Scientists Report Steep Decline in Algae Critical to Marine Food Chain
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.
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.
The impacts of human industry on the planet’s ecosystems continue to pile up.
Affecting the food web of the oceans at a very fundamental level ought to raise alarms.
The scientific paper itself was published in Nature, which makes this story their current headline:
Marine phytoplankton have a crucial role in Earth’s biogeochemical cycles, and form the basis of marine ecosystems. Data from satellite remote sensing — available since 1979 — have provided evidence that phytoplankton biomass has fluctuated on the decadal scale, linked to climate forcing, but a few decades of data are insufficient to indicate long-term trends.
Daniel Boyce and colleagues now put these results in a long-term context by estimating local, regional and global trends in phytoplankton biomass since 1899, based on a range of sources including measurements of ocean transparency with a device known as a Secchi disk, and shipboard analyses of various types. What emerges from the records is a century of decline of global phytoplankton biomass.
The authors estimate that the decline of phytoplankton standing stock has been greatest at high latitudes, in equatorial regions, in oceanic areas and in more recent years. Trends in most areas are correlated significantly to increasing ocean warming, and leading climate indices.
This research, if confirmed and well understood, could stand out as one of the most important findings in recent years about man’s effects on the biosphere, and on a real emerging problem for the 21st century.