tag:blogger.com,1999:blog-6568915967186844196.post1639734575208216153..comments2024-03-26T14:19:33.332-07:00Comments on Bench Grass: Postblogging Technology, July 1944, I: Victory Comes LateErik Lundhttp://www.blogger.com/profile/05728486209757153685noreply@blogger.comBlogger7125tag:blogger.com,1999:blog-6568915967186844196.post-67019949808858922032014-08-22T12:02:23.176-07:002014-08-22T12:02:23.176-07:00The Banks are young as fish habitat; exposed to ai...The Banks are young as fish habitat; exposed to air during the last glacial maximum, inundated about 8000 BP. (Much like Doggerland.)<br /><br />I'd want to know, not that the worm species are a genetic match, but that there was something there to replace at all. Bird transport (of eggs or young; there's recent work where snails have a better than 10% survival rate in bird guts...) back and forth strikes me as the null hypothesis.Graydonhttps://www.blogger.com/profile/09839374676813519438noreply@blogger.comtag:blogger.com,1999:blog-6568915967186844196.post-44813731399798999222014-08-22T04:20:27.914-07:002014-08-22T04:20:27.914-07:00This is some serious loonposting right here, but:
...This is some serious loonposting right here, but:<br /><br />estuarial mud is given by the geotechnical literature as having a density of 1.3g/cm^3. One square metre to depth 15 cm = (100cm*100cm)*15cm. Multiply cubic cm by 1.3 for grams. Divide by 1000 for kg, 195kg, that's some heavy stuff, no wonder they used it for ballast. You get about 5 of those to the tonne, or 4928 worms/tonne @ 961 per sq m. The <a href="http://www.international.icomos.org/risk/2006/28keith2006an.pdf" rel="nofollow">Molasses Reef</a> wreck used stone but at least it gives us a number, 40 tonnes, which is getting on for 200,000 worms/sailing. They can have between 1000-10000 young.Alexhttps://www.blogger.com/profile/17153530634675543954noreply@blogger.comtag:blogger.com,1999:blog-6568915967186844196.post-69985097679762732622014-08-22T03:48:27.867-07:002014-08-22T03:48:27.867-07:00First point; you don't have to make the strong...First point; you don't have to make the strong-form argument that it created the Banks ex nihilo. Drawing more and bigger shoals and maintaining them over time would be a big historical factor in itself.<br /><br />Second point: ecological changes can be quick, especially in those critical interface zones, when something important changes. It's pretty much the paradigm case of a systems dynamics tipping point wotsname. And we know that, well, there are European critters in the mud, rather than North American ones. <br /><br />Which leaves us with two options: either there weren't any, and the ecological niche was unoccupied, or there were, and these ones outcompeted and replaced them, i.e. they had some kind of adaptation to the environment the hypothetical others didn't. (It's as if this spookily mirrors some other debate about North American history! Although polychaete worms can't go back and fix the parish records or maintain legends about Indian princesses.) Either way this implies change. Cod are pelagic, after all, so they move. A limiting factor is the fish generation time, as IIRC they're quite long-lived. As for the critters, the amphipods produce a generation per year and barely overlap, so the population could flip very quickly. <br /><br />Except in the upper Fundy, where they reproduce *twice as fast*: http://personal.colby.edu/~whwilson/Wilson%20pdf%27s/Wilson&Parker1996.pdf OH HAI I AM YR IMMIGRANT COMING OVER HERE TAKING OUR FEMALES.<br /><br />I found that looking for basic data on generation times, but it turns out to contain a smoking gun. Not only are there distinct populations that reproduce twice as fast, the same distinction exists in Europe, and the twice-as-nicers come from the British Isles (specifically the Dovey in Wales and Whitby in Yorkshire) and are all over Nova Scotia. They discuss various explanations, but we now know that they're genetically different. The worms are longer-lived but they do two generations/year, so again there is the possibility of rapid introduction.<br /><br />Third point: if I really wanted to go full-on tinfoil I'd unfreeze Kirsten Seaver out of the Greenland ice cap and theorise that the transition from fishermen calling in Greenland to pick up deck crew for the season, to fishermen sailing direct to the Banks ex-Bristol or Lisbon, is actually a technological change. The big secret that the Portuguese and Bristolmen are keeping is that they're artificially seeding the fishing grounds and hence developing more and more of the coast as a fishery. They have a great source for the right stock - the Bristol channel, the wattenzee, whereever - which the Greenlanders emphatically don't. Hence the Greenlanders' role goes from being sought after Newfoundland pilots, to just being casual labour, and then to no particular role and so they give up and leave. It's not like fishermen wouldn't know that fish eat lugworms, after all, even if they think of it as bait or something. That is, however, officially tinfoil territory.<br /><br />An interesting question that you might be able to answer is how much mud ballast was being delivered to the far side of the ocean. The marine biologists have a pretty good handle on the population density, so you could get an estimate of how much genetic material is being introduced from ((sailings * average tonnage)/ballast fraction)*population density per tonne. Apparently you get as many as 961 worms per square meter, but obviously you'd need to fudge a conversion to cubic meters. They dig down to 15 cm, so we can assume a 1 sq m*0.15m.<br /><br />(It's as if this whole story weirdly mirrors some other issue in North American history or something. leaky pump iz leaking, into the muddy stinky bilges.)Alexhttps://www.blogger.com/profile/17153530634675543954noreply@blogger.comtag:blogger.com,1999:blog-6568915967186844196.post-49487750840444954662014-08-21T11:43:24.570-07:002014-08-21T11:43:24.570-07:00Cod shoals were noted on the banks as of 1497. If ...Cod shoals were noted on the banks as of 1497. If they're anthropogenic, then that's a license to put on our tinfoil (horned) hats and wander off in search of ancient Viking seafarers. <br /><br />If. This strikes me as an implausibly largescale environmental change. It looks like we're not going to see it in the genetics of cod, either, as there is interchange between adjacent cod stocks. I certainly vote for Fishery and Oceans giving large grants to all, though. MOAR science, plz!Erik Lundhttps://www.blogger.com/profile/05728486209757153685noreply@blogger.comtag:blogger.com,1999:blog-6568915967186844196.post-34262331504491871352014-08-21T04:12:07.120-07:002014-08-21T04:12:07.120-07:00Hmm, the amphipods are considered an ecological ke...Hmm, the amphipods are considered an ecological keystone species in Fundy, and seem to prevent the mudflats consolidating into biologically less productive saltmarsh. They are a very big food source for shore birds and also fish:<br /><br />http://www.bofep.org/corophiu.htm<br /><br />The ornithology is better understood because you can watch them more easily than you can watch fish, but I think the fish are actually more interesting for their economic consequences. As for the ragworms, everyone knows they're bait, but there's also this (http://link.springer.com/article/10.1023%2FA%3A1015681605656):<br /><br /><em>The construction of burrows by individuals increases the sediment–water interface. When they ventilate their burrows, individuals verticalize oxic zones into the sediment and promote microbial and meiofaunal growth alongside their burrows.</em><br /><br />i.e. they're driving oxygen and hence primary productivity deeper into the sediment. Productivity that then gets cycled up into the open water by the amphipods.<br /><br />Swinging for the fences with some wild speculation, perhaps we should think of the banks fisheries as semi-artificial ecosystems? The more ships, the more ballast mud, the more little beasts upcycling micro-flora and runoff into cod and haddock...the more ships. Obviously, if I controlled the Environment Canada grantmaking process I would immediately want Dr Addison to have his student Einfeldt go catch some critters off Newfoundland, and perhaps check his DNA sequences against the Bristol Channel and the Tagus and hell, why not somewhere in West Africa to boot?Alexhttps://www.blogger.com/profile/17153530634675543954noreply@blogger.comtag:blogger.com,1999:blog-6568915967186844196.post-79538543108257856092014-08-20T10:41:22.199-07:002014-08-20T10:41:22.199-07:00It's hard for me to believe at first blush tha...It's hard for me to believe at first blush that the actual biotic productivity of the Fundy (and Gulf of Maine) intertidals experienced a significant peri-contact boost, but the genetic tracing to Bay of Biscay (Fundy) and North/Norwegian Sea (Maine) populations seems on target. All we're missing now are Channel and Portuguese littoral populations.<br /><br />Now, if get evidence of a spike in biotic productivity, I would still be very surprised if it happened as late as Champlain's voyages. In fact, if the transformation had gone to completion by Champlain's time (can we infer that from the failure of the first colonists to observe it oingoing?) might even point us to a much earlier date. Since it's hard to put European mud in the bottoms of our beloved Greenland Norse, a solid early dating would give more credence to the hypothesis of pre-Columbian Bristol fishers --people I am a bit more agnostic on. (Unexplained westward fishing expeditions from Bristol can as easily be going to poach pilchards on the Cornwall coast as to North America, and would have a great more reason to keep it secret.)Erik Lundhttps://www.blogger.com/profile/05728486209757153685noreply@blogger.comtag:blogger.com,1999:blog-6568915967186844196.post-20431712215661217922014-08-20T06:42:06.789-07:002014-08-20T06:42:06.789-07:00http://www.cbc.ca/news/canada/new-brunswick/mariti...http://www.cbc.ca/news/canada/new-brunswick/maritime-sea-life-linked-to-early-european-explorers-1.2735279?cmp=rss<br /><br />Much off topic, but the fact that the marine ecosystem of the northeast coast seems to have been transformed by peri-contact invasive species sounds right up your street.Alexhttps://www.blogger.com/profile/17153530634675543954noreply@blogger.com