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Thread: Whales enrich the ocean.

  1. #1 Whales enrich the ocean. 
    Forum Radioactive Isotope skeptic's Avatar
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    A very interesting article in New Scientist - paper issue 9 July 2011, page 37 - tells of the effect whales once had in enriching the oceans. Once, there were millions of whales around Antarctica, and in other places. Historic records suggest that the population of krill was also many times as high as it is today. As whales were killed off, krill numbers fell also. It is possible also, that fish numbers followed.

    The article, by marine biologist Steve Nicol (Australian Antarctic Division), suggests that whales enrich the ocean, when there are enough of them. They do this by three methods.
    1. Swimming through the summer thermocline, creating turbulence to permit nutrient rich waters from deeper down to mix with impoverished surface waters, generating phytoplankton growth.
    2. Feeding at depth, and bringing the food to the surface, where whale feces also create enrichment.
    3. Converting krill into whale poop. Krill also feed at depth, and bring nutrients (especially iron) into sunlit surface waters, if they are eaten by whales.

    Normally, we would expect krill numbers to increase as whale numbers fall, but the reverse happened. This strongly suggests the enrichment process, generating more food in the form of phytoplankton.

    At this stage more research is needed, but it is a very interesting hypothesis, and should be publicised, especially to counter the rationalisations of whaling nations.


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  3. #2  
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    I am surprised this hasn't gotten any responses.
    I found it very interesting, and am in general very interested in the effects keystone species have on their environments.

    I found this much more amazing than the impact of wolves, who since their reintroduction into Yellowstone have also had quite an impressive impact. The ecosystem being so dependent on the presence of whales that even the populations of their prey species drop in their absence (or reduced presence) is a spectacular find in my opinion.

    Perhaps there isn't much to be added (and thus no discussion)?


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  4. #3  
    Moderator Moderator AlexP's Avatar
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    That's very interesting. Just goes to show how intricately everything is linked. I saw an article once...don't remember where it was, perhaps National Geographic...about the huge amount of life that whale carcasses gather on the seabottom. It was very interesting.
    "There is a kind of lazy pleasure in useless and out-of-the-way erudition." -Jorge Luis Borges
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  5. #4  
    Forum Freshman chakazul's Avatar
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    Thanks Skeptic for the news.
    I hope there will be researches to follow up this kind of study -- the ecological role of the whales. The old simple-minded thinking assumes that if one kills the top predator, the lower layers will increase in number, so some people may have excuses to kill the precious species like whales, dolphins, or even sharks, in hope of increasing their economical profits. But this is not even scientifically true, provided the complexity of the marine ecosystems.

    If it turns out that the whales are enriching the oceans, at least we have a strong argument against commercial whaling in Japan, Norway etc.

    Chak
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  6. #5  
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    There's another way that whales contribute - The carcasses of dead whales support specialised ocean floor ecosystems. See <a href="http://www.scientificamerican.com/article.cfm?id=the-prolific-afterlife-of-whales"> 'The prolific afterlife of whales' - Scientific American's Feb 2010 edition</a>. A whale carcass can apparently continue to provide food to a variety of species for as long as 5 decades.
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