Star clusters are commonly featured in cosmic photoshoots, and are also well-loved by the keen eye of the NASA/ESA Hubble Space Telescope. These large gatherings of celestial gems are striking sights — and the subject of this Picture of the Week, Messier 2, is certainly no exception. Messier 2 is located in the constellation of Aquarius (The Water-Bearer), about 55 000 light-years away. It is a globular cluster, a spherical group of stars all tightly bound together by gravity. With a diameter of roughly 175 light-years, a population of 150 000 stars, and an age of 13 billion years, Messier 2 is one of the largest clusters of its kind and one of the oldest associated with the Milky Way. Most of the cluster’s mass is concentrated at its centre, with shimmering streams of stars extending outwards into space. It is bright enough that it can even be seen with the naked eye when observing conditions are extremely good.

SCIENCE NEWS: Clams and water pumping explain phytoplankton decline in the Delta; Falling levels of air pollution drove decline in California’s tule fog; One river remains; Mountain glaciers are major contributors to rising seas; and more …

Star clusters, courtesy of the Hubble Space Telescope.  Photo by NASA.  Click on image for more information.
In science news this week:

Clams and Water Pumping Explain Phytoplankton Decline in San Francisco Estuary:  “A combination of invasive clams and water pumping explains the drastic suppression of phytoplankton in the San Francisco Estuary, according to a study from the University of California, Davis.  Previous studies linked fish declines in the estuary in part to a limited supply of phytoplankton. These tiny microscopic algae make up the base of the food web: Fish eat zooplankton, which eat phytoplankton.  The study, published in the journal Environmental Management, used several modeling steps to investigate the drivers behind the decline. … ”  Read more from UC Davis here:  Clams and Water Pumping Explain Phytoplankton Decline in San Francisco Estuary

Stanford study offers a way to map where flooded fields best replenish groundwater:  “In California, the amount of water exiting aquifers under the state’s most productive farming region far surpasses the amount of water trickling back in. That rampant overdraft has caused land across much of the region to sink like a squeezed out sponge, permanently depleting groundwater storage capacity and damaging infrastructure.  The trend – and a 2014 mandate for sustainable groundwater management in the state – has ignited interest in replenishing aquifers in California’s Central Valley through managed flooding of the ground above them. … ”  Read more from Stanford News here:  Stanford study offers a way to map where flooded fields best replenish groundwater

Falling levels of air pollution drove decline in California’s tule fog:  “The Central Valley’s heavy wintertime tule fog – known for snarling traffic and closing schools — has been on the decline over the past 30 years, and falling levels of air pollution are the cause, says a new study by scientists at the University of California, Berkeley.  Tule fog, named for a sedge grass that populates California’s wetlands, is a thick ground fog that periodically blankets the Central Valley during the winter months.  To find out why the fog is fading, the researchers analyzed meteorological and air pollution data from the Central Valley reaching back to 1930. They found that while yearly fluctuations in fog frequency could be explained by changes in annual weather patterns, the long-term trends matched those of pollutants in the air. … ”  Read more from UC Berkeley here:  Falling levels of air pollution drove decline in California’s tule fog

State of the San Lorenzo Marks 40 Years of Santa Cruz Conservation:  “Flowing directly through the heart of Santa Cruz, California, the San Lorenzo River serves as a vital water source for people, fish, and numerous other animals and plants that call the region home. Locals have long understood the ecological and economic importance of this coastal stream, and the San Lorenzo was one of the first rivers in California to have its own watershed conservation plan. With 2019 marking the 40th anniversary of the plan, the recent State of the San Lorenzo Symposium focused on the accomplishments of this conservation legacy and what the future holds for the river, as well as for the imperiled aquatic species and nearly 100,000 humans who rely on it. … ”  Read more from FishBio here:  State of the San Lorenzo Marks 40 Years of Santa Cruz Conservation

One river remains:  “Southern California rivers are not known for their abundance of water flow. Yet, when the rains do come, the rivers can swell in dramatic fashion.  Attempts to tame inconstant rivers have resulted in channelized, dammed or leveed waterways that resemble concrete canals more than Instagram-worthy landscapes. But one wild river remains: the Santa Clara River.  Beginning with headwaters in both the Los Padres and Angeles National Forests, the river meanders for more than 100 miles through Los Angeles and Ventura counties before flowing into the estuary on McGrath State Beach. In dry months, many areas of the Santa Clara River flow completely underground.  Despite this lack of water, much of the Santa Clara River is alive with riparian trees and shrubs like willows, fragrant mule fat and native pollinators like buckwheat. … ”  Read more from the US FWS here:  One river remains

Conservation Through Destruction: American Rivers Provides Huge Boost to Nature By Removing Defunct Dams:  “”There are hundreds of dams all over the country that are no longer serving a purpose. These obsolete dams have no useful function, they damage rivers and can be dangerous for people,” says Laura Craig, Director of the River Restoration Program at American Rivers. “That’s where American Rivers comes in. Along with our partners, we identify dam removals that would provide the most ecological benefit and take them down in the safest way possible. We then use our collective knowledge and expertise to restore the area to its natural state.”  Craig has extensive expertise in dam removal. She has been managing and facilitating dam removals at American Rivers for eight and a half years. She also has a Ph.D. in Aquatic Ecology from the University of Maryland at College Park. … ”  Read more from Environmental Monitor here:  Conservation Through Destruction: American Rivers Provides Huge Boost to Nature By Removing Defunct Dams

Untold Arizona: Tracing The Ancient Origins Of Arizona Rivers:  “In Medieval Europe, all roads led to Rome. In Arizona, all rivers lead to the Colorado.  In fact, it’s no exaggeration to say the state of Arizona lies almost entirely within the Colorado River drainage basin, which also sprawls across southwestern Wyoming and down through parts of Utah, Colorado, Nevada, California and New Mexico.  Were it not for the vast system of dams and irrigation systems that lock up their waters and put them to work, the Gila and Salt Rivers, along with the Verde River to the north, would drain the Mogollon Rim and mountain ranges, wash their waters down through the canyons and valleys and deliver them into the Gulf of California. ... ”  Read more from KJZZ here:  Untold Arizona: Tracing The Ancient Origins Of Arizona Rivers

Mountain Glaciers Are Major Contributors to Rising Seas:  “Melting mountain glaciers could account for nearly a third of the sea-level rise that’s occurred in the last 60 years, new research suggests. That makes their contributions to global ocean levels on par with the massive Greenland ice sheet and far more significant than Antarctica.  As glaciers melt, much of the water runs into nearby rivers and eventually into the oceans. So even though they tend to be located in mountainous regions of the world, they’re immediate contributors to rising seas.  The only bigger contributor to global sea-level rise is the warming of the oceans themselves, which causes water to expand. … ”  Read more from Scientific American here:  Mountain Glaciers Are Major Contributors to Rising Seas

Socioeconomic impacts of harmful algal blooms:  “The human dimensions of harmful algal blooms (HABs) are becoming more apparent as they increase in frequency, magnitude and geographic scope. This includes human illness and mortality associated with consuming seafood contaminated with HAB toxins as well as economic losses associated with lost fisheries landings and tourism revenue, food insecurity from loss of subsistence harvest activities, disruption of cultural practices, and loss of community identity and social interactions tied to coastal resource use.  … ”  Read more from NOAA here:  Socioeconomic impacts of harmful algal blooms

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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