Tag: Life Sciences

If We Let Them Go, They Won’t Come Crawling Back

One in every five species of reptiles is facing extinction.

There are over 12,000 species of reptiles crawling our planet, but according to a new international study, involving researchers from Tel Aviv University and Ben-Gurion University of the Negev, 21% of these, or a total of about 2,000 species, are threatened with extinction. How can we save them? Or is it too late?

15.6B Years of Evolution Down the Drain?

The comprehensive study, the first of its kind in history, was conducted by the International Union for Conservation of Nature (IUCN) and included 52 researchers from around the world, including Prof. Shai Meiri of Tel Aviv University’s School of Zoology, The George S. Wise Faculty of Life Sciences and the Steinhardt Museum of Natural History, and Dr. Uri Roll of Ben-Gurion University of the Negev. The study was published in the prestigious journal Nature.

The findings of the study show that 30% of forest-dwelling reptiles and about 14% of those living in arid areas are threatened, and that 58% of all turtle species and 50% of all crocodile species are in danger of becoming extinct. The researchers sadly point out that if all of the 1,829 species of turtles, crocodiles, lizards, and snakes that have been found to be threatened do indeed become extinct in the coming years, the world will lose a cumulative wealth of 15.6 billion years of evolution.

Fortunately, no species of reptile has become extinct in Israel in the last decade, but there are many species that are endangered, such as the Hermon Gecko, the Be’er Sheva fringe-fingered lizard and several more.

 

50% of all crocodile species are in danger of becoming extinct

Mapping Out the Threats

The IUCN is an international body whose role is, among other things, to assess the threat of extinction posed to various species. Each species of animal or plant receives a score on a five-point scale. The purpose of this ranking is to define those species that are the most endangered, thereby enabling decision makers and various bodies, such the Israel Nature and Parks Authority, to outline policies accordingly.

In 2004, the IUCN released a comprehensive report on amphibians, and a few years later it issued reports on birds and mammals. The IUCN has been working on the reptile report for the past 18 years, having invited experts on this taxonomic group from all over the world to participate.

“In general, the state of reptiles in the world is bad,” says Prof. Meiri. “It’s worse than that of birds and mammals, though not as bad as that of the amphibians. And of course there are a lot of nuances. We see that turtles are in a worse position than lizards and snakes, but that may be because we know more about turtles. Perhaps if we knew more about snakes, we would see that they, too, are in big trouble.”

“The biggest threat to reptiles is the destruction of their habitats due to agriculture, deforestation, and urban development, and less because of direct hunting, which mainly affects turtles and crocodiles. We created detailed maps of these threats. For example, if a particular species is highly threatened in the Israel’s Arava desert, but not in the rest of its habitat range that may span the entire Arabian Peninsula, then globally it is not considered a threatened species. The new assessments, for more than 10,000 species of reptiles, will allow us to understand their conservation needs, and hopefully enable us to find far more intelligent solutions for them than we have been able to so far.”

 

Prof. Shai Meiri

Dr. Uri Roll adds, “This is important work that forms the initial basis for risk assessment among various reptiles around the world, but is certainly not the end of the story. We still lack a lot of information about the various risks facing reptiles. For example, climate change is expected to have significant effects on reptiles. The current assessment that has just been published does not yet include these future threats in its reptile risk assessments. We still have a lot of work ahead of us.”

When asked whether it is still possible to stop the wheels from turning, Prof. Meiri says that “There’s room for optimism, but not overly so. It is finally possible, thanks in part to this study, to plan dedicated nature conservations for reptiles as well – there is more awareness and there are ways in which we can help them. In Israel, great efforts are made to protect various kinds of turtles. Less attention is paid to most species of lizards and snakes, however, which make up the vast majority.”

Featured image: Endangered: Egyptian mastigure (Photo: Alex slavenko)

Diagnosing Diseases in Space

TAU researchers successfully test genetic diagnosis under microgravity conditions.

If pursuing the unknown in space is on your bucket list, you can take comfort in knowing that TAU researchers recently conducted a unique experiment at the International Space Station to test genetic diagnosis under microgravity conditions. The researchers launched a kit together with Israeli astronaut Eytan Stibbe to space and proved that an existing technology based on a bacterial immune system against viruses, ‘CRISPR’, can be used to identify viruses and bacteria infecting crew members during space missions.

The study was led by Dr. Dudu Burstein from the Shmunis School of Biomedicine and Cancer Research, Tel Aviv University and Dr. Gur Pines from the Volcani Institute. The experiment was conducted by Stibbe as part of the “Rakia” mission in April, under the leadership of the Ramon Foundation and the Israel Space Agency.

Suited for Astronauts

CRISPR systems are the immune systems of bacteria from viruses. Bacteria use the CRISPR-Cas systems as a sort of molecular ‘search engine’ to locate viral sequences and cleave them to disable viruses.

As part of their scientific vision, the researchers hypothesized that genetic diagnostics using this method, which requires minimal and easily operated equipment, could be suitable for long space missions: “Conditions in space are extremely problematic,” explains Burstein. “Treatment methods are limited, so it is essential to identify pathogens [= a microorganism that can cause disease] in a rapid, reliable, and straightforward method.” The method stands in contrast to tests like PCR (which we are now all familiar with due to Covid-19), which Burstein notes require trained personnel and relatively complex equipment.”

 

Researchers discussing the experimental design. From left to right: Dan Alon, Dr. David Burstein, Dr. Gur Pines (Photo: Ella Rannon)

Burstein outlines the process: “First, the DNA is amplified: each targeted DNA molecule is repeatedly duplicated many times. Then the CRISPR-Cas goes into action: If it identifies the target DNA, it activates a fluorescent molecular marker. The fluorescence lets us know whether the bacteria or viruses of interest are indeed present in the sample. This whole process can be conducted in one tiny test tube, so it is well suited for the astronauts’ needs.”

Zero Gravity? No problem!

Dr. Burstein describes the preparation for the space experiment: “Doctoral student Dan Alon and Dr. Karin Mittelman planned the experiment in detail and conducted it countless times in the lab under various conditions. After reaching the desired result, they prepared a kit, including the CRISPR-Cas system and the other components required for detection. Eventually, the kit was launched with Eytan Stibbe to the International Space Station.”

The experiments conducted by Stibbe were very successful, and proved that it is indeed possible to perform precise and sensitive CRISPR-based diagnosis – even in an environment with virtually no gravity.

What now? “This is the first step towards the simple and rapid diagnosis of diseases and pathogens on space missions,” says Burstein, adding that there is still some work to do on the next stages, including, “simple extraction of DNA from samples, making the system more efficient, so that it will be able to test a variety of organisms in one test tube, and diagnosis of more complex samples.”

“It was inspiring to see our test kit in Eytan’s hands at the Space Station, and we’re even more excited by the possibility that such kits will help future astronauts on their extraterrestrial missions,” he concludes.

 

Eytan Stibbe executing the experiment on the International Space Station (Photo: the Ramon Foundation and the Israel Space Agency)

Featured image: International space station on orbit of planet Earth 

Two New Planets Found in Milky Way

TAU team leads discovery of giant planets, similar in size to Jupiter, in remote corner of the galaxy.

Tel Aviv University researchers led the recent discovery of two new planets in remote solar systems within the Milky Way galaxy. They identified the giant planets, named Gaia-1b and Gaia-2b, as part of a study in collaboration with teams from the European Space Agency (ESA) and the body’s Gaia spacecraft.

The development marks the first time that the Gaia spacecraft successfully detected new planets. Gaia is a star-surveying satellite on a mission to chart a 3D map of the Milky Way with unprecedented accuracy comparable to standing on Earth and identifying a 10-shekel coin (roughly the size of a U.S. nickel) on the Moon.  

TAU’s Prof. Shay Zucker, Head of the Porter School of the Environment and Earth Sciences, and doctoral student Aviad Panhi from the Raymond and Beverly Sackler School of Physics & Astronomy led the initiative. The findings were published in the scientific journal Astronomy & Astrophysics. 

More Discoveries on the Horizon

“The discovery of the two new planets was made in the wake of precise searches, using methods of artificial intelligence,” said Prof. Zucker. “We have also published 40 more candidates we detected by Gaia. The astronomical community will now have to try to corroborate their planetary nature, like we did for the first two candidates.”

The two new planets are referred to as “Hot Jupiters” due to their size and proximity to their host star: “The measurements we made with the telescope in the U.S. confirmed that these were in fact two giant planets, similar in size to the planet Jupiter in our solar system, and located so close to their suns that they complete an orbit in less than four days, meaning that each Earth year is comparable to 90 years of that planet,” he adds.  

Giant Leaps for Astronomy 

There are eight planets in our solar system. Less known are the hundreds of thousands of other planets in the Milky Way, which contains an untold number of solar systems. Planets in remote solar systems were first discovered in 1995 and have been an ongoing subject of astronomers’ research ever since, in hopes of using them to learn more about our own solar system.  

To fulfill its mission, Gaia scans the skies while rotating around an axis, tracking the locations of about 2 billion suns, stars at the center of a solar system, in our galaxy with precision of up to a millionth of a degree. While tracking the location of the stars, Gaia also measures their brightness — an incomparably important feature in observational astronomy, since it relays significant information about the physical characteristics of celestial bodies around them. Changes documented in the brightness of the two remote stars were what led to the discovery. Aviad Panhi explains: “The planets were discovered thanks to the fact that they partially hide their suns every time they complete an orbit, and thus cause a cyclical drop in the intensity of the light reaching us from that distant sun.”

To confirm that the celestial bodies were in fact planets, the researchers performed tracking measurements with the Large Binocular Telescope, in Arizona, one of the largest telescopes in the world today. The telescope makes it possible to track small fluctuations in a star’s movement which are caused by the presence of an orbiting planet.

The discovery marks another milestone in the scientific contribution of the Gaia spacecraft’s mission, which has already been credited with a true revolution in the world of astronomy. Gaia’s ability to discover planets via the partial occultation method, which generally requires continuous monitoring over a long period of time, has been doubted up to now. The research team charged with this mission developed an algorithm specially adapted to Gaia’s characteristics, and searched for years for these signals in the cumulative databases from the spaceship.  

Signs of Life?

What about the possibility of life on the surface of those remote new planets? “The new planets are very close to their suns, and therefore the temperature there is extremely high, about 1,000 degrees Celsius, so there is zero chance of life developing there,” explains Panhi. Still, he says, “I’m convinced that there are countless others that do have life on them, and it’s reasonable to assume that in the next few years we will discover signs of organic molecules in the atmospheres of remote planets. Most likely we will not get to visit those distant worlds any time soon, but we’re just starting the journey, and it’s very exciting to be part of the search.” 

How are the Birds Coping with Climate Change?

Researchers detect changes in birds’ bodies, probably caused by global warming.

Researchers at Tel Aviv University have found changes in the morphology of many birds in Israel over the past 70 years, which they interpret to be a response to climate change. The body mass of some species decreased, while in others body length increased – in both cases increasing the ratio between surface area and volume. The researchers contend that these are strategies to facilitate heat loss to the environment: “The birds evidently changed in response to the changing climate. However, this solution may not be fully adequate, especially as temperatures continue to rise.”

Relying on the vast bird collection preserved by The Steinhardt Museum of Natural History at TAU, the researchers looked for changes in bird morphology over the past 70 years in Israel. They examined approximately 8,000 adult specimens of 106 different species – including migratory birds that annually pass through Israel (such as the common chiffchaff, white stork, and black buzzard), resident wild birds (like the Eurasian jay, Eurasian eagle-owl, and rock partridge), and commensal birds, that live near humans. They built a complex statistical model consisting of various parameters to assess morphological changes – in the birds’ body mass, body length and wing length – during the relevant period.

The study was led by Prof. Shai Meiri and PhD student Shahar Dubiner of the School of Zoology, The George S. Wise Faculty of Life Sciences, and the Steinhardt Museum of Natural History at Tel Aviv University. The paper was published in the scientific journal Global Ecology and Biogeography.

Cooling Down

Prof. Meiri explains that according to Bergmann’s rule, formulated in the 19th century, members of bird and mammal species living in a cold climate tend to be larger than members of the same species living in a warmer climate. This is because the ratio of surface area to volume is higher in smaller animals, permitting more heat loss (an advantage in warm regions), and lower in larger bodies, minimizing heat loss (a benefit in colder climates). Based on this rule, scientists have recently predicted that global warming will lead to a reduction in animal size, with a possible exception: birds living in the human environment (such as pigeons, house sparrows, and the hooded crow) may gain size due to increased food availability, a phenomenon already witnessed in mammals such as jackals and wolves.

Either Long or Slender

Shahar Dubiner: “Our findings revealed a complicated picture. We identified two different types of morphological changes: some species had become lighter – their mass had decreased while their body length remained unchanged; while others had become longer – their body length had increased, while their mass remained unchanged. These together represent more than half of the species examined, but there was practically no overlap between the two groups – almost none of the birds had become both lighter and longer. We think that these are two different strategies for coping with the same problem, namely the rising temperatures. In both cases, the surface area to volume ratio is increased (by either increasing the numerator or reducing the denominator) – which helps the body lose heat to its environment. The opposite, namely a decrease in this ratio, was not observed in any of the species.”

 

The researchers (from left to right): Shahar Dubiner and Prof. Shai Meiri

Global Phenomenon

Sadly, flying away from global warming is not an option. These findings were observed across the country, regardless of nutrition, and in all types of species: resident birds; commensal species living in the human environment – which, contrary to predictions, exhibited changes similar to those of other birds; and migrants.

A difference was identified, however, between the two strategies: changes in body length tended to occur more in migrants, while changes in body mass were more typical of non-migratory birds. The very fact that such changes were found in migratory birds coming from Asia, Europe, and Africa, suggests that we are witnessing a global phenomenon.

The study also found that the impact of climate change over time on bird morphology (the birds’ change in either weight or length over time, relative to the actual temperature change during that time) is ten times greater than the impact of similar differences in temperature between geographical areas (the birds’ differences in weight or length in different geographical areas, relative to the temperature differences between those areas).

What is the Limit of Evolutionary Flexibility?

Shahar Dubiner: “Our findings indicate that global warming causes fast and significant changes in bird morphology. But what are the implications of these changes? Should we be concerned? Is this a problem, or rather an encouraging ability to adapt to a changing environment? Such morphological changes over a few decades probably do not represent an evolutionary adaptation, but rather certain phenotypic flexibility exhibited by the birds. We are concerned that over such a short period of time, there is a limit to the flexibility or evolutionary potential of these traits, and the birds might run out of effective solutions as temperatures continue to rise.”

Featured image: Israeli birds have become either longer or slenderer over the past 70 years

The Ultimate Solution to Global Warming?

Breakthrough TAU discovery may accelerate an industrial transition to sustainable energy.

Hydrogen-powered bicycles and cars have been in serial production for years. In these vehicles, the regular polluting lithium battery has been replaced by a fuel cell that converts hydrogen, a non-polluting fuel, to electricity. Most of today’s hydrogen is, however, still produced from natural gas in a highly polluting process and is therefore referred to as gray hydrogen. Not only is natural gas a non-renewable source of energy, but it also creates carbon dioxide gas when burned, damaging our environment and contributing to global warming.

Enter a new TAU discovery, which may boost the industrial transition from using polluting gray hydrogen to environmentally friendly green hydrogen: Researchers identified a mutant of a known strain of microscopic algae that allows, for the first time, the production of green hydrogen gas via photosynthesis on a scale suited to industrial requirements. Hydrogen gas can thus be produced solely through renewable energy and in a climate-neutral manner, reducing our carbon footprint and greenhouse gas emissions dramatically to stabilize global temperatures. 

Humanity’s transition to the use of green hydrogen may be the ultimate solution to the problem of global warming.

The microscopic algae

Continuous Production Achieved

The study was led by doctoral student Tamar Elman, under the supervision of Prof. Iftach Yacoby from the Renewable Energy Laboratory of The George S. Wise Faculty of Life Sciences at Tel Aviv University. The study was recently published in the prestigious journal Cell Reports Physical Science

While production of green hydrogen is possible through solar panels wired to devices that perform water breakdown into hydrogen and oxygen (electrolysers), the researchers explain that this is an expensive process, requiring precious metals and distilled water. In nature, hydrogen is produced as a by-product of photosynthesis for periods of minutes by micro-algae, unicellular algae found in every water reservoir and even in the soil. For this biological process to become a sustainable source of energy, however, humanity must engineer micro-algae strains that produce hydrogen for days and weeks.

Prof. Yacoby explains that as part of the laboratory tests, the researchers identified a new mutant in microscopic algae that prevents oxygen from accumulating at any lighting intensity, and therefore hypothesized that continuous hydrogen production could be achieved from it. With the help of bioreactor measurements in liter volumes, they were indeed able to prove that hydrogen can be produced continuously for more than 12 days.

According to Prof. Yacoby, the new mutant overcomes two major barriers that have so far hindered continuous production of hydrogen:

  1. Accumulation of oxygen in the process of photosynthesis – As a rule, oxygen poisons the enzyme that produces hydrogen in algae, but in the mutation, increased respiration eliminates the oxygen and allows favorable conditions for continuous hydrogen production.
  1. Loss of energy to competing processes – And this includes carbon dioxide fixation into sugar. This, too, has been solved in the mutant and most of the energy is being channeled for continuous hydrogen production.

To industrialize these results, the research team led by Prof. Yacoby is working on a pilot program of larger volumes and the development of methods that will allow the time of hydrogen harvest to be extended, in order to reduce its cost to competitive levels. “The rate of hydrogen production from the new mutant reaches one-tenth of the possible theoretical rate, and with the help of additional research it is possible to improve it even further,” concludes Prof. Yacoby.

 

Tamar Elman and Prof. Iftach Yacoby in the lab

Featured image: Tamar Elman and the microscopic algae

Work created by TAU-affiliated artists can’t exist on earth

Many think that physics is an exact science that requires the application of analytical and quantitative abilities, while art is based on emotion and creativity. A collaboration between the physicist Dr. Yasmine Meroz of Tel Aviv University (TAU) and the contemporary artist Liat Segal challenges the boundaries between the two fields. Their joint work, called “Impossible Object,” will be launched in April to the International Space Station (ISS), as part of the “Rakia” mission of the Israeli astronaut Eitan Stiva.

Dr. Meroz is a senior faculty member at the School of Plant Sciences and Food Security at TAU’s Wise Faculty of Life Sciences, whose lab studies the physics of plant systems. Segal studied Computer Science and Biology and worked in the hi-tech industry for several years, before shifting her career to arts. The special bond between the two was created when they were graduate students at the same lab at TAU.

“Impossible Object” is a sculpture made of water. The liquid’s three-dimensional form does not get its shape from any vessel and so cannot exist on earth, but only in outer space in the absence of gravity.

The sculpture is made of interconnected brass pipes and rods, through which water is flown. In the absence of gravity, the water adheres to the rods and forms a liquid layer shaped by water tension, which envelopes the brass structure, yielding a three-dimensional shape that changes over time. The underlying brass structure is reminiscent of a wavy and directionless staircase, raising questions about shape and form in the absence of gravity and directionality. In particular, what is the shape of water? What does a “slice of the sea” or a “handful of a wave” look like?

“There is much in common between art and scientific research: Both are the result of a thought process in which creativity plays a central role and are motivated by the desire to ask interesting questions,” Dr. Meroz says. “‘Impossible Object’ is a research-based artwork, where the medium is basically the physics underpinning water behavior in the absence of gravity. I learned a lot in the process, and I have no doubt it will contribute to research in my laboratory. In this respect, this work expresses the unrealized potential of the synergy between art and scientific research.”

“I am very happy about my collaboration with Yasmine,” Segal adds. “In this collaboration we not only shared knowledge and inspiration, but we were also able to bring about a true co-creation, which could not have been realized by each one of us individually. ‘Impossible Object’ is timely, weighing the role of culture and art at an era when humanity is experiencing accelerated scientific and technological developments. Following incredible technological and scientific achievements in space, and as space tourism becomes tangible, it is important to reflect on the place of culture and arts in our lives, on earth and beyond.”

This is their second collaboration; their previous artwork, “Tropism,” has been exhibited at TAU’s Genia Schreiber University Art Gallery.

Inventive Study to Develop Biological Solutions for Agriculture

TAU and ag-biotech company PlantArcBio to collaborate on development of RNAi-based products.

Genetically improved plants can be a real-life magic stick for solving global famine issues. In a first-of-its-kind study, Ramot, the Technology Transfer Company of Tel Aviv University will cooperate with ag-biotech company PlantArcBio to develop innovative RNAi-based biological solutions for agriculture.

RNAi technology enables a temporary external disruption of RNA (ribonucleic acid) molecules, diminishing the amount of Messenger RNA (mRNA), thus temporarily reducing the expression of specific genes, without modifying or genetically engineering the organism’s DNA. Externally applied RNAi molecules affect specific genes for a specific time period, as required for positive effects like crop protection and yield enhancement. 

Specifically, the research will focus on testing the joint technology’s contribution to the stability of RNAi-based products and their ability to penetrate plants and insects.

Joining Forces

The first-of-its-kind joint study will examine the efficacy of PlantArcBio‘s RNAi technology for agriculture, combined with the unique lipid-based RNA delivery technology developed by Prof. Dan Peer, TAU’s Vice President for R&D, head of the Center for Translational Medicine and a member of both the Shmunis School of Biomedicine and Cancer ResearchGeorge S. Wise Faculty of Life Sciences, and the Center for Nanoscience and Nanotechnology, and a pioneer using RNA to manipulate cells in cancer and other immune related diseases.  

 

Prof. Dan Peer

“We see great value in contributing to the development of RNAi-based products addressing global issues and providing an ecological and environmentally friendly solution to the global challenges of sustainability in agriculture and food security,” says Peer.

Keren Primor Cohen, CEO of Ramot, believes there is “extensive commercial potential for this combined technology” and welcomes the collaboration with PlantArcBio.

The research will be carried out both at PlantArcBio‘s Laboratories and at Prof. Dan Peer’s Laboratory of Precision NanoMedicine at Tel Aviv University. According to Dror Shalitin, Founder and CEO of PlantArcBio, the results are expected within approximately 12 months.

Reading Tea Leaves

What is the origin of tea, and does the climate crisis threaten its production?

Tea – the ancient beverage comes in different flavors and colors. The Queen of England will never go without her afternoon tea, in India it’s enjoyed with milk and spices and we all like to pour ourselves an occasional cup of Earl Grey, especially when winter comes knocking. But have you ever wondered whether the saying “all the tea in China” really does indicate where tea drinking started? Or if the soothing drink may be affected by the climate crisis? Should we, in fact, be drinking it? We have, and our researchers explained, surprised us and busted some myths in the process.

When the Chinese Mystics Met the Tea Plant

We’re not going to keep you in suspense: It turns out that the coveted drink was sipped by the Indian Buddhist monks two thousand years ago – long before it became an integral part of Chinese culture and a long, long time before it became popular in Western cultures.

“The tea plant was known in China as early as the first centuries BCE, but recent studies show that the custom of drinking tea was brought to China from India,” explains Prof. Meir Shahar from The Department of East Asian Studies of The Lester and Sally Entin Faculty of Humanities at Tel Aviv University, who researches, among other things, the influence of Indian culture on Chinese religion and literature.

“In the first centuries CE Buddhism came to China from India and the Buddhist monks, who wanted to stay awake during the meditation, used to drink tea. The Chinese monks would observe this, and went on to adopt the custom as well, which then continued to spread to the rest of the Chinese population.”

While tea originates from India, the origin of the word ‘tea’ in most of the world’s languages, however, is Chinese. “In northern China it is called cha, hence the Russian chai, and in southern China it is pronounced as tcha, which is the origin of the English word tea,” reveals Prof. Shahar.

Buddhist monks on their tea break

What’s in Your Cuppa?

Buddhist monks realized long ago that tea keeps them awake and today, thanks to science, we are able to explain how the active ingredients of the plant affect us.

“Contrary to many people’s beliefs, all types of tea are produced from the same plant, namely the leaves and buds of the Camellia Sinensis plant. While there are several varieties of the plant, the types of tea that we are familiar with – white, green, oolong and black – differ according to the part of the plant from which they are produced and the way they’re processed. Green tea, for example, contains less caffeine than black tea. The leaves used to produce green tea undergo a minimal drying process while the leaves intended for black tea undergo drying and fermentation,” explains Guy Shalmon, a sports nutritionist and exercise physiologist at the Sylvan Adams Sports Institute.

“Tea leaves contain substances known as flavonoids. Their composition, however, varies from one tea to another. For example, green tea has a higher concentration of a substance called epigallocatechin 3-gallate, known for short as ‘EGCG’, than black tea which undergoes a prolonged processing process. It has antioxidant activity and is attributed various health effects,” says Guy.

“Having said that, tea may reduce the absorption of iron-derived iron minerals. The polyphenols (compounds with antioxidant properties), which exist in tea leaves, may bind inorganic iron mineral before it is excreted in the feces. In order to prevent this, one does not need to give up drinking tea, but instead make sure not to drink it while consuming iron-rich plant foods,” he advises.

Will Tea Survive the Climate Crisis?

The climate crisis brings with it many changes and different regions of the world are experiencing major climate fluctuations, ranging from heat and droughts to floods, storms and extreme cold. This could threaten the continued survival of agricultural crops. Some plants have crossed oceans and been absorbed by other continents, but what about those that require special conditions to thrive? Will the tea plant survive the changing conditions?

“A plant can adapt to new conditions up to a certain limit,” says Prof. Shaul Yalovsky of the School of Plant Sciences and Food Security at The George S. Wise Faculty of Life Sciences, who studies plant development mechanisms and their response to environmental stresses. His lab has succeeded in developing tomato varieties that consume less water and still deliver the same amounts of fruit while maintaining its quality.

“Tea is a crop that grows in very rainy areas. Therefore, it is not cultivated in an area like Israel, for example. Tea plantations are usually located on hills, where the weather is humid and cool to the appropriate extent and the soil is deep enough.”

The tea fields stretching over hills and mountains. Tea harvest in action


Disguised as Tea

Did you know that red “tea” (also known as “red bush tea”) is actually an infusion from the Rooibos plant that grows in South Africa? Because it is processed in the same way as the tea plant, it is commonly referred to as “red tea”, while in reality it is not a tea, but an herbal infusion. It is naturally caffeine-free.


Just like many other plants, tea requires specific conditions to grow: deep and airy soil rich in minerals, and an optimal temperature range between 18 and 20 degrees Celsius. “Tea is sensitive to cold, dryness, humidity and lighting conditions. For example, high humidity impairs the quality of the tea while periods of dryness increase its quality, and growing at high altitudes increases the quality of the tea but lowers the amount of crop,” explains Prof. Yalovsky.

The tea is grown in Asia, Africa and South America. The six largest tea producers in the world are China, India, Kenya, Sri Lanka, Vietnam and Turkey. So what happens if growing conditions in East and Southeast Asia change? Prof. Yalovsky explains that it is necessary to adapt the types of tea plants according to their growing areas. “What works at one location does not necessarily work elsewhere: what grows well in East and Southeast Asia will not necessarily grow well in Kenya or Turkey, for example. Even if we should manage to copy a crop from one place to another, we may not succeed in maintaining its qualities and taste.”

When we drink Earl Grey tea we expect a very specific taste, and if the same tree were to be grown elsewhere – where the temperature may be the same as the original habitat but the soil is not – we would likely notice a change in the taste of the product. This is possibly one of the reasons why drinking Japanese green tea differs in taste from Chinese green tea.

With regard to the future of the in-demand beverage, Prof. Yalovsky says: “Even if the regions of the cultivated areas should experience floods – the tea plantations are positioned on the slopes of hills and mountains so it should not become an issue.” Another good news is that unlike many crops that depend on pollination to develop fruit – the tea plant is less reliant on this. “In the production of tea, we use its leaves and not its flowers or fruits and so it can be propagated by pruning (cutting a branch from a mature plant, a so-called ‘mother plant’, and creating a new plant through rooting). This method also ensures the genetic uniformity of the ‘daughter plants’, with everything that implies,” he concludes.

We made sure to ask Guy Shalmon which type of tea (if any) he recommends that our students drink during the exam period, to which he replied: “Actually, I wouldn’t say there’s any unique advantage or need to drink tea during an exam period. I’d say drink the kind of tea that you fancy and, ideally, try to rotate different types of tea. If the need for caffeine is the main consideration, black tea is the best choice, as it has the highest caffeine concentration. Black tea contains approx. 60-40 mg of caffeine per cup, while green tea contains only 20-15 mg.”

Well, who needs the exams as an excuse, anyway? If you’re like us, we suggest you pour yourself a cuppa on any day of the week – no special occasion required – and enjoy a peaceful break from everything and everyone.

Hitting Rock Bottom?

First meta-analysis of its kind shows warming of Mediterranean Sea causes marine species to migrate.

As has been heavily discussed at the recent the UN Climate Change Conference (COP26) in Glasgow, our entire planet has been warming in recent decades. This process has been particularly marked in the Mediterranean Sea, where the average water temperature rises by one degree every thirty years, and the rate is only accelerating. One of the urgent questions that must be asked is how, if at all, the various species living in the Mediterranean will adapt to this sudden warming.

In recent years, evidence has accumulated that some species have deepened their habitats in order to adapt to global warming, while other studies have found that species are limited in their ability to deepen into cooler water. A new TAU study shows that there are species of marine animals such as fish, crustaceans and mollusks (for example squid) that change their habitats and deepen an average of 55 meters across the climatic gradient of the Mediterranean (spanning a range of 60 C) to live in cooler waters.

The Mediterranean – An Ideal Test Case

“It should be remembered that the Mediterranean was hot in the first place, and now we are reaching the limit of many species’ capacity,” explains Prof. Jonathan Belmaker from the School of Zoology in The George S. Wise Faculty of Life Sciences. “Moreover, the temperature range in the Mediterranean is extreme – cold in the northwest and very hot in the southeast. Both of these factors make the Mediterranean an ideal test case for species’ adaptation to global warming.”

The groundbreaking study was led by PhD student Shahar Chaikin under the supervision of Prof. Jonathan Belmaker, and along with researchers Shahar Dubiner, all from the School of Zoology in The George S. Wise Faculty of Life Sciences and The Steinhardt Museum of Natural History at Tel Aviv University. The results of the study were published in the journal Global Ecology and Biogeography, and have far-reaching implications for both fishing and future marine nature reserves.

Life at the Bottom

Cause for Preparation

The results of the study have many implications for the future, in the Mediterranean and in general, given that the response of each species to rising temperatures can be predicted according to its traits, such as temperature preference. This, for the first time, offers researchers the opportunity to forecast changes in the composition of the marine community, as well as for the public the opportunity to prepare for these changes accordingly.

“Our research clearly shows that species do respond to climate change by changing their depth distribution,” Chaikin concludes, “and when we think about the future, decision-makers will have to prepare in advance for the deepening of species. For example, future marine nature reserves will need to be defined so that they can also provide shelter to species that have migrated to greater depths. And on the other hand, fishing in the future will involve fishing the same fish at greater depths, which means sailing further into the sea and burning more fuel.”

So, How Deep is Our Love?

In the framework of the study, the Tel Aviv University researchers conducted a meta-analysis of data on the depth distribution of 236 marine species collected in previous bottom-trawl surveys. The data collected revealed for the first time that species deepen their minimum depth limits in parallel with warming seawater temperatures, from the west to the east Mediterranean, and on average deepen 55 meters across the Mediterranean (a range of 60 C).

However, the pattern of deepening is not uniform between species: cold-water species were found to deepen significantly more than warm-water species, species that live along a narrow depth range deepen less than species that live along a wide depth gradient, and species that can function within in a wider temperature range deepen more than those who can function only within a narrow temperature range.

“Various studies collect fishing data from trawling – that is, a boat that drags a net along the seabed and collects various species – and these studies often also measure the depth at which the species were caught in the net,” says Shahar Chaikin. “We cross-referenced these data with water temperature data, and by analyzing 236 different species we came to a broad and compelling conclusion: there has been a deepening of the depth limits of species’ habitats. The minimum depths for species in the Mediterranean are getting deeper, while the maximum depths remain stable. The deepening effect was found to be more significant among cold-water species. In contrast, there are species that function within a narrow temperature range and at a certain depth that deepen much less, probably because they cannot survive in deeper water.”

 

“Even if species deepen to escape the warm waters and this rapid adaptation helps them, there is still a limit – and that limit is the seabed,” adds Prof. Belmaker. “We are already seeing deep-sea fish like cod whose numbers are declining, probably because they had nowhere deeper to go.”