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      Some coral reef damage can be fixed

      news.movim.eu / ArsTechnica · Wednesday, 13 March - 16:24

    Image of a large school of fish above a reef.

    Enlarge (credit: Reinhard Dirscherl )

    Coral reefs, some of the most stunningly beautiful marine ecosystems on Earth, are dying. Ninety percent of them will likely be gone by 2050 due to rising ocean temperatures and pollution. “But it’s not that when they are gone, they are gone forever. We can rebuild them,” said Dr. Timothy Lamont, a marine biologist working at Lancaster University.

    Lamont’s team evaluated coral reef restoration efforts done through the MARS Coral Reef Restoration Program on the coast of Indonesia and found that planting corals on a network of sand-coated steel frames brought a completely dead reef back to life in just four years. It seems like we can fix something for once.

    Growing up in rubble

    The restored reef examined by Lamont’s team was damaged by blast fishing done 30–40 years ago. “People were using dynamite to blow up the reef. It kills all the fish, the fish float to the surface, and you can scoop them all up. Obviously, this is very damaging to the habitat and leaves behind loose rubble fields with lots of coral skeletons,” said Lamont.

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      Otherworldly mini-Yellowstone found in the deep sea

      news.movim.eu / ArsTechnica · Thursday, 28 December - 13:14 · 1 minute

    A large collection of white crabs arrayed across rocks on the bottom of the ocean.

    Enlarge / "Leading us like breadcrumbs..." A trail of squat lobsters helped researchers locate previously unknown hydrothermal vents. The hydrothermal vents create chemosynthetic ecosystems, so in areas that are mostly barren of life, the appearance of larger animals can be an indicator of vents nearby. (credit: Schmidt Ocean Institute )

    Spectacular scenery, from lush rainforests to towering mountain ranges, dots the surface of our planet. But some of Earth’s most iconic landmarks––ones that may harbor clues to the origin of life on Earth and possibly elsewhere––lay hidden at the bottom of the ocean. Scientists recently found one such treasure in Ecuadorian waters: a submerged mini Yellowstone called Sendero del Cangrejo.

    This hazy alien realm simmers in the deep sea in an area called the Western Galápagos Spreading Center––an underwater mountain range where tectonic plates are slowly moving away from each other. Magma wells up from Earth’s mantle here to create new oceanic crust in a process that created the Galápagos Islands and smaller underwater features, like hydrothermal vents. These vents, which pump heated, mineral-rich water into the ocean in billowing plumes, may offer clues to the origin of life on Earth. Studying Earth’s hydrothermal vents could also offer a gateway to finding life, or at least its building blocks, on other worlds.

    The newly discovered Sendero del Cangrejo contains a chain of hydrothermal vents that spans nearly two football fields. It hosts hot springs and geyser chimneys that support an array of creatures, from giant, spaghetti-like tube worms to alabaster Galatheid crabs.

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      Move over, Cordyceps, there’s a new “zombie” parasite to haunt our dreams

      news.movim.eu / ArsTechnica · Wednesday, 20 September, 2023 - 20:33 · 1 minute

    tiny ant on a blade of grass

    Enlarge / An ant infected by the lancet liver fluke climbs up and clamps its powerful jaws onto the top of a blade of grass, making it more likely to be eaten by grazers such as cattle and deer. (credit: University of Copenhagen)

    Parasites that control and alter the behavior of their hosts are well-known in nature. Most notably, there is a family of zombifying parasitic fungi called Cordyceps —more than 400 different species , each targeting a particular insect species, whether it be ants, dragonflies, cockroaches, aphids, or beetles. In fact, Cordyceps inspired the premise of The Last of Us game and subsequent TV series. And earlier this month we reported on a study of how a parasitic worm ( trematode ) targets a particular species of marsh-dwelling brown shrimp ( amphipod ), turning the shrimp an orange hue and altering the host shrimp's behavior.

    Then there's the lancet liver fluke , whose complicated life cycle relies on successfully invading successive hosts: snails, ants, and grazing mammals. (Some liver flukes have also been known to infect the occasional unfortunate human .) Scientists at the University of Copenhagen in Denmark have discovered that the way the liver fluke "zombifies" ants to alter their behavior incorporates a kind of "on/off" switch that, in turn, is dependent on temperature. The researcherse described their findings in a recent paper published in the journal Behavioral Ecology.

    "Historically, parasites have never really been focused on that much, despite there being scientific sources which say that parasitism is the most widespread life form," said co-author Brian Lund Fredensborg . "This is in part due to the fact that parasites are quite difficult to study. Nevertheless, the hidden world of parasites forms a significant part of biodiversity, and by changing the host's behavior, they can help determine who eats what in nature. That's why they're important for us to understand."

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      Genomes could help enigmatic, endangered nocturnal parrot make a comeback

      news.movim.eu / ArsTechnica · Tuesday, 12 September, 2023 - 16:57 · 1 minute

    Image of a large, green parrot.

    Enlarge (credit: Liu Yang )

    On an island off the coast of New Zealand, in the shadows of a primeval forest, an eerie sound resonates through the night. It's a deep boom that can sometimes be heard from miles away. This is the mating call of one of the strangest and most intriguing creatures in the region. Meet the critically endangered kākāpō .

    Kākāpō (its name means “night parrot” in Māori) are large flightless parrots endemic to New Zealand. In 1894, conservationist Richard Henry relocated mainland birds to a supposedly safe island, but they were met by unsuspected predators. More kākāpō were found on the mainland and some surrounding islands in the 1970s. Though the mainland birds were later moved to those islands, only one survived. He was appropriately named Richard Henry.

    The peculiar parrots now roam five islands free of predators, and their population has risen from a precarious 51 in 1995 to 252 in 2022. Still, the limited genetic diversity of such a small population has made breeding problematic. Breeding programs have found that most kākāpō are severely inbred and susceptible to disease and infertility. In an unprecedented move to conserve the species, researchers from the University of Otago have now sequenced the genome of nearly all existing birds in an effort to find out whether there are genetic variants in the population that could help keep the kākāpō from vanishing.

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      How these parasitic worms turn brown shrimp into bright orange “zombies”

      news.movim.eu / ArsTechnica · Thursday, 7 September, 2023 - 21:02 · 1 minute

    a bright orange shrimp

    Enlarge / Orange amphipods caught the eye (and interest) of Brown University graduate students conducting field research. (credit: David Johnson)

    Scour the salt marshes of Plum Island Estuary in Massachusetts and you're likely to spot bright orange shrimp lurking among the vegetation and detritus. That unusual hue is a sign that a shrimp has been infected with a parasitic worm, which also seems to affect the shrimp's behavior. Infected shrimp typically become sluggish and spend more time exposed in the open marsh, easy pickings for hungry birds. Now biologists at Brown University have sequenced the DNA of these shrimp to hone in on the molecular mechanisms behind the changes, according to a recent paper published in the journal Molecular Ecology.

    “This may be an example of a parasite manipulating an intermediate host to ensure its own transmission between hosts,” said co-author David Rand of Brown University, drawing an analogy to how malaria spreads to humans via the intermediary of mosquito bites. “Rabies could be another relevant example: it drives infected individuals ‘mad’ so they bite others and infect the next host. Learning the molecular mechanisms of these kinds of host-parasite interactions can have important implications for how to manage pathogens generally, and in humans.”

    Parasites that control and alter the behavior of their hosts are well-known in nature. Most notably, there is a family of zombifying parasitic fungi called Cordyceps —more than 400 different species , each targeting a particular insect species, whether it be ants, dragonflies, cockroaches, aphids, or beetles. In fact, The Last of Us game co-creator Neil Druckmann has said the premise was partly inspired by an episode of the BBC nature documentary Planet Earth (narrated by Sir David Attenborough) portraying the "zombification" of an ant in vivid detail . Scientists are keen to study Cordyceps to learn more about the origins and intricate mechanisms behind these kinds of pathogen-based diseases.

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      The Namibian fairy circle debate rages on: Could it be sand termites after all?

      news.movim.eu / ArsTechnica · Wednesday, 26 July, 2023 - 21:48 · 1 minute

    Fairy circles in the Namib Desert.

    Enlarge / Bare, reddish-hued circular patches in the Namib Desert known as "fairy circles" are also found in northwestern Australia. (credit: UHH/MIN/Juergens)

    Himba bushmen in the Namibian grasslands have long passed down legends about the region's mysterious fairy circles: bare, reddish-hued circular patches that are also found in northwestern Australia. In the last 10 years, scientists have heatedly debated whether these unusual patterns are due to sand termites or to an ecological version of a self-organizing Turing mechanism. Last year, a team of scientists reported what they deemed definitive evidence of the latter, thus ruling out sand termites, but their declaration of victory may have been premature. A recent paper published in the journal Perspectives in Plant Ecology, Evolution, and Systematics offers a careful rebuttal of those 2022 findings, concluding that sand termites may be to blame after all.

    As we've reported previously, the fairy circles can be as large as several feet in diameter. Dubbed "footprints of the gods," it's often said they are the work of the Himba deity Mukuru , or an underground dragon whose poisonous breath kills anything growing inside those circles. Scientists have their own ideas.

    One theory—espoused by study co-author Norbert Jürgens, a biologist at the University of Hamburg in Germany—attributed the phenomenon to a particular species of termite ( Psammmotermes allocerus ), whose burrowing damages plant roots, resulting in extra rainwater seeping into the sandy soil before the plants can suck it up—giving the termites a handy water trap as a resource. As a result, the plants die back in a circle from the site of an insect nest. The circles expand in diameter during droughts because the termites must venture farther out for food.

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      Cocoa production linked to major deforestation in Africa

      news.movim.eu / ArsTechnica · Friday, 26 May, 2023 - 16:33

    Image of a yellow fruit growing on a small tree.

    Enlarge / A cocoa pod, this one grown in Asia. (credit: Tan Dao Duy )

    Cocoa farmers in Ghana and Côte d'Ivoire make less than a dollar a day. And there are almost 2 million of them; the two countries are the world’s largest cocoa producers, supplying two-thirds of the global supply. Cocoa is the primary perennial crop in both places.

    However, there are no up-to-date, accurate maps of their cocoa plantations. This is a problem since cocoa is known to be a primary driver of deforestation in the region. Besides decimating biodiversity that may never recover, clear-cutting forests to plant cocoa (or for any other reason) makes it hotter and makes storms stronger, both locally in Africa and across the planet .

    So a team of European researchers made a deep neural network to collate publicly available satellite images of both countries with georeferenced cocoa farms, identified by their regular polygons. They then had a team in Côte d'Ivoire trekking around for three months to visit the farms and verify their results.

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      Pacific garbage patch providing a deep ocean home for coastal species

      news.movim.eu / ArsTechnica · Monday, 17 April, 2023 - 19:01

    A hand holding a plastic bottle above the sand, with waves in the background.

    Enlarge (credit: Seamind Panadda / EyeEm )

    A survey of plastic waste picked up in the North Pacific Subtropical Gyre—aka the Giant Pacific Garbage Patch—has revealed that the garbage is providing a home to species that would otherwise not be found in the deep ocean. Over two-thirds of the trash examined plays host to coastal marine species, many of which are clearly reproducing in what would otherwise be a foreign habitat.

    The findings suggest that, as far as coastal species are concerned, there was nothing inhospitable about the open ocean other than the lack of something solid to latch on to.

    Into the deep

    The work isn't a complete surprise, given the aftermath of the 2011 Tōhoku earthquake and tsunami, which swept a variety of debris, including entire docks and boats, across the Pacific Ocean and onto North American shores. Coming ashore with the wreckage were a number of Japanese coastal marine species, which indicated that they could survive for long periods adrift in the ocean—the longest officially recorded trip was six years, although the debris might have been in coastal environments for part of that time.

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      Argentina lost one-fifth of its Atlantic Forest in the last four decades

      news.movim.eu / ArsTechnica · Friday, 10 February, 2023 - 18:53

    Image of a large waterfall embedded in a tropical forest.

    Enlarge / The Iguassu Waterfall and nearby forests straddle Argentina, Brazil, and Paraguay. (credit: Craig Hastings )

    Deforestation not only causes the loss of important natural resources; it also contributes to global warming. Deforestation is the cause of about 20 percent of carbon dioxide emissions globally, which is higher than both passenger vehicles and trucks emit.

    Large-scale deforestation of the Amazon began several decades ago and has accelerated in recent years, placing Brazil among the countries with the most. But the loss of forests in South America is not an Amazon-specific issue. According to a recent report released by MapBiomas, Argentina has lost almost 20 percent of the Atlantic Forest in the last 37 years.

    The Atlantic Forest

    The Atlantic Forest is a region shared among Argentina (3 percent), Brazil (90 percent), and Paraguay (7 percent). It is composed of tropical and subtropical rainforests extending more than 3,000 kilometers along the Brazilian Atlantic coast and runs inland to the west for almost 1,000 kilometers from the sea, reaching Northeast Argentina and Eastern Paraguay.

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