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Stretchy material inspired by Islamic art
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in Brief Lost at sea due to ocean acidification
Carnivorous waterwheel plants face extinction DON’T bank on it. An icon of evolution, it may be, but the waterwheel plant is facing extinction – and even preservation in a seed bank looks doubtful. It is the only aquatic plant known to use jaw-like snap-traps on its leaves to catch prey. It fascinated Charles Darwin, whose experiments showed it was adapted for capturing water fleas and mosquito larvae. Habitat destruction and illegal collection mean that its abundance has dropped by almost 90 per cent over the past century. And a study now says that a common way of conserving plants – seed banks – might
not work for this species, which rarely produces seeds. Adam Cross at the University of Western Australia in Perth, and his colleagues analysed how well waterwheel plant seeds survive storage. They found that most seeds stored above freezing temperatures – as found in nature – failed to germinate after a year. “Our data suggests that in natural seed banks, seeds would be lost to fungal attack very rapidly,” says Cross. “This means they are unlikely to persist between seasons.” Seeds stored for three months at the sub-zero temperatures found in artificial seed banks also failed to germinate (Botanical Journal of the Linnean Society, doi.org/bdgp). Habitat protection and cryostorage of plants or embryos should be explored for conservation instead, Cross says.
Stretchy material inspired by Islamic art IT’S utility from beauty. A class of futuristic materials that grow when stretched get their abilities from the geometries of ancient Islamic art. Pull on most materials and they stretch in one direction and become thinner in the other. But some metamaterials, engineered to have properties not found in nature, grow wider when stretched. This is due to their
geometric substructure, which when stationary looks like a series of connected squares. When the material is stretched, the squares turn relative to each other. This causes the material to increase in size and decrease in density. But this twisting means that the materials lose their overall shape as they expand, making them useless for potential applications. To find ones that would keep their
shape, Ahmad Rafsanjani of McGill University in Montreal, Canada, and colleagues picked patterns from the walls of two ancient Iranian mausoleums. They then fashioned the metamaterial from natural rubber. Rafsanjani presented the work at a meeting of the American Physical Society on 15 March. The material could be useful when inserting medical devices in veins and arteries, or for satellites that unfold in space.
SNAP, crackle, hush. Snapping shrimp – which produce ubiquitous crackles that guide fish larvae to reefs – may become quieter by the end of the century. This is a probable outcome of ocean acidification, according to a study that looked at its effects on ocean soundscapes. Ivan Nagelkerken at the University of Adelaide in Australia and his team recorded sounds at natural carbon dioxide vents, where pH levels ranged from current levels up to those expected in oceans by the end of the century. They also recorded shrimp in varying levels of pH in the lab. Sound levels were much lower in more acidic waters in both cases (Proceedings of the Royal Society B, doi.org/bdgq). This could affect larvae that rely on sounds to guide them from the open ocean to reefs where they settle. “They may become lost at sea,” Nagelkerken says.
Tiny flea makes for murky lake waters QUITE literally, a bad case of murky waters. The invasive spiny water flea (Bythotrephes longimanus) has cut visibility in Lake Mendota in Madison, Wisconsin, by 1 metre since it was first spotted there in 2009. It did so by feasting on native plankton, which keep water clearer by eating algae. The economic costs of murkier water where residents enjoy boating, fishing and swimming has been estimated at $140 million (PNAS, DOI: 10.1073/pnas.1600366113). “Previous attempts to put a price tag on invasive species impacts haven’t come close to the true cost,” says study author Jake Walsh, who thinks the results justify spending more money on eradicating the flea. 26 March 2016 | NewScientist | 17
in Brief Lost at sea due to ocean acidification
Carnivorous waterwheel plants face extinction DON’T bank on it. An icon of evolution, it may be, but the waterwheel plant is facing extinction – and even preservation in a seed bank looks doubtful. It is the only aquatic plant known to use jaw-like snap-traps on its leaves to catch prey. It fascinated Charles Darwin, whose experiments showed it was adapted for capturing water fleas and mosquito larvae. Habitat destruction and illegal collection mean that its abundance has dropped by almost 90 per cent over the past century. And a study now says that a common way of conserving plants – seed banks – might
not work for this species, which rarely produces seeds. Adam Cross at the University of Western Australia in Perth, and his colleagues analysed how well waterwheel plant seeds survive storage. They found that most seeds stored above freezing temperatures – as found in nature – failed to germinate after a year. “Our data suggests that in natural seed banks, seeds would be lost to fungal attack very rapidly,” says Cross. “This means they are unlikely to persist between seasons.” Seeds stored for three months at the sub-zero temperatures found in artificial seed banks also failed to germinate (Botanical Journal of the Linnean Society, doi.org/bdgp). Habitat protection and cryostorage of plants or embryos should be explored for conservation instead, Cross says.
Stretchy material inspired by Islamic art IT’S utility from beauty. A class of futuristic materials that grow when stretched get their abilities from the geometries of ancient Islamic art. Pull on most materials and they stretch in one direction and become thinner in the other. But some metamaterials, engineered to have properties not found in nature, grow wider when stretched. This is due to their
geometric substructure, which when stationary looks like a series of connected squares. When the material is stretched, the squares turn relative to each other. This causes the material to increase in size and decrease in density. But this twisting means that the materials lose their overall shape as they expand, making them useless for potential applications. To find ones that would keep their
shape, Ahmad Rafsanjani of McGill University in Montreal, Canada, and colleagues picked patterns from the walls of two ancient Iranian mausoleums. They then fashioned the metamaterial from natural rubber. Rafsanjani presented the work at a meeting of the American Physical Society on 15 March. The material could be useful when inserting medical devices in veins and arteries, or for satellites that unfold in space.
SNAP, crackle, hush. Snapping shrimp – which produce ubiquitous crackles that guide fish larvae to reefs – may become quieter by the end of the century. This is a probable outcome of ocean acidification, according to a study that looked at its effects on ocean soundscapes. Ivan Nagelkerken at the University of Adelaide in Australia and his team recorded sounds at natural carbon dioxide vents, where pH levels ranged from current levels up to those expected in oceans by the end of the century. They also recorded shrimp in varying levels of pH in the lab. Sound levels were much lower in more acidic waters in both cases (Proceedings of the Royal Society B, doi.org/bdgq). This could affect larvae that rely on sounds to guide them from the open ocean to reefs where they settle. “They may become lost at sea,” Nagelkerken says.
Tiny flea makes for murky lake waters QUITE literally, a bad case of murky waters. The invasive spiny water flea (Bythotrephes longimanus) has cut visibility in Lake Mendota in Madison, Wisconsin, by 1 metre since it was first spotted there in 2009. It did so by feasting on native plankton, which keep water clearer by eating algae. The economic costs of murkier water where residents enjoy boating, fishing and swimming has been estimated at $140 million (PNAS, DOI: 10.1073/pnas.1600366113). “Previous attempts to put a price tag on invasive species impacts haven’t come close to the true cost,” says study author Jake Walsh, who thinks the results justify spending more money on eradicating the flea. 26 March 2016 | NewScientist | 17