How Man-made Nitrogen Deposition May Alter World’s Oceans Permanently

photo by Ian Sanderson via Flickr

Nitrogen deposition in the world’s oceans has increased dramatically–more than doubling in the past 100 years. What does that mean for both sea life and the environment as a whole?

National Science Foundation-funded research has revealed that the impact of a rising Nitrogen content in the earth’s oceans, caused by air pollution and agricultural practices, is far greater than once expected.

The problem

Researchers have been observing the effects of pollution in the earth’s atmosphere and in the oceans for decades, but what makes this particular revelation noteworthy, isn’t just the source (industry and agriculture) but the level of impact.

According to Professor David Karl, who has studied nitrogen deposition for over half a century, the rate at which man-made nitrogen is affecting the world’s oceans is troubling to say the least.

“This is a sobering result, one that I would not have predicted…The North Pacific is so vast it is hard to imagine that humans could impact the natural nitrogen cycle.” – David Karl

How is man made nitrogen deposited into the ocean? It works as follows:

  • Nitrogen, a common by-product of industry and large scale agricultural facilities is first pumped into the atmosphere
  • This nitrogen is then swept up and temporarily deposited into cloud systems
  • Rain–tainted by man-made nitrogen–then finds its way back into the ocean through said precipitation

Though nitrogen fixation–the process by which atmospheric nitrogen is used by some oceanic organisms–occurs naturally, the study finds that man-made nitrogen is now being deposited at a magnitude which equals about half of the world’s natural process–a rate that experts say will only increase.

The impact

According to the report, the effects of an increasing rate of nitrogen deposition could have some significant changes on the ocean and consequently sea life.

Some possible outcomes could be:

  • Toxic algal blooms – algal blooms, (which are essentially just rapid increases in an areas algae population) much like the one observed most recently in Cleveland, may only become more common since such organisms feed off of the atmospheres nitrogen. These blooms could disrupt water supplies and sea life.
  • Disruption of the ecosystem – the report warns that the increase in nitrogen rates in may alter the ocean floor upon which other ocean life feeds.
  • A spread of carbon-rich material – scientists warn that an increased rate of photosynthesis caused by increased nitrogen will cause carbon rich material to be pushed further into ocean depths. Such material may alter the PH of ocean water, harming sea life and altering ecosystems further.

The takeaway

When it comes to nitrogen pollution, outside of increased regulation on industry and agriculture, there’s likely little in the way of concrete solutions. In fact, such pollution will probably only increase if industry continues to expand.

Here are the key points on :

  • Nitrogen is being pumped into the atmosphere more than ever
  • The consequences of such nitrogen pollution will eventually alter and even harm the world’s oceans
  • The increased nitrogen deposition has been proven to stem from man made sources and man-made nitrogen deposition accounts for a 50 percent increase in the world’s oceans.

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James Pero