Showing posts with label marine. Show all posts
Showing posts with label marine. Show all posts
Thursday, May 6, 2010
Thursday, March 18, 2010
David Gallo on life in the deep oceans - a TED talk
via ted.com
A lecture accompanied by some astonishing deep sea videos that I showed in intro bio class this week when we were discussing the potential origins of life at hydrothermal vents on the ocean bottom.
Friday, January 15, 2010
Did the Pier 39 Sea Lions disappear because of 20th anniversary blues?
via abclocal.go.com
Perhaps they skipped town because they got wind of a party being thrown to mark the 20th anniversary of their taking over San Francisco's Pier 39. I imagine it could be depressing for these wonderful creatures of the open sea to realize that they've spent almost 20 years hanging out in an urban tourist trap! And not merely hang out, but actually become the bait in that tourist trap... yikes! Surely that's reason enough to hightail it out of there?!
All kidding aside, back on shore, someone over at the Marine Mammal Center has got to be wondering why on earth no one thought of tagging some of these beasts! You know, with one of them GPS transponder things so they could have kept track of them at times like these. Did no one ever think the animals might just take off some day, as abruptly as they had appeared?
Meanwhile, they had to postpone the anniversary party to a later date when, hopefully, the guests of honor will actually deign to be present! I sure hope they do return...
Sunday, March 8, 2009
Mysteries in the Kingdom of the Blue Whale
One strand follows biologists tagging and tracking the whales from the California coast all the way into the warm tropical "nursery" of the Costa Rica dome (watch the show to find out what a "dome" might mean in the ocean), trying to solve the puzzles of their life-cycle, which is surprisingly poorly understood for the largest creatures on the planet! Sanzari, who spent a year in the field with her mom studying another charismatic yet elusive (and much smaller!) mammal, the Slender Loris, in the forests of southern India, could relate to the challenges of tagging the whales, but couldn't quite imagine tracking them across half an ocean! Tough to scale up from tracking the tiny lorises, hard enough to track in their several hectare sized home-ranges, to creatures occupying half of the world's biggest ocean!! She therefore enjoyed it when the biologists got their payoff after months on the ocean, including sad episodes when they found whales dead from being hit by ships!
Intertwined with this is a second thread which follows researchers investigating the whale meat market in Japan, using undercover operatives and portable genetics labs set up in hotel rooms! Exciting stuff, especially when they teamed up with a local female biologist who posed as a regular shopper to obtain samples from the whale meat market; and when they hung up the "do not disturb" sign on their hotel door to set up the portable genetics lab to extract DNA from the samples. What Nancy Drew fan wouldn't want to do such investigative work? Although we did wonder why the biologists weren't simply collaborating with Japanese scientists to analyze the samples in a proper lab?! What's the story there?
The whale-meat trade itself provoked some anger in the girls (carnivorous though they both are), with the sushi-loving Sanzari fuming all the way through about the Japanese and the Icelanders who wouldn't stop hunting whales! The genetic findings from one sample were even more intriguing to me... but I better not give that away before the show airs, eh? If you can't wait, or don't get the channel, check out this clip on the show's website.
What I can't resist giving away, however, is this money-shot at the end, when the first team finally caught up with a mother and infant:
I am simply amazed that we share our planet with such magnificent creatures - and also that we know so little about even some of the largest living animals! And I hope we can find ways to ensure that my girls' generation, and future ones too, get the opportunity to see the Blue Whales thrive once again.
Monday, April 28, 2008
Benefits of invading exotic organisms in a marine environment
Student post submitted by Darin Alexander.
When we think of invading exotic species you already have a negitive view in your mind. There is a high rate of negative publicity on exotic species. They are thought to be destructive, and can cause large amounts of stress and possible extinction of native species. This is a true statement when it comes to terrestrial or aquatic species, but what about marine? In this article John Briggs discusses the benefits, yes benefits, invasive species can have on marine environments. (Continues below...)
Briggs discusses the ongoing situation taking place in the Mediterranean. Since the opening of the Suez Canal in 1869 there has been a steady stream of invading species to the Mediterranean from the red sea. 300 of these organisms are now established in the area. The organisms documented are 59 fish species, 129 mollusk species and 49 crustacean species. You would think with all these new entering species they must be pushing out native ones. This is a surprisingly wrong assumption. From the data collected there have been no extinctions due to the newly invading species. They have actually increases the community’s biodiversity and has been beneficial. Introduced primary consumers have increased consumption of producers and allowed more access to energy. This helps increase the community’s productivity. People commonly lump the problem of aquatic and terrestrial invaded species with marine but this is a mistake.
It has been shown that there is no obvious detrimental effect invading species have on marine environment. In most instances marine invaders are needed to help keep up the populations biodiversity. This article also talks about the migration of mollusks 5.4 billion years ago across the Bering Strait. The mollusks came from the pacific region of the U.S and settled on the coast of Europe and Eastern America. A statistic given is now 47% of the original pacific species established on the east coast has diverged into a separate species. This is Evolution and species divergence at hand. Also with fossil records they were able to prove that the invading species caused no extinction of the original native species and in some cases the populations assimilated together.
This was a very interesting article and it shows different aspects of things we have leaned in class this year. We go from migration, to competition, to nitch differentiation, to species divergence, then to assimilation and eventually evolution. It also sheds some light on the benefits of exotic organism invasion and shows us that it is not always bad.
Reference:
Briggs, J.C. (2007). Marine biogeography and ecology: invasions and introductions. Journal of Biogeography, 34(2), 193-198. DOI: 10.1111/j.1365-2699.2006.01632.x
Abstract:
Although biogeography and ecology had previously been considered distinct disciplines, this outlook began to change in the early 1990s. Several people expressed interest in creating a link that would help ecologists become more aware of external influences on communities and help biogeography’s realize that distribution patterns had their genesis at the community level. They proposed an interdisciplinary approach called macroecology. This concept has been aided by the advent of phylogeography, for a better knowledge of genetic relationships has had great interdisciplinary value. Two areas of research that should obviously benefit from a macroecological approach are: (1) the question of local vs. regional diversity and (2) the question of whether invader species pose a threat to biodiversity. The two questions are related, because both deal with the vulnerability of ecosystems to penetration by invading species. Biogeographers, who have studied the broad oceanic patterns of dispersal and colonization, tend to regard isolated communities as being open to invasion from areas with greater biodiversity. It became evident that many wide-ranging species were produced in centres of origin, and that the location of communities with respect to such centres had a direct effect on the level of species diversity. Ecologists, in earlier years, thought that a community could become saturated with species and would thereafter be self-sustaining. But recent research has shown that saturation is probably never achieved and that the assembly of communities and their maintenance is more or less dependent on the invasion of species from elsewhere. The study of invasions that take place in coastal areas, usually the result of ship traffic and/or aquaculture imports, has special importance due to numerous opinions expressed by scientists and policy-makers that such invasions are a major threat to biodiversity. However, none of the studies so far conducted has identified the extinction of a single, native marine species due to the influence of an exotic invader. Furthermore, fossil evidence of historical invasions does not indicate that invasive species have caused native extinctions or reductions in biodiversity.
Subscribe to:
Posts (Atom)
Posts
