SCIENCE NEWS: California’s mercury legacy; Seasonal rain and snow trigger small earthquakes on California faults; Why the world’s rivers are losing sediment – and why it matters; and more …

Saturn, in ultraviolet. Photo by NASA.

In science news this week: Reclaiming the Sierra: California’s mercury legacy; Seasonal rain and snow trigger small earthquakes on California faults; Why the world’s rivers are losing sediment – and why it matters; Billion-dollar dams are making water shortages, not solving them; Dryland cropping systems research addresses future hunger and drought issues; and Eyes on Nature: How satellite imagery is transforming conservation science

Reclaiming the Sierra: California’s mercury legacy:  “Mercury has left a significant imprint on California’s environment as a result of historical mining. An estimated 26 million pounds of mercury was used to extract gold from rock deposits in the late 1800s and early 1900s, and up to one third of that may have been lost to the environment. Once in the environment, mercury can accumulate in animals like fish and later be consumed by humans, where it causes impairment to the nervous system, particularly in children, pregnant women, or breastfeeding mothers. FISHBIO recently attended the 2017 Sierra Fund Conference, Reclaiming the Sierra: Headwater Resiliency, which was hosted at California State University, Sacramento. The goal of the conference was to collaborate on a vision of headwater management to address mercury concerns, with a focus on current conditions of historical mining areas, ongoing research, new analytical tools, and public outreach strategies. … ”  Read more from the FishBio blog here:  Reclaiming the Sierra: California’s mercury legacy

Seasonal rain and snow trigger small earthquakes on California faults:  “California’s winter rains and snow depress the Sierra Nevada and Coast Ranges, which then rebound during the summer, changing the stress on the state’s earthquake faults and causing seasonal upticks in small quakes, according to a new study by University of California, Berkeley seismologists.  The weight of winter snow and stream water pushes down the Sierra Nevada mountains by about a centimeter, or three-eighths of an inch, while ground and stream water depress the Coast Ranges by about half that. This loading and the summer rebound — the rise of the land after all the snow has melted and much of the water has flowed downhill — makes the earth’s crust flex, pushing and pulling on the state’s faults, including its largest, the San Andreas. … ”  Continue reading at Science Daily here:  Seasonal rain and snow trigger small earthquakes on California faults

Why the world’s rivers are losing sediment – and why it matters:  “In September 2011, after 20 years of planning, workers began dismantling the Elwha and Glines dams on the Elwha River in northwestern Washington state. At the time, it was the largest dam removal project in U.S. history, and it took nearly three years for both barriers to be dismantled and for the river to once again flow freely.  Over the course of their nearly century-long lives, the two dams collected more than 24 million cubic yards of sediment behind them, enough to fill the Seattle Seahawks football stadium eight times. And since their removal, the Elwha has taken back the trapped sediment and distributed it downstream, causing the riverine ecosystem to be rebuilt and transformed. Massive quantities of silt, sand, and gravel have been carried to the coast, resurrecting a wetlands ecosystem long deprived of sediment. … ” Read more from Yale 360 here:  Why the world’s rivers are losing sediment – and why it matters

Billion-dollar dams are making water shortages, not solving them:  “Dams are supposed to collect water from rivers and redistribute it to alleviate water shortages, right? Not so fast. It turns out that in most cases they actually create water scarcity, especially for people living downstream.  Almost a quarter of the global population experiences significant decreases in water availability through human interventions on rivers, says Ted Veldkamp at Vrije University in Amsterdam, the Netherlands. Those interventions primarily involve dams that take water for irrigation or cities, or to generate hydroelectricity. … ”  Read more from New Scientist here:  Billion-dollar dams are making water shortages, not solving them

Dryland cropping systems research addresses future hunger and drought issues:  “Murali Darapuneni recalls stories about how difficult it was for his ancestors during times of drought conditions and famine in India in the early 1900s.  “They had limited resources and research at that time,” he said. “My grandparents told me about those stories and how difficult it was to feed the people.”  Darapuneni is now an assistant professor of semi-arid cropping systems in the New Mexico State University College of Agricultural, Consumer and Environmental Sciences. Part of the Department of Plant and Environmental Sciences, he is researching efficient dryland cropping systems at the NMSU Agricultural Science Center at Tucumcari. … ” Read more from Science Daily here:  Dryland cropping systems research addresses future hunger and drought issues

Eyes on Nature: How satellite imagery is transforming conservation science:  “As recently as the 1980s, gray seals were effectively extinct on Cape Cod. So when researchers announced last week that the population there has recovered not to 15,000 gray seals, the previous official estimate, but to as many as 50,000, it was dramatic evidence of how quickly conservation can sometimes work.  But the researchers, writing in the journal BioScience, weren’t just interested in the seals. They also sought to demonstrate the rapidly evolving potential of satellites to count and monitor wildlife populations and to answer big questions about the natural world.  … ”  Read more from Yale 360 here:  Eyes on Nature: How satellite imagery is transforming conservation science

Maven’s XKCD Comic Pick of the Week …

 

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About Science News and Reports: This weekly feature, posted every Thursday, is a collection of the latest scientific research and reports with a focus on relevant issues to the Delta and to California water, although other issues such as climate change are sometimes included. Do you have an item to be included here? Submissions of relevant research and other materials is welcome. Email Maven

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