Although less than one per cent of all water in the world is freshwater, it is what we drink and use for agriculture. In other words, it’s vital to human survival. York University researchers have just created a publicly available water quality database for close to 12,000 freshwater lakes globally—almost half of the world’s freshwater supply—that will help scientists monitor and manage the health of these lakes.
The study, led by Faculty of Science Postdoctoral Fellow Alessandro Filazzola and Master’s student Octavia Mahdiyan, collected data for lakes in 72 countries, from Antarctica to the United States and Canada. Hundreds of the lakes are in Ontario.
“The database can be used by scientists to answer questions about what lakes or regions may be faring worse than others, how water quality has changed over the years and which environmental stressors are most important in driving changes in water quality,” says Filazzola.
The team included a host of graduate and undergraduate students working in the laboratory of Associate Professor Sapna Sharma in addition to a collaboration with Assistant Professor Derek Gray of Wilfrid Laurier University, Associate Professor Catherine O’Reilly of Illinois State University and York University Associate Professor Roberto Quinlan.
The researchers reviewed 3,322 studies from as far back as the 1950s along with online data repositories to collect data on chlorophyll levels, a commonly used marker to determine lake and ecosystem health. Chlorophyll is a predictor of the amount of vegetation and algae in lakes, known as primary production, including invasive species such as milfoil.
“Human activity, climate warming, agricultural, urban runoff and phosphorus from land use can all increase the level of chlorophyll in lakes. The primary production is most represented by the amount of chlorophyll in the lake, which has a cascading impact on the phytoplankton that eat the algae and the fish that eat the phytoplankton and the fish that eat those fish,” says Filazzola. “If the chlorophyll is too low, it can have cascading negative effects on the entire ecosystem, while too much can cause an abundance of algae growth, which is not always good.”
Warming summer temperatures and increased solar radiation from decreased cloud cover in the northern hemisphere also contributes to an increase in chlorophyll, while more storm events caused by climate change contribute to degraded water quality, says Sharma. “Agricultural areas and urban watersheds are more associated with degraded water quality conditions because of the amount of nutrients input into these lakes.”
The researchers also gathered data on phosphorous and nitrogen levels—often a predictor of chlorophyll—as well as lake characteristics, land use variables, and climate data for each lake. Freshwater lakes are particularly vulnerable to changes in nutrient levels, climate, land use and pollution.
“In addition to drinking water, freshwater is important for transportation, agriculture, and recreation, and provides habitats for more than 100,000 species of invertebrates, insects, animals and plants,” says Sharma. “The database can be used to improve our understanding of how chlorophyll levels respond to global environmental change and it provides baseline comparisons for environmental managers responsible for maintaining water quality in lakes.”
The researchers started looking only at Ontario lakes, but quickly expanded it globally as although there are thousands of lakes in Ontario a lot of the data is not as readily available as it is in other regions of the world.
“The creation of this database is a feat typically only accomplished by very large teams with millions of dollars, not by a single lab with a few small grants, which is why I am especially proud of this research,” says Sharma.
The research is published in Nature’s Scientific Data journal.
Scientific Data, DOI: 10.1038/s41597-020-00648-2
New freshwater database tells water quality story for 12K lakes globally (2020, September 22)
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NASA says probe successfully stowed sample from asteroid – FRANCE 24
Issued on: 29/10/2020 – 22:32
NASA said Thursday its robotic spacecraft Osiris-Rex was able to stow a rock and dust sample scooped up from the asteroid Bennu, after a flap that had wedged open put the mission at risk.
“We are here to announce today that we’ve successfully completed that operation,” said Rich Burns, the mission’s project manager.
The probe is on a mission to collect fragments that scientists hope will help unravel the origins of our solar system, but hit a snag after it picked up too big of a sample.
Fragments from the asteroid’s surface in a collector at the end of the probe’s three-meter (10-foot) arm had been slowly escaping into space because some rocks prevented the compartment from closing completely.
That arm is what came into contact with Bennu for a few seconds last Tuesday in the culmination of a mission launched from Earth some four years ago.
On Thursday, NASA said it had been able a day earlier to maneuver the robotic arm holding the leaking particles to a storage capsule near the center of the spacecraft, drop off the sample and close the capsule’s lid.
It was a delicate two-day procedure, requiring the team at each step to assess images and data from the previous step.
The probe is 200 million miles (320 million kilometers) away, so it takes 18.5 minutes for its transmissions to reach Earth, and any signal from the control room requires the same amount of time to reach Osiris-Rex.
“My heart breaks for loss of sample,” said Dante Lauretta, the mission’s chief scientist, but he noted that they had successfully stowed hundreds of grams (several ounces) of fragments, far in excess of their minimum goal.
“Now we can look forward to receiving the sample here on Earth and opening up that capsule,” he said.
Osiris-Rex is set to come home in September 2023, hopefully with the largest sample returned from space since the Apollo era.
© 2020 AFP
Asteroid samples tucked into capsule for return to Earth – Virden Empire Advance
CAPE CANAVERAL, Fla. — A NASA spacecraft more than 200 million miles away has tucked asteroid samples into a capsule for return to Earth, after losing some of its precious loot, scientists said Thursday.
Flight controllers moved up the crucial operation after some of the collected rubble spilled into space last week.
The Osiris-Rex spacecraft gathered pebbles and other pieces of asteroid Bennu on Oct. 20, briefly touching the surface with its robot arm and sucking up whatever was there. So much was collected — an estimated hundreds of grams’ worth — that rocks got wedged in the rim of the container and jammed it open, allowing some samples to escape.
Whatever is left won’t depart Bennu’s neighbourhood until March, when the asteroid and Earth are properly aligned. It will be 2023 — seven years after Osiris-Rex rocketed from Cape Canaveral — before the samples arrive here.
This is the first U.S. mission to go after asteroid samples. Japan has done it twice at other space rocks and expects its latest batch to arrive in December.
Rich in carbon, the solar-orbiting Bennu is believed to hold the preserved building blocks of the solar system. Scientists said the remnants can help explain how our solar system’s planets formed billions of years ago and how life on Earth came to be. The samples also can help improve our odds, they said, if a doomsday rock heads our way.
Bennu — a black, roundish rock bigger than New York’s Empire State Building — could come dangerously close to Earth late in the next decade. The odds of a strike are 1-in-2,700. The good news is that while packing a punch, it won’t wipe out the home planet.
The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.
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