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Marine Migrations through Global warming

Jul 22nd 2011 at 12:31 PM

The largest movement of marine species that has occurred on Earth in over two million years, according to scientists, is the result of global warming. Melting Arctic sea ice in recent summers has opened a permanent passage between the Pacific and the North Atlantic, so that plankton, fish and even whales tare moving through the oceans as never before in human history

Delicate marine food webs, that humanity has become accustomed to, could become quite easily unbalanced, leading to extinctions, as food competition between invaders and native species pushes resources beyond sustainable limits. The fact that the seas are warming up is allowing sub-tropical region species to migrate northwards.

The northeast Atlantic now, for instance, has become home to the venomous warm-water species The Portugese Man of War jellyfish, forcing beaches to close and now becoming increasingly common in British waters, as is the form of algae known as dinoflagellates, great blooms of them using up the oxygen and producing toxins that make shellfish poisonous to eat.

Over the past 70 years, research has revealed that species of plankton, normally only found in the Pacific have now become common in the Atlantic, moving through an Arctic sea-ice passage that has opened up. Larger species have also been found to have made the journey through the passage, this vast area of sea opening up for the first time in thousands of years.

This inevitably means that now, between Alaska and the west of Greenland, a huge transfer of water and species is beginning to occur between the two oceans, a species found, in 1999, in the Atlantic that had not been seen before, yet is abundant in the Pacific. It had died out, because of glaciation in the Atlantic around 800,000 years ago, and the last time there was a species incursion between oceans was two to three million yearsin the past.

When large numbers of species migrate from the Pacific, lots of lAtlantic species are likely to become extinct, the impact on salmon and other fish resources very dramatic, quite probably. If the ice is continues to melt as it has been, complete melting within30 years, which would see huge species migrations occurring.

Dutch studies found that warmer water means more North and Irish sea species moving from more southerly areas, the west of Scotland ending up with fewer, the signs already pointing to far more trouble from climate change than any possible benefit that might arise damaging upheavals inevitable as the actions of humanity overturn the incredibly complex and important workings of a system that we barely understand to start with.

That these changes will have serious implications for commercial fisheries, and on the marine environment as a whole is no longer in question, but the reversal of the damage done may simply no longer be a realistic possibility. Nature has always found a way o cope with the idiotic behavior of the human race, but in that part of the world that covers 75% of our planet, the oceans, we may already have provided the last straw.

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