Algae blooms in the Baltic Sea; Photo by European Space Agency

SCIENCE NEWS: Coho climate challenge: identifying at-risk populations; Chinook salmon declines related to changes in freshwater conditions; Forecast errors and uncertainties in atmospheric rivers; Rising sea levels and river delta growth; and more …

Coho climate challenge: identifying at-risk populations:  “A wealth of data about the past can make it easier to predict the future. Biologists studying economically valuable salmon often have the advantage of working with extensive, long-term ecological data sets. A long history of using dams to regulate water also gives these scientists access to extensive data on environmental conditions in the rivers salmon inhabit. Researchers in Oregon leveraged abundant data on river conditions and fish passage at dams to assess the movement of coho salmon (Oncorhynchus kisutch) in relation to changes in flow and water temperature, and to compare these relationships with future hydrological conditions predicted by climate change models (Flitcroft et al. 2018). Their findings help to identify when and where coho populations may be most vulnerable, such as the first adults returning to rivers in late summer and early autumn – knowledge which may be essential for targeting future management efforts. ... ”  Read more from FishBio here:  Coho climate challenge: identifying at-risk populations

Chinook salmon declines related to changes in freshwater conditions:  “A new University of Alaska-led study provides the first evidence that declines in many of Alaska’s chinook salmon populations can be attributed in part to climate-driven changes in their freshwater habitats.  Alaska chinook salmon runs have decreased during the past decade, leading to fisheries closures and prolonged economic and cultural impacts to local communities. With Alaska’s climate warming twice as fast as the global average and experiencing changes in precipitation and streamflow, the research team set out to understand if changing conditions in fresh water—where salmon spawn and rear—played a role in recent declines of chinook populations in the Cook Inlet basin of Southcentral Alaska. ... ”  Read more from PhysOrg here:  Chinook salmon declines related to changes in freshwater conditions

Supporting winged wildlife: Beale Air Force Base is new monarch butterfly hot spot:  “Beale Air Force Base is known for its fast jets and top pilots, but it’s also gaining recognition as a home for monarch butterflies. Hundreds have been observed stopping to rest at Beale as they travel from their winter home on California’s coast to warmer areas to lay eggs. To support the butterflies’ long journey, Beale has built pollinator gardens that provide essential food and habitat.  “Monarch butterfly populations have declined significantly over the past two decades,” said Cathy Johnson, a scientist in the U.S. Fish and Wildlife Service’s Sacramento Field Office. In addition to serving as the liaison to Beale, Johnson worked extensively on the Service’s national pollinator recovery efforts. “When partners like Beale want to build habitat, we provide all the help we can.” … ”  Read more from the US FWS here: Supporting winged wildlife: Beale Air Force Base is new monarch butterfly hot spot

California condors spotted in Sequoia National Park, first time in nearly half a century:  “Recently reintroduced endangered California condors continue to reoccupy parts of their historic range, including the Sierra Nevada Mountains of California and adjacent foothills. Condors were spotted atop Moro Rock, a popular hiking destination in Sequoia National Park, in late May. They are back to the towering trees and cliffs of the parks after being absent for nearly 50 years.  “Condors were consistently seen throughout the parks until the late 1970s. Observations became increasingly rare throughout the latter portion of the century as the population declined,” said Tyler Coleman, a wildlife biologist with Sequoia and Kings Canyon National Parks. “Four condors have been spotted flying near the Giant Forest and at least two near Moro Rock.”  National Park Service staff weren’t the only ones to notice the birds in the parks. … ”  Read more from the US FWS here: California condors spotted in Sequoia National Park, first time in nearly half a century

Extreme atmospheric rivers: what will California’s strongest storms look like in a warming climate? Atmospheric rivers (ARs)—long, sinuous corridors of water vapor in motion in the lower half of Earth’s atmosphere—are a key aspect of California’s cool-season climate. ARs are in many cases pretty unremarkable when they’re out over the open ocean, visible on satellite as a narrow ribbon of cloudiness and (usually) light precipitation. But when these moisture plumes attach themselves to wintertime low pressure systems and make landfall along the California coast, the consequences can be dramatic—prolonged heavy rain and mountain snow often result, along with sometimes powerful winds. AR-related precipitation is strongly orographic, meaning that it tends to be strongly modulated by local topography. As a result, the most dramatic AR-related precipitation totals usually occur on the windward (south and west-facing) slopes of California’s coastal and inland mountain ranges. Precipitation accumulations in such regions during the most extreme AR events are comparable to that received along the Gulf Coast or Eastern Seaboard during landfalling hurricane events—and are occasionally measured in feet, rather than inches. As such, ARs can be either blessing or a curse, depending on context and antecedent conditions: they are responsible for up to 50% of California’s overall water supply, but also the vast majority of the region’s flood risk. … ”  Continue reading at the Weather West here: Extreme atmospheric rivers: what will California’s strongest storms look like in a warming climate?

Forecast errors and uncertainties in atmospheric rivers:  “ECMWF scientist and former CW3E postdoc, Dr. David Lavers published an article in May 2020 in Weather and Forecasting. Co-authors included representatives from leading global numerical weather prediction centers, several of whom serve on the AR Recon Modeling and Data Assimilation Steering Committee (as given by asterisks): Bruce Ingleby, David Richardson, Mark Rodwell, and Florian Pappenberger* of ECMWF; Vijay Tallapragada* of NCEP; Jim Doyle* and Carolyn Reynolds* of the Naval Research Laboratory; and multiple key academic partners including Aneesh Subramanian* of CU Boulder, Ryan Torn of SUNY Albany, and CW3E Director F. Martin Ralph*. The collaboration on this article between global operational numerical weather prediction centers and academic institutions is an example of how the Atmospheric River Reconnaissance (AR Recon) Program brings together scientific leaders to leverage airborne observations offshore in and around ARs to support improved forecasts of ARs. … ”  Read more from the Center for Western Weather and Water Extremes here: Forecast errors and uncertainties in atmospheric rivers

Snowmelt causes different limitations on transpiration in a Sierra Nevada conifer forest:  “CW3E field researcher Ava Cooper, along with her Master’s advisor and CW3E collaborator, Adrian Harpold and their University of Nevada, Reno (Ben Sullivan and Scott Tyler), National Center for Atmospheric Research (Danica Lombadozzi), and ETH Zürich (James Krichner and Sebastian Wolf) collaborators published a paper in Agricultural and Forest Meteorology titled “Snowmelt causes different limitations on transpiration in a Sierra Nevada conifer forest”. This article summarizes Ava’s work for her hydrology Master’s at the University of Nevada, Reno where she studied sap flow in trees (a proxy for transpiration) in relation to snow. While this work was not done at CW3E, the results can inform the monitoring and projections of climate variability and change priority of the CW3E strategic plan as a baseline for impacts of snow on ecohydrology to compare to future changes in snow. ... ”  Continue reading at the Center for Western Weather and Water Extremes here: Snowmelt causes different limitations on transpiration in a Sierra Nevada conifer forest

New models detail how major rivers will respond to changing environmental conditions:  “From the Nile to the Mississippi and from the Amazon to the Yangzi, human civilization is inextricably linked to the great rivers along which our societies developed. But rivers are mutable, and the benefits they bestow can quickly become disasters when these waterways change course.  Scientists are working to understand how environmental changes alter river dynamics. A new study in the Proceedings of the National Academy of Sciences coauthored by UC Santa Barbara geomorphologist Vamsi Ganti has outlined the factors that dictate how often rivers jump course, or avulse, and the effects this will have on river deltas. The results promise to help scientists and planners prepare for a future of sea-level rise and changing land use. … ”  Read more from Phys Org here: New models detail how major rivers will respond to changing environmental conditions

Rising sea levels and river delta growth:  “Sea-level rise and subsidence, which can drown river deltas, can also drive the phenomenon of river avulsion, in which rivers rapidly change course, according to a new study.  A US team used field data and modelling to investigate the timing of river avulsions and found that the frequency is related to the rate of sea-level rise, the rate of subsidence, and the supply of sediment that drives delta growth.  The balance of the rates also determines whether a delta advances or retreats, they write in a paper in the journal Proceedings of the National Academy of Sciences. ... ”  Read more from the Cosmos here: Rising sea levels and river delta growth

Geochemical analysis from the last ice age may hold clues for future climate change and preparedness strategies:  “Stalagmites from Lake Shasta Caverns (LSC) – located in northern California within an important transitional climate zone between the Pacific Northwest and southwestern United States  – hold geochemical clues to help researchers understand how climate changed during the end of the last ice age (14,000 – 37,000 years ago) and predict what may happen amid climatic changes in modern times.  … ”  Read more from Vanderbilt University here:  Geochemical analysis from the last ice age may hold clues for future climate change and preparedness strategies

Monitoring groundwater changes more precisely:  “A new method could help to track groundwater changes better than before. To this end, researchers from Potsdam and Oberlin, Ohio (USA), have compared gravity field data from the GRACE and GRACE-Follow On satellite missions with other measuring methods. They investigated the seasonal water storage in almost 250 river basins in Asia, whose water regime is dominated by monsoon. The results allow the large-scale GRACE data to be scaled down to smaller regions. The researchers report on this in the journal Earth and Planetary Science Letters.  … ”  Read more from Phys Org here: Monitoring groundwater changes more precisely

Featured image credit: Baltic blooms by the European Space Agency

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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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