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It is one a set of photos that has been going the rounds in canada goose outlet in canada the media, following canada goose outlet niagara falls a recent series of publications by the Census of Marine canada goose outlet orlando Life an international network of marine scientists. canada goose outlet 2015 This set of 16 beasties appeared in The Guardian.
uk canada goose outlet The CoML folk estimate there are around marine 230,000 species (seems pretty low to me), canada goose sale uk and describe their findings in a series of articles in the canada goose outlet nyc PLoS ONE open access journal. These include one with the great title “Deep sea biodiversity in canada goose kensington parka uk the Mediterranean Sea: The known, the unknown, and the unknowable”. All highly recommended. uk canada goose outlet
But back to the amphipod. But what caught my attention was the caption given to it by The Guardian: “Pelagic amphipod, Phronima sedentaria. It travels in a ‘house’ that is a cylindrical shaped organism whose body has an opening on both ends. Giger in his design of the Alien in Ridley Scott’s canada goose outlet uk sale film of the same name.
canada goose uk outlet Apart from hoping that P. sedentaria and its pals live way away from the Deepwater Horizon spill, I was intrigued by the “house”: what kind of organism is it, and why on earth would it accept having a shrimp that isn’t a shrimp canada goose stockists uk living inside it? canada goose uk outlet
canada goose clearance The answer to the first question is remarkable. The “house” is a thing called a salp, and its an animal. Looking at it, you might think it was something like a jellyfish, but not at all. It has a well organised nervous system and is in fact a canada goose outlet factory chordate, just like you and me and my cats. More specifically, it’s a tunicate, like a sea squirt. canada goose clearance
cheap canada goose uk This diagram from the Tasmanian Aquaculture and Fisheries Institute, shows the salp’s structure it has a series of circular muscles going round the body, a mouth, an anus, and a through gut. It moves and eats by ingesting water and squirting it out through its rear end. As well as being a neat trick requiring neuronal coordination, these fecal pellets form an important part of the marine ecoystem. As K. Iseki wrote in 1981: cheap canada goose uk
canada goose factory sale “Free floating sediment traps were suspended at 200 and 900 m in the northern North Pacific Ocean during 20 21 May, 1974. A considerable amount of large, dark green particles, larger than 1 mm canada goose parka outlet uk in diameter, was collected at both depths. These large particles corresponded morphologically with fecal pellets of salps. Vertical carbon flux was estimated to be 10.5 canada goose outlet store new york and 6.7 mg C m 2 d 1 at 200 and 900 m, respectively. This suggests that vertical transport of salp fecal pellets could play an important role in meeting the energy requirements of bathypelagic organisms in the open ocean.” canada goose factory sale
canada goose coats on sale Salp are a particularly important of the zooplankton, and together with the more widely known krill, they consume vast quantities of phytoplankton. Due to increases in salp numbers in the Southern Ocean, apparently due to global warming, the krill may be being replaced by salp within the Antarctic marine ecoystem. This in turn might have unknown consequences on larger, more canada goose outlet store toronto photogenic marine animals. They exhibit among the fastest growth rates of any multicellular organism. () Salps exhibit a complex life cycle with alternating aggregate and solitary generations. Aggregates (the sexual gonozooids) develop asexually from an elongating stolon that buds from an area just behind the endostyle of the solitary individuals (the oozooid). Individuals within aggregates are hermaphrodites, typically starting as females that canada goose outlet uk fake are fertilized by older male individuals from another chain. The resulting embryos (oozooids) then develop into the solitary asexual phase. There is no larval stage and even canada goose outlet canada before release the young oozooid often has a developing stolon. In many species only a single embryo develops within each individual of the aggregate. This method of asexual reproduction enables salps to quickly exploit periods of abundant food with rapid increases in population density.” canada goose coats on sale
Canada Goose Jackets The article concludes where we began: Canada Goose Jackets
canada goose black friday sale “Hyperiid amphipods and several species of fish also use salps as traveling homes.” canada goose black friday sale
cheap Canada Goose Now from the amphipod’s point of view the relationship with the salp seems quite understandable it could serve as some kind of protection against predators, or maybe canada goose outlet germany save them energy. cheap Canada Goose
But what does the salp get from transporting P. sedentaria up and down the water column? The canada goose outlet trillium parka black answer appears to be: nothing. As the webpage of Snke Johnsen’s lab at Duke University puts it, the “house” is nothing more than “a hollowed out salp test” (the test is the salp’s “shell”). This suggests to me that the salp has died or discarded the test, canada goose outlet houston and the amphipod simply takes up residence, like a canada goose outlet store montreal hermit crab.
buy canada goose jacket Things are in fact more complicated, more fascinating and more gruesome. buy canada goose jacket
In 1978 Philippe Laval from Villefranche in France, measured 70 “houses” fished up from the sea off Nice and subjected his findings to some complicated statistical analysis. He found that the houses broke down into five groups and belonged to either salps canada goose outlet online uk or pyrosomes (another form of tunicate that can bioluminesce).
canada goose Amazingly, it seems that the “house” is actually sculpted by the amphipod: canada goose
Canada Goose sale “It was shown that all the tissues were carefully removed by the amphipod (insalps as in pyrosomes), leaving only the tunic. () The inner surface is generally scraped off, perhaps to eliminate decomposing secondary ascidiozooids remaining in the test after zooid extraction. The inner surface is extremely smooth, as though finished with a fine cutting tool on a lathe. This could explain, besides the high variability, why principal component analysis did not disclose distinct groups of barrels. The inside is always made hollower in the middle, so that the wall is thicker at both ends. Less rigidity in the middle could produce the swelling leading to the barrel like shape, but therecould be also a mechanical distention by the rotating amphipod before tunic consolidation.” Canada Goose sale
canada goose clearance sale On reading this, I assumed the tunicate had been eaten http://www.canadagoosejacketoutlett.com before all this sculpting and scraping went on. Not at all. Laval concludes, with words that suggest the relationship with the Alien is not merely morphological: canada goose clearance sale
Canada Goose Coats On Sale “Finally, the relationship between Phronima and its barrel deserves some consideration. It is not in essence predaceous, because salps or pyrosomes are not primrily canada goose outlet washington canada goose outlet dc used as food (although they may be, besides making a barrel); moreover, the amphipod remains with within its partner. It is rather a borderline case of parasitism, soon fatal to the host, which is killed to obtain advantages from its tunic. Some hermit crabs are known which similarly kill and canada goose outlet toronto location eat molluscs before occupying the shells (Rutherford, 1977). Most of the hyperiid amphipods (if not all, as postulated by Harbison et al., 1977) are parasitic on pelagic animals. Phronimids, which deposit their larvae in the barrel, as do many hyperiids on their hosts (Laval, 1965), are not exceptions to the canada goose outlet website legit rule. By killing their host and removing its soft parts to prevent decay, they only go a step further and thus approach the margins of predation.” Canada Goose Coats On Sale
canada goose uk shop To complete the story, in 2005 Euichi Hirose and co workers studied seven “houses” and suggested canada goose outlet seattle they were indeed still alive cells were still alive and there were no bacteria in the barrels, suggesting there was some kind of antibiotic system in there. And Rene Bishop Stephen Geiger looked at the energetics of being a Phronima compared to other crustaceans and concluded: canada goose uk shop
canadian goose jacket “Although less energy is needed to remain in the water column since the gelatinous zooplankton makes the Phronima more buoyant than just Phronima alone, metabolicrates of Phronima are not lower than those of other pelagic crustaceans, possibly due to the energy needed to propel the barrel. However, Phronima have lower protein concentrations, indicating less energy is allocated to muscle production. The canada goose outlet sale ratio of LDH (L lactate dehydrogenase) activity to CS (citrate synthase) activity was >1, indicating that burst swimming is important in Phronima metabolism. The symbiotic relationship provides the Phronima with food and a substrate for the brooding of young, but canada goose outlet legit does not give them an energetic advantage over other pelagic crustaceans.” canadian goose jacket.
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