A Picture is Worth... Ocean Deserts Expanding
by Tim McGee, Helena, MT, USA on 03. 9.08
The black areas represent the least productive areas of the ocean, which have increased 15% from 1998 to 2007. The warming of the surface of the ocean is thought to increase stratification within the water column, preventing the nutrients in the cool deep ocean from rising to the surface. Without the mixing, there is limited ability for life to take hold.
We humans have an odd relationship to the ocean, treating it both as a bounty and an endless dump. This dualistic relationship has its costs. Addressing ocean health is tied to terrestrial problems and global warming. The good news is there is a lot we can do to help the ocean recover and stay resilient despite change. Jeremy provides an overview of ocean health issues, and even 10 solutions we can do to mitigate this growing problem.
this may sound stupid, but what is exactly is a "water column" in the ocean?
A water column is simply looking at the ocean from the surface into the depths. A vertical view.
That is a rather frightening picture.
Just to distinguish, the words "dead zones" is slightly ambiguous here. Typically a dead zone is a area overwhelmed by nutrient surpluses (usually nitrogen) to the point that all the oxygen is used up in decomposition. Demersal and benthic creatures then die of suffocation. A serious problem, most recently observed off the Oregon coast and now chronic at the mouths of many rivers, most notably the Mississippi.
The "dead zones" in the article are the oligotrophic regions of the ocean, which are full of life, but depend on a very efficient recycling of available nutrients.
I can't speak to the validity of the mechanism mentioned here, it sounds loosely plausible , but calling these regions "dead zones" is misleading. A bit like calling a desert a dead zone.
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Authors Note: You are correct- it is misleading. The title has been changed to reflect the correct ecological context and meaning. Thank you.
It is not only due to thermal stratification. Aeolian deposition of iron and other trace nutrients has been reduced over the last several decades, in those zones. For that there are also climatic explanations.
But wait: aren't these zones precisely the places that the now defunct Planktos had plans for iron seeding? Why yes...of course. Until the "greens" who have no clue about the earth's bio-geochemical cycles attacked them, accusing them of upsetting ecosystems, etc.
I wonder if you could pump carbon dioxide from power plants into dead zones, allowing photosynthetic plankton to grow, which would then release oxygen, allowing other things to grow.
Just a thought.
JL:
It strikes me that the carbon footprint of an iron seeding operation on this massive scale would be quite huge. IF these ocean deserts are attributable to global warming, should the effort be put into reversing the process, rather than treating one symptom of the disfunction? It strikes me that mitigation of global warming on a grand scale is the only way to assure other symptoms similar to this one won't pop up.
Rob. I would agree with that. The iron seeding notion can be understood metaphorically. When a patient enters the emergency room in serious distress, the doctors must first stabilize him/her before treatment. Iron seeding was to stabilize patient-earth. THe long term cure is as you said. Those who portrayed it as a way of avoiding the necessary lifestyle changes were either ignorant or disingenuous or simply anti-capitalist, not believing that business can be set up to do good things.
There's just about no clean water left to go windsurfing on. I think most politicians hang out in bars and commity rooms. Oh I guess I got that wrong it's actually brothels.