant professor of Earth, environmental and planetary sciences. Emanuel is the Cecil & Ida Green Professor of Atmospheric Science and co-director of the Lorenz Center at MIT.

Abstract released at: AGU

Source/Credit: Rice University

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