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Weekly Ocean News
The failed tsunami warning in Indonesia; a newly discovered gland that drives octopuses' terminal breeding; and more in this week's Ocean News.
Posted on October 5, 2018
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Ecosystems and Biodiversity

Despite a global ban on the use of polychlorinated biphenyls (PCBs) in 2004, the chemicals persist in the environment and have accumulated up the food chain. High levels of PCBs have been found in the blubber of killer whales. A model has shown that more than half of the 19 orca populations studied will decline due to its toxic effects. PCBs will impair reproduction enough that these groups may dwindle and disappear in the next 50 years. PCBs also threaten other animals as well, including polar bears, seals and sharks. Via Science Magazine

The age at which steelhead trout leave their breeding grounds and head to the sea depends on temperature, the presence of other salmonids, and other factors. They normally migrate when they are five years old and about 30 centimetres long. But researchers at Simon Fraser University have found that after a particularly heavy pink salmon run, steelhead trout will leave even if they are only one year old. Paradoxically, it likely isn’t competition for food that results in this, but availability. The salmon eggs provide a rich food source and more trout can leave at a younger age. As many populations of steelhead have been struggling, this additional insight may be valuable in future conservation efforts. Via EurekAlert!

A female octopus pours all her energy into protecting her eggs and, shortly afterward, she breeds, she dies. Things aren’t much better for the male: if a female octopus doesn’t eat him as post-sex snack, he dies a few months later. A decades-old study revealed that if you remove the optic gland (similar to the pituitary gland of most land animals), an octopus will abandon her eggs, resume feeding, and sometimes even mate again. The “self-destruct” hormone sent out by this gland inhibit the neuropeptides that connect neurons, causing the mother to become sluggish and cease hunting. Recent studies are now looking into how this mechanism evolved, using modern genetic sequencing tools. Via Science Daily

Climate Change

The Panamanian golden frog is just one of many amphibian species endangered in the wild.

While a warming climate doesn’t help, it isn’t the main driver behind declining numbers of amphibians. A study involving more than 500,000 samples of 81 species shows that 3.4% of species disappear each year —  the equivalent of losing half the species in any wetland, stream reach or forest site every 20 years. It seems there is no single source for the declinc,  but that pollution and habitat loss are the most common causes, coupled with  chytrid fungus and ranaviruses. Via Phys.org

America’s National Highway Traffic Safety Administration released an environmental impact statement to support the proposed removal of emissions caps on U.S. automotive manufacturers.  It contains the assumption that global temperature will rise by 4 °Celsius from pre-industrial levels by 2100, seven times the warming that has already taken place, considered disastrous by most scientists. The impact statement says the increased emissions would be insignificant in a world where no actions are taken to control climate change. Via Washington Post

California’s Coastal Commission, which oversees development along 1,100 miles of coast, is likely to change its planning assumptions to include 3.1 metre of sea level rise by 2100. This is an increase from the assumed 1.5 metres. This new guidance will be used by California’s cities when planning new projects. However, cities and developers are questioning the wisdom of using a worst-case assumption. Via Scientific American

Scientists in Florida have been using underwater structures to make coral nurseries: controlled environments to raise coral which can then be transplanted to patch up dying reefs. Florida has the world’s third largest barrier reef, but levels of acropora, the primary genus of reef-building corals, has dropped by 97% due to rises in human population and overuse of agricultural fertilizers. The coral grows much faster in the nurseries than in the wild, and within a few months they can be transplanted onto a damaged reef. Via The Guardian

Water Ways

The death toll from last week’s tsunami in Indonesia may have been lower if communities like Palu had been warned. A number of earthquakes culminated in an intense, shallow 7.5-magnitude temblor centered about 10 kilometres beneath the surface. But the plates had slipped sideways, rather than producing the vertical movement which is usually associated with tsunami. Consequently, a warning was issued, but withdrawn at about the same time the wave arrived. It’s likely that the final tremor caused an underwater landslide which displaced large volumes of water, which were magnified by the topography of the bay near Palu. Via National Geographic

A new way of filtering water uses a smartphone and a lens made from an inkjet printer.

The University of Houston has developed an extremely sensitive way of detecting lead ions in water using a smartphone and a lens made with an adapted inkjet printer. The printer is used to create an elastomer lens which is attached to the camera, and when chromate ions are added to the sample, the resulting fluorescence can be detected by the phone.  Drinking water is required by the EPA to have no more than 15 parts per billion of lead, and this system can detect lead concentrations at 5 parts per billion in tap water. Via Science Daily

Cornell University has been using a bacteriophage to detect and destroy coliform bacteria in water.  The engineered virus contains an enzyme similar to the protein that gives fireflies the ability to glow. When the bacteriophage finds E. coli in water, it infects it and starts to luminesce – which acts as an indicator of E. coli’s presence. The bacteriophage then goes on to kill the bacteria. This removes the need to wait days for traditional analysis of water samples, making it advantageous for more remote areas of the world. Via  Science Daily

Government Initiatives

Seabird conservationists in South Africa have used concrete lookalikes to entice endangered African penguins to start a new colony near better fishing grounds. Hunting and guano mining has reduced their numbers from millions to just a few tens of thousands, at the same time as fishing has driven away the anchovies and sardines they feed on. The conservationists are working with the South African government to create fenced-in areas where the penguins can breed safely, watched by their concrete pals. Via Hakai Magazine

Energy and Power

Electricity in rural Bangladesh is intermittent and extremely expensive. As a result, the country has a growing number of solar panels, but no way of using excess energy. A new startup is installing meters and cabling systems in communities, allowing generators to sell power cheaply to their neighbours using micropayments over a mobile phone network. These peer-to-peer grids are growing fast, and could be useful in isolated communities around the world. Via Fast Company


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