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

    New EU Asylum Rules Could Boost Rightists

    New regulations will seek to correct EU failures in dealing with migrant crisis, most notably inability to get member states to absorb a total of 160,000 refugees

    More Political Turmoil Likely in Iraq as Iran Waits in the Wings

    Analysts warn that Tehran, even though it may not be engineering the Sadrist protests in Baghdad, is seeking to leverage its influence on its neighbor

    Goodbye Ketchup, Hello Sriracha!

    How immigrants are triggering a great transformation in American cuisine

    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.
    Tensions Rising Ahead of South China Sea Rulingi
    X
    May 03, 2016 5:16 PM
    As the Philippines awaits an international arbitration ruling on a challenge to China's claims to nearly all of the South China Sea, it is already becoming clear that regardless of which way the decision goes, the dispute is intensifying. VOA’s Bill Ide has more from Beijing.
    Video

    Video Tensions Rising Ahead of South China Sea Ruling

    As the Philippines awaits an international arbitration ruling on a challenge to China's claims to nearly all of the South China Sea, it is already becoming clear that regardless of which way the decision goes, the dispute is intensifying. VOA’s Bill Ide has more from Beijing.
    Video

    Video Painting Captures President Lincoln Assassination Aftermath

    A newly restored painting captures the moments following President Abraham Lincoln’s assassination in 1865. It was recently unveiled at Ford’s Theatre in Washington, where America’s 16th president was shot. It is the only known painting by an eyewitness that captures the horror of that fateful night. VOA’s Julie Taboh tells us more about the painting and what it took to restore it to its original condition.
    Video

    Video Elephant Summit Results in $5M in Pledges, Presidential Support

    Attended and supported by three African presidents, a three-day anti-poaching summit has concluded in Kenya, resulting in $5 million in pledges and a united message to the world that elephants are worth more alive than dead. The summit culminated at the Nairobi National Park with the largest ivory burn in history. VOA’s Jill Craig attended the summit and has this report about the outcomes.
    Video

    Video Displaced By War, Syrian Artist Finds Inspiration Abroad

    Saudi-born Syrian painter Mohammad Zaza is among the millions who fled their home for an uncertain future after Syria's civil war broke out. Since fleeing Syria, Zaza has lived in Lebanon, Egypt, Jordan and now Turkey where his latest exhibition, “Earth is Blue like an Orange,” opened in Istanbul. He spoke with VOA about how being displaced by the Syrian civil war has affected the country's artists.
    Video

    Video Ethiopia’s Drought Takes Toll on Children

    Ethiopia is dealing with its worst drought in decades, thanks to El Nino weather patterns. An estimated 10 million people urgently need food aid. Six million of them are children, whose development may be compromised without sufficient help, Marthe van der Wolf reports for VOA from the Metahara district.
    Video

    Video Little Havana - a Slice of Cuban Culture in Florida

    Hispanic culture permeates everything in Miami’s Little Havana area: elderly men playing dominoes as they discuss politics, cigar rollers deep at work, or Cuban exiles talking with presidential candidates at a Cuban coffee window. With the recent rapprochement between Cuba and United States, one can only expect stronger ties between South Florida and Cuba.
    Video

    Video California Republicans Weigh Presidential Choices Amid Protests

    Republican presidential candidates have been wooing local party leaders in California, a state that could be decisive in selecting the party's nominee for U.S. president. VOA's Mike O’Sullivan reports delegates to the California party convention have been evaluating choices, while front-runner Donald Trump drew hundreds of raucous protesters Friday.
    Video

    Video Kurdish Football Team Helps War-Torn City Cope

    With the conflict still raging across much of Turkey’s predominantly Kurdish southeast, between the rebel PKK and the Turkish state, many Kurds are trying to escape the turmoil by focusing on the success of their football team Amedspor in Diyarbakir. The club is increasingly becoming a symbol for Kurds, not only in Diyarbakir but beyond. Dorian Jones reports from southeast Turkey.
    Video

    Video ‘The Lights of Africa’ - Through the Eyes of 54 Artists

    An exhibition bringing together the work of 54 African artists, one from each country, is touring the continent after debuting at COP21 in Paris. Called "Lumières d'Afrique," the show centers on access to electricity and, more figuratively, ideas that enlighten. Emilie Iob reports from Abidjan, the exhibition's first stop.
    Video

    Video Florida’s Weeki Wachee ‘Mermaids’ Make a Splash

    Since 1947, ‘mermaids’ have fascinated tourists at central Florida’s Weeki Wachee Springs State Park with their fluid movements and synchronized ballet. Performing underwater has its challenges, including cold temperatures and a steady current, as VOA’s Lin Yang and Joseph Mok report.
    Video

    Video Somali, African Union Forces Face Resurgent Al-Shabab

    The Islamic State terror group claimed its first attack in Somalia earlier this week, though the claim has not been verified by forces on the ground. Meanwhile, al-Shabab militants have stepped up their attacks as Somalia prepares for elections later this year. Henry Ridgwell reports there are growing frustrations among Somalia’s Western backers over the country’s slow progress in forming its own armed forces to establish security after 25 years of chaos.
    Video

    Video Nigerians Feel Bite of Buhari Economic Policy

    Despite the global drop in the price of oil, Nigerian President Muhammadu Buhari has refused to allow the country's currency to devalue, leading to a shortage of foreign exchange. Chris Stein reports from Lagos businessmen and consumers are feeling the impact as the country deals with a severe fuel shortage.

    Special Report

    Adrift The Invisible African Diaspora