It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Tuesday, November 04, 2025
A new pink sea anemone that “builds a home” for hermit crabs discovered off Japan’s deep-sea coast
Kumamoto University-led team identifies Paracalliactis tsukisome sp. nov., revealing a rare example of co-evolution in the deep sea
Paracalliactis tsukisome, a newly discovered sea anemone living in symbiosis with hermit crabs on the deep-sea floor off Japan. Its name is derived from the ancient Japanese poetry anthology Man'yōshū.
Researchers from Kumamoto University and collaborating institutions have discovered a new species of deep-sea sea anemone that builds shell-like “homes” for hermit crabs — an extraordinary case of mutualism and co-evolution in the ocean depths.
The newly identified species, Paracalliactis tsukisome sp. nov., was found living on the shells inhabited by the hermit crab Oncopagurus monstrosus at depths of 200–500 meters off the Pacific coasts of Mie and Shizuoka Prefectures, Japan. Unlike typical sea anemones, which lack hard skeletons, this species secretes a shell-like structure known as a carcinoecium, which expands and reinforces the crab’s shell.
Stable isotope analyses revealed that the anemone feeds partly on organic particles and the crab’s feces — an unusual but efficient form of recycling on the deep-sea floor. Meanwhile, 3D imaging using micro-CT scanning showed that the anemone attaches to the shell in a consistent, one-directional pattern that may be linked to both feeding and shell-building behavior. The hermit crab, in turn, benefits from this partnership by achieving a larger body size than its relatives, suggesting a true mutualistic relationship between the two species.
The soft pink anemone was named tsukisome （桃花褐）— meaning “pale pink color” — after an ancient Japanese word found in the Man'yōshū (万葉集), Japan’s oldest anthology of poetry. In ancient poetry, a “tsukisome-dyed kimono” symbolized gentle yet sincere affection-a fitting tribute to the anemone’s delicate color and its faithful partnership with its hermit crab host.
“This discovery shows how even simple animals like sea anemones can evolve surprisingly sophisticated behaviors,” said Associate Professor Akihiro Yoshikawa of Kumamoto University’s Aitsu Marine Station, who led the study. “Their ability to build a shell-like structure is a fascinating clue to understanding how animals perceive space and direction.”
The study was published in Royal Society Open Science on October 22, 2025.
Small clouds of strontium atoms (blue) and rubidium atoms (red) are trapped together. The well-known properties of rubidium can be used to calibrate the applied magnetic field very precisely, which in turn allows for the properties of strontium to be measured with extreme accuracy.
Having good neighbours can be very valuable – even in the atomic world. A team of Amsterdam physicists was able to determine an important property of strontium atoms, a highly useful element for modern applications in atomic clocks and quantum computers, to unprecedented precision. To achieve this, they made clever use of a nearby cloud of rubidium atoms. The results were published in the journal Physical Review Letters this week.
Strontium. It is perhaps not the most popularly known chemical element, but among a group of physicists it has a much better reputation – and rightfully so.
Strontium is one of six so-called alkaline earth metals, meaning that it shares properties with better-known cousins like magnesium, calcium and radium. Strontium atoms have 38 protons in their nucleus, and a varying number of neutrons – for the variations (or isotopes) of strontium that can be found in nature, either 46, 48, 49 or 50.
A mathematically inclined person might remark that only one of these numbers, 49, is odd. While this may seem like just a curious observation, it is actually that particular isotope of strontium, the one with 87 particles total in its nucleus, that has the most special properties. The odd number turns the nucleus into a type of object known as a fermion, whereas all other strontium nuclei are bosons. Importantly, the odd number also turns the nucleus into a tiny bar magnet, through a property called spin. While all the subatomic particles have spin, the two spins of a pair of identical particles can cancel each other completely, leading to total spin zero. This is exactly what happens in the bosonic isotopes of strontium, where the total spin of each of the (even-numbered) subatomic species (protons, neutrons and electrons) cancels to zero, and as a result the total spin of the atom is zero. It is the fermionic strontium atom that, through its nonzero nuclear spin, has the special properties that have inspired physicists for years now.
Atomic clocks and quantum computers
To begin with, 87Sr, as the isotope is commonly abbreviated, is one of the prime candidate isotopes to be used in the next generation of atomic clocks – so-called optical clocks. Such clocks draw their extreme timing precision from very precisely determined frequencies of light that atoms emit or absorb. The emission or absorption arises when the atom transitions from one state to another. In the strontium atom, the most precise optical frequency corresponds to clear, red-colored light, with a wavelength of 698 nanometres. However, the problem with the bosonic versions of the atom is that the rules related to (zero) spin strictly forbid emission or absorption at what otherwise would be the ideal transition. Here the nuclear spin of the fermionic isotope comes to the rescue. The nuclear magnet resulting from the spin of 87Sr allows “breaking” the spin rules just enough – yet not too much – for the optical clock transition to be viable for absorption and emission while remaining at a very well-defined and stable frequency. Furthermore, the strength of the nuclear magnet in 87Sr is an important parameter for the operation of the clock.
This brings us to an effect discovered by Dutch Nobel Prize winner Pieter Zeeman in 1896, nowadays known as the Zeeman effect. In its original form, it describes the splitting of the different energy levels in which the electrons of an atom can be, and as a result outgoing photons – particles of light – can have many different but precisely determinable frequencies. At a more technical level, the same Zeeman effect occurs in an atomic nucleus that has spin, and the strength of the nuclear magnet determines the amount of splitting and the specific radio frequency (a much-lower-frequency form of light) with which one can flip the nuclear magnet from one state to another. As mentioned, this magnetic moment plays a key role in the operation of the optical clock, and its accurate determination can help researchers improve the calibration of such a clock.
Another special property, of the 87Sr nucleus is that, through the Zeeman effect, its energy level splits into no less than ten (equally spaced) energy levels when a magnetic field is applied. These ten different states in which the nucleus can be, can be used as building blocks for a quantum computer. Where a classical computer uses bits that can be in two states – usually interpreted as “0” and “1” – a quantum computer uses qubits that can also be in a combined state – roughly “a little bit 0 and a little bit 1”. This notion of a qubit (and especially the controlled combination of many of these qubits) makes quantum computers much more powerful than classical computers when performing certain computations. However, the ten-fold degeneracy (and ten-fold splitting in a magnetic field) of the 87Sr states opens up the possibility of also using qudits – analogues of qubits that can be in combinations of states “0”, “1”, “2”… all the way up to “9”. Such qudits would form even more versatile building blocks for quantum computers and quantum simulators.
The g-factor
In all of these applications, the Zeeman effect plays a central role, and so to get the most out of the potential uses of strontium, physicists want to know as accurately as possible by how much the energy levels of 87Sr split. In other words: what is the strength of the nuclear magnet originating from its spin? The amount of splitting is determined by a quantity known as the g-factor of 87Sr, and so the task is to determine this g-factor as precisely as possible. The small print: the value of the g-factor not only depends on the magnetic properties of the nucleus, but also on the small amount of magnetic shielding by the electron cloud surrounding the nucleus, constituting the total neutral atom. Calculating this to the desired level of precision is a seemingly insurmountable challenge, and hence precision measurement is crucial.
Very precise measurements of the g-factor had already been made more than fifty years ago, and so far these measurements had stood the test of time; no improvements were made afterwards. Now, however, a team of five physicists from the University of Amsterdam and quantum software research centre QuSoft have managed to achieve a hundredfold improvement of the previously known value.
As is so often the case, the breakthrough came from a rather unexpected direction. First author Premjith Thekkeppatt, who worked on the research as a PhD student in the Amsterdam group and is now a postdoctoral researcher at the Niels Bohr Institute in Copenhagen, explains: “The work grew out of our efforts to merge strontium atoms with another element, rubidium, to create rubidium-strontium molecules. This turned out to be extremely challenging, prompting us to investigate what we could achieve by having both species in one another’s vicinity, while avoiding overlap. Using a technique called optical trapping, we could achieve such a configuration.”
It turned out that trapping 87Sr and very nearby also trapping rubidium atoms did not immediately help in building the desired molecules, but when employing a measuring technique known as nuclear magnetic resonance (in essence measuring the frequency corresponding to the energy splitting), it did help in very accurately determining the g-factor and therefore in determining the precise size of the Zeeman effect. The reason was that the properties of rubidium have been established extremely accurately, and so these could be used to precisely calibrate the magnetic field strength in the vacuum where both types of atom were trapped. This in turn enabled the strongly improved determination of the 87Sr g-factor.
A challenging benchmark
The newly achieved precision will not only open the door for more precise strontium-based applications in atomic clocks and quantum computing, but may also lead to other steps forward. Thekkeppatt: “Our results form a new challenging benchmark for atomic structure calculations. We have shown that this new method works very well for precision measurements, and the demonstrated methods will inspire extension to further atomic species and states relevant for all sorts of applications.”
With the widespread use of plastic products a large amount of microplastics (MPs) have entered soil ecosystems, leading to a continuous decline in soil environmental quality. MPs in the soil can adhere to the surfaces of plant roots, hindering nutrient absorption and disrupting physiological metabolism. Furthermore, MPs can affect water and nutrient cycles in the soil, alter soil microbial communities, and indirectly increase stress on plant growth.
Due to the complexity of soil ecosystems, mitigating the harmful effects of MPs pollution on plants remains challenging. Recently, a Chinese research team published findings in Environmental Chemistry and Ecotoxicology, revealing the role of earthworms in alleviating the negative impact of microplastics on plants. The team found that earthworms can reduce the adverse effects of microplastics on plant growth by promoting soil nutrient and organic matter cycling, improving microbial communities, and regulating plant gene expression.
Hailong Wang, who led the study, pointed out that earthworms also promote an increase in the relative abundance of microbial communities involved in nitrogen, phosphorus, and carbon cycling in soils contaminated with MPs, which is beneficial for promoting the nutrient cycling processes of nitrogen, phosphorus, and organic matter in the soil. “
“Our research further reveals that earthworms can alleviate the adverse effects of MPs on plant growth by regulating gene expression in plants,” says Wang.“In MPs contaminated soils, the addition of earthworms upregulates genes related to ribosomal protein synthesis in the roots of Astragalus sinicusL, improving the efficiency of protein synthesis and supporting cell development and repair.”
At the same time, earthworms also promote the expression of genes related to nutrient accumulation and energy metabolism in Astragalus sinicusL, enhancing the plant's resistance to environmental stress. “We hope that the results of this study can be applied in future ecological restoration efforts and provide a scientific basis and solutions for mitigating the adverse effects of microplastic pollution on plant growth,” adds Wang.
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Contact the author: Yanru Cao, Resource and Environmental Biology, College of Agriculture and Life Sciences & School of Medicine,Kunming University, Kunming, China, yanrucao3@aliyun.com
The publisher KeAi was established by Elsevier and China Science Publishing & Media Ltd to unfold quality research globally. In 2013, our focus shifted to open access publishing. We now proudly publish more than 200 world-class, open access, English language journals, spanning all scientific disciplines. Many of these are titles we publish in partnership with prestigious societies and academic institutions, such as the National Natural Science Foundation of China (NSFC).
Modulation of soil microenvironment and plant gene expression by earthworms reduces polypropylene microplastic-induced growth stress in Chinese milk vetch (Astragalus sinicus L.)
Chitosan-modified Biochar unveils new mechanism for efficient removal of nitrogen-containing pollutants from water
Neonicotinoid pesticides, once considered efficient and low-toxicity solutions, have caused global water contamination due to their extensive use. Growing evidence reveals their far-reaching harms, ranging from triggering colony collapse disorder in honeybees and population declines in insectivorous birds, to posing potential threats to human health—including reproductive risks and impaired neurodevelopment. Compounding the problem, conventional water treatment technologies are ineffective at removing these pesticides.
In a study published in the KeAi journal Environmental Chemistry and Ecotoxicology, a research team from China has developed a solution using an engineered “nitrogen-doped” biochar. By subjecting common biomass—white melon seed shells—and chitosan to high-temperature pyrolysis, they produced a highly efficient adsorbent named NBC900.
“This material demonstrated a capacity for capturing imidacloprid (IMI) from water, achieving a removal rate of 97.2% and an adsorption capacity of 140.1 mg/g—performance that surpasses most existing adsorbents,” shares senior and co-corresponding author Guorui Liu, a professor at the Zhejiang Key Laboratory of Digital Intelligence Monitoring and Restoration of Watershed Environment, Zhejiang Normal University.
Characterization studies revealed that nitrogen groups (specifically pyridinic-N) incorporated into the biochar act as electron donors, engaging in strong "Lewis acid-base" interactions with electron-accepting groups on the IMI molecule. This, combined with other mechanisms like pore-filling and π-π interactions, drives the effective adsorption.
“NBC900 acts as a versatile and powerful magnet for the pesticide; the nitrogen modification we introduced is crucial, as it creates more active sites and facilitates stronger chemical bonding with the nitrogen-containing pollutant,” explains Liu. “It performed consistently across a wide range of water conditions (pH 2-11), showed strong resistance to interference from common ions, and maintained its effectiveness even after multiple regeneration cycles.”
According to co-corresponding author Song Cui, a professor at the International Joint Research Center for Persistent Toxic Substances of Northeast Agricultural University, while the study demonstrates immediate application in IMI removal, its deeper value lies in significantly advancing the mechanistic understanding of biochar's interaction with NNIs and similar N-containing pollutants.
“We hope these findings encourage the broader development of N-modified graphitic biochar as efficient, targeted, and sustainable tools for environmental remediation, ultimately advancing both resource utilization and ecological protection in a meaningful and impactful way,” says Cui.
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Contact the author:
Song Cui, International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin, China, cuisong-bq@neau.edu.cn
Guorui Liu, Zhejiang Key Laboratory of Digital Intelligence Monitoring and Restoration of Watershed Environment, College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, China, liiugr@zjnu.edu.cn
The publisher KeAi was established by Elsevier and China Science Publishing & Media Ltd to unfold quality research globally. In 2013, our focus shifted to open access publishing. We now proudly publish more than 200 world-class, open access, English language journals, spanning all scientific disciplines. Many of these are titles we publish in partnership with prestigious societies and academic institutions, such as the National Natural Science Foundation of China (NSFC).
Unveiling the role of nitrogen-related functional groups in Imidacloprid adsorption by chitosan-modified graphitic biochar: A mechanistic insight into N-containing pollutant removal
