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[Music]

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[Applause]

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hey everyone um i said i'm annaliese

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Meyer and from the University of

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Victoria just up the coast in BC thanks

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that can be news for a great session so

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far today I'll be discussing rare earth

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element distributions in the Allegra

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trophic gyre of the Sargasso Sea so

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that's the subtropical North Atlantic

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and their influence on aerobic bacteria

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Lilith Anna trophy we developed this

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project over the past a year as a

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collaboration between university of

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victoria and the bermuda institute of

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ocean science which yes is a great place

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to do fieldwork so over the past couple

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of field seasons thank you we've been

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looking at the vertical distribution of

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rare elements throughout the entire

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water column at the bermuda Atlantic

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time study series station or bats which

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is about 4.5 kilometers water depth

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we've also been looking at the dissolved

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methane profiles dissolved nitrous oxide

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profiles and begun to assess the genetic

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and metabolic properties of marine

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methyl it rose and MANET rose now

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hopping over to land this is solfatara

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and Italy it's a geothermal normal site

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where a methyl is that a film Hugh Mario

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lick'em Sol V was first discovered and

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the interesting thing about this

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organism is that it required direct mud

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pot water from this region of Italy to

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allow its growth and there was some

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confusion about why exactly this was and

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it eventually was narrowed down to the

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presence of lanthanides in the water and

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that this marked this organism

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discovered by pol 8l as the first

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organism to acquire rare earth elements

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for life so they managed to grow this

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continuous bill my god continuously in

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culture using lanthanide supplemented

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tap water if I added tap water to my

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cultures I'd probably be fired but you

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know there you have it so this was only

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found at 2007 and before 1985 there

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wasn't any sort of speculation that

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biogeochemical cycling of rare earth

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elements and might exist whatsoever in

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1985 debarred I'll propose that maybe

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there was passive scavenging of rare

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earth elements onto biological particles

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in the water column but any sort of

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active metabolic role for these

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organisms wasn't even in the picture so

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I'll run quickly through the biochemical

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basis for rare earth element requirement

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from matheno trophy before getting into

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the results

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implications of this research for

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astrobiology some Spanish groups oxidize

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methane through a multi-step pathway and

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the either assimilated into biomass or

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dissimulate it into co2 through a couple

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different pathways that distinguish the

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types of meth addict rows each oxidation

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step produces Quinn tones and electron

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carriers to provide reducing power for

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ATP generation so this is a multi-step

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pathway but I'm just going to be

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focusing on methanol dehydrogenase today

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so this protein is the x-ray

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crystallography structure of one subunit

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of the Holmwood I'm Eric XO xf methanol

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dehydrogenase isoform from the

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previously mentioned med pot organism as

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you can see this version uses a pqq

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cofactor and a cerium ion in its active

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site other method i trophic species have

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been noted to use other rare earth

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elements but what I particularly want

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you to note here is that it's only the

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light rare earth elements so cerium

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lanthanum occasionally europium that

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have ever been observed so there is some

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confusion as to why this is and - and -

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why these rare earth elements are at all

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incorporated into these organisms before

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2007 the only eisah form of methanol

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dehydrogenase known used calcium in its

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active site which is pretty commonly

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used in metallo enzymes and is very

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abundant in both the ocean and other

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other environments it's thought that

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perhaps rare earth elements and as they

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are better loose Lewis acids than

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calcium might provide more efficient

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catalysts but it's still unclear as to

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the regulation of these two isoforms and

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in most meth ana toast both isoforms are

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found so to set the stage for a sampling

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I have to put some section plots of the

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transect between Bermuda and Puerto Rico

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from September 2018 so as you can see

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it's fairly oxic and stream lycée Lyon

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warm and extremely little dig of trophic

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and this red arrow here just indicates

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the location of bats these plots are all

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interrelated from CTD data so bottle

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data was used to calibrate these now to

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zoom in on fluorescence

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this green over here arrow here

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highlights the deep chlorophyll max and

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that's generally where we expect to find

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the most photosynthetic biomass however

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we expect to find meth Anna Torv sitting

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slightly lower around 300 meters there's

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higher nutrient concentrations there

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lower oxygen levels which is preferred

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by type 1 with Anna tros and most

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importantly it's welat of the euphotic

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zone mini-myth anna tropes are light

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inhibited so this is a pretty strict

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requirement now the location of both the

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chlorophyll Max and the Masada toph max

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will vary seasonally primarily due to

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the deep storm mixing in the winter so

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this makes a layer shown by this black

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line here drives the mixed layer much

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deeper in the winter and summer

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stratification shallows it quite

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dramatically

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so this deep winter storm mixing will

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drive the methane concentrations from

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atmospheric exchange deeper probably

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also allowing the Madonna crows to sit a

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little bit deeper deeper so now that

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we've gone over the dissolved gas

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chemistry of this area we'll dig into

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the depth of the matter which is the

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earth element distributions so all of

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our samples were collected in geo traces

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clean bottles so that's essentially a

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several month cleaning process to

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prevent any sort of trace metal

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contamination then pre concentrated on a

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chelating resin column the functional

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groups are pictured here it works

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equally well for trace metals and rare

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earth elements and analyzed with icp-ms

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so we got profiles that looked pretty

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consistently like this i've only

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highlighted the rare earth elements of

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particular interest to us in these

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profiles so that's lanthanum and cerium

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and contrasted them against a heavy

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earth element you have terbium so you

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can see that your turbine has quite a

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static profile whereas both cerium and

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lanthanum exhibit this drawdown feature

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sitting around 300 meters so cerium does

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can show continue to drop and that's due

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to its nature as a redox species so any

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sort of nutrient like effects of cerium

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are masked by this redox profile however

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lanthanum does exhibit a shockingly

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nutrient like profile especially if you

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view it from 300 meters down rather than

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from the surface as as usual

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this behavior was conserved throughout

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our entire autumn time series we did get

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an interesting mid-depth intrusion in

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lanthanum that appeared on october and

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persisted into november we're still

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looking into that with sediment wrapped

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data but it's likely a water mass

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movement in fact rather than micro

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billion mediated so we're not gonna dig

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too deeply into it today now things get

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really interesting when we normalized

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the light birth elements to a heavier

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rare earth element so in this case we've

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taken lanthanum see it cerium and

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neodymium and normalize them to the you

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terbium profile so this deep profile

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becomes a lot more static indicating

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what happens in the deep is likely

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conserved across the entire lanthanides

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sweet and not microbe alia mediated but

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that 300-meter proof drawdown feature

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that I called your attention to earlier

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becomes even more pronounced so this

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light worth element drawdown effect has

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been observed before by Alan Shiller a

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tile in the wake of the Deepwater

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Horizon blowout so these red dots here

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are from early May 2010 the blue

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triangles from late May 2010 and the

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yellow diamonds from October 2011 but a

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year and a half after the accident when

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the when the water column returned to

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normal huh so you can see that lanthanum

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is preferentially drawn down around

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1,100 meters and that's where there's

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this intrusion of natural gas Schiller a

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tile did also note that xox F methanol

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dehydrogenase was being expressed

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particularly in this area so that's the

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cerium or lanthanum bearing isoform of

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methanol hydrogenase so that's

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indicating that this methane oxidized

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oxidation is driving this drawdown so

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this drawdown bares a striking

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similarity to that drawdown feature that

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were noting in our in our rare earth

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element profiles and just note that this

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scale has changed in in these depth

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profiles so as the deepwater horizon

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drawdown around 1,100 meters was caused

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by this methane oxidation this gives us

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decent reason to believe that this

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drawdown is also caused by methane

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oxidation and the expression of this EXO

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xf gene so these are at wildly different

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depths and that reflects the control of

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methane concentration

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we're in getting those methane profiles

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ready for print so that we can actually

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correlate the rare earth element

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concentrations to the methane and the

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water column so the weight of this only

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comes when we can actually prove that

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it's methane oxidation causing this

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light rare earth element drawdown effect

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this portion of our research is still in

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our in its infancy but our preliminary

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methods for enriching communities with

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meth additives and methyl ropes have

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shown some success so far we've been

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purging cultures with methane and

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nitrogen and growing them up on solid

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supplemented seawater media under a

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methane mixed air atmosphere and that

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gave us enough growth to do some

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preliminary DNA extractions and PCR just

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to detect whether or not these genes are

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even present so we probe these methane

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cultures with primers designed to target

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the five main clades of EXO XF genes as

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defined by our date Alan 2015 and this

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gave us a decently strong signal from

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EXO xf 5 there was also smaller signals

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from EXO X F 1 & 2 but those were

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inconclusive so were gonna look a little

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further into that so this showed us that

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at the very least organisms carrying

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these EXO XF genes are present in the

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water column at where the sample was

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taken which is 300 meters whether or not

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this is being expressed in any abundance

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is still yet to be determined and we're

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looking into that but for a first step

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this was really promising so the final

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piece to discuss today's the use of this

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light worth element fractionation as a

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lasting metabolic signature so this is a

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principal component analysis for the

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molar ratios of lanthanum cerium and

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neodymium in samples of ancient

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hydrocarbon seeps from Fayette Alan 2009

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ranging in age from the middle devonian

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to the alig Essene i've also compared it

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to a variety of chongwu chondritic

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meteorites just to provide some scale

278
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chondritic meteorites are often used for

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rare earth element normalization instead

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of the heavier elements that we've been

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using here and as you can see these oxic

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seeps highlighted sorry these anoxic

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seeps highlighted in red which were

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inferred from a negative cerium anomaly

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as well as the presence of amina Pentel

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which is a bacterial helping polyol that

287
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allows for the positive identification

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of aerobic madonna trophy these anoxic

289
00:11:24,800 --> 00:11:22,230
seep seep sites do group more or less

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away from the oxic seep sites and it

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seems to have to do with the enrichment

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of lanthanum in these rocks so our

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00:11:36,710 --> 00:11:34,040
proposed explanation for this is that

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organisms which are performing aerobic

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Madonna trophy will selectively uptake

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lanthanum from the water column to

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perform or perform this aerobic method

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oxidation and once lanthanum is bound to

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these biological particles will be more

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easily buried and solidified as these as

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these reactions are occurring at the sea

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floor so to wrap things up if these as

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these rare earth elements are so

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insoluble in water

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00:12:09,080 --> 00:12:05,400
why has this xoxox F gene been so

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prolific and so persistent why has it

307
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persisted through the evolution of

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Madonna trophy and it is noted to be

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present in almost Alma Thanatos that

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have been studied in in combination with

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the normal calcium bearing isoform some

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explanations we have thought of are that

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perhaps mechana crows originated in some

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some environment in which were elements

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were more abundant like perhaps certain

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hot springs or hydrothermal vents I'm

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not going to comment on which I think it

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is because it'll get me in trouble or

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perhaps and the xof gene was simply the

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first version of this isuh form and the

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ability to use the more abundant calcium

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evolved later if you'd like to talk

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about phylogeny please find me later

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because there's some interesting

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thoughts on that however the most

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interesting part of this research from

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my perspective is not only the insight

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that these organisms can give us on the

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marine methane cycle but the idea that

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this light worth element fractionation

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might be useful as a lasting metabolic

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signature throughout geologic time and

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the insight that the rollover earth

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elements played in meth and meth Anna

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trove meth Anna trove evolution might

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give us about the origin and

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colonization of life on Earth

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and with that I'd like to thank you for

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your time and note my appreciation for

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my collaborators Jay Cullen and Damon

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Grendel as well as everyone else who's

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helped me so much on this project and

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insert' and the canadian associates of

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bios for my funding and with that I'll

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take any questions have you started to

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do competition studies with these to see

347
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if there's any like preference do they

348
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always go for the calcium isoform if

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you've introduced both so it I just was

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00:14:07,090 --> 00:14:05,480
wondering if you had you know any kind

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of direct competition where you could

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give ample metal availability to see if

353
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there's a preference biologically yeah

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00:14:17,820 --> 00:14:15,680
so that's um that's in the works we

355
00:14:20,769 --> 00:14:17,830
haven't yet started that as we've just

356
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my last week in the lab was when we

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managed to get these actually growing

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properly we're going to be looking at

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particularly rate with these - with the

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expression of each enzyme so we're doing

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some heavy isotope analysis with

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provided methane and hopefully that'll

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give some idea of which is which is the

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preference and which enzyme is actually

365
00:14:48,940 --> 00:14:47,120
more efficient my intuition would lead

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to the rare earth element very isoform

367
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being more efficient given its

368
00:14:56,800 --> 00:14:54,440
characteristic has a stronger lewis acid

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but we'll see so we had one more

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question here the one in the back and

371
00:15:12,340 --> 00:15:09,190
thank you nice talk Annalise sounds

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great so there's been some work showing

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that certain groups of microbes will

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actually take up to lyrium but it's

375
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unclear kind of what its fate is so that

376
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I guess the first question is you've

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00:15:26,290 --> 00:15:24,320
shown us some data on some of the some

378
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of the lanthanides have you been able to

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00:15:30,610 --> 00:15:28,100
extend it and look at some of the other

380
00:15:33,280 --> 00:15:30,620
lanthanides or is that on your radar

381
00:15:34,930 --> 00:15:33,290
yes we've we've analyzed for the suite

382
00:15:37,000 --> 00:15:34,940
of sixteen lanthanides and chemically

383
00:15:39,120 --> 00:15:37,010
similar elements these were the ones

384
00:15:42,250 --> 00:15:39,130
that showed the most dramatic

385
00:15:44,710 --> 00:15:42,260
differences the heavier elements beyond

386
00:15:46,060 --> 00:15:44,720
europium really show more of the profile

387
00:15:47,410 --> 00:15:46,070
that I showed like you terbium that's

388
00:15:49,780 --> 00:15:47,420
pretty static throughout the water

389
00:15:52,060 --> 00:15:49,790
column and all of the structural

390
00:15:55,270 --> 00:15:52,070
analysis that's been done on xox F genes

391
00:15:57,370 --> 00:15:55,280
that's our XF proteins have shown only

392
00:15:59,670 --> 00:15:57,380
lanthanum and cerium occasionally

393
00:16:03,010 --> 00:15:59,680
neodymium being used and one analysis

394
00:16:07,410 --> 00:16:03,020
artificially used europium and got a

395
00:16:09,940 --> 00:16:07,420
slightly lower rate but it did still

396
00:16:12,070 --> 00:16:09,950
catalyze but they have everyone's don't

397
00:16:15,150 --> 00:16:12,080
seem to use understood thank you thank

398
00:16:23,100 --> 00:16:21,000
I wanted to ask a question about how we

399
00:16:25,440 --> 00:16:23,110
think about the preservation of these

400
00:16:29,250 --> 00:16:25,450
genes that in the local environment seem

401
00:16:31,080 --> 00:16:29,260
to be strange and whether or not this

402
00:16:34,530 --> 00:16:31,090
should be providing us information about

403
00:16:36,300 --> 00:16:34,540
the sort of global suite of

404
00:16:38,250 --> 00:16:36,310
circumstances that organisms may be

405
00:16:40,230 --> 00:16:38,260
reflecting if we think about vent

406
00:16:42,540 --> 00:16:40,240
organisms we find that for instance mat

407
00:16:43,830 --> 00:16:42,550
formers and endosymbionts advents all

408
00:16:45,450 --> 00:16:43,840
around the world are more closely

409
00:16:48,270 --> 00:16:45,460
related to each other than they are to

410
00:16:50,070 --> 00:16:48,280
anything somewhere else and so I wonder

411
00:16:54,150 --> 00:16:50,080
if something slow like the complete

412
00:16:56,460 --> 00:16:54,160
abandonment of a gene might occur on

413
00:16:58,410 --> 00:16:56,470
time scale so much slower than organism

414
00:17:00,630 --> 00:16:58,420
sample environments all over the world

415
00:17:02,820 --> 00:17:00,640
that what we're seeing is an averaging

416
00:17:05,340 --> 00:17:02,830
over ecosystems of many different types

417
00:17:08,370 --> 00:17:05,350
even when we sample things that seem to

418
00:17:09,900 --> 00:17:08,380
be locally adapted is is that reasonable

419
00:17:13,040 --> 00:17:09,910
given what you know about these systems

420
00:17:16,140 --> 00:17:13,050
I would say that's a very good thought

421
00:17:19,439 --> 00:17:16,150
based on some very preliminary sequence

422
00:17:25,020 --> 00:17:19,449
analysis of these genes it does seem

423
00:17:28,890 --> 00:17:25,030
like they are being preserved fairly

424
00:17:30,870 --> 00:17:28,900
well there had there's been between xsf

425
00:17:33,180 --> 00:17:30,880
genes from many different environments

426
00:17:35,280 --> 00:17:33,190
the sequence similarity is quite

427
00:17:38,270 --> 00:17:35,290
shocking there's more sequence

428
00:17:41,390 --> 00:17:38,280
similarity between X Y X F genes of

429
00:17:46,500 --> 00:17:41,400
diverse organisms than there is between

430
00:17:48,870 --> 00:17:46,510
the very conserved MX a or calcium

431
00:17:53,580 --> 00:17:48,880
bearing isoform of the same organism so

432
00:17:56,970 --> 00:17:53,590
for context those two genes are over 15%

433
00:17:59,430 --> 00:17:56,980
sorry over 50% identical at the amino

434
00:18:01,980 --> 00:17:59,440
acid level and at the active site level

435
00:18:04,860 --> 00:18:01,990
there's only one amino acid different

436
00:18:06,630 --> 00:18:04,870
between calcium and whichever like where

437
00:18:10,590 --> 00:18:06,640
earth element is being used however

438
00:18:13,610 --> 00:18:10,600
between XO s F bearing isoforms that

439
00:18:16,020 --> 00:18:13,620
sequence identity jumps up to 80 percent

440
00:18:17,790 --> 00:18:16,030
so I would I would say at the moment

441
00:18:19,790 --> 00:18:17,800
it's hard to say whether or not we're

442
00:18:22,590 --> 00:18:19,800
getting a slow fading out of these genes

443
00:18:24,510 --> 00:18:22,600
versus some sort of other reason to

444
00:18:27,289 --> 00:18:24,520
maintain them but it's definitely