Study reveals new clues about how 'Earth's thermostat' controls climate

The Amazon, Earth’s largest river, transporting weathering solutes from the Andes to the Atlantic Ocean in Brazil.
Photo Credit: Michael Vite

Rocks, rain and carbon dioxide help control Earth’s climate over thousands of years — like a thermostat — through a process called weathering. A new study led by Penn State scientists may improve our understanding of how this thermostat responds as temperatures change.

“Life has been on this planet for billions of years, so we know Earth’s temperature has remained consistent enough for there to be liquid water and to support life,” said Susan Brantley, Evan Pugh University Professor and Barnes Professor of Geosciences at Penn State. “The idea is that silicate rock weathering is this thermostat, but no one has ever really agreed on its temperature sensitivity.”

Because many factors go into weathering, it has been challenging to use results of laboratory experiments alone to create global estimates of how weathering responds to temperature changes, the scientists said.

The team combined laboratory measurements and soil analysis from 45 soil sites around the world and many watersheds to better understand weathering of the major rock types on Earth and used those findings to create a global estimate for how weathering responds to temperature.

Small isolated wetlands are pollution-catching powerhouses

Photo Credit: Herbert Aust

Small isolated wetlands that are full for only part of the year are often the first to be removed for development or agriculture, but a new study shows that they can be twice as effective in protecting downstream lake or river ecosystems than if they were connected to them. 

Using a new method involving satellite imagery and computer modelling, researchers from the University of Waterloo found that since these small wetlands are disconnected, pollutants such as nitrogen and phosphorous get trapped. This is the first study to use satellite data for estimating nutrient retention. 

All wetlands act like sponges, providing flood protection by absorbing the vast volume of water that can be suddenly released from rainfall or snowmelt. Improving water quality, providing habitat, increasing biodiversity and trapping carbon are just some of the many environmental benefits wetlands provide. Their destruction increases our vulnerability to the extreme effects of climate change, including flooding, drought and the frequency of storms. 

Algae bio hacks itself in adapting to climate change

Phytoplankton - the foundation of the oceanic food chain.
Photo Credit: NOAA

Clear evidence that marine phytoplankton are much more resilient to future climate change than previously thought is the focus of a study published in Science Advances by an international team of scientists, including University of Hawaiʻi at Mānoa oceanography professor David Karl.

“Knowing how marine algae will respond to global warming and to associated decline of nutrients in upper ocean waters is crucial for understanding the long-term habitability of our planet,” said Karl.

Combining data from the long-term Hawaiʻi Ocean Time-series program at UH Mānoa with new climate model simulations conducted on one of South Korea’s fastest supercomputers, the scientists revealed that a mechanism, known as nutrient uptake plasticity, allows marine algae to adapt and cope with nutrient-poor ocean conditions that are expected to occur over the next decades in response to global warming of the upper ocean.

Like mushroom out ants

Argentine ant workers with brood. Ants react immediately to contamination with pathogens and not only to the later developing symptoms of a disease. The nest comrades efficiently clean colony members of infectious particles.
Photo Credit: Sina Metzler & Roland Ferrigato / ISTA

An Austrian-German research team discovered how disease-causing fungi adapt to the collective hygiene measures of ants.

Ants show many social behaviors. For example, they care for sick individuals and make it difficult to spread pathogens among the people with joint hygiene measures. Germs not only have to outsmart the immune system of individual ants, but also the health care of the whole group.

A new study, the journal, shows how the pathogens do this Nature Ecology & Evolution is published. It was presented by the team of Professor Sylvia Cremer from the Institute of Science and Technology Austria (ISTA) in cooperation with the animal ecologist Professor Thomas Schmitt from the Biozentrum of the Julius Maximilians University in Würzburg (JMU).

Understanding plants can boost wildland-fire modeling in uncertain future

How a fire burns and whether the vegetation survives or dies depend on how the live fuels — plants — use water and carbon. New research creates a framework for bringing those dynamics into wildland-fire models to more accurately predict wildfire and prescribed-burn behavior and resulting effects.
Photo Credit: Pixabay

A new conceptual framework for incorporating the way plants use carbon and water, or plant dynamics, into fine-scale computer models of wildland fire provides a critical first step toward improved global fire forecasting.

“Understanding the influences of vegetation structure and physiology on wildland fire is crucial to accurately predicting the behavior of fire and its effects,” said L. Turin Dickman, a plant ecophysiologist at Los Alamos National Laboratory. Dickman is corresponding author of a paper on plants and fire modeling in the journal New Phytologist. “Our research can be used to improve models that fire managers need to navigate an uncertain future.”

Honey bee colony loss in the U.S. linked to mites, extreme weather, pesticides

A new study by Penn State researchers is is the first to concurrently consider a variety of potential honey bee stressors at a national scale and suggests several areas of concern to prioritize in beekeeping practices.
Photo Credit: Pixabay

About one-third of the food eaten by Americans comes from crops pollinated by honey bees, yet the insect is dying off at alarming rates. In one year alone, between April of 2019 and April of 2020, one study reported a 43% colony loss in honey bees across the United States.

A new study led by Penn State researchers provides preliminary insight on the potential effects of several variables, including some linked to climate change, on honey bees. Their findings show that honey bee colony loss in the U.S. over the last five years is primarily related to the presence of parasitic mites, extreme weather events, nearby pesticides, as well as challenges with overwintering. The study took advantage of novel statistical methods and is the first to concurrently consider a variety of potential honey bee stressors at a national scale. The study, published online in the journal Scientific Reports, suggests several areas of concern to prioritize in beekeeping practices.

Monitoring an ‘anti-greenhouse’ gas: Dimethyl sulfide in Arctic air

Sumito Matoba (left) and Yoshinori Iizuka (right) on the southeastern dome in Greenland, drilling the ice core used in the study
Photo Credit: Sumito Matoba

Data stored in ice cores dating back 55 years brings new insight into atmospheric levels of a molecule that can significantly affect weather and climate.

Dimethyl sulfide (C2H6S) is a small molecule released by phytoplankton in the ocean, which can play a big role in regulating the Earth’s climate. It encourages cloud formation above the sea, and is often called an ‘anti-greenhouse gas’, since clouds block radiation from the sun and lower sea surface temperatures. At least some blocked heat will be retained in the atmosphere, however, so the effects can be complex. Researchers at Hokkaido University have charted evidence for increasing dimethyl sulfide emissions linked to the retreat of sea ice from Greenland as the planet warms. They reported their findings in the journal Communications Earth & Environment.

The 'brown food web': dead vegetation plays essential role in desert ecosystems

Researchers from UNSW say these insights could be used by the conservation managers of arid ecosystems in Australia.
Resized Image using AI by SFLORG
Photo Credit: Prof. Mike Letnic.

A reduction in decaying vegetation can have significant impacts on the desert food chain, UNSW scientists have found.  

It’s well understood that overgrazing by herbivores like kangaroos can change ecosystems dramatically, but the impact excessive grazing has on the cover of dead vegetation – and cascading effects on small vertebrates like lizards, desert frogs and dunnarts – hasn’t been extensively studied.

Now, scientists at UNSW Sydney have shown that overgrazing can disrupt the desert food webs that exist between dead plant material, termites and animals that rely on termites as their main food source. This latest discovery has important implications for the conservation of biodiversity in arid Australia.

Researchers from the School of Biological, Earth & Environmental Sciences carried out field work in the arid region of South Australia and published their findings in the journal Ecosystems. 

Earth likely to cross critical climate thresholds even if emissions decline

Already, the world is 1.1 degrees Celsius hotter on average than it was before fossil fuel combustion took off in the 1800s. More extreme rainfall and flooding are among the litany of impacts from that warming.
Photo Credit: Chris Gallagher

Artificial intelligence provides new evidence our planet will cross the global warming threshold of 1.5 degrees Celsius within 10 to 15 years. Even with low emissions, we could see 2 C of warming. But a future with less warming remains within reach.

A new study has found that emission goals designed to achieve the world’s most ambitious climate target – 1.5 degrees Celsius above pre-industrial levels – may in fact be required to avoid more extreme climate change of 2 degrees Celsius.

The study, published Jan. 30 in Proceedings of the National Academy of Sciences, provides new evidence that global warming is on track to reach 1.5 degrees Celsius (2.7 Fahrenheit) above pre-industrial averages in the early 2030s, regardless of how much greenhouse gas emissions rise or fall in the coming decade.

The new “time to threshold” estimate results from an analysis that employs artificial intelligence to predict climate change using recent temperature observations from around the world.

Climate Change May Cut U.S. Forest Inventory by a Fifth This Century

Mountain forests.
Photo Credit  Alek Kalinowsk

A study led by a North Carolina State University researcher found that under more severe climate warming scenarios, the inventory of trees used for timber in the continental United States could decline by as much as 23% by 2100. The largest inventory losses would occur in two of the leading timber regions in the U.S., which are both in the South.

Researchers say their findings show modest impacts on forest product prices through the end of the century, but suggest bigger impacts in terms of storing carbon in U.S. forests. Two-thirds of U.S. forests are classified as timberlands.

“We already see some inventory decline at baseline in our analysis, but relative to that, you could lose, additionally, as much as 23% of the U.S. forest inventory,” said the study’s lead author Justin Baker, associate professor of forestry and environmental resources at North Carolina State University. “That’s a pretty dramatic change in standing forests.”

Ancestral variation guides future environmental adaptations

A sea campion in its natural habitat on the coast.
Photo Credit: Bangor University

The humble sea campion flower can show us how species adapt.

The speed of environmental change is very challenging for wild organisms. When exposed to a new environment individual plants and animals can potentially adjust their biology to better cope with new pressures they are exposed to - this is known as phenotypic plasticity.

Plasticity is likely to be important in the early stages of colonizing new places or when exposed to toxic substances in the environment. New research published in Nature Ecology & Evolution, shows that early plasticity can influence the ability to subsequently evolve genetic adaptations to conquer new habitats.

A study on the rotation of the Earth’s solid core confuses the mainstream media. Scientists of the Royal Observatory of Belgium clarify it

Earth Structure
Illustration Credit: Courtesy of Royal Observatory of Belgium

An article in Nature Geoscience on the rotation of the Earth’s core (more precisely its solid inner core) was recently published. However, the media have been misled by the press release of the science journal into thinking that the inner core stopped rotating or was even rotating in the opposite direction to that of the Earth surface, which is not the case at all. Scientists of the Royal Observatory of Belgium specialized in the rotation of the Earth and planets clarify the study and provide some information on the structure and rotation of the Earth.

Internal structure and rotation of the Earth

The interior of the Earth is divided into concentric layers. A few tens of kilometers below the surface begins the solid mantle, which extends to a depth of about 2900 km. Below that is the Earth’s core, which consists mainly of iron. The core is subdivided into an upper liquid layer down to a depth of about 5150 km and a central solid inner core with a radius of about 1220 km. The article in Nature Geoscience article is about the solid inner core.

The Earth revolves around its axis of rotation in 24 hours. Movements in the Earth’s atmosphere, hydrosphere and liquid core can cause small variations in the rotational period, so-called “length-of-day variations”, which can be on the order of milliseconds. The different layers that make up the Earth are linked by gravity and the frictional force and the electromagnetic force between the core and the solid parts. Therefore, the rotational period of the solid inner core can show small variations compared to the rotation of the mantle.

Kill Dates for Re-Exposed Black Mosses

Cape Rasmussen, one of the study sites mentioned in the paper.
Photo Credit: Derek J. Ford.

In their new paper for the Geological Society of America journal Geology, Dulcinea Groff and colleagues used radiocarbon ages (kill dates) of previously ice-entombed dead black mosses to reveal that glaciers advanced during three distinct phases in the northern Antarctic Peninsula over the past 1,500 years.

The terrestrial cryosphere and biosphere of the Antarctic Peninsula are changing rapidly as “first responders” to polar warming. We know from other studies that large glaciers of the Antarctic Peninsula are responding quickly to warmer summer air temperatures, and scientists have modeled that the glaciers expanded in the past because of cooler temperatures, and not increased precipitation. However, we know much less about how this plays out at sea level where ice, ocean, and sensitive coastal life interact. Knowing when glaciers advanced and retreated in the past would improve our understanding of biodiverse coastal ecosystems—thriving with seals, penguins, and plants—and their sensitivity in the Antarctic Peninsula. One of the limitations of reconstructing glacier history is that there are not that many types of terrestrial archives we can use to constrain past glacier behavior. Re-exposed dead plants, abandoned penguin colonies, and rocks can be dated to better know the timing of permanent snow or glacier advance in the past.

Rapid plant evolution may make coastal regions more susceptible to flooding and sea level rise

Brady Stiller, University of Notre Dame
Photo Credit: Courtesy University of Notre Dame

Evolution has occurred more rapidly than previously thought in the Chesapeake Bay wetlands, which may decrease the chance that coastal marshes can withstand future sea level rise, researchers at the University of Notre Dame and collaborators demonstrated in a recent publication in Science.

 Jason McLachlan, an associate professor in the Department of Biological Sciences, evaluated the role evolution plays in ecosystems in the Chesapeake Bay by studying a type of grass-like plant, Schoenoplectus americanus, also called chairmaker’s bulrush. The research team used a combination of historical seeds found in core sediment samples, modern plants, and computational models to demonstrate that “resurrected” plants were allocating more resources in their roots below ground, allowing them to store carbon more quickly than modern plants.

Mercury Helps to Detail Earth’s Most Massive Extinction Event

The Karoo Basin in South Africa yields clues about the largest mass extinction in earth's history
Photo Credit: Juanita Swart

The Latest Permian Mass Extinction (LPME) was the largest extinction in Earth’s history to date, killing between 80-90% of life on the planet, though finding definitive evidence for what caused the dramatic changes in climate has eluded experts.

An international team of scientists, including UConn Department of Earth Sciences researchers Professor and Department Head Tracy Frank and Professor Christopher Fielding, are working to understand the cause and how the events of the LPME unfolded by focusing on mercury from Siberian volcanoes that ended up in sediments in Australia and South Africa. The research has been published in Nature Communications.

Though the LPME happened over 250 million years ago, there are similarities to the major climate changes happening today, explains Frank:

“It’s relevant to understanding what might happen on earth in the future. The main cause of climate change is related to a massive injection of carbon dioxide into the atmosphere around the time of the extinction, which led to rapid warming.”

What crocodile DNA reveals about the Ice Age

McGill University postdoctoral fellow José Avila-Cervantes with an American Crocodile (Crocodylus acutus).
Photo Credit: Hans Larsson

What drives crocodile evolution? Is climate a major factor or changes in sea levels? Determined to find answers to these questions, researchers from McGill University discovered that while changing temperatures and rainfall had little impact on the crocodiles’ gene flow over the past three million years, changes to sea levels during the Ice Age had a different effect.

“The American crocodile tolerates huge variations in temperature and rainfall. But about 20,000 years ago – when much of the world's water was frozen, forming the vast ice sheets of the last glacial maximum – sea levels dropped by more than 100 meters. This created a geographical barrier that separated the gene flow of crocodiles in Panama,” says postdoctoral fellow José Avila-Cervantes, working under the supervision of McGill professor Hans Larsson.

Global study of hypoxia in rivers shows it is more prevalent than previously thought

High-frequency sensors deployed in streams, such as those being installed by Joanna Blaszczak in a stream in Montana, can provide continuous data that captures night-time hypoxic conditions.
Photo Credit: Malgosia Blaszczak.

New research led by University of Nevada, Reno Assistant Professor Joanna Blaszczak shows hypoxia in rivers and streams is generally much more prevalent across the globe than previously thought. Hypoxia is low or depleted oxygen levels in surface waters that can be harmful to aquatic species and can in some cases increase production of harmful greenhouse gases from rivers.

The research, published recently in the journal Limnology and Oceanography Letters, compiles over 118 million readings of dissolved oxygen and temperature taken from over 125,000 locations in rivers across six continents and 93 countries and spanning over 100 years, from 1900 to 2018. Hypoxia, defined in this study as dissolved oxygen concentrations below 2 milligrams per liter, was detected in rivers and streams in 53 countries, with 12.6% of all locations exhibiting at least one hypoxic measurement.

“Hypoxia in coastal waters and lakes is widely recognized as a detrimental environmental issue, yet we have lacked a comparable understanding of hypoxia in rivers,” Blaszczak, with the University’s College of Agriculture, Biotechnology & Natural Resources, said. “While 12.6% might not seem like a huge percentage, previously it was generally thought that occurrences of hypoxia in rivers and streams were exceedingly rare. Having shown presence of hypoxia in one of every eight river locations with data is definitely a game changer in terms of how we need to think of and give attention to the issue of hypoxia in rivers and streams.”

Stress may trigger male defense against predators

Photo Credit: Jörgen Wiklund

Only males among the fish species crucian carp have developed a strategy to protect themselves from hungry predators, according to a new study from Lund University in Sweden. The explanation could lie in that the surrounding environment affects the stress system in males and females differently.

Some animals have evolved the ability to swiftly change appearance to defend themselves against predators when necessary - while avoiding the unnecessary costs of that appearance when it is not needed. This is an advantage for animals that live in environments where the risk of being eaten by predators varies. However, there is a difference in the ability of females and males to escape the enemy in this way. Researchers at Lund University have investigated the crucian carp fish species.

“When the smell of predatory fish spreads in the water, the male crucian carp begins to change its appearance, much like a character from Transformers. From having grown in length, the presence of the predatory fish causes the male carp to instead grow in height. The new body shape makes it much more difficult for gape-size limited predators to swallow them. The shape also provides better acceleration, which is an advantage when the fish has to escape from an attacking pike”, explains Jerker Vinterstare, biologist at Lund University.

Pheasants at risk on unfamiliar ground

Male pheasant
Researchers assessed the performance of 126 captive-reared pheasant chicks on a range of cognitive puzzles
Photo Credit: Jan Temmel

Pheasants are most likely to be killed by predators on unfamiliar ground, according to new research involving the University of Plymouth. 

A new study showed most animals live within a certain area, known as their “home range”, and they know the central areas better than the edges.

To examine how this impacted their outcomes, researchers assessed the performance of 126 captive-reared pheasant chicks on a range of cognitive puzzles. They were then released into the wild and tracked using a high-precision tagging system.

About 40% were killed by predators during the six-month study period – almost all by foxes – and the pheasants were far more likely to die towards the edge of their range.

The findings show this was due to inexperience in these areas, because other birds that knew the same spots well were not likely to die there.

Brunt Ice Shelf in Antarctica calves giant iceberg

Chasm-1 remained dormant for many years but has now created a new iceberg.
Photo Credit: British Antarctic Survey

A huge iceberg (1550 km²), almost the size of Greater London, has broken off the 150m thick Brunt Ice Shelf. It calved after cracks that have been developing naturally over the last few years extended across the entire ice shelf, causing the new iceberg to break free. This occurred on Sunday 22 January between 19.00 and 20.00 UTC during spring tide. 

The iceberg calved when the crack known as Chasm-1 fully extended through the ice shelf. The break off is the second major calving from this area in the last two years and has taken place a decade after scientists at British Antarctic Survey (BAS) first detected growth of vast cracks in the ice. 

The Brunt Ice Shelf is the location of BAS Halley Research Station. BAS glaciologists, who have been monitoring the behavior of the ice shelf, say that the area of the ice shelf where the research station is located currently remains unaffected by the recent calving events.  

 The glaciological structure of the Brunt Ice Shelf is complex, and the impact of calving events is unpredictable.  In 2016, BAS took the precaution of relocating Halley Research Station 23 km inland of Chasm-1 after it began to widen.