Growing low-oxygen zones in oceans worry scientists

[FourScore]

Growing low-oxygen zones in oceans worry scientists
McClatchy Newspapers
By Les Blumenthal, McClatchy Newspapers Les Blumenthal, Mcclatchy Newspapers – Sun Mar 7, 12:01 pm ET

WASHINGTON — Lower levels of oxygen in the Earth's oceans, particularly off the United States' Pacific Northwest coast, could be another sign of fundamental changes linked to global climate change, scientists say.

They warn that the oceans' complex undersea ecosystems and fragile food chains could be disrupted.

In some spots off Washington state and Oregon , the almost complete absence of oxygen has left piles of Dungeness crab carcasses littering the ocean floor, killed off 25-year-old sea stars, crippled colonies of sea anemones and produced mats of potentially noxious bacteria that thrive in such conditions.

Areas of hypoxia, or low oxygen, have long existed in the deep ocean. These areas — in the Pacific, Atlantic and Indian oceans — appear to be spreading, however, covering more square miles, creeping toward the surface and in some places, such as the Pacific Northwest , encroaching on the continental shelf within sight of the coastline.

"The depletion of oxygen levels in all three oceans is striking," said Gregory Johnson , an oceanographer with the National Oceanic and Atmospheric Administration in Seattle...

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[kestrel91316]

1. Fertilizer runoff + ocean acidification = death

[Motown_Johnny]

2. Fertilizer or Pesticide ? Or both?

I think pesticides are the problem but perhaps I am wrong

[kestrel91316]

3. Ecsessive nitrogen and phorphorus cause algal blooms that tie up all the oxygen.

Of course, herbicides and pesticides are not helpful either, but the Dead Zones are definitively linked to fertilizer runoff levels. It's in large part due to corn production, at least in the Midwest/Mississippi/Gulf.