Declining algae threatens ocean food chain: study

A century-long decline in tiny algae called phytoplankton could disrupt the global ocean food chain, including the human consumption of fish, according to a study released Wednesday.

The microscopic organisms - which prop up the pyramid of marine animal life from shrimps to killer whales - have been disappearing globally at a rate of one percent per year, researchers reported.

Since 1950, phytoplankon mass has dropped by about 40 percent, most likely due to the accelerating impact of global warming, they reported.

"Phytoplankton is the fuel on which marine ecosystems run," said lead author Daniel Boyce, a professor at Dalhousie University in the Canadian province of Nova Scotia.

"A decline affects everything up the food chain, including humans."

The pace of the decline - heavist in polar and tropical regions - matched the rate at which surface ocean temperatures have increased as a result of climate change, the study said.

Like all plants, phytoplankton need sunlight and nutrients to grow.

But warmer oceans become more stratified, creating a "dead zone" at the surface in which fewer nutrients are delivered from deeper layers.

The findings are worrying, the researchers said.

"Phytoplankton are a critical part of our planetary support system - they produce half the oxygen we breathe, draw down surface carbon dioxide, and ultimately support all fisheries," said co-author Boris Worm.

Boyce and colleagues combined historical and high-tech data to measure the marine algae's progressive ebb.

Satellites provided the most accurate gauge, but usable images from space of Earth's ocean biosphere have only been available since the late 1990s - too recent to show longterm trends.

To reach back further in time, Boyce and colleagues combed through logs compiled since the late 19th century using a 20-centimetre (eight-inch) white disk lowered into sea water until an observer lost sight of it.

The degree to which light penetrates the ocean's top layer, it turns out, is a good measure of the concentration of the chlorophyll found in all phytoplankton.

The study, published in Nature, "does not portend well for pelagic, or open water, ecosystems in a world that is likely to be warmer," David Siegel, a researcher at the University of California at Santa Barbara, and Bryan Franz, an ocean biologist at NASA Goddard Space Flight Center, said in a commentary.

In a separate study, also in Nature, a team of researchers led by Derek Tittensor of Dalhousie found a close tie between sea temperatures and the concentration of biodiversity in the world's oceans.

Across more than 11,000 species ranging from zooplankton to whales, the only environmental factor linked to all species groups was temperature.

"This relationship suggests that ocean warming, such as that due to climate change, may rearrange the distribution of ocean life," Tittensor said in a statement.

Life and Style
ebookNow available in paperback
ebooks
ebookA delicious collection of 50 meaty main courses
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
SPONSORED FEATURES

ES Rentals

    Independent Dating
    and  

    By clicking 'Search' you
    are agreeing to our
    Terms of Use.

    iJobs Job Widget
    iJobs General

    Recruitment Genius: Senior Environmental Adviser - Maternity Cover

    £37040 - £43600 per annum: Recruitment Genius: The UK's export credit agency a...

    Recruitment Genius: CBM & Lubrication Technician

    £25000 - £27500 per annum: Recruitment Genius: This company provides a compreh...

    Recruitment Genius: Care Worker - Residential Emergency Service

    £16800 - £19500 per annum: Recruitment Genius: Would you like to join an organ...

    Recruitment Genius: Senior Landscaper

    £25000 - £28000 per annum: Recruitment Genius: In the last five years this com...

    Day In a Page

    The long walk west: they fled war in Syria, only to get held up in Hungary – now hundreds of refugees have set off on foot for Austria

    They fled war in Syria...

    ...only to get stuck and sidetracked in Hungary
    From The Prisoner to Mad Men, elaborate title sequences are one of the keys to a great TV series

    Title sequences: From The Prisoner to Mad Men

    Elaborate title sequences are one of the keys to a great TV series. But why does the art form have such a chequered history?
    Giorgio Armani Beauty's fabric-inspired foundations: Get back to basics this autumn

    Giorgio Armani Beauty's foundations

    Sumptuous fabrics meet luscious cosmetics for this elegant look
    From stowaways to Operation Stack: Life in a transcontinental lorry cab

    Life from the inside of a trucker's cab

    From stowaways to Operation Stack, it's a challenging time to be a trucker heading to and from the Continent
    Kelis interview: The songwriter and sauce-maker on cooking for Pharrell and crying over potatoes

    Kelis interview

    The singer and sauce-maker on cooking for Pharrell
    Refugee crisis: David Cameron lowered the flag for the dead king of Saudi Arabia - will he do the same honour for little Aylan Kurdi?

    Cameron lowered the flag for the dead king of Saudi Arabia...

    But will he do the same honour for little Aylan Kurdi, asks Robert Fisk
    Our leaders lack courage in this refugee crisis. We are shamed by our European neighbours

    Our leaders lack courage in this refugee crisis. We are shamed by our European neighbours

    Humanity must be at the heart of politics, says Jeremy Corbyn
    Joe Biden's 'tease tour': Could the US Vice-President be testing the water for a presidential run?

    Joe Biden's 'tease tour'

    Could the US Vice-President be testing the water for a presidential run?
    Britain's 24-hour culture: With the 'leisured society' a distant dream we're working longer and less regular hours than ever

    Britain's 24-hour culture

    With the 'leisured society' a distant dream we're working longer and less regular hours than ever
    Diplomacy board game: Treachery is the way to win - which makes it just like the real thing

    The addictive nature of Diplomacy

    Bullying, betrayal, aggression – it may be just a board game, but the family that plays Diplomacy may never look at each other in the same way again
    Lady Chatterley's Lover: Racy underwear for fans of DH Lawrence's equally racy tome

    Fashion: Ooh, Lady Chatterley!

    Take inspiration from DH Lawrence's racy tome with equally racy underwear
    8 best children's clocks

    Tick-tock: 8 best children's clocks

    Whether you’re teaching them to tell the time or putting the finishing touches to a nursery, there’s a ticker for that
    Charlie Austin: Queens Park Rangers striker says ‘If the move is not right, I’m not going’

    Charlie Austin: ‘If the move is not right, I’m not going’

    After hitting 18 goals in the Premier League last season, the QPR striker was the great non-deal of transfer deadline day. But he says he'd preferred another shot at promotion
    Isis profits from destruction of antiquities by selling relics to dealers - and then blowing up the buildings they come from to conceal the evidence of looting

    How Isis profits from destruction of antiquities

    Robert Fisk on the terrorist group's manipulation of the market to increase the price of artefacts
    Labour leadership: Andy Burnham urges Jeremy Corbyn voters to think again in last-minute plea

    'If we lose touch we’ll end up with two decades of the Tories'

    In an exclusive interview, Andy Burnham urges Jeremy Corbyn voters to think again in last-minute plea