News / Science & Technology

Scientists Report Steep Decline in Algae Critical to Marine Food Chain

Enlargement of phytoplankton cells
Enlargement of phytoplankton cells

The global population of a marine algae called phytoplankton has declined by 50 percent since the middle of the last century, threatening marine creatures that depend on the microscopic plant for food. Scientists blame global warming for the trend.

Tiny green phytoplankton are a food staple for many ocean creatures, according to marine biologist Daniel Boyce of Dalhousie University in Nova Scotia, Canada.  Boyce says phytoplankton are similar to trees and grass on land.

"They produce energy through the process of photosynthesis.  So in the presence of sunlight, they convert inorganic energy to organic energy.  And by doing this, they form the base of the entire marine ecosystem.  So they are the food for everything -- from little zooplankton up to the big whales," he said.

Boyce and his colleagues compiled and analyzed data going back to the 1800s.  Researchers found that the amount of phytoplankton had decreased about one percent of the global average per year with about a 40 percent decline since 1950.  The strongest trends were found in the Northern Hemisphere.  

Boyce says researchers analyzed the data derived from a low tech device called a secchi disc.

"It looks like a white dinner plate.  It's a disc with a rope attached to it.  And the person collecting data lowers this disc into the water, while [it is] attached to the rope.  And they measure the depth where the disc can no longer be seen.  And that's recorded as the water clarity or the secchi depth.  And it turns out that this depth, this water clarity, correlates quite well to the amount of phytoplankton in the upper oceans.  So it's a good measure of the amount of algae in the upper oceans," he said.

Combining the secchi disc data with information from more modern algae measurement tools, Boyce says researchers constructed a database of almost a half-a-million ocean measurements dating to the year 1899.

Biologists then plugged the measurements into a computer model that estimated global changes in the amount of phytoplankton over time.  Scientists say the greatest algae declines have occurred in the polar and tropical regions and the open oceans, where most phytoplankton production occurs.

Researchers say that rising ocean surface temperatures, due to global warming, are affecting the growth of phytoplankton, which need sunlight and nutrients from below the surface to grow.  They say that warmer water limits the amount of nutrients that are delivered to the surface from the cooler ocean depths.

Phytoplankton are critical to the health of our planet, according to Boyce, who says ocean algae produce half of the oxygen we breathe and reduce the amount of carbon dioxide that otherwise would contribute to global warming. "They affect the stability of our global climate.  And they can have the potential to affect our fisheries as well.  So phytoplankton are extremely important to us and we should be very concerned that phytoplankton has declined over this long time period," he said.

An article highlighting global reductions in marine algae is published in the journal Nature.

You May Like

Bernie Sanders Surge Reflects US Shift on Socialism

Although most analysts say it is unlikely he will get the Democratic nomination, Sanders' campaign opens up questions and issues that are otherwise marginalized More

Crowdfunding Helps Save Neil Armstrong's Spacesuit

Smithsonian turns to Kickstarter to raise more than $700,000 to help preserve the spacesuit worn by the first man to walk on the moon More

Video On IS Frontline, Kurdish Fighters Ready for Offensive

Peshmerga soldiers say although they need more heavy artillery, they are poised to take the fight to the Islamic State extremists on their turf More

This forum has been closed.
Comments
     
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Drowned Migrant Toddler Photo Triggers European Outragei
X
Henry Ridgwell
September 04, 2015 11:36 AM
The harrowing picture of a drowned three-year-old Syrian boy washed up on a Turkish beach appears to have galvanized Europe’s leaders into doing more to address the refugee crisis. France, Germany and Italy issued a joint call Thursday for compulsory quotas of refugees for all EU states. But there were chaotic scenes in Hungary as police tried to force migrants off a train heading for Austria. Henry Ridgwell has more. And a caution, some of the images in this report may be disturbing.
Video

Video Drowned Migrant Toddler Photo Triggers European Outrage

The harrowing picture of a drowned three-year-old Syrian boy washed up on a Turkish beach appears to have galvanized Europe’s leaders into doing more to address the refugee crisis. France, Germany and Italy issued a joint call Thursday for compulsory quotas of refugees for all EU states. But there were chaotic scenes in Hungary as police tried to force migrants off a train heading for Austria. Henry Ridgwell has more. And a caution, some of the images in this report may be disturbing.
Video

Video Russians Observe 11th Anniversary of Beslan School Attack

This week, Russians have been observing the 11th anniversary of the attack by Islamic militants on a school in Russia's North Caucasus region that killed more than 330 hostages, including 186 children. The three-day siege and massacre that started on September 1, 2004 took place in Beslan, a town in the republic of North Ossetia, and is one of the bloodiest terrorist acts ever in Russia. VOA's Mike Richman reports.
Video

Video Native Americans Debate: Father Serra, Saint or Sinner?

Pope Francis will canonize an 18th century missionary to Spanish California during a papal visit to the United States this month.  But some Native Americans have criticized the elevation to sainthood of the missionary priest, Junipero Serra. VOA's Mike O’Sullivan has more from Los Angeles.
Video

Video Calais School Offers Another Face of Europe’s Migrant Crisis

Europe is facing mounting criticism over how it’s handling its biggest migration crisis since World War II. But not all Europeans believe building walls or passing repressive policies are the answer. A school for migrants in the French port city of Calais, is opening doors and building bonds across nationalities. VOA's Lisa Bryant reports.
Video

Video Kurdish Fighters on IS Frontline Ready for Offensive

Finger on the trigger, the Kurdish Peshmerga soldier stared across the dust at a village taken over by Islamic State extremists. The Kurdistan’s Khazir frontline, just 45 minutes from the Islamic State stronghold of Mosul. And at this point, the militants were less than two kilometers away. VOA's Sharon Behn reports.
Video

Video China Announces Troop Cuts at WWII Parade

Chinese President Xi Jinping Thursday announced plans to cut the world’s largest military force by 300,000 troops. The announcement was made during a massive military parade to commemorate victory over Japan in World War II. The event was shunned by most Western leaders and for some is raising fresh concerns about China’s military ambitions. VOA’s Bill Ide has more from Beijing.
Video

Video Russia-Japan Relations Cool as Putin Visits China for WWII Anniversary

Russian President Vladimir Putin is in Beijing for commemorations of the 70th anniversary of China's WWII victory over Japan. Putin is expected to visit Japan later this year, but tensions between Tokyo and Moscow over islands disputed since the war, and sanctions over Ukraine, could pour cold water on the plan. VOA's Daniel Schearf reports.
Video

Video Yemen ‘on Brink of Disaster’ as Medical Shortages Soar

Aid agencies warn Yemen is on the brink of humanitarian disaster – with up to half a million children facing severe malnutrition, and hospitals running out of basic medicines. There are fears Yemen's civil war could escalate as the coalition led by Saudi Arabia tries to drive back Houthi rebels, who seized control of much of the country earlier this year. Henry Ridgwell reports.
Video

Video Apps Helping Kenyan Businesses Stay Ahead of Counterfeiters

Counterfeit goods in Kenya cost the government as much as $1 billion each year in lost tax revenues. The fake goods also hurt entrepreneurs who find it hard to carve out a niche in the market and retain customers. But as Lenny Ruvaga reports from Nairobi, information technology is being used to try to beat the problem.
Video

Video Nobel Prize Winner Malala Talks to VOA

Nobel Peace Prize winner Malala Yousafzai met with VOA's Deewa service in Washington Sunday to talk about women’s rights and unveil a trailer for her new documentary. VOA's Katherine Gypson has more.
Video

Video War, Drought Threaten Iraq's Marshlands

Iraq's southern wetlands are in crisis. These areas are the spawning ground for Gulf fisheries, a resting place for migrating wildfowl, and source of livelihood for fishermen and herders. Faith Lapidus has more.
Video

Video Colombians Flee Venezuela as Border Crisis Escalates

Hundreds of Colombians have fled Venezuela since last week, amid an escalating border crisis between the two countries. Last week, Venezuelan President Nicolas Maduro ordered the closure of a key border crossing after smugglers injured three Venezuelan soldiers and a civilian. The president also ordered the deportation of Colombians who are in Venezuela illegally. Zlatica Hoke reports.
Video

Video Rebuilding New Orleans' Music Scene

Ten years after Hurricane Katrina inundated New Orleans, threatening to wash away its vibrant musical heritage along with its neighborhoods, the beat goes on. As Bronwyn Benito and Faith Lapidus report, a Musicians' Village is preserving the city's unique sound.
Video

Video In Russia, Auto Industry in Tailspin

Industry insiders say country relies too heavily on imports as inflation cuts too many consumers out of the market. Daniel Schearf has more from Moscow.
Video

Video Scientist Calls Use of Fetal Tissue in Medical Research Essential

An anti-abortion group responsible for secret recordings of workers at a women's health care organization claims the workers shown are offering baby parts for sale, a charge the organization strongly denies. While the selling of fetal tissue is against the law in the United States, abortion and the use of donated fetal tissue for medical research are both legal. VOA’s Julie Taboh reports.

VOA Blogs