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

Brutality Eroding IS Financial Support

Director of National Intelligence James Clapper says IS's penchant for publicizing beheadings, other brutal forms of punishment hurts group’s bottom line More

Studies: Climate Change a Factor in Disasters in Syria, California

The studies point to the possibility of clear and present dangers from a threat often considered to be far in the future More

Video Afghan Refugees Complain of Harassment in Pakistan

Afghan officials and human rights organizations assert that Pakistani authorities are using deadly attack at school in Peshawar as pretext to push out Afghan refugees 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.
Kerry Seeks Assurances of Russian Non-Interference in Ukrainei
X
March 03, 2015 3:11 AM
U.S. Secretary of State John Kerry has told his Russian counterpart, Sergei Lavrov, that his country could face further consequences to what he called its “already strained economy” if Moscow does not fully comply with a cease-fire in Ukraine. The two met, on Monday, on the sidelines of a U.N. Human Rights Council meeting in Geneva, where Kerry outlined human rights violations in Russian-annexed Crimea and eastern Ukraine. VOA State Department correspondent Pam Dockins reports from Geneva.
Video

Video Kerry Seeks Assurances of Russian Non-Interference in Ukraine

U.S. Secretary of State John Kerry has told his Russian counterpart, Sergei Lavrov, that his country could face further consequences to what he called its “already strained economy” if Moscow does not fully comply with a cease-fire in Ukraine. The two met, on Monday, on the sidelines of a U.N. Human Rights Council meeting in Geneva, where Kerry outlined human rights violations in Russian-annexed Crimea and eastern Ukraine. VOA State Department correspondent Pam Dockins reports from Geneva.
Video

Video Smartphones May Help in Diagnosing HIV

Diagnosing infections such as HIV requires expensive clinical tests, making the procedure too costly for many poor patients or those living in remote areas. But a new technology called lab-on-a-chip may make the tests more accessible to many. VOA’s George Putic reports.
Video

Video Afghan Refugees Complain of Harassment in Pakistan

Afghan officials have expressed concern over reports of a crackdown on Afghan refugees in Pakistan following the Peshawar school attack in December. Reports of mass arrests and police harassment coupled with fear of an uncertain future are making life difficult for a population that fled its homeland to escape war. VOA’s Ayesha Tanzeem reports from Islamabad.
Video

Video Ukrainian Volunteers Prepare to Defend Mariupol

Despite the ongoing ceasefire in Ukraine, soldiers in the city of Mariupol fear that pro-Russian separatists may be getting ready to attack. The separatists must take or encircle the city if they wish to gain land access to Crimea, which was annexed by Russia early last year. But Ukrainian forces, many of them volunteers, say they are determined to defend it. Patrick Wells reports from Mariupol.
Video

Video Moscow Restaurants Suffer in Bad Economy, Look for Opportunity

As low oil prices and Western sanctions force Russia's economy into recession, thousands of Moscow restaurants are expected to close their doors. Restaurant owners face rents tied to foreign currency, while rising food prices mean Russians are spending less when they dine out. One entrepreneur in Moscow has started a dinner kit delivery service for those who want to cook at home to save money but not skimp on quality. VOA's Daniel Schearf reports.
Video

Video US, Cuba Report Progress in Latest Talks to Restore Ties

The United States and Cuba say they have made progress in the second round of talks on restoring diplomatic relations more than 50 years after breaking off ties. Delegations from both sides met in Washington on Friday to work on opening embassies in Havana and Washington and iron out key obstacles to historic change. VOA’s Mary Alice Salinas reports from the State Department.
Video

Video Presidential Hopefuls Battle for Conservative Hearts and Minds

One after another, presumptive Republican presidential contenders auditioned for conservative support this week at the Conservative Political Action Conference held outside Washington. The rhetoric was tough as a large field of potential candidates tried to woo conservative support with red-meat attacks on President Barack Obama and Democrats in Congress. VOA Political Columnist Jim Malone takes a look.
Video

Video NYC's Restaurant Week: An Economic Boom in Fine Dining

New Yorkers take pride in setting world trends — in fashion, the arts and fine dining. The city’s famous biannual Restaurant Week plays a significant role in a booming tourism industry that sustains 359,000 jobs and generates $61 billion in yearly revenue. VOA's Ramon Taylor reports.
Video

Video Brookhaven at Cutting Edge of US Energy Research

Issues like the Keystone XL pipeline, fracking and instability in the Middle East are driving debate in the U.S. about making America energy independent. Recently, the American Energy Innovation Council urged Congress and the White House to make expanded energy research a priority. One beneficiary of increased energy spending would be the Brookhaven National Lab, where clean, renewable, efficient energy is the goal. VOA's Bernard Shusman reports.
Video

Video Southern US Cities Preserve Civil Rights Heritage to Boost Tourism

There has been a surge of interest in the American civil rights movement of the 1950s and '60s, thanks in part to the Hollywood motion picture "Selma." Five decades later, communities in the South are embracing the dark chapters of their past with hopes of luring tourism dollars. VOA's Chris Simkins reports.
Video

Video Deep Under Antarctic Ice Sheet, Life!

With the end of summer in the Southern hemisphere, the Antarctic research season is over. Scientists from Northern Illinois University are back in their laboratory after a 3-month expedition on the Ross Ice Shelf, the world’s largest floating ice sheet. As VOA’s Rosanne Skirble reports, they hope to find clues to explain the dynamics of the rapidly melting ice and its impact on sea level rise.
Video

Video Lao Dam Project Runs Into Opposition

A Lao dam project on a section of the Mekong River is drawing opposition from local fishermen, international environmental groups and neighboring countries. VOA's Say Mony visited the region to investigate the concerns. Colin Lovett narrates.

All About America

Circumventing Censorship

An Internet Primer for Healthy Web Habits

As surveillance and censoring technologies advance, so, too, do new tools for your computer or mobile device that help protect your privacy and break through Internet censorship.
More