Trees in the eastern U.S. are adapting to the local climate
Scientists analyzed over 23,000 tree cores to gain a better understanding of how trees respond to climate change. The study revealed that trees growing in temperate forests in the eastern United States are highly adaptable to local climate.
The research team included experts from the USDA Forest Service and was led by Charles Canham, a forest ecologist at Cary Institute of Ecosystem Studies.
“By looking at data in tree rings, we were able to reveal how individual trees responded to variations in climate during a roughly 40 year period. There is evidence of pervasive local adaptation,” explained Canham.
The tree rings had been obtained by the Forest Service’s Forest Inventory and Analysis (FIA) Program in the 1980s. Cores were collected from trees at 7,010 plots in six New England states and in Pennsylvania, West Virginia, and Ohio.
The team tested alternate models of how much the trees grew from year to year as a function of age, size, temperature, and precipitation between 1940 and 1984.
“Trees responded to climate based on deviation from the long-term mean conditions in the location where they were growing,” said Canham. “For all 14 species, models that used deviation from the local, long-term mean were superior, with all 14 species showing strong adaptation or acclimation to local climate.”
Across most species, tree growth was highest in years that were cooler and wetter than the long-term average of a site. According to the researchers, more work is needed to determine if trees are exhibiting genetic differentiation, phenotypic acclimation, or both.
Adaptation based on genetic diversity could make trees more sensitive to climate change than expected. On the other hand, phenotypic acclimation, or the ability to adapt to the local environment, could make trees more resilient.
“These tree species have been around for tens of millions of years. But the pace of climate change that we anticipate is faster than anything any tree in one location has seen during its evolutionary history,” said Canham. “We need to know – is the future pace of change so fast that it will swamp either of these mechanisms?”
“There is no simple takeaway. Based on these cores, trees are cleverer than we give them credit for – but we don’t know how they are pulling it off or if they can keep pace with climate change.”
The study is published in the journal Ecosphere.
The hidden secrets of the Carlsbad Caverns in New Mexico
Caves are special, mysterious places. I felt it first when I was very young and visited Jewell Cave in South Dakota. I felt it again during high school geology class on a field trip to a small show cave in Colorado. When I first visited Carlsbad Caverns in New Mexico though, I was blown away. Seeing the truly awe-inspiring size and scope of Carlsbad was what first inspired me to try caving. Will Rogers called the place, “Grand Canyon with a roof on it.”
Above the caves, the boundaries of the National Park enclose an amazing landscape. On the edge of the Chihuahuan desert that extends south, and on the border of the great plains extending to the east and rugged canyon and mountain country extending to the west, Carlsbad is in a unique position. The nature of different ecosystems converging in one area increases the biodiversity of Carlsbad Caverns National Park.
Cacti common in the Chihuahuan Desert, extending south deep into Mexico, live in Carlsbad along with desert animals like tortoises, lizards and rattlesnakes. There are also scrubland plants like juniper, mesquite and the creosote bush which smells of the desert after rain. Rattlesnake springs maintains a small pool of water and water loving species of plants such as willow and cottonwood.
Over 300 bird species have also been noted at Rattlesnake Springs, which is considered an Important Bird Area (IBA). According to the National Park Service, there are 67 species of mammals found at the park. There are 17 species of bats found in Carlsbad, including 3 species of free tailed bats. Two foxes live in Carlsbad and the raccoon resides along with its more mysterious desert relative, the ringtail cat. 55 species of reptile and amphibian have been identified in the park. Three species of rattlesnake a gecko and 8 species of horned or spiny lizards call Carlsbad home. There are only 5 known species of fish found in Carlsbad but at let 600 species of insect, with new ones being discovered all the time.
There are 85 ‘plant associations’ known in Carlsbad Caverns National Park, 28 of which seem to be unique to the park itself. Plant associations are unique communities of plants such as grasslands or woodlands. There are at least 900 species of vascular plants in Carlsbad, ranging from ferns, spike-moss and horsetails to 4 species of juniper, 4 pines and even 6 plants in the cashew family. There is an impressive number of cacti at 25 known species.
Being a place of desert and caves, both habitats known for a distinct lack of life, Carlsbad hides its biodiversity well and holds its secrets close.
Hiking in through the natural entrance gives you the place a certain scope that the quick trip down in an elevator lacks. The natural entrance seems enormous and as you take steps downward and inward, you can watch the patch of sunlight from outside dwindle to nothing behind you.
The scale of the caverns is hard to explain. Darkness is the dominant element and the whole place has a slightly hushed feel to it, like a cathedral. According to US Parks, the Big Room of Carlsbad Caverns alone is approximately the size of 6.2 football fields. In the main area of Carlsbad, only 3 miles of paved trails is available to visit but more than thirty miles of passages have been mapped to date, according to National Geographic. The less accessible Lechuguilla Cave which is also part of Carlsbad Caverns National Park has over 134.6 miles of passageway surveyed and rooms half as tall as New York’s Chrysler Building, according to Live Science.
Carlsbad Caverns National Park is made up of over 119 caves buried below the Chihuahuan desert. The geology of area is composed of an ancient reef system, the Capitan Reef which was mainly sponges and algae in a shallow sea 265 million years ago. The reef system created large deposits of limestone out of which the famous caverns are carved.
The subterranean geology of Carlsbad is so hidden that it wasn’t until a local cowboy, Jim White was chasing cattle in 1898 and saw a swarm of bats which from a distance appeared to be a giant plume of smoke erupting from the desert. Jim rode closer and then walked towards a gaping hole in the earth. He described the moment when he discovered Carlsbad Caverns, “I found myself gazing into the biggest and blackest hole I had ever seen, out of which the bats seemed literally to boil”.
Jim returned a few days later with a rope, wire and a hatchet he used to make a ladder with and began the still ongoing work of exploring the caves.
In the early days Jim White, lowered visitors into Carlsbad Caverns in a large bucket tied to a bucket used to collect guano. Guano was mined and sold to citrus farmers in California to be used as fertilizer. It wasn’t until 1923 that Carlsbad was turned into a National Monument and 1930 that the National Park was created.
Unlike most caves in the world Carlsbad Caverns seems to have been created largely by sulfuric acid instead of carbonic acid. Cracks, faults and other weaknesses formed in limestone naturally and sulfuric acid leaked into this cracks, enlarging them over enormous amounts of time to form caves. As the Guadalupe Mountains rose, the sulfuric acid drained away from the caves, leaving them empty. As sulfuric acid drained away it left gypsum crystals behind.
Once the caves were dry and relatively empty, formations: enormous stone columns, sharp stalactites and smooth flowstone formed over millions of years, by minerals deposited tiny drip by tiny drip. Erosion and collapse of the cave created Carlsbad’s natural entrance, letting air into the cave and allowing the chemistry that created beautiful cave formations. Columns now appear like massive candles where melted limestone stands in for wax. Side passages open, bristling with a thousand sharp projections like the stone fangs of some monstrous mouth. Shadow and light play over an alien landscape ready to be painted by the imagination.
Today, Carlsbad Caverns is home to more than 250,000 Brazilian Free-tailed Bats. Along with the bats, a colony of cave swallows also lives near the natural entrance of the cave. Three species of cave adapted crickets live within the caverns, eating fungi and algae as well as providing food for others by being eaten along with their eggs and dung. Beetles, millipedes, centipedes and other arthropods live in or around the cave, feeding on cave crickets. In the dark there are probably many other species of arthropods hiding.
In other caves in the southwest, pseudoscorpions (similar to scorpions but without a tail), centipedes and spiders have been found adapted to and living in caves. Cracks, small passages and undiscovered rooms are all places new species can hide. Even turning over and looking under small rocks on a cave floor can reveal new animals to science.
In a place like Carlsbad Caverns, the possibilities are endless. It’s uncertain how many caves there actually are or if caves now known might someday be found to connect to each other. Cave exploration can’t be done with satellites or GPS, but must like the old days be carried out largely by people under their own power creeping into the unknown. Research on strange bacteria is being carried out in Lechuguilla Cave in Carlsbad. Exploration is active and ongoing throughout the park. Even above ground new species of insects are commonly found. For the visitor, Carlsbad is a glimpse into the unknown, a reminder that the world is still often wild and strange.
Here’s what gives pine trees that fresh scent
Pine trees have an unmistakable scent due to the tree’s release of volatile gasses but until now, researchers were not sure why pine trees emitted these glasses.
According to the results published in the journal Nature Geoscience, the scent is the result of volatile gasses emitted from pine forests that help refract light.
It’s been shown that particles in the atmosphere scatter sunlight, which is why light from the sun goes all directions rather just from the direction of the sun.
For forests, the scattered light or diffuse light makes sure that more leaves are exposed to sunlight that would otherwise be in the shade under direct sunlight.
The researchers discovered that the gasses emitted by pine trees oxidize in the atmosphere and forms particles which help diffuse even more light from the sun, exposing more leaves to sunlight and improving photosynthesis.
After running several model simulations, the researchers found that the increased particles in the atmosphere from plant volatiles improves carbon absorption by pine forests by an amount equal to ten percent of global fossil fuel emissions and industrial emissions.
“Amazingly we found that by emitting volatile gases forests are altering the Earth’s atmosphere in a way which benefits the forests themselves,” said Alexandru Rap, the study’s lead author.
“While emitting volatile gases costs a great deal of energy, we found that the forests get back more than twice as much benefit through the effect the increased diffuse light has on their photosynthesis.”
Extracts from maple leaves could prevent wrinkles
Scientists have identified an extract from maple leaves that may help to prevent wrinkles. The discovery was made after the team analyzed the chemistry and health benefits in the sap and syrup of red maple and sugar maple trees.
According to study lead investigator Dr. Navindra P. Seeram, there was evidence that other parts of the tree could also be useful.
“Native Americans used leaves from red maple trees in their traditional system of medicine, so why should we ignore the leaves?” said Dr. Seeram.
Proteins such as elastin help skin maintain its elasticity. As part of the aging process, the enzyme elastase breaks down elastin in the skin, causing wrinkles to develop.
“We wanted to see whether leaf extracts from red maple trees could block the activity of elastase,” explained Dr. Hang Ma, a research associate in Dr. Seeram’s lab at the University of Rhode Island.
The researchers focused their investigation on phenolic compounds in the leaves known as glucitol-core-containing gallotannins (GCGs). In test tubes, they analyzed the ability of each compound to inhibit elastase activity.
Computational studies were also used to examine how the GCGs interact with elastase to block its activity, and how the structure of the molecules affects this ability.
GCGs containing multiple galloyl groups were found to be more effective than those with a single galloyl group. Previous research by the team demonstrated that these compounds may also protect the skin from inflammation and lighten dark spots, including freckles and age spots.
“You could imagine that these extracts might tighten up human skin like a plant-based Botox, though they would be a topical application, not an injected toxin,”said Dr. Seeram.
The extracts would provide a natural plant-based alternative for skincare consumers, and the scientists have already taken steps to incorporate the extracts into products. They have developed a patent-pending formula containing GCGs from summer and fall maple leaves and maple sap, which they named MaplifaTM. The products could ultimately benefit the local economy.
“Many botanical ingredients traditionally come from China, India and the Mediterranean, but the sugar maple and the red maple only grow in eastern North America,” said Dr. Seeram.
Farmers in the region, who currently only harvest sap from the maple trees, could have an additional source of income by utilizing the leaves, and the process would be sustainable.
The research was presented at the 256th National Meeting & Exposition of the American Chemical Society (ACS).
Eating these vegetables may help to prevent colon cancer
A new study from the Francis Crick Institute suggests that vegetables such as kale, broccoli, and cabbage could help prevent gut inflammation and colon cancer. The researchers have discovered that the mechanism underlying these health benefits is a protein that is activated by a diet rich in indole-3-carbinol (I3C).
As our bodies digest vegetables from the Brassica genus, I3C is produced. The researchers found that mice who received regular doses of I3C were protected from gut inflammation and colon cancer.
This study is the first of its kind to show how vegetables in the diet can protect the colon and the gut by activating a protein called the aryl hydrocarbon receptor (AhR). This protein sends signals to immune cells and epithelial cells in the lining of the gut to prevent inflammatory responses to trillions of bacteria that are present.
“We studied genetically modified mice that cannot produce or activate AhR in their guts, and found that they readily developed gut inflammation which progressed to colon cancer,” explained study first author Dr. Amina Metidji.
“However, when we fed them a diet enriched with I3C, they did not develop inflammation or cancer. Interestingly, when mice whose cancer was already developing were switched to the I3C-enriched diet, they ended up with significantly fewer tumors which were also more benign.”
The analysis of mouse gut organoids made from stem cells revealed that AhR is critical for repairing damaged epithelial cells. Intestinal stem cells need AhR to differentiate into specialized epithelial cells that absorb nutrients. Without it, the stem cells divide uncontrollably, which can ultimately lead to colon cancer.
“Seeing the profound effect of diet on gut inflammation and colon cancer was very striking,” said senior author Dr. Gitta Stockinger. “We often think of colon cancer as a disease promoted by a Western diet rich in fat and poor in vegetable content, and our results suggest a mechanism behind this observation.”
“Many vegetables produce chemicals that keep AhR stimulated in the gut. We found that AhR-promoting chemicals in the diet can correct defects caused by insufficient AhR stimulation. This can restore epithelial cell differentiation, offering resistance to intestinal infections and preventing colon cancer.”
“These findings are a cause for optimism; while we can’t change the genetic factors that increase our risk of cancer, we can probably mitigate these risks by adopting an appropriate diet with plenty of vegetables.”
The team hopes to follow up on this research with additional experiments in organoids made from human gut biopsies and human trials.
“A number of epidemiological studies suggested that vegetables may be protective against cancer,” said Dr. Gitta. “However, there is very little literature on which vegetables are the most beneficial or why. Now that we’ve demonstrated the mechanistic basis for this in mice, we’re going to investigate these effects in human cells and people. In the meantime, there’s certainly no harm in eating more vegetables!”
The study is published in the journal Immunity.
Defense mechanisms in corn actually attract its worst enemy
In past research, scientists at the University of Bern established that rootworm larvae are not only resistant to benzoxazinoids, metabolites that help to defend maize plants against pests, but can actually use the compounds for their own defense. A new study by the same team has revealed which benzoxazinoids are recognized by the rootworms that draw the larvae to the corn plants in the first place.
The Western corn rootworm causes more than two billion dollars in corn production losses annually, making it one of the biggest pests in agriculture. The researchers have demonstrated that natural defense compounds in maize plants are actually attracting this notorious pest.
Benzoxazinoids are not only critical as a defense mechanism in maize, but also help improve the growth of the plants. When these metabolites are released from the roots of young corn plants, they bind to iron and form complexes in the soil that make iron more available.
In the current study, the experts have found that these same benzoxazinoid-iron complexes are used by the rootworm as well. The rootworm larvae use the iron complexes to guide them to the roots of maize plants. The larvae also consume these complexes for their own needs.
“The corn rootworm has evolved a clever strategy to exploit its host plant’s ability to make iron biologically available. Tragically, this strategy enables the insect to severely damage maize plants and thereby cause massive crop failure,” said study co-author Christelle Robert.
“This behavior also poses a dilemma for plant breeders: In order to get rid of rootworms, they would have to reduce the release of benzoxazinoids in the roots. However, this would also undermine the plants’ ability to absorb iron. Nevertheless, now that we understand how rootworms orient in the soil, we can start looking for ways to reduce rootworm damage.”
Robert explained that iron complexes could potentially be used to attract rootworms and divert them away from maize roots.
Jonathan Gershenzon from the Max Planck Institute for Chemical Ecology said that more resilient maize plants may be the best solution.
“Since benzoxazinoids function both in herbivore defense and nutrient uptake, it is difficult for the plant to immediately stop producing a defense compound that has so many other important functions,” said Gershenzon. “The challenge will be to grow maize plants that are better able to defend themselves against the most damaging maize pest in the world without compromising their iron nutrition.”
The ability of the Western corn rootworm to detect iron complexes and adjust its behavior accordingly is providing scientists with a new understanding of food chains.
“Many important trace elements are bound to organic molecules in nature,” said study co-author Matthias Erb. “We therefore expect that other higher organisms also have the ability to perceive biologically available forms of trace elements and to ingest them to improve their nutrient balance. The Western corn rootworm is a frustrating, yet highly fascinating pest that has just taught us a new trick of nature.”
The study is published in the journal Science.
High quality genome sequence will revolutionize wheat crops
After 13 years of international collaboration, scientists have produced the highest quality genome sequence for wheat in existence. The International Wheat Genome Sequencing Consortium (IWGSC) is a detailed description of the genome of bread wheat, which is the most widely cultivated crop in the world.
The study involved over 200 scientists from 73 institutions in 20 different countries. The work will ultimately lead to wheat varieties that have enhanced nutritional quality, are more resilient against climate change, and produce higher yields.
Wheat plays a major role in global food security and accounts for almost 20 percent of the total calories and protein consumed worldwide, which is more than any other single food source. Wheat serves as a staple food for over a third of the global population, and is an important source of vitamins and minerals.
The world population is expected to grow to 9.6 billion by the year 2050. In order to meet this level of demand, wheat productivity must increase by 1.6 percent every year. In addition, this must be achieved primarily on land that is already cultivated in order to preserve biodiversity and other resources.
The new genome sequence provides crop breeders with the necessary tools to address these challenges. Using the DNA sequence, they will be able to identify underlying complex traits to produce wheat varieties that are more resilient.
“The wheat genome sequence lets us look inside the wheat engine,” said Professor Rudi Appels of the University of Melbourne. “What we see is beautifully put-together to allow for variation and adaptation to different environments through selection, as well as sufficient stability to maintain basic structures for survival under various climatic conditions.”
Wheat is expected to improve over the next few decades as a result of the high-quality genome sequence.
“How do you thank a team of scientists who persevered and succeeded in sequencing the wheat genome and changed wheat breeding forever?” said Professor Stephen Baenziger of the University of Nebraska-Lincoln. “Perhaps it is not with the words of a scientist, but with the smiles of well-nourished children and their families whose lives have been changed for the better.”
The study is published in the journal Science.
Image Credit: Isabelle Caugant
Beetle preserved in amber reveals first insect-pollinated plant
An ancient boganiid beetle that was preserved in amber and dates back 99 million years may have pollinated the first insect-pollinated plant: a type of evergreen called a cycad.
Cycads are examples of gymnosperms which unlike angiosperms, produce unprotected seeds.
A new study conducted by researchers from the Nanjing Institute of Geology and Paleontology uncovered the earliest fossil evidence of a pollinator-plant relationship dating back to the time of the dinosaurs.
The results were published in the journal Current Biology.
A nearly 100 million-year-old boganiid beetle found trapped in Burmese amber was the basis for the study and there were grains of cycad pollen trapped in the amber with the beetle.
Upon closer inspection of the beetle, the researchers also found that the specimen had specially adapted mandibular patches to help transport pollen strengthening the hypothesis that this beetle was an early pollinator.
“Boganiid beetles have been ancient pollinators for cycads since the Age of Cycads and Dinosaurs,” said Chenyang Cai, an author of the study. “Our find indicates a probable ancient origin of beetle pollination of cycads at least in the Early Jurassic, long before angiosperm dominance and the radiation of flowering-plant pollinators, such as bees, later in the Cretaceous.”
Cai analyzed the boganiid beetle and with the aid of a microscope noticed the specimen carried clumps of pollen grains which were confirmed to belong to a cycad.
As part of the study, the researchers also reviewed the phylogenetics and distribution of the boganiid beetle family tree. The boganiid beetle, the researches found, belonged to a group of Australian beetles that currently pollinate the cycad Macrozamia riedlei.
The distribution of related beetle cycad pollinators supports the idea that the boganiid beetle was an ancient first pollinator of cycads and that cycads were the first insect-pollinated plant.
Image Credit: Chenyang Cai
There’s a market for mushrooms from above and below the ground
Fungi are important, as they assist plants by joining their roots and supplying nutrients that plants have a hard time obtaining on their own. Fungi also break down rotting things, creating soil of old trees and dung. Without fungi, forests may be overrun with old logs, refusing to break down. Fungi are also delicious and important sources of food for many animals, including humans.
For all of human history, wild edible plants and fungi have been part of our diet. Traditionally different plants, animals, shells, and stones were traded between groups of people living in different geographic locations. Only relatively recently have people begun to sell wild plants and fungi for a profit.
Truffles are one of the most valuable of wild edible products. According to Mental Floss, Black Truffles sold for $95 per ounce in recent years, and White Truffles going for $168 per ounce. Most of these pricey truffles are found in Italy and other parts of Europe, but American truffles can be sold for a good price as well. According to Eater, some US truffles are now selling for $40 to $800 per pound depending on the variety.
Truffles have been on earth longer than humans, according to TruffleSpecialty, truffles are about 280 to 360 million years old. Ancient Babylonians around 3000 BC were already searching for truffles to eat and the Ancient Greeks attributed aphrodisiac powers to the strange fungi.
It’s perhaps France that’s best known for truffles though, along with other cuisine of course. An article in Discover Magazine reports that before World War I, France produced as much as 1,000 tons of the finest variety of truffle. The annual harvest in France was around 30 tons in 2,000. Traditionally in places like France, farmers planted oak trees in the hopes that the roots of the tree would become inoculated with truffle spores and grow a subterranean crop.
Truffles form a symbiotic relationship with certain trees, giving and taking certain nutrients from the tree roots, both organisms benefit from the relationship. No fungi can synthesize carbohydrates the way plants can, which is why many grow on dead trees or in herbivore dung, to collect carbohydrates. Some fungi like truffles partner with living trees to get carbohydrates and offer the trees other nutrients that tree roots can’t easily absorb. Until recently, trees were just planted in hopes of attracting truffles but now farmers can directly inoculate tree roots with spores, giving them a greater likelihood of growing the valuable fungi. Still most truffles are collected in the wild by people searching in forests.
It’s hard for humans to find truffles alone, as they’re underground and it takes a keener nose than the ones Homo sapiens use to sniff them out. It is possible to collect truffles without help but it’s also more damaging. Trees that often grow truffles will have bare patches of dirt over the mushrooms and some people simply rake up all the truffles below. Raking causes a lot of damage to the fungi supporting the truffle fruit and sometimes brings up unripe (and useless) truffles.
The strong smell of truffles attracts a number of rodents and other animals, intent on eating the fungi fruit. Being eaten is actually what the truffle “wants” as this is how truffle spores are spread and what makes reproduction successful.
At one time, pigs were the animal of choice for truffle hunters. Apparently black truffles contain a sex hormone found in male pigs; which explains the attraction. Although later experiments showed pigs ignore the hormone by itself and go crazy over the truffles, so perhaps pigs just like a good mushroom, like humans. The biggest problem with using pigs to hunt for truffles is that the pigs love eating the mushrooms as well. It can be hard for a person to take a truffle from a pig and sell it. Dogs are becoming more popular for truffle hunters, canines don’t seem as interested in truffles, instead being happy just to get a treat from a human for their work.
The ascendency of dogs being used to hunt for truffles has led to a whole new enterprise: classes to teach your dog truffle hunting procedures. WideOpenPets suggests five dogs for truffle hunting: Lagotto Romagnolo (specifically bred for truffle hunting), Springer Spaniel, Hounds, Standard Poodle and Belgian Malinois (very similar to a German Shepherd). Really almost any dog can be trained to sniff out truffles, though. What’s important is that a dog is capable of walking possibly long distances through the forest, has a good sense of smell and the desire to please.
Dog trainers have started offering courses in mushroom sniffing in the United States. A two day class at the Oregon Truffle Festival in January 2018 cost $595.00 for one dog and one person to attend. The Truffle Dog Company offers cheaper classes in Washington. For $235, two people and two dogs can attend classes for six sessions and get included online instruction available for a year after signing up. Online classes are even cheaper but I wonder how effective they could be for truffle hunting. There’s also an online list of instructors, mostly in Oregon and Washington but also Tennessee and New Zealand.
Truffles aren’t the only mushroom to be found with foraging and many others are easier to find. Morels and chanterelles have fairly distinct forms and are also found to be delicious by many. Oregon Mushrooms is now selling chanterelles for $25 per pound and dried morels at 2 ounces for $17.50. These are just two examples of the many mushrooms that are edible in the US. Puffball mushrooms for example are also edible.. before they go to spores and live up to their name.
According to one study, there are an estimated 5.1 million species of fungi on earth but only 70,000 of them have been described. This means that chances are high you’ll encounter a poorly understood fungi sometime, whether in searching for mushrooms or just wandering the forest or seeing bread mold at home. Even with well-known mushrooms, things can be tricky. There’s one species of mushroom that was traditionally used by indigenous people in Alaska as a hallucinogen, the same species is said to be deadly in Colorado due to differences in soil or environment.
Many mushrooms look similar to others. Some are poisonous but look similar to edibles. Some are technically edible but not very good. According to AmericanMushrooms, there are thousands of mushroom species in North America, 250 of which are significantly poisonous.
Some mushrooms are very hard to identify and it’s often best to bring an expert with you while collecting mushrooms to eat (or sell). With reasonable caution though, many people can learn to identify at least a few of the most obvious edible mushrooms, given they live in an area rich with fungi. Good guide books focus mostly on the relevant region and show which dangerous varieties are similar in appearance to edibles.
If you’re careful, hunting for mushrooms in the wild might be a good hobby job or a fun way to collect delicious food for yourself, or a nice activity for you and your dog. One thing to keep in mind is that some areas require permits for collecting, so it’s best to check before you head to the woods.
Phytoplankton can influence cloud formation and movement
A new study published by Cell Press has identified a species of phytoplankton that cause changes in the properties of clouds. According to the researchers, Emiliania huxleyi and a virus that is closely associated with it can influence cloud formation and movement.
Study first author Miri Trainic is an Earth scientist at the Weizmann Institute of Science.
“Our aim is to better understand the effects that marine ecology can have on atmospheric properties like radiation and cloud formation,” said Trainic. “This slim air-sea interface controls fluxes of energy, particles, and gases, so if we want to understand climate and climate change, we must understand how microscopic biological activity in the ocean alters this balance.”
When E. huxleyi is infected by the virus EhV, pieces of its shell that are made of chalky calcium carbonate are released into the air. These shell fragments then become part of a class of marine emissions called seaspray aerosols, or SSAs.
“SSAs are particles emitted into the atmosphere when bubbles in the ocean burst,” explained study co-author Ilan Koren. “They cover 70% of the atmosphere and can serve as cloud condensation nuclei, be surfaces for chemical reactions, and significantly contribute to the Earth radiation budget (the balance of how much solar energy Earth absorbs and how much it emits back into space) because they are very reflective.”
When the team observed a model of this process in the lab, they discovered that the volume of SSA emissions from E. huxleyi as well as the particles themselves were much larger than what was expected. The unanticipated abundance of bigger particles would be much more reflective and have a stronger influence on cloud properties.
“Although E. huxleyi is extremely abundant, responsible for algal blooms covering thousands of kilometers, we didn’t expect to measure such a large flux of SSAs emitted from them into the air. Plus, we expected no larger than a 1-micron diameter but measured 3 and 4 microns,” said Trainic. “Before this work, we didn’t know that such large particles would be so abundant in the marine-atmospheric size distribution.”
The experts were also surprised by the complex structure of the SSAs.
“What we found was that we don’t need to look at just the size of the SSA, but also its density,” said Weizmann environmental scientist Assaf Vardi. “These ones are shaped like parachutes; they have an intricate structure of calcium carbonate with lots of space within it, which extends the particle’s lifetime in the atmosphere.”
The team plans to continue this research in regions such as Norway, where the phytoplankton blooms and their SSA emissions can be observed in their natural environment.
“This study focuses on one species and its virus, but in a broader context it can show that the state of the atmosphere actually depends on the daily interactions in the seawater,” said Trainic. “Now we must do our best to further understand that relationship.”
The study is published in the journal iScience.
The net of life: Hybridization and evolution
The evolution of life on Earth is classically envisioned as a tree.
In this model, species diverge from their parent organisms and head off on their own paths, never to fraternize with their progenitors, or any of their other offshoots, again. This calcified and rigid view of the evolutionary process became dogma in the works of scientists such as Ernst Mayer. In the 1940s, Mayer argued that the definition of a species rested on its inability to breed successfully with other species and that hybridization was usually an accidental and evolutionarily useless event. Nonetheless, the notion that hybridization plays a role in evolutionary processes has been the subject of speculation for ages—it was worthy of a chapter in Charles Darwin’s On the Origin of Species.
A large body of research now supports the notion that not only does hybridization play a significant role in evolution, but in some cases it may serve as a primary driver of the process. Hybridization is thought to occur in 25% of plants and 6-12% of animals worldwide per a 2006 study. Remarkably, in some environments, hybrid tendencies are even more prevalent. Some 25% of all plant species in Great Britain hybridize with at least one other species and 75% of British ducks are known to mate with other species of duck. (British ducks aren’t the only ones who step out on their conspecifics; they’re notoriously promiscuous worldwide.)
Though on a short timescale, cross-specific, or introgressive, mating is somewhat rare, on a longer timescale it has been shown to be quite common. And even though only a few individuals in a population may mate outside the population, the genetic transfer can have major effects down the line if the genes from the other species provide adaptive benefits to the species as a whole. This suggests that life is best envisioned as reticulated rather than terminally branching. That is: it is a net or web rather than a tree. Branches diverge and then converge again, as in the delicate fretwork of a lichen or bryozoan.
This process is most visible and perhaps most important during disruptive events, such as the formation of islands and lakes, where enormous stretches of ecosystem are uncolonized. So, too, when overlapping species hybridize at the edge of their respective ranges, novel gene combinations allow adaptive radiation into new territories, often quite rapidly.
A 2003 study on sunflowers in the southern United States demonstrated that the harshest habitats were occupied mainly by ancient hybrids of sunflowers that occurred at the edges of differing ecosystems. While the parent species were unable to grow in salt marshes or dry sandy deserts, the new gene combinations in the hybrids allowed them to radiate into these difficult environments.
Most British dog roses have been found to have hybrid origin due to the presence of tetraploid eggs and haploid pollen, which indicate separate parent species early in their lineage. This has also happened with cichlids in Lake Malawi and Lake Tanganyika and with sculpins in Lake Baikal. The few initial species radiated into hundreds, assisted by frequent backcrosses to parent and related species.
Interestingly, this still happens. A 2004 study found that a hybrid between a species of cichlid from one end of Lake Malawi introduced to the other end hybridized with a species native to the area. The hybrids colonized the perimeter of an entire island. Even Darwin’s finches, which are thought to have diverged perhaps 2-3 million years ago in response to their sui generis island home, are thought to have developed partially through hybridization at the overlap zones between the various species. And hybridization continues to happen in the Galapagos to this day.
Newer disruptions may also cause hybrid events. Species of butterfly fish around Christmas Island were found to hybridize with formerly allopatric, or geographically separated species brought into contact by changing temperatures and currents.
One of the more sensational instances of recent hybrid evolution has happened within the last 90 years in the United States and Canada. Coyotes, once mostly restricted to the Great Plains, moved up through Canada, where they hybridized with wolves, and then colonized the eastern seaboard, where native wolves were largely extirpated. The “eastern coyote” is actually a hybrid between wolves and coyotes. This is evidenced both in its morphology, which is intermediate between coyotes and wolves, and in its behavior. The eastern coyote hunts in packs like wolves and takes down large prey such as deer, unlike the western coyote, which is largely solitary and hunts small mammals and birds. Though larger than the western coyote, it is smaller than a wolf. Sexual dimorphism is also more wolf-like in the eastern coyote; western coyotes are not nearly as sexually dimorphic. The eastern coyote filled the niche abandoned by wolves on the east coast when they were eliminated from the area early in the 19th century. The rapid occupation of abandoned niches like this is known as hybrid swarming.
The phenomenon of hybrid evolution has major implications for humans as well. Some of our food species have evolved through hybrid evolution, notably in certain varieties of cacao. And other species of economic important have hybrid origins as well, notably tobacco. And we’ve caused hybrid evolution ourselves through the introduction of non-native species that may hybridize with natives and take over entire ecosystems, and through climate change, which has brought previously allopatric species back into contact. The so-called pizzly, a hybrid between a grizzly bear and a polar pear, is a great example. Polar bears evolved from grizzly bears. While once separated by their ecological niches, warming climates have brought polar bears further south and grizzlies further north. Due to their remaining genetic similarities, they are still able to breed.
We as a species have hybrid origins as well. Homo sapiens is known to have interbred with two other supposedly distinct species, Neanderthals and the Denisovans. This is mirrored in the behavior of other primates, which often interbreed at so-called hybrid zones. Studies of these zones and their hybrid products are invaluable in analyzing possible hominid hybrids in the fossil record. Because fossil bones may not be useful in genetic analysis, morphological characteristics become important in discerning possible hybrids. Hybrid zones between the various species of baboon have proven useful in this regard. They have shown that even in cases of hybridization, morphology may or may not be a useful indicator. Sometimes, hybrids favor one parent or the other.
Genetic studies have determined definitively that modern day humans express genes from both Neanderthals and Denisovans. So, ponder this: what is a human? Amd what is a species?
Algae that support corals have been around since the dinosaurs
Researchers from Pennsylvania State University have discovered that corals and the photosynthetic algae that enable them to construct reefs have maintained relationships that are much older and more complex than what was previously realized.
According to the study, these coral-algal partnerships have endured climate change events in the past, and many will survive the challenges of global warming that we face today.
“Past estimates placed the initiation of these symbiotic relationships at 50 to 65 million years ago,” said study co-author Professor Todd LaJeunesse.
“Our research indicates that modern corals and their algal partners have been entwined with each other for much longer – since the time of the dinosaurs, approximately 160 million years ago. During their long existence, they have faced severe episodes of environmental change, but have managed to bounce back after each one.”
The micro-algae, which are commonly called zooxanthellae, live inside the cells of corals and allow them to acquire energy from sunlight. This ultimately enables the corals to build massive reefs that are invaluable to some marine ecosystems.
“The fossil record shows that today’s reef-building corals exploded in diversity around 160 million years ago,” said Professor LaJeunesse.
“Finding that the origin of the algal symbionts corresponds to major increases in the abundance and diversity of reef-building corals implies that the partnership with Symbiodiniaceae was one of the major reasons for the success of modern corals.”
The team used genetic evidence such as DNA sequences and genome comparisons to calculate the approximate age of the micro-algae. They also used classical morphological techniques.
The study revealed that, in addition to being older, the algae family is far more diverse than what has been assumed.
“Presently, numerous algal lineages, called clades, are lumped into just one genus,” said study co-author John Parkinson of Oregon State University. “Using genetic techniques, we provide evidence that the family actually comprises at least 15 genera, including hundreds and possibly thousands of species worldwide.”
Parkinson explained that some micro-algal symbionts have characteristics that make them more resilient to changes in the environment than others.
“The updated naming scheme offers a clear framework to identify different symbionts,” said Parkinson. “Accurate taxonomy (the identification and naming of species) is a critical step in any biological research.”
“This is especially true for studies attempting to understand how the partnership between reef corals and their micro-algae, which are needed for survival and growth, may adapt to climate change. For example, when many corals are exposed to high temperatures they lose their symbiotic algae and die. Others are far more tolerant of heat, and some of this resilience is based on the species of algae they have.”
Parkinson pointed out that the team has been working for almost a decade to modernize coral symbiont taxonomy in an effort to better inform researchers and advance future research on corals.
“Until now, studies on the physiology and ecology of these algae attempted to compare apples to apples,” said Parkinson. “Considering how different some of them are, we now recognize that often we were comparing apples to oranges. These changes will help researchers to think more accurately about the comparisons they are making in experiments.”
The study is published in the journal Current Biology.
Image Credit: Robin T. Smith