A newly released study by Dalhousie University researchers suggests that the most basic foundation of the ocean’s food chain, phytoplankton, is disappearing at an alarming rate. Phytoplankton is the generic term used to cover a myriad of tiny plant species that float freely in the waters of the oceans. The study, performed by Dalhousie researcher, Daniel Boyce, shows a forty percent decline in the amount of phytoplankton in the oceans since 1950.
Ocean’s food chain losing vital link
Phytoplankton is a key source of food for many species of sea creatures which, in turn provide food for other, larger creatures. Boyce found that rising ocean temperatures appears to be the main cause of the decline. “As the water temperature rises, the ocean becomes more stable,” warns Boyce, “which limit’s the amount of nutrients in the water.” Without the nutrients brought up from the ocean floor, the ocean is less able to support phytoplankton. Because phytoplankton fuels the ocean’s food chain, the majority of ocean life may be threatened, in turn.
Ocean dead zones growing in size and number
At the same time, NASA is reporting that satellite imaging has revealed a dramatic increase in the size and number of low oxygen dead zones in the Earth’s oceans over the last fifty years. The increasing dead zones are most often associated with fertilizer run-off and other man-made pollutants being carried into the oceans by rivers which collect these materials over their full course before emptying into the oceans. Dead zones are places where there is not enough oxygen in the water to support life. Fish and other aquatic creatures that find themselves in a dead zone suffocate.
Oceans losing ability to produce oxygen
The effects of these events are not limited to aquatic life. “Half of the world‘s oxygen is produced via phytoplankton photosynthesis,” says National Geographic News. The other half is produced by trees and other land-based plants. While the turbulence of air is almost certainly too great to permit dead zones, loss of a key portion of the world’s oxygen production may lower the overall oxygen content of the atmosphere over time. Phytoplankton also provides a carbon sink by absorbing carbon and incorporating it into its tissues. The decline of phytoplankton due to rising ocean temperatures, therefore, reduces the oceans’ ability to act as a storage tank for the excess carbon that is being produced by human industrial activities. This self-reinforcing cycle is likely to accelerate global warming over the next decades.
Is it too late to save the oceans?
The Dalhousie study provides another strong piece of evidence that rising temperatures are impacting the Earth’s ability to support life and suggests that we may be in the early stages of one of the greatest mass extinctions that our planet has ever faced. As we diminish the capacity of the Earth’s natural systems to absorb and mitigate the effects of greenhouse gases, we multiply their effect upon global temperatures. The scientific consensus is that we could not stop global warming at this point, even if we ceased all greenhouse gas production immediately. We have borrowed deeply against our environment and will be paying it back with interest for centuries. Limiting further damage, however, is still an important goal even as we learn to deal with global conditions that are less friendly to life in general.
Sources:
Hennigar, Melissa. Phytoplankton in Retreat. July 28, 2010. Dalhousie University News. Retrieved from dalnews.dal.ca/2010/07/28/photoplank.html on July 30, 2010.
Roach, John. Source of Half Earth’s Oxygen Gets Little Credit. June 7, 2004. National Geographic News. Retrieved from news.nationalgeographic.com/news/2004/06/0607_040607_phytoplankton.html on July 30, 2010.
NASA. Aquatic Dead Zones. July 17, 2010. Earth Observatory. Retrieved from earthobservatory.nasa.gov/IOTD/view.php?id=44677 on July 30, 2010.
Comments
You guys really have no shame. This is coming out at the end of a El Nino, what would you expect.
"The scientific consensus is that we could not stop global warming at this point, even if we ceased all greenhouse gas production immediately"
So shut up already
Jorge,
The two separate studies represent a compilation of data stretching back more than 50 years from multiple sources, El Nino is not a factor and citing it shows a complete lack of understanding of the issues. While we cannot undo what we have already set in motion, we can certainly make it much, much worse by continuing on our present course. Global warming deniers sow confusion among those who are not familiar with the facts of the situation and delay the necessary action. Delay means more people will die. Not just in third world countries where the wealth and resources to cope with drought and increased heat does not exist, but in rich countries as well were the economic impact of global warming will bankrupt farmers, corporations, and families alike. I will not "shut up" while lives are at stake.
Actually, Brad, the researchers at Dalhousie University analyzed 110 years (1899-2008) of data, not 50, and detected a long-term declining trend in phytoplankton populations of roughly 1% per year. Using the more extensive and higher quality data available since 1950 only, they estimate a decline of about 40% (or an average rate of about 0.7%) according to reporting elsewhere. (Info based on study abstract published online at Nature journal site, a BBC news report, and a press report at Dalhousie U.)
None of the news reports preceding your article took note of the rising incidence and scope of oceanic dead zones. While warming oceans might explain the changes in phytoplankton populations, it is not clear the oceanic dead zone issue you addressed and known declines in populations of many commercial fish species were considered as explanations of, or contributing factors to, phytoplankton population developments.
Brad, we didn't have global warming 110 years ago.
You want to tell us all exactly how much the oceans temperatures have risen?
Then explain how plankton is so sensitive?
The take home message in this poor excuse for science, is that plankton is dying out because of lack of food. Dead zones are dead because of too much plankton food.
Unless we create more dead zones, we're all going to die.
Sad part is, now even biologists are claiming to be climate scientists and trying to get their piece of the money.
And while you're at it Brad, check the satellite data on ocean temperatures. Ocean temps have not risen in the past 10 years.
Jorge,
I don't know who's lying to you about ocean temps over the last 10 years, but here's real data: climate.nasa.gov/keyIndicators/index.cfm#GlobalTemperature
You throw up straw arguments and as they fall you refute your own earlier "evidence" as needed to confuse the real facts. First you said El Nino is the cause, then you said it was a gradual decline over 110 years (which is true as I pointed out). I guess it's good that you admit that your first argument was bogus.
Dead zones are a separate issue from the overall plankton declines. As noted, dead zones are the result of excess nitrogen, primarily from farm-land run-off causing a very temporary unsustainable algae bloom. The decomposing algae consumes oxygen creating a dead zone.
Dave, yes, 110 is indeed "more than 50 years" as I said. whether it is 50 or longer, the point is that a single El Nino is irrelevant to the discussion.
The NASA data shows "exactly how much the temperature has risen.
In response to my comment you say, "..., yes, 110 is indeed "more than 50 years" as I said. whether it is 50 or longer, the point is that a single El Nino is irrelevant to the discussion"? Hardly!
My point, expressed candidly rather than gently as before, was your "news" article was inadequately researched, shallow and biased.
Brad, HadISST is the official ocean temperature. What you linked is not.
HadISST dataset says ocean temps have risen 4/10 th of one degree in the last 100 years.
Do you really think 4/10th of a degree is going to make that big of a difference?
What they just showed is that the oceans are becoming limiting on iron and phosphorus. The oceans are getting cleaner.
With the decline in phyto it's possible that the oceans are releasing CO2, which can explain the rise in atmospheric CO2.
Brad, everyone that knows anything about global warming, knows you can show anything by where you start and stop your lines on a graph.
What they did was start their graph at the highest peak of a plankton bloom, where it had no place to go but down.
110 years ago was 1900. Look up the volcano dust index chart 1800 to 1900. volcano dust puts a lot of iron ect in the ocean, and that's fertilizer for plankton
They started their graph right after one of the highest centuries for volcano activity. Which means one of the highest centuries for plankton fertilizer, which means one of the highest centuries for plankton levels.
If phyto levels have gone down 50%, and NASA says phyto sequesters 100 million tons of CO2 a day, then the drop in phyto would explain 100% of the rise in atmospheric CO2.
Global warming has nothing to do with it, it's because the oceans have gotten cleaner and will not support those old phyto levels.
Global warming isn’t the only thing that is causing this rapid decline in sea life. The sky high levels of plastic and garbage in the ocean, in particular, the North Pacific Gyre, are greatly endangering our marine wildlife. Ocean Voyage Institute (a nonprofit) will going to be going out to clean up all of this trash, however, they need your support! Please check out www.dreamsailraffle.com or post their website on your facebook page.
Warmer oceans and more CO2 are beneficial to phytoplankton, as they are to all photo-synthesing life forms, hence plankton numbers are higher in summer than winter, leading to plankton blooms in some oceans in the Spring.
Mixing of data is a classic source of error as in the hockeystick and in ice cores. Homogenous data back to 1899? I don’t think so. Sampling methods are notoriously suspect: “Data recently collected in the northern Pacific Ocean shows two to three times more organic matter produced by photosynthesis than had been reported previously. Some biologists think that the open ocean has not been sampled often enough to catch periods of high productivity, resulting in low productivity assumptions. Others think that the sampling techniques themselves may have been responsible for erroneous results. Phytoplankcton are delicate organisms that can easily be damaged by the collecting techniques.
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