New study show plankton in decline

by bohm 1 Replies latest jw friends

  • bohm

    Question: About half of all organic matter produced on earth is plankton. Pretty much all thats going on in the oceans are based on plankton, and they also convert a hell of a lot of carbon dioxide to oxygen every day. 40% of all planktion has vanished in 50 years most likely due to mans activities. Does that seem like a good plan?

    Writeup on yahoo:

    WASHINGTON – Despite their tiny size, plant plankton found in the world's oceans are crucial to much of life on Earth. They are the foundation of the bountiful marine food web, produce half the world's oxygen and suck up harmful carbon dioxide.

    And they are declining sharply.

    Worldwide phytoplankton levels are down 40 percent since the 1950s, according to a study published Wednesday in the journal Nature. The likely cause is global warming, which makes it hard for the plant plankton to get vital nutrients, researchers say.

    The numbers are both staggering and disturbing, say the Canadian scientists who did the study and a top U.S. government scientist.

    "It's concerning because phytoplankton is the basic currency for everything going on in the ocean," said Dalhousie University biology professor Boris Worm, a study co-author. "It's almost like a recession ... that has been going on for decades."

    Half a million datapoints dating to 1899 show that plant plankton levels in nearly all of the world's oceans started to drop in the 1950s. The biggest changes are in the Arctic, southern and equatorial Atlantic and equatorial Pacific oceans. Only the Indian Ocean is not showing a decline. The study's authors said it's too early to say that plant plankton is on the verge of vanishing.

    Virginia Burkett, the chief climate change scientist for U.S. Geological Survey, said the plankton numbers are worrisome and show problems that can't be seen just by watching bigger more charismatic species like dolphins or whales.

    "These tiny species are indicating that large-scale changes in the ocean are affecting the primary productivity of the planet," said Burkett, who wasn't involved in the study.

    When plant plankton plummet — like they do during El Nino climate cycles_ sea birds and marine mammalsstarve and die in huge numbers, experts said.

    "Phytoplankton ultimately affects all of us in our daily lives," said lead author Daniel Boyce, also of Dalhousie University in Halifax, Nova Scotia. "Much of the oxygen in our atmosphere today was produced by phytoplankton or phytoplankton precursors over the past 2 billion years."

    Plant plankton — some of it visible, some microscopic — help keep Earth cool. They take carbon dioxide — the key greenhouse gas — out of the air to keep the world from getting even warmer, Boyce said.

    Worm said when the surface of the ocean gets warmer, the warm water at the top doesn't mix as easily with the cooler water below. That makes it tougher for the plant plankton which are light and often live near the ocean surface to get nutrients in deeper, cooler water. It also matches other global warming trends, with the biggest effects at the poles and around the equator.

    Previous plankton research has mostly relied on satellite data that only goes back to 1978. But Worm and colleagues used a low-tech technology — disks devised by Vatican scientist Pietro Angelo Secchi, in the 19th century. These disks measure the murkiness of the ocean. The murkier the waters, the more plankton.

    It's a proxy the scientific community has long accepted as legitimate, said Paul Falkowski of Rutgers University, who has used Secchi disk data for his work.

    He and other independent scientists said the methods and conclusions of the new study made sense.

    Abstract and conclusion from nature article:

    In the oceans, ubiquitous microscopic phototrophs (phytoplankton) account for approximately half the production of organic matter on Earth. Analyses of satellite-derived phytoplankton concentration (available since 1979) have suggested decadal-scale fluctuations linked to climate forcing, but the length of this record is insufficient to resolve longer-term trends. Here we combine available ocean transparency measurements and in situ chlorophyll observations to estimate the time dependence of phytoplankton biomass at local, regional and global scales since 1899. We observe declines in eight out of ten ocean regions, and estimate a global rate of decline of ~1% of the global median per year. Our analyses further reveal interannual to decadal phytoplankton fluctuations superimposed on long-term trends. These fluctuations are strongly correlated with basin-scale climate indices, whereas long-term declining trends are related to increasing sea surface temperatures. We conclude that global phytoplankton concentration has declined over the past century; this decline will need to be considered in future studies of marine ecosystems, geochemical cycling, ocean circulation and fisheries.


    Our analysis suggests that global Chl concentration has declined since the beginning of oceanographic measurements in the late 1800s. Multiple lines of evidence suggest that these changes are generally related to climatic and oceanographic variability and particularly to increasing SST over the past century (Fig. 6). The negative effects of SST on Chl trends are particularly pronounced in tropical and subtropical oceans, where increasing stratification limits nutrient supply. Regional climate variability can induce variation around these long-term trends (Fig. 4), and coastal processes such as land runoff may modify Chl trends in nearshore waters. The long-term global declines observed here are, however, unequivocal. These results provide a larger context for recently observed declines in remotely sensed Chl 7, 10, 22 , and are consistent with the hypothesis that increasing ocean warming is contributing to a restructuring of marine ecosystems 36, 37 , with implications for biogeochemical cycling 15 , fishery yields 38 and ocean circulation 3 . Such consequences provide incentive for an enhanced in situ and space-borne observational basis to reduce uncertainties in future projections.

  • SacrificialLoon

    Who needs phytoplankton? With the advent of the hydrogen economy we'll just crack water through electrolysis and dump the oxygen into the atmosphere, thus solving the problem now and forever.

    Seriously though, that's some disturbing findings. I wonder if they used secchi disc readings today to compare to sattelite data on the same day to come up with estimations of historical plankton levels? I would imagine that would've had to.

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