The Earth
No, autumn leaves are not changing color later because of climate change
“Have scientists observed any changes in the timing or intensity of leaf color changes?”
Fall foliage on the Danforth Campus of Washington University in St. Louis.
It’s that time of year again. The days are getting shorter, and the nights are cooling down. But when will the natural fireworks display of autumn leaves actually begin this year?
Many people believe that climate change is pushing back the start of fall leaf color to later in the year. The general thinking is that the warmer conditions anticipated under climate change will mean that trees can “hang on” to their green, energy-producing leaves longer. But scientists do not actually see this happening across North American forests, according to an expert at Washington University in St. Louis.
“Warmer temperatures in September and October reduce anthocyanin production in leaves, which could mean that fall colors would become less brilliantly red or purple,” said Susanne S. Renner, honorary professor of biology in Arts & Sciences. “This effect is well documented in certain species, such as sugar maple, where experimental cooling of branches increases anthocyanin concentration and color brilliance. If the first frost comes later than it used to, the brilliant foliage will appear later than it used to.
“However, other factors counteract this. Most important is that trees drop their leaves earlier if they have had a very productive spring and summer. This overrides any delaying effects of a warm fall.
“The end result is that leaves still start to die after about the same amount of time on the tree as they have in years and even decades past,” she said.
In fact, under some scenarios we might even see leaves turning red and yellow earlier. Renner co-authored a 2020 study in the journal Science that showed that increased growing-season productivity drives earlier autumn leaf senescence — the process through which plants break down and reabsorb key nutrients that had been deployed in leaves — in temperate trees.
“If climate warming continues unabated, the situation is likely to change after about 2040, with senescence then starting earlier than it does now,” Renner said.
Here, Renner answers a few additional questions related to autumn leaf color change.
How do temperature and moisture conditions affect leaf color?
Yellow color in fall leaves is due to the retention of carotenoid pigments (xanthophylls) in senescing chloroplasts. Red and purplish color is due to the accumulation of anthocyanins in vacuoles, starting around September.
Rain does not affect these basic processes. Cold temperatures, however, enhance anthocyanin production, as shown experimentally in sugar maple. One can observe this in the sugar maple trees along St. Louis streets, which start turning colors at the very top, where the microclimate is coldest.
How might climate change alter color dynamics?
Because climate warming has resulted in warmer falls, in Canada and North America we are seeing less brilliant fall colors. Color brilliance is hard to quantify, but the effect has been experimentally demonstrated in sugar maple trees.
An interesting confounding factor is cleaner air. Thus, in Europe, atmospheric brightening due to cleaner air since 1983 has led to higher plant photosynthesis in the spring and summer — and earlier leaf senescence (compared with 1950-1982). These data, however, concern the breakdown of chlorophyll, not the production of red or yellow colors.
Will all kinds of trees respond in the same ways?
Absolutely not. Experimental work is revealing great species-specific differences. For example, trees that have nitrogen-fixing symbionts never turn red or yellow. Both pigments help protect leaves against damage from sunlight that is no longer usable for photosynthesis because of the massive degradation of chloroplast proteins in aging leaves. Trees with steady access to nitrogen may not bother with costly anthocyanin, but instead simply drop their leaves while still relatively green.
Are scientists already seeing changes to the timing or intensity of leaf color changes?
Warmer falls reduce the brilliance of red and yellow leaf colors, but brilliance is hard to quantify in long time series for many species. Also, many species simply do not turn red or yellow.
We have a paper under review that analyzes satellite data on “greenness” in Northern Hemisphere forests. We found that across a large majority of forest areas, higher spring and summer temperatures have led to an earlier (!!!) senescence by, on average, about 1.5 days per degree Celsius. Senescence here refers to degradation of chlorophyll or greenness.
Where in the world are autumn leaves most likely to be affected by climate change?
Species that change leaf color to red or yellow are much more frequent in North America than in Europe. With continued climate warming and lack of frost nights in October, colors will be less brilliant, but the onset or dates of color change will not change much because of the counteracting factors that I mentioned earlier. In the more distant future (after about 2040), and with unmitigated climate change, leaf senescence in Northern Hemisphere trees and shrubs will occur ever earlier.
Source: Washington University in St. Louis
- Untreated sewage and fertilizer runoff threaten the Florida manatee’s main food source, contributing to malnutrition
Aarin-Conrad Allen, Florida International University The gentle, slow-moving Florida manatee has no natural predators. And yet, these charismatic mammals face numerous threats. Manatees are struck by vessels in busy waterways across the state, and a majority bear scars from these collisions. Harmful algal blooms – characterized by the rapid growth of algae that degrades water… Read more: Untreated sewage and fertilizer runoff threaten the Florida manatee’s main food source, contributing to malnutrition - Blue Origin’s New Shepard NS-28: Aiming for the Stars on November 22nd
Blue Origin’s New Shepard NS-28 mission, launching on November 22, features a significant crewed aspect, promoting broader space access. The mission patch symbolizes the journey’s educational and inspirational goals. Join the excitement! - NASA Coverage of the Upcoming Progress 90 Cargo Resupply Mission
Excitement is building as NASA prepares for the upcoming launch of the Progress 90 spacecraft, a critical mission that will deliver essential supplies to the crew aboard the International Space Station (ISS). With a launch scheduled for 7:22 a.m. EST on Thursday, November 21, from the Baikonur Cosmodrome in Kazakhstan, this unpiloted Roscosmos cargo spacecraft… Read more: NASA Coverage of the Upcoming Progress 90 Cargo Resupply Mission - Saltwater flooding is a serious fire threat for EVs and other devices with lithium-ion batteries
Xinyu Huang, University of South Carolina Flooding from hurricanes Helene and Milton inflicted billions of dollars in damage across the Southeast in September and October 2024, pushing buildings off their foundations and undercutting roads and bridges. It also caused dozens of electric vehicles and other battery-powered objects, such as scooters and golf carts, to catch… Read more: Saltwater flooding is a serious fire threat for EVs and other devices with lithium-ion batteries - Blue Origin’s NS-28 Mission: A Stellar Crew Ready for Space!
Blue Origin has announced an exciting lineup for its 28th New Shepard mission, NS-28, which marks yet another milestone in the company’s quest to democratize access to space. This mission features six remarkable individuals, including renowned science communicator Emily Calandrelli and two returning space travelers, Sharon and Marc Hagle. As excitement builds for this journey,… Read more: Blue Origin’s NS-28 Mission: A Stellar Crew Ready for Space!
Author
Discover more from Daily News
Subscribe to get the latest posts sent to your email.
News
Untreated sewage and fertilizer runoff threaten the Florida manatee’s main food source, contributing to malnutrition
Aarin-Conrad Allen, Florida International University
The gentle, slow-moving Florida manatee has no natural predators.
And yet, these charismatic mammals face numerous threats.
Manatees are struck by vessels in busy waterways across the state, and a majority bear scars from these collisions.
Harmful algal blooms – characterized by the rapid growth of algae that degrades water quality – can impair their nervous systems.
With less blubber, or fat, compared with other marine mammals like whales, dolphins, seals and sea lions, manatees are vulnerable to cold-stress syndrome during winter months.
And they can ingest or get entangled in marine debris like derelict fishing gear and drown or be crushed by floodgate and water control structures.
I am a doctoral candidate in marine biology at Florida International University’s Institute of Environment. Over the past 15 years, I have gained extensive experience working with marine mammals, particularly manatees.
Recently, my colleagues at the United States Geological Survey, Florida Department of Environmental Protection and I documented a change in the dietary pattern of manatees. We found that manatees are eating less seagrass – traditionally their primary food source – and more algae than in decades past. This change occurred along Florida’s Atlantic coast during a period of extensive seagrass decline.
We believe this represents an emerging threat to the species’ survival.
Protected species
Manatees were listed as an endangered species under the Endangered Species Act of 1973. By the early 1990s, the manatee population in Florida had dwindled to less than 1,300.
Researchers believe that federal protection, along with additional state measures such as slow-speed zones and no-entry refuges, has contributed to the growth of the manatee population in Florida.
In 2017, manatees were reclassified from endangered to threatened. Surveyors counted 5,733 individual manatees during a statewide aerial survey conducted in 2019.
Florida manatees average 9-12 feet (2.7-3.7 meters) in length and typically weigh about 1,000 pounds (450 kilograms), but they can grow as large as 3,500 pounds (1,600 kilograms). As the largest fully aquatic herbivore, they consume 5% to 10% of their body weight in vegetation each day.
While manatees eat a broad diet of over 60 different plants, they most commonly feed on species of seagrass. Seagrasses are marine plants that, like land plants, have leaves, flowers, roots and seeds, and make their food through photosynthesis.
So what happens when these seagrasses are no longer available?
A changing estuary
The Indian River Lagoon is an estuary along Florida’s east coast that covers roughly 350 square miles (560 square kilometers) between the mainland and barrier islands, from Ponce Inlet to Jupiter Inlet.
It is a critical habitat for manatees, which feed on native seagrass meadows in the lagoon during their seasonal migrations.
Seagrasses are vital to the health of marine ecosystems. They are a habitat for juvenile fish and other marine organisms, provide food for aquatic herbivores, reduce carbon in the atmosphere and improve water quality. They also protect coastal habitats by stabilizing sediments and reducing wave energy that can erode shorelines and damage coastal infrastructure, especially during hurricanes.
For more than a decade, the Indian River Lagoon has experienced extensive loss of seagrass meadows, due to a series of algae blooms associated with nutrient runoff and degraded water quality from septic overflow leaching into the environment.
When untreated sewage and fertilizers flow into the estuary, they add nitrogen, phosphorus and other nutrients that drive excessive algal growth. These harmful algal blooms deplete oxygen levels and block sunlight, which seagrass needs for photosynthesis.
Between 2011 and 2019, over 50% of all seagrass in the lagoon was lost. This led to an increase in macroalgae and even led to a change in the animal communities that live in the lagoon. For example, among finfish, sheepshead populations declined, while seabream numbers increased. Invertebrate communities were also affected, with bryozoans colonizing areas previously dominated by barnacles.
Manatees along the Atlantic coast have suffered two unusual mortality events since the seagrass decline, including one that is ongoing. Researchers attribute the increase in manatee deaths to malnutrition due to a shortage of seagrasses in the Indian River Lagoon.
A shift in manatees’ diet
In our study, we examined 193 manatee stomach samples collected from carcasses recovered from the Indian River Lagoon during two time periods – one before and one after the onset of the seagrass loss in 2011.
We compared stomach sample contents from carcasses collected between 1977 and 1989 with samples collected between 2013 and 2015.
Our findings indicate that manatees consumed 45% less seagrass and 74% more algae after the seagrass decline.
Recently, in a study supported by FIU’s Center for Aquatic Chemistry and Environment, I investigated differences in the nutritional composition – like protein, fat, carbohydrate and fiber – of items identified in manatee stomach samples. My preliminary results show notable differences in the nutritional composition of seagrass and algae.
Marine mammals are particularly vulnerable to dietary shifts due to their large size and high energy demands. Such changes can worsen their physical health and increase the likelihood of starvation.
Depleted oxygen levels are having a similar impact on aquatic vegetation and seagrass meadows in other regions of Florida, like Biscayne Bay and the Caloosahatchee River and Estuary. This suggests that the ecological challenges seen in the Indian River Lagoon could become more widespread.
What is the solution?
Remediation efforts within the lagoon have incorporated the restoration of seagrass through aquaculture and replanting strategies, similar to efforts to restore coral reefs.
While the lagoon’s seagrass has recently shown signs of regrowth, the rehabilitation of the ecosystem must begin with improving and maintaining water quality.
Counties along the lagoon have enacted fertilizer bans that aim to reduce the levels of nitrogen and phosphorus in the water that drive algal blooms.
New research, however, indicates that these restrictions alone will not fix the problem, as residential septic systems are the primary source of nutrient pollution in the lagoon.
Furthermore, many of the factors contributing to harmful algal blooms are intensified by global warming and changing climate, which could accelerate the decline of seagrass in Florida and elsewhere.
Given the multiple, synergistic threats facing manatees, I believe that improving water quality, protecting their food sources, and further research – coupled with community outreach and education – are critical to ensure the long-term survival of this iconic Florida species.
Aarin-Conrad Allen, Ph.D. Candidate in Marine Sciences, Florida International University
This article is republished from The Conversation under a Creative Commons license. Read the original article.
The science section of our news blog STM Daily News provides readers with captivating and up-to-date information on the latest scientific discoveries, breakthroughs, and innovations across various fields. We offer engaging and accessible content, ensuring that readers with different levels of scientific knowledge can stay informed. Whether it’s exploring advancements in medicine, astronomy, technology, or environmental sciences, our science section strives to shed light on the intriguing world of scientific exploration and its profound impact on our daily lives. From thought-provoking articles to informative interviews with experts in the field, STM Daily News Science offers a harmonious blend of factual reporting, analysis, and exploration, making it a go-to source for science enthusiasts and curious minds alike. https://stmdailynews.com/category/science/
Discover more from Daily News
Subscribe to get the latest posts sent to your email.
Science
Saltwater flooding is a serious fire threat for EVs and other devices with lithium-ion batteries
Xinyu Huang, University of South Carolina
Flooding from hurricanes Helene and Milton inflicted billions of dollars in damage across the Southeast in September and October 2024, pushing buildings off their foundations and undercutting roads and bridges. It also caused dozens of electric vehicles and other battery-powered objects, such as scooters and golf carts, to catch fire.
According to one tally, 11 electric cars and 48 lithium-ion batteries caught fire after exposure to salty floodwater from Helene. In some cases, these fires spread to homes.
When a lithium-ion battery pack bursts into flames, it releases toxic fumes, burns violently and is extremely hard to put out. Frequently, firefighters’ only option is to let it burn out by itself.
Particularly when these batteries are soaked in saltwater, they can become “ticking time bombs,” in the words of Florida State Fire Marshall Jimmy Patronis. That’s because the fire doesn’t always occur immediately when the battery is flooded. According to the National Highway Traffic Safety Administration, about 36 EVs flooded by Hurricane Ian in Florida in 2022 caught fire, including several that were being towed after the storm on flatbed trailers.
Many consumers are unaware of this risk, and lithium-ion batteries are widely used in EVs and hybrid cars, e-bikes and scooters, electric lawnmowers and cordless power tools.
I’m a mechanical engineer and am working to help solve battery safety issues for our increasingly electrified society. Here’s what all owners should know about water and the risk of battery fires: https://www.youtube.com/embed/gWkEGEbpqFc?wmode=transparent&start=10 Emergency responders handle EVs that were immersed in saltwater during Hurricane Ian in Florida in 2022, including some that ignited.
The threat of saltwater
The trigger for lithium-ion battery fires is a process called thermal runaway – a cascading sequence of heat-releasing reactions inside the battery cell.
Under normal operating conditions, the probability of a lithium-ion cell going into thermal runaway is less than 1 in 10 million. But it increases sharply if the cell is subjected to electrical, thermal or mechanical stress, such as short-circuiting, overheating or puncture.
Saltwater is a particular problem for batteries because salt dissolved in water is conductive, which means that electric current readily flows through it. Pure water is not very conductive, but the electrical conductivity of seawater can be more than a thousand times higher than that of fresh water.
All EV battery pack enclosures use gaskets to seal off their internal space from the elements outside. Typically, they have waterproof ratings of IP66 or IP67. While these ratings are high, they do not guarantee that a battery will be watertight when it is immersed for a long period of time – say, over 30 minutes.
Battery packs also have various ports to equalize pressure inside the battery and move electrical power in and out. These can be potential pathways for water to leak into the pack enclosure. Inadequate seal ratings and manufacturing defects can also enable water to find its way into the battery pack if it is immersed.
How water leads to fire
All batteries have two terminals: One is marked positive (+), and the other is marked negative (-). When the terminals are connected to a device that uses electricity to do work, such as a light bulb, chemical reactions occur inside the battery that cause electrons to flow from the negative to the positive terminal. This creates an electric current and releases the energy stored in the battery.
Electrons flow between a battery’s terminals because the chemical reactions inside the battery create different electrical potentials between the two terminals. This difference is also known as voltage. When saltwater comes into contact with metal battery terminals with different electrical potentials, the battery can short-circuit, inducing rapid corrosion and electric arcing, and generating excessive current and heat. The more conductive the liquid is that penetrates the battery pack, the higher the shorting current and rate of corrosion.
Rapid corrosion reactions within the battery pack produce hydrogen and oxygen, corroding away materials from metallic terminals on the positive side of the battery and depositing them onto the negative side. Even after the water drains away, these deposited materials can form solid shorting bridges that remain inside the battery pack, causing a delayed thermal runaway. A fire can start days after the battery is flooded.
Even a battery pack that is fully discharged isn’t necessarily safe during flooding. A lithium-ion cell, even at 0% state of charge, still has about a three-volt potential difference between its positive and negative terminals, so some current can flow between them. For a battery string with many cells in a series – a typical configuration in electric cars – residual voltage can still be high enough to drive these reactions.
Many scientists, including me and my colleagues, are working to understand the exact sequence of events that can occur in a battery pack after it is exposed to saltwater and lead to thermal runaway. We also are looking for ways to help reduce fire risks from flooded battery packs.
These could include finding better ways to seal the battery packs; using alternative, more corrosion-resistant materials for the battery terminals; and applying waterproof coatings to exposed terminals inside the battery pack.
What EV owners should know
Electric cars are still very safe to drive and own in most circumstances. However, during extreme situations like hurricanes and flooding, it is very important to keep EV battery packs from becoming submerged in water, particularly saltwater. The same is true for other products that contain lithium-ion batteries.
For EVs, this means evacuating cars out of the affected zone or parking them on high ground before flooding occurs. Smaller objects, like e-bikes and power tools, can be moved to upper floors of buildings or stored on high shelves.
If you own an EV that has been submerged in water for hours to days, particularly in saltwater, public safety experts recommend treating it as a fire hazard and placing it on open ground away from other valuable property. Do not attempt to charge or operate it. Contact the manufacturer for an inspection to assess battery damage.
Often, a flooded electric vehicle will need to be towed away for further inspection. However, since thermal runaway can occur well after submersion, the car should not be moved until it has been professionally assessed.
Xinyu Huang, Associate Professor of Mechanical Engineering, University of South Carolina
This article is republished from The Conversation under a Creative Commons license. Read the original article.
The science section of our news blog STM Daily News provides readers with captivating and up-to-date information on the latest scientific discoveries, breakthroughs, and innovations across various fields. We offer engaging and accessible content, ensuring that readers with different levels of scientific knowledge can stay informed. Whether it’s exploring advancements in medicine, astronomy, technology, or environmental sciences, our science section strives to shed light on the intriguing world of scientific exploration and its profound impact on our daily lives. From thought-provoking articles to informative interviews with experts in the field, STM Daily News Science offers a harmonious blend of factual reporting, analysis, and exploration, making it a go-to source for science enthusiasts and curious minds alike. https://stmdailynews.com/category/science/
Discover more from Daily News
Subscribe to get the latest posts sent to your email.
Strategic collaborations above 60,000 feet unlocks new potential for traffic and climate management, earth observation and imaging, methane, storm, and wildfire detection, and more
ROSWELL, N.M. /PRNewswire/ — Sceye, a leading U.S. aerospace company specializing in High-Altitude Platform Systems (HAPS), announced a cooperating research and development agreement with United States Geological Survey (USGS) and a Space Act agreement with NASA. The purpose of these agreements is to enhance climate and environmental imaging, monitoring, and data collection from the stratosphere. This partnership builds on Sceye’s successful 2024 flight program, which concluded with a milestone launch on October 24, 2024, demonstrating the platform’s readiness for commercialization and long-duration missions in 2025.
This collaboration positions Sceye’s HAPS technology as a critical partner in providing precise earth observation and lifting multi-mission payloads. Using advanced hyperspectral imaging, Sceye will help NASA and USGS detect methane “super emitters,” monitor wildfire activity, storms, earthquakes, and other extreme weather events. The partnership will help track essential environmental data and metrics in real-time and also positions Sceye to support NASA and USGS in expanding the range of climate data collection and in strengthening forecasting models.
“Our partnership with NASA and USGS is built on the potential of HAPS to stay over an area of operation for long periods of time. In contrast to satellites, HAPS can do that below orbital altitude, thereby offering a unique vantage point to address climate change and better prepare for extreme weather events,” said Mikkel Vestergaard Frandsen, CEO and Founder of Sceye. “We are unlocking the stratosphere as the next frontier to make important scientific advancements that will help communities across the world.”
With climate change accelerating and methane emissions at record levels, Sceye’s HAPS technology offers a solution to precisely detect emissions down to the pixel. Sceye is also collaborating with the Environmental Protection Agency (EPA) and the New Mexico Environmental Department on a five-year program to detect methane emissions across the state. Sceye’s last flight of the year demonstrates the platform’s operational readiness by capturing essential data through onboard infrared cameras.
Sceye’s HAPS are powered by solar energy captured during daylight and stored in batteries to operate throughout the night. This enables continuous flight above 60,000 feet, where few technologies can operate effectively.
“HAPS are a gamechanger for the scientific community because they can linger over events, take high resolution data continuously in real time, and give a more accurate understanding of what may happen before, during, and after an event,” said Jonathan Stock, Director, USGS National Innovation Center.
The final launch of Sceye’s 2024 flight program completed a successful flight year and the full characterization of the vehicle, including achieving the important milestones of controlled relocation, full diurnal flight, and the ability to stay over an area of operation for long periods of time.
With a focus on commercialization and endurance in 2025, Sceye will transition to testing the platform’s capacity to sustain long-duration “seasonal flights.” These missions will enable continuous monitoring during critical periods like wildfire season, supporting rapid response efforts with near real-time data on evolving threats.
Following a successful Series C round that raised the company’s pre-money valuation to $525 million, Sceye is advancing its mission to create world-changing solutions.
About Sceye
Founded in 2014, Sceye is an aerospace company dedicated to advancing stratospheric technology to connect people and protect the planet. Sceye leads the High-Altitude Platform Systems (HAPS) industry, focusing on universal connectivity, climate monitoring, natural resource management, and disaster prevention.
SOURCE Sceye
The science section of our news blog STM Daily News provides readers with captivating and up-to-date information on the latest scientific discoveries, breakthroughs, and innovations across various fields. We offer engaging and accessible content, ensuring that readers with different levels of scientific knowledge can stay informed. Whether it’s exploring advancements in medicine, astronomy, technology, or environmental sciences, our science section strives to shed light on the intriguing world of scientific exploration and its profound impact on our daily lives. From thought-provoking articles to informative interviews with experts in the field, STM Daily News Science offers a harmonious blend of factual reporting, analysis, and exploration, making it a go-to source for science enthusiasts and curious minds alike. https://stmdailynews.com/category/science/
Discover more from Daily News
Subscribe to get the latest posts sent to your email.
-
Urbanism1 year agoSignal Hill, California: A Historic Enclave Surrounded by Long Beach
-
News2 years agoDiana Gregory Talks to us about Diana Gregory’s Outreach Services
-
Senior Pickleball Report2 years agoThe Absolute Most Comfortable Pickleball Shoe I’ve Ever Worn!
-
Senior Pickleball Report2 years agoACE PICKLEBALL CLUB TO DEBUT THEIR HIGHLY ANTICIPATED INDOOR PICKLEBALL FRANCHISES IN THE US, IN EARLY 2023
-
STM Blog2 years agoWorld Naked Gardening Day: Celebrating Body Acceptance and Nature
-
Automotive2 years ago2023 Nissan Sentra pricing starts at $19,950
-
Travel2 years agoUnique Experiences at the CitizenM
-
Senior Pickleball Report2 years ago“THE PEOPLE’S CHOICE AWARDS OF PICKLEBALL” – VOTING OPEN