July 1, 2022

Hundreds of Lakes in US, Europe Losing Oxygen, Study Finds | Voice of America

Oxygen levels have dropped in hundreds of lakes in the United States and Europe over the last four decades, a new study found.
 
And the authors said declining oxygen could lead to increased fish kills, algal blooms and methane emissions.
 
Researchers examined the temperature and dissolved oxygen — the amount of oxygen in the water — in nearly 400 lakes and found that declines were widespread. Their study, published Wednesday in the journal Nature, found dissolved oxygen fell 5.5 % in surface waters of these lakes and 18.6% in deep waters.
 
The authors said their findings suggest that warming temperatures and decreased water clarity from human activity are causing the oxygen decline.
 
“Oxygen is one of the best indicators of ecosystem health, and changes in this study reflect a pronounced human footprint,” said co-author Craig E. Williamson, a biology professor at Miami University in Ohio.  
 
That footprint includes warming caused by climate change and decreased water clarity caused in part by runoff from sewage, fertilizer, cars and power plants.
 
Dissolved oxygen losses in Earth’s water systems have been reported before. A 2017 study of oxygen levels in the world’s oceans showed a 2% decline since 1960. But less was known about lakes, which lost two to nine times as much oxygen as oceans, the new study’s authors said.
 
Prior to this study, other researchers had reported on oxygen declines in individual lakes over a long period of time. But none have looked at as many lakes around the world, said Samuel B. Fey, a Reed College biology professor who studies lakes and was not involved in this study.
 
“I think one of the really interesting findings here is that the authors were able to show that there’s this pretty pronounced decline in dissolved oxygen concentrations in both the surface and (deep) parts of the lake,” Fey said.  
 
The deep water drop in oxygen levels is critical for aquatic organisms that are more sensitive to temperature increases, such as cold water fish. During summer months, they depend on cooler temperatures found deeper in the water, but if deep waters are low on oxygen, these organisms can’t survive.
 
“Those are the conditions that sometimes lead to fish kills in water bodies,” said study co-author Kevin C. Rose, a professor of biology at Rensselaer Polytechnic Institute. “It really means that a lot of habitats for cold water fish could become inhospitable.”
 
Other organisms, Rose said, are more tolerant of warmer temperatures found at the surface level and can get enough oxygen by remaining near the surface, where water meets air.
 
About a quarter of the lakes examined actually showed increasing oxygen in surface waters, which Rose says is a bad sign because it’s likely attributable to increased algal blooms — sudden growth of blue green algae.
 
In these lakes, he said, dissolved oxygen was “very low” in deep waters and was unlivable for many species.
 
And the sediment in such oxygen-starved lakes tends to give off methane, a potent greenhouse gas, research shows.
 
Lakes examined in the new study were in the U.S. or Europe, except for one in Japan and a few in New Zealand. The authors said there was insufficient data to include other parts of the world.
 
Rose said lakes outside the study area probably are experiencing drops in dissolved oxygen, too. The reason, he said, is that warmer temperatures from climate change reduce the ability of oxygen to dissolve in water — its solubility.
 
“We know that most or many places around the planet are warming,” he said. “And so, we would expect to see declining solubility.”

 

in U.S.
Related Posts

US Training Mission Uncertain as Afghan Withdrawal Nears End     | Voice of America

June 2, 2021

June 2, 2021

PENTAGON – The fate of the international effort to train Afghan national security forces has become increasingly unclear as Pentagon...

NFL Fines Washington $10M After Misconduct Investigation | Voice of America

July 2, 2021

July 2, 2021

The NFL has fined the Washington Football Team $10 million and owner Dan Snyder is stepping away from day-to-day operations...

Child Lost During Afghanistan Evacuation Reunites With Mother in US

November 20, 2021

November 20, 2021

Thousands of Afghans flocked to the Kabul airport in a desperate bid to escape Afghanistan after the Taliban took control...

US Highlights Commitment to Women’s Reproductive Rights | Voice of America

June 7, 2021

June 7, 2021

NEW YORK – The U.S. Ambassador to the United Nations met Monday with the head of the U.N. Population Fund...

US ‘Neither Optimistic nor Pessimistic’ on Reviving Iran Deal | Voice of America

June 5, 2021

June 5, 2021

State Department spokesperson Ned Price said the United States negotiating team is “neither optimistic nor pessimistic” that a deal can...

US Jobless Benefit Claims Drop for 6th Straight Week | Voice of America

June 10, 2021

June 10, 2021

WASHINGTON – New claims for jobless benefits in the United States continued to fall last week, dropping for the sixth...

New York Film Industry Booming Despite COVID Pandemic | Voice of America

June 6, 2021

June 6, 2021

As New York COVID restrictions ease, Broadway is hoping to draw people back to the theater while the movie industry...

Rep. Greene Apologizes for Comparing Safety Masks, Holocaust | Voice of America

June 15, 2021

June 15, 2021

WASHINGTON – Rep. Marjorie Taylor Greene apologized Monday for affronting people with recent comments comparing the required wearing of safety...

Biden Fires Head of US Federal Housing Finance Agency After Court Ruling | Voice of America

June 24, 2021

June 24, 2021

U.S. President Joe Biden has fired the head of the agency that oversees major mortgage entities Fannie Mae and Freddie...

Augmented Reality Event Honors Breonna Taylor’s Memory | Voice of America

June 22, 2021

June 22, 2021

After the shooting death of Breonna Taylor in 2020, her sister Ju’Niyah Palmer not only had to deal with her...

Study: Half of US Cosmetics Contain Toxic Chemicals | Voice of America

June 16, 2021

June 16, 2021

More than half the cosmetics sold in the United States and Canada are awash with a toxic industrial compound associated...

Blinken Urges US Allies to Keep Up Islamic State Fight | Voice of America

June 28, 2021

June 28, 2021

U.S. Secretary of State Antony Blinken urged allies Monday to maintain a focus on defeating the Islamic State group, with a particular...

Blinken Heads to Rome Focusing on Syria and Defeating IS Terrorists | Voice of America

June 27, 2021

June 27, 2021

After being warmly welcomed in France and Germany, Secretary of State Antony Blinken heads to Italy on Sunday to meet...

US-Based Non-Profit Group Works to Reunite Ethiopian Families Separated by Adoption | Voice of America

June 7, 2021

June 7, 2021

The letter delivered to Måns Clausen brought startling news. It advised the Swedish actor that his biological mother in Ethiopia,...

Closing Arguments Continue in Case of Men Accused of Murdering Ahmaud Arbery

November 23, 2021

November 23, 2021

Closing arguments continue Tuesday in the trial of three white men charged with murdering a Black man in the southern...