Record-early Alaska river thaw follows high winter temperatures

Record-early Alaska river thaw follows high winter temperatures

SOURCE: Reuters DATE: April 15, 2019 SNIP: Key Alaska rivers that are usually frozen at this time of year are now free-flowing, with record-early thaws following record-high winter and spring temperatures. In the interior Alaska city of Nenana, ice on the Tanana River gave way just after midnight on Sunday. It was by far the earliest breakup in the 102-year history of the Nenana Ice Classic, an iconic Alaska betting pool in which participants predict when thaw will sink a wooden tripod placed on the ice. The previous earliest breakup of the Tanana, a tributary of the Yukon River, was April 20, a mark reached in 1998 and 1940. Another record-early thaw happened on Friday on the Kuskokwim River at the southwestern city of Bethel. The previous earliest ice-breakup date for the Kuskokwim Ice Classic was also April 20, in 2016. The Friday ice breakup was the earliest for that part of the Kuskokwim in 92 years of records kept by the National Weather Service. At both rivers, records show that breakup has been happening, on average, about a week earlier since the 1960s, not counting this year’s record thaws. This year’s breakups followed an extraordinarily warm Alaska winter with near-record-low ice in the Bering Sea and a record-hot March...
Sharks more vulnerable than originally thought

Sharks more vulnerable than originally thought

SOURCE: Phys.org DATE: April 15, 2019 SNIP: A study of small-scale fisheries operating from Kenya, Zanzibar and Madagascar, has revealed the massive underreporting of sharks and rays caught annually in the region. Led by experts at Newcastle University, UK, and published in the academic journal Biological Conservation, the team say the study highlights the substantial underreporting of catches by small scale fisheries and the urgent need to expand efforts globally to assess their impact on vulnerable species. Thousands of miles of nets and lines are set in the world’s oceans each day and the unintentional capture of non-target species – often termed as bycatch – is unavoidable. It is estimated about 40 percent of the catch worldwide is unintentionally caught, and includes vulnerable species such as dolphins, marine turtles, sharks and seabirds. In large-scale commercial fishing the bycatch is wasted, thrown back into the sea dead or dying, but in small scale fisheries, such as those studied by the Newcastle team, the non-target species are generally retained and sold, in some cases illegally. Senior author Dr. Per Berggren, Head of the Marine Megafauna Lab at Newcastle University said: “We looked at just one region of the world but it’s likely that similar underreporting is happening in small scale fisheries globally – which means our 2,500,000 unreported sharks and rays only represent a small portion of the total global...
Melting Permafrost Releasing High Levels of Nitrous Oxide, A Potent Greenhouse Gas

Melting Permafrost Releasing High Levels of Nitrous Oxide, A Potent Greenhouse Gas

SOURCE: Yale e360 and Atmospheric Chemistry and Physics DATE: April 15, 2019 SNIP: Thawing permafrost in the Arctic may be releasing 12 times as much nitrous oxide as previously thought, according to a new study published in the journal Atmospheric Chemistry and Physics. Nitrous oxide, a powerful greenhouse gas 300 times more potent than carbon dioxide, can remain in the atmosphere for up to 114 years, according to the U.S. Environmental Protection Agency (EPA). The research, led by scientists at Harvard University, involved measuring greenhouse gas levels over 120 square miles of melting permafrost in the North Slope of Alaska. The data, collected using a small plane, showed that the nitrous oxide emitted over the course of just one month of sampling in 2013 was equal to what was thought to be the region’s yearly emissions. The findings back up similar results from other recent studies that used core samples from Arctic peat to measure rising nitrous oxide emissions. Nitrous oxide emissions have been rising globally in recent decades thanks to the expansion of industry and intense fertilizer use. But scientists had long thought that emissions of the gas from melting permafrost were “negligible,” as the EPA described it in a 2010...
Turtles’ absence from Nicaraguan stronghold raises alarm for future

Turtles’ absence from Nicaraguan stronghold raises alarm for future

SOURCE: The Guardian DATE: April 15, 2019 SNIP: Every year, from November through March, leatherback sea turtles arrive to the secluded shores of the Río Escalante Chacocente wildlife reserve on Nicaragua’s Pacific coast to lay their eggs. Though leatherback nesting habits vary, Chacocente has been a reliable egg-laying site for as long as conservationists have collected nesting data. But this year, not a single leatherback came to Chacocente, and conservation groups in Costa Rica and Mexico, have recorded declines in sightings of the huge turtles. Leatherback populations face threats from human activity, and the eastern Pacific population of leatherbacks is classified as critically endangered. Both legal and illegal fishing have helped drive the decline, as well as egg poaching. In Central America sea turtle eggs are considered a delicacy and in some communities are held to be an aphrodisiac. While conservation efforts have focused on countering human harvesting of turtles, there is also growing evidence that warming temperatures could play a role in the population decline. In leatherbacks and other species of sea turtles, the sex of a turtle hatchling is determined by the temperature of the sand where the egg incubated. Higher temperatures produce female eggs, and scientists suspect that a large portion of sea turtle hatchlings are now...
Siren sounds on nuclear fallout embedded in melting glaciers

Siren sounds on nuclear fallout embedded in melting glaciers

SOURCE: Phys.org DATE: April 10, 2019 SNIP: Radioactive fallout from nuclear meltdowns and weapons testing is nestled in glaciers across the world, scientists said Wednesday, warning of a potentially hazardous time bomb as rising temperatures melt the icy residue. For the first time, an international team of scientists has studied the presence of nuclear fallout in ice surface sediments on glaciers across the Arctic, Iceland the Alps, Caucasus mountains, British Columbia and Antarctica. It found manmade radioactive material at all 17 survey sites, often at concentrations at least 10 times higher than levels elsewhere. When radioactive material is released into the atmosphere, it falls to earth as acid rain, some of which is absorbed by plants and soil. But when it falls as snow and settles in the ice, it forms heavier sediment which collects in glaciers, concentrating the levels of nuclear residue. As well as disasters, radioactive material produced from weapons testing was also detected at several research sites. One of the most potentially hazardous residues of human nuclear activity is Americium, which is produced when Plutonium decays. Whereas Plutonium has a half-life of 14 years, Americium lasts 400. “Americium is more soluble in the environment and it is a stronger alpha (radiation) emitter. Both of those things are bad in terms of uptake into the food chain,” said...