Why the mystifying axolotl must be saved from extinction

February 20, 2020 by  
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Today’s axolotls are experiencing extirpation, but scientists and pet enthusiasts are saving them from true  extinction . Why? Axolotls have long fascinated the learned and laymen alike, thanks to the animal’s powers of regenerating and self-healing. While all organisms can regenerate to some degree, the axolotl’s capabilities are far more advanced. Historical documentation cites Spallanzani, in 1768, as the first Western observer of an axolotl’s complete regeneration of tail and limb. Then in 1804, renowned naturalist Alexander von Humboldt collected the first wild specimens, shipping them to Europe . By 1863, axolotls first debuted in official science laboratories when a French expedition shipped 34 of them to the Natural History Museum in Paris. French zoologist Auguste Duméril received six of those original 34. His successfully bred lines launched the global axolotl diaspora as he shared line progeny with international colleagues. Related:  Light pollution, habitat loss and pesticides push fireflies toward extinction Present-day wild axolotls have not fared well. Despite its status as “the most widely distributed amphibian around the world in pet shops and labs,” the wild axolotl is nearing extirpation, said Richard Griffiths, an ecologist at the University of Kent in Canterbury, UK, to  Scientific American . The International Union for the Conservation of Nature (IUCN)  catalogs axolotls on the Red List, delineating threat risks from  habitat loss ,  water pollution , fierce competition with non-native species, predation by invasive species, climate change-induced droughts, disease and inbreeding. Only popularity in both the pet and laboratory industries keeps axolotls from all-out extinction. But what are axolotls exactly? They are  amphibians  in the Ambystomatidae family of mole salamanders and are identified by neoteny. That is, they retain larval traits or juvenile characteristics. What distinguishes them from juveniles of other salamander species is retention of their unmetamorphosed larva appearance, even as adults. Peculiarly, they appear as “sexually mature tadpoles,” spending entire lives underwater , veritably breeding in that form, unlike other salamanders that metamorphose and crawl onto land. Of course, with iodine, axolotls can be induced into metamorphosis, even developing into bona fide salamanders that phenotypically resemble tiger salamanders. However, metamorphosed axolotls experience much-diminished lifespans compared to neotenous counterparts. The most widely recognized axolotl is  Ambystoma mexicanum , whose only remaining natural  habitat  is Mexico City’s canal system. Legend says while the Aztecs built Tenochtitlan, their capital, they discovered, in the lake, a large, feathery-gilled salamander. They named it after Xolotl, their fire and lightning deity. As Quetzalcoatl’s twin brother, Xolotl enjoyed shapeshifting powers.  Live Science  explains how Xolotl apparently “transformed into a salamander, among other forms, to avoid being sacrificed so the sun and moon could move in the sky,” showcasing even then how axolotls captivated the fancy of this ancient civilization and garnered placement in their pantheon. Regrettably, Mexico’s endemic axolotls are dwindling drastically. From JSTOR Daily , the “first robust count of axolotls” in their natural habitat amounted to an estimated 6,000 axolotls per square kilometer. That population survey transpired in 1998. By 2015, the population plummeted, numbering “only 35 per square kilometer,” therefore revealing precipitous extirpation. Formerly at the  food chain  apex, what changed for axolotls? Development sprawl, tourism and recreational use drained the natural water levels of axolotl habitats. Whatever water has remained is polluted by litter and offal, pesticides and non-organic fertilizers, heavy metals and toxic chemical runoff. Because axolotls breathe through their highly permeable skin, they are incredibly susceptible to pollution, which adversely affects axolotl health, growth and development. Moreover, from the 1970s to 1980s, tilapia and carp, non-native fish that reproduce faster than can be caught, were released into the canals, disrupting local food webs and  ecosystems . Tilapia and carp also forage around the canals’ aquatic plants, where axolotls lay eggs, further reducing offspring numbers even more in a prelude to the grim species-level extirpation of wild axolotls. Additionally,  climate change  and severe weather, which the IUCN acknowledges as threats to the axolotl, in turn, perpetuate drought conditions, again decimating the axolotls’ natural habitat. It is feared only a few hundred axolotls remain in the wild. Whereas wild axolotls might not all be rescued from Mexico’s canals, the species are nonetheless thriving in captive breeding programs at universities and scientific laboratories as well as in private aquariums of pet owners. Indeed,  Scientific American  documented that “tens of thousands can be found in home aquariums and research laboratories around the world. They are bred so widely in captivity that certain restaurants in Japan even serve them up deep-fried.” In fact, from Duméril’s progeny lines, scientists continue to successfully breed axolotls to this day. This accounts for the  Journal of Experimental Zoology ’s assertion of axolotls being “the oldest self-sustaining laboratory animal population.” Duméril’s generosity ignited Europe and America’s axolotl breeding craze, says  Scientific American , giving way to the 1930s breeding stock at the University at Buffalo, New York. That stock was then hybridized with both wild axolotls and tiger salamanders ( Ambystoma tigrinum ). As that hybridized lineage population flourished, it was then relocated to the University of Kentucky – Lexington, where the current Ambystoma  Genetic Stock Center has evolved into academia’s epicenter of global axolotl breeding. From there, tens of thousands of axolotl embryos are sent to contemporary research labs. For more than 150 years, the scientific community has remained intrigued by axolotl regenerative abilities, which are quite unlike those in mammals . Axolotls, for one, can completely regenerate amputated limbs, even after multiple amputations, with each new limb as functional as the original. From  American Zoologist , their cells ‘know’ what to regrow, even supernumerary limbs when regenerating tissue grafted onto other body quadrants. Should axolotls have damaged internal organs, they would be regrown. Crushed spinal cords can be fully repaired as well. In other words, no other animal comes close to axolotl regeneration and self-healing. Likewise,  Science  journal has documented axolotls readily receiving transplanted heads. By the same token, back in 1865, “Duméril’s second generation of axolotls spontaneously transformed into air-breathing adults.” This hidden developmental stage led to 20th-century researchers discovering thyroid hormones, explains  Nova . Nowadays, the axolotl  genome  has been sequenced, and  Max Planck Institute  reveals it “is more than ten times larger than the human genome.” Besides being the largest genome decoded so far, the axolotl’s genome contains an “enormous number of large repetitive sequences.” Could these account for axolotl plasticity in developmental, regenerative and evolutionary assets, such as why it retains its tadpole-like qualities into adulthood? By studying the axolotl genome, scientists hope for ample opportunities to understand the gene regulation processes that make regeneration possible. These findings would revolutionize medicine and aging science. Meanwhile, laboratory-bred axolotls are still vulnerable to loss — from inbreeding,  disease  or laboratory disasters like fires. Crossbreeding is not without its challenges. For more genetic diversity, the lab-bred stock must be crossbred with wilds, but wilds are being extirpated, making their collection difficult. That leaves hybridization with tiger salamanders, but the true axolotl gene pool gets diluted as a result. With numbers in the wild not likely to rebound without help, it’s imperative to strengthen axolotl  conservation  efforts. Perhaps establishing sanctuaries and ecological refuges in the wild, as well as enacting more enforceable legislation, can help save axolotls from extirpation. No matter the case, axolotl conservation will require heavy human involvement. Once this exceptional organism goes extinct, the world loses out on all the knowledge they can provide. Via Nova and Scientific American Images via Pexels and Pixabay

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Why the mystifying axolotl must be saved from extinction

Check out Glasir, the tree-shaped urban farming solution

February 20, 2020 by  
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In a bid to revolutionize agriculture, New York City and Bergen-based innovation studio  Framlab  has proposed Glasir, a community-based system for urban farming that combines the flexibility of modularity with aeroponics to vastly reduce the environmental footprint for growing food. Created in the likeness of a tree, the space-saving conceptual design grows vertically and can be installed in even the densest of urban areas. The high-yield, vertical farming proposal would be integrated with smart technology, sensors, and renewable systems such as solar panels to optimize production and minimize its carbon footprint. Named after a fabled and supernatural tree in Norse mythology, Glasir was conceived by Framlab as a response to the World Health Organization’s estimates that half of the world’s population will be living in water-stressed areas by 2025. To curb the water-guzzling and land-intensive processes of modern  agriculture , Framlab developed Glasir as an alternative that would provide neighborhoods with affordable, local produce year-round. The self-regulating system comprises a monopodial trunk that is expanded with branch-like modules and would occupy only a two-by-two-foot space, about the same size needed for a small street tree on a sidewalk.  The basic components for a Glasir system comprise ten base  modules : five growth modules, three production modules, and two access modules. The modules are all interconnected and feed information to one another through an artificial intelligence program. Environmental sensors track and evaluate site conditions such as solar gain, temperature levels, and winds to optimize growth. The system can be assembled in a variety of configurations to fit the needs of the community that it serves.  Related: Sustainable agriculture cleans up rivers in Cuba In addition to the use of extremely water-efficient aeroponic growing methods, Glasir reduces its environmental impact with translucent photovoltaic cells that power its electricity needs. A  rainwater collection  system stores, purifies and redirects runoff for irrigation in the production modules. The exterior of the modules will also be coated in Titanium Oxide to help clean air pollutants.  + Framlab Images via Framlab

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Marc Thorpe designs live/work buildings built from earth bricks

February 20, 2020 by  
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New York-based architecture studio Marc Thorpe Design has unveiled renderings for the Dakar Houses, a series of live/work spaces for the artisans of furniture brand Moroso, located on the outskirts of the Senegalese capital of Dakar. Designed with compressed earth bricks, a common building material in western Senegal, the multipurpose units take inspiration from the local architectural vernacular. The economical earth bricks also have the advantage of thermal mass to provide comfortable indoor temperatures without artificial heating or cooling.  Created to house Moroso’s Dakar-based artisans, the Dakar Houses will consist of two apartments that flank a central workshop for manufacturing the furniture brand’s decade-old line of handcrafted and brightly colored outdoor furnishings. In echoing the furniture line’s celebration of local craftsmanship, the Dakar Houses also pay homage to building materials and techniques common to the West African region.  Related: Ancient green building technique helps ease West Africa housing crisis “The intention was to create a work-based community allowing a village to develop around a central economic constituent,” Marc Thorpe Design explained. “The units are designed to house the workers as well as various parts of the manufacturing process of M’Afrique’s furniture , such as the handicraft work of welding and weaving. The apartments would be designed based on the required space for each individual family.” Each unit comprises three volumes — two apartments and a central workspace — that are staggered to create favorable solar shading conditions. Steeply pitched roofs top the minimalist units, which are left unadorned to emphasize the earth bricks. Made from local soil, the bricks are cured over several weeks. Next, they are soaked in water each morning, then baked in the sun beneath a tarp until they are ready for construction. During the day, the earthen walls absorb heat to provide a cool indoor environment; at night, that heat is slowly dissipated and warms the air.  + Marc Thorpe Design Images via Marc Thorpe Design

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