Linking critical zone water storage and ecosystems

Consider a seasonally dry landscape in a hilly or mountainous region where little or no rain or snow falls for months at a time. How is it that months into the dry period, forests can remain green and productive and streams can keep flowing? The answer must be that earlier precipitation remains available, as subsurface moisture to trees and as groundwater that slowly drains to rivers. This subsurface water supply maintains not only trees and streams but also entire water-dependent terrestrial and river ecosystems. These streams also become the rivers that serve as the main water supplies for downstream hydropower and for agricultural and urban users.  All of this water storage occurs in the critical zone, the near-surface layer of Earth where coevolving geomorphic, hydrologic, geochemical, and ecological processes create dynamic, deep water-storing systems out of solid, nearly impermeable bedrock. … ”  Read more from EOS here: Linking critical zone water storage and ecosystems

Geologists raise the speed limit for how fast continental crust can form

Although we can’t see it in action, the Earth is constantly churning out new land. This takes place at subduction zones, where tectonic plates crush against each other and in the process plow up chains of volcanos that magma can rise through. Some of this magma does not spew out, but instead mixes and morphs just below the surface. It then crystallizes as new continental crust, in the form of a mountain range.  Scientists have thought that the Earth’s mountain ranges are formed through this process over many millions of years. But MIT geologists have now found that the planet can generate new land far more quickly than previously thought.  In a paper published in the journal Geology, the team shows that parts of the Sierra Nevada mountain range in California rose up surprisingly fast, over a period of just 1.39 million years — more than twice as fast as expected for the region. ... ”  Read more from MIT News here:  Geologists raise the speed limit for how fast continental crust can form

Researchers look into the effects of repeated droughts on different kinds of forests

Drought is endemic to the American West along with heatwaves and intense wildfires. But scientists are only beginning to understand how the effects of multiple droughts can compound to affect forests differently than a single drought alone.  UC Santa Barbara forest ecologist Anna Trugman — along with her colleagues at the University of Utah, Stanford University and the U.S. Forest Service — investigated the effects of repeated, extreme droughts on various types of forests across the globe. … ”  Read more from UC Santa Barabara here:  Researchers look into the effects of repeated droughts on different kinds of forests

Where will snow survive in a warming world?

Climate change is transforming winters throughout the western U.S. Warmer temperatures and winter rainfall reduce the magnitude of snow accumulation and alter the timing of snowmelt. Snowcapped mountaintops, characteristic of the western U.S, melt earlier in the spring, sending water rushing downriver. Not only is snowmelt occurring earlier, but it is bringing less water with it – threatening snow-dependent ecosystems and communities.  Despite increasing winter temperatures, more intense precipitation – another consequence of climate change – may be able to sustain some snowpack. Even if mean annual snowfall decreases, an increase in the intensity of snowfall events could prevent snow ablation, or the loss of snow due to melting, sublimation or evaporation. Some physically based models have suggested that more extreme snowfall events may reduce snow ablation. A recent paper by Marshall et al. (2020) is the first study to use empirical data to test this relationship between snow intensity and ablation across the mountainous western U.S. … ” Read more from AGU-H3S here:  Where will snow survive in a warming world?

More accurate modeling of climate change impacts on water resources

To better document the repercussions of climate change on regional water resources, researchers from around the world now have access to HYSETS, a database of hydrometric, meteorological and physiographic data created by a team at the École de technologie supérieure (ÉTS), which contains 70 years’ worth of data on 14,425 North American watersheds.  “Given the diversity of its data and the number of regions documented, HYSETS will allow you to develop models for virtually any type of climate,” explained Richard Arsenault, professor of construction engineering and a member of the Hydrology, Climate and Climate Change Laboratory (HC3), at ÉTS, who spearheaded the project. These ready-to-use data are offered free of charge. … ”  Read more at Science Daily here:  More accurate modeling of climate change impacts on water resources

A new way to fingerprint drivers of water cycle change

Rising temperatures are intensifying Earth’s water cycle, increasing the amount of moisture in the air and modifying regional precipitation and evaporation rates. These changes are also affecting long-distance moisture transport globally, further altering precipitation patterns. But disentangling different drivers of water cycle change to evaluate each one’s relative influence has proven difficult due to their strong interdependence.  Risi et al. present a novel way to distinguish effects due to changes in large-scale atmospheric circulation from those resulting from increasing temperatures. … ”  Read more from EOS here: A new way to fingerprint drivers of water cycle change

The ocean-land connection of droughts

Droughts can have detrimental impacts on water, food, and energy security, as well as water-dependent ecosystems. Understanding how and why droughts develop is therefore of seminal importance.  Herrera‐Estrada and Diffenbaugh [2020] identify areas with anomalously low values of “precipitation minus evaporation” over the ocean and follow their course with methods previously used for tracking cyclones and atmospheric rivers. They find that landfalling droughts – droughts that develop over the ocean and end upon land – are significantly larger and more intense than droughts that develop over land. They also link the genesis of these landfalling droughts to large weather patterns over the ocean, which opens up the potential to improve seasonal‐scale prediction of extreme droughts over land. … ”  Read more from EOS here: The ocean-land connection of droughts

As waters warm, ocean heatwaves are growing more severe

Off the coast of California this August a sea monster of record size was spotted: a patch of warm water that grew to the size of Canada, 9.8 million square kilometers simmering up to 4 degrees Celsius warmer than usual. “It’s off the chart,” says Andrew Leising, a fisheries oceanographer at the National Oceanic and Atmospheric Administration who is mapping the marine heatwave on his website, nicknamed the Blobtracker. By Leising’s reckoning, in September, the unglamorously-named “NEP20b” became the biggest-yet-spotted blob of warm water there since satellite records began in the early 1980s. ... ”  Read more from Yale E360 here: As waters warm, ocean heatwaves are growing more severe

Research: the deep sea is slowly warming: Understanding deep ocean warming can help improve seasonal weather, climate prediction

New research reveals temperatures in the deep sea fluctuate more than scientists previously thought and a warming trend is now detectable at the bottom of the ocean.  In a new study in AGU’s journal Geophysical Research Letters, researchers analyzed a decade of hourly temperature recordings from moorings anchored at four depths in the Atlantic Ocean’s Argentine Basin off the coast of Uruguay. The depths represent a range around the average ocean depth of 3,682 meters (12,080 feet), with the shallowest at 1,360 meters (4,460 feet) and the deepest at 4,757 meters (15,600 feet). … ”  Read more from NOAA here: Research: the deep sea is slowly warming

Featured Image Credit: The Ecology of the Mojave Desert; photo by Pacific Northwest National Labs

Maven’s XKCD Comic Pick of the Week …

 

 


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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