Lee Kump, Penn State – Part I

broke out of this place 30 years ago exactly wasn’t that long teak nut wasn’t it we go back a ways because they’re the National Association of geology teachers has a program where they give scholarships and he got the scholarship to come work with this little group on a little island called Fisher Island and so leaking to us as a na GT student which means we didn’t have to pay anything in free but then later he stayed on and he was a gs5 geologist for the USGS for a while and first thing we discovered there wasn’t anything he couldn’t do he could fix everything and did all kinds of things and probably most important thing is he transitioned us from typewriters to those infernal we have to use he was a lot smarter than we would well my dissertation was the first one on a computer the one before mine was typed by a typist so okay so then the well I heard I heard stories about Lee and that promised I wouldn’t tell any of the the bad ones but you know why but i think my most interesting stories and i reconfirmed it you all know who sister Teresa is my mother her mother Teresa yeah when he was a kid mother Teresa would come to the states and stay at his house with his mother and he would play the guitar for her when he was taking guitar lessons and as you all know she’s up for sainthood I don’t think Lee’s up for saying yeah Eddie know I know miracles there yeah ok so then he said he was going to come over to this school to get his master’s and he came over and just bypass the Masters he got with Bob Darrell’s a very famous person who was also a friend of james lovelock in england and if you can google him if you want one of my one of my heroes whose biologist and he was on the block was on his committee and love locks one of my heroes because in his autobiography he talks about the various tribes there are the biological tribes and the geological tribes and he has both tribes and them sort but mostly fish drives here I think anyhow that’s that’s a little background and so we won’t build anything beyond we won’t tell any of other stories when we were working in the Florida Keys on groundwater oh he went to Penn State right away right after that and and that was 30 years ago and he’s still there and when we were working on groundwater to Florida Keys he brings students down and help us do the drilling and put in the tracers to see which way the ground water was moving so we got back together then and so that’s how we know each other for quite a while and there was one other thing you want some award here from the school outstanding outstanding now it’s the Distinguished Alumnus distinguish Columbia and so we see a lot of time working at the keys Marine Lab which is no one by fo so with all that background let me introduce dr. Lee Kum Penn State oh great thanks gene it’s great actually you know part of that skipping over the Masters is an important part of the story because my master’s thesis was supposed to be with Al heinen and gene shin and in fact al had been supporting me for a couple of years probably by the time I decided to switch and I actually always always remember that because al came to me and said listen you don’t seem very excited about this project and and you’ve got you know the world’s greatest geochemist and you liked your chemistry you’ve got this opportunity why don’t you go work with him and I thought you know that was really amazing that somebody you know I essentially bailed on the project I went down in two genes place and impregnated a few more cores and then that was the end of that project and and it’s probably still tilt still orphaned down there at Fisher Island but anyway so that really had a

made a big impression upon me in terms of the graciousness of val and gene with letting me follow a different direction and and so I feel bad about putting up a first slide that shirt infuriate gene cuz i’m talking about ocean acidification and showing some slides from him of the coral demise in the in the Florida Keys that I didn’t keep that ocean acidification be the last thing that he would ever ascribe the the demise of those corals to but I really actually show it only because Jean you know as you’ve seen I’ve seen the posters around here had a long series of photographs of various parts of the Florida Keys and looking at the spread of disease and the demise of the reefs that go way back into the 50s and his wife Pat was usually the model for those pictures but but this summer I was fortunate enough to go out with with Gene and pat on their boat and it was too cold out and Pat didn’t want to go in the water one last time and so I got to be the model and so that’s me actually up there not nearly as photogenic as as Pat’s been for the photo so I’m in the 2015 I’m the 2015 model for the series of coral reef anyway I thought coming back here in fact looking around the room and seeing some of the old faces remind you the last time I standing right here during my dissertation defense of sweating even more than than I was and now looking out at some of these same faces and and and so yeah it’s actually 30 years ago almost to the date that I flew up to pens to state college for my job interview at Penn State so so it’s a great great to be back here among old friends and looking out and seeing how vibrant the department especially when you know at the end of a major national meeting glad you’re all able to be here anyway I’m going to talk about ocean acidification but from the perspective of Earth’s deep past and and explore one possible analogue for modern ocean acidification that is associated with the paleocene-eocene boundary 56 million years ago so since I left here I really have been focusing more on Earth history and looking for you know to draw upon my oceanographic background from usf but to apply it to to the ancient earth and so I’ll give a little bit of background on ocean acidification you know probably unnecessary among this crowd especially but just so we’re all on the same page of course you know what we know is that the carbon dioxide content of the atmosphere has been going up for for the last couple hundred years a result of fossil fuel burning the the famous Keeling curve and that progressive increase in carbon dioxide concentrations has had clearly in effect on the climate but that’s a very difficult one to get a strong handle on what seems to be more obvious at least from my training here in in in in marine chemistry is that it would have an effect on the chemistry of the surface ocean because as the ocean takes up carbon dioxide it tight rates out the carbonate ion content of seawater convert the net reaction being the conversion of carbonate ion to bicarbonate and so one of the major impacts of ocean acidification is the is affected could potentially have on carbonate producing organisms who depend on the the availability of carbon for the precipitation of their skeletons and you know this obvious this also has a observational basis this is a time series from Hawaii showing this increase in co2 content of the atmosphere progressive increase in the pco2 of the surface waters from Hawaii declining pH and a declining saturation state with respect to a ragga night one of the calcium carbonate Polly Morse code from 1972 2014 so it’s a you know it’s easy to demonstrate and it’s and it’s intuitive that the build-up of co2 in the atmosphere would cause a decrease in the pH and the carbonate ion content of seawater now the implications of that are a little bit more challenging to to demonstrate and this is just an old slide from from from clypeus and Yates worked of Chris Langdon looking at the effect from biosphere 2 experiments of the change the effect of the change in saturation state with declining saturation States to the right on community calcification from the biosphere to reef and like has been shown in aquaria and other experiments before and since there’s a there in many situations not all there’s a declining rate of calcification with respect to decreasing saturation States of seawater so the implication is that the build-up of co2 in the atmosphere could pose a threat to the to the future of calcifying organisms not just coral reefs of course but all calcifying

organisms and from an earth historians point of view then then the question becomes since most everything that human activity is doing to the planet has been foreshadowed through natural events can we look in july in the geologic record for any indication that there was a time in the past when a co2 build-up in the atmosphere caused an acidification event in the oceans and what was implicit implications of that for for the marine biota so we’ve been working like many people have on the paleocene-eocene boundary this is 56 million years ago looking for this analog not just of ocean acidification but even before that for for an episode of co2 driven global warming and the the Palestinian scene event was really first recognized by Shackleton and kennett looking at deep-sea cores calcium carbonate rich cores from the deep sea floor where they’re looking at the isotopic composition of Fryman if Earl skeletons through time and and noted that at a period of 55 56 million years ago there are a couple samples in there coarsely sampled cores that seem to have an ominously low delta 18 0 and low Delta 13 c carbon-carbon encompass compositions and that was followed by work largely by jim’s a coset santa cruz who really spent the time where people thought it was a waste of time to sample that court at extremely high resolution to pull together a more detailed record he’s done that now through it you know long part of the last 65 million years of cenozoic he and others have put together a fairly comprehensive record in this case of the oxygen isotopic composition of benthic foraminifera through through earth history and these are really charting the change in temperature mostly of high latitude deep water forming regions through time and you can see there’s this progressive cooling that’s been well well known for a long time what what was a particular interest to this talk is this spike in the temperature which is a drop in the delta t know of the octave the benthic foraminifera that seemed to suggest a fairly significant warming and and so zachos among others have really dived into that interval and sample that at high resolution and have demonstrated that that spike is real it’s a short global warming episode from they say 56 million years ago so what what characterizes the PTM the it looks like the average global increase in temperature is about 5 degrees Celsius that there’s a range of temperatures from about 4 degrees in the tropics up to maybe nine degrees of warming at at at higher latitudes there’s a large negative carbon isotope that’s that’s excursion that’s associated with that and we’ll focus on that is what that means but it tells some really important information that links this global warming episode 2 to the carbon cycle it’s an event of about total duration I don’t think to slide here on that of about 150,000 years rapid onset as you’ll see and then a much more belong prolonged recovery from from that event it it’s an interesting event because for the most part it wasn’t that disruptive to the to the biosphere in the sense that it wasn’t a mass extinction event like has occurred at other intervals of Earth history in in North America it drove a large mammal migration to to to to higher latitudes plant biomes and ecosystems in general migrated you know thousands of kilometers northward dirt to follow the progressive warming of this event and that led to mammal diversification so it’s an important event from the point of view of of the rise of mammals but really only in terms of a mass extinction event is it is it impacting on the seafloor and one thing that’s understood about the PTM is that there’s widespread dissolution of carbonates on the relatively shallow marine seafloor and and that together with evidence for abrupt warming and perhaps low oxygen concentrations on the seafloor did lead to a mass extinction among benthic foraminifera so the benthic foraminifera who had survived the the Cretaceous Paleogene mass extinction that the time period when the dinosaurs went extinct we’re actually hit very hard at the paley scene eocene boundary and so there’s something weird

about what’s going on on the seafloor we know that the carbonates were being dissolved but there is also sufficient stressors on the benthic foraminifera that there was a widespread extinction of benthic foraminiferal lineages anyway here’s some of the record of that these are deep sea cores from walvis Ridge so in and this is in the southern Atlantic off the coast of Africa it’s a series of cores that Zack owes and colleagues collected in from this area along a transect on the edge of the ribs are trying to track down how much did the saturation horizon within the ocean the lice acclaim and then also the carbonate compensation depth shallow in in in response to this to this event what they found here in terms of increasing depths of the core these are modern depths so if you reconstruct because the seafloor subsides if you reconstruct the the palest seen water depths hear something from maybe 1,500 meters water depth down to 3,500 meters or so paleo water depth a of these cores this is this is these are photographs of the cores you can see this abrupt transition here which is shown also in the blue lines drop in the calcium carbonate content of the sediments there these are carbonate news is so large you know high proportions of calcium carbonate prior to the event a drop to zero even in the shallowest environments here rapid dropped to zero clearly there’s been dissolution and by the way loss of the record that’s one of the problems trying to reconstruct this event by using deep-sea sediments in carbonate uses is that the record itself has been destroyed by the event and so you see this abrupt drop here that’s affecting all all depths along the margins of walvis ridge and then this more gradual recovery in space we of course have to convert this to time to think about the pace pace of this affair because sedimentation rates have clearly been varying over this interval of time that speed the paper Court has been turning has has varied through time and at some points it’s been you know the tapes been lost and spliced back together so it’s a it’s a disconnected record but you see this abrupt drop in the carbonate content of the deep sea floor so clearly there was a dissolution and and the CCD rose above 1500 meters whereas today typical depths in Atlantic are more like 4,000 meters four to five thousand meters okay here’s one of those isotope records that’s actually one of the older ones but it’s a nice one showing the oxygen and carbon isotope records on the same same graph and so time going forward now to the right and you see this is the onset there most of this part of the records missing so it’s it’s extrapolated the onset of the vent a significant warming here interpreted warming from from this site of about eight degrees and then and in a in a drop in the Delta 13c of the calcium carbonate and then this then this recovery over a few tens of thousands of years and that’s that’s a characteristic shape of this excursion no matter where you find it here’s just another in record once again from walvis ridge of the same same event these are the carbonate records we saw before put on the same record from shallow to deep water settings now trying to convert it into time here from 55 million years ago on this older time scale up to 50 4.75 and you see the carbon isotope excursion and the oxygen isotope excursion coinciding so a warming event with clear indications that there was something happening with the carbon isotope composition of seawater so what was that event well one thing that this tells us without going into all the details is that this was an interval of fossil fuel addition this had to have been an injection of carbon from a sedimentary or long-lived reservoir long-lived with respect to the duration of this event so this is not just the burning of forests for example or a reduction in photosynthetic rates are increasing respiration and soils because the carbon that those represent were just recently extracted from from the from the ocean atmosphere the fact that this is a prolonged disturbance tells us that the carbon that was released into the atmosphere ocean system came from reservoir that had been stored for hundreds of thousands if not millions of years before that so we know that this is a good analogue fossil fuel carbon edition I don’t mean you know coal oil and natural gas in this case just old carbon from some source and it had to have been light low Delta 13c carbon so it has to have had an organic source whether it was methane or coal or sedimentary

carbon we know that it was an organic carbon source okay so people have speculated on what that source might be there’s clear evidence that that there was contemporaneous volcanism in the North Atlantic at this time this is part of the rifting of the of the North Atlantic widespread submarine volcanism and explosive volcanism associated with that the problem with volcanism as a source of the carbon is that the carbonation topic composition of volcanic co2 is not that isotopically light it’s you know minus 52 minus 7 so to explain that large shift in the ocean atmosphere is Delta 13 c would require a tremendous amount of carbon in this case something like 10,000 pedda grams or gigatonnes of carbon or or more a popular explanation is destabilization of methane hydrates from the sea floor because methane hydrates this is methane trapped in in ice Cade ice cages stable under high pressure and low temperature conditions warming of the sea floor would could potentially destabilize the methane hydrates and so methane hydrate is another potential source and because methane has such a low Delta 13c value then then the hydrates could could serve as a significant source of that and then we had actually proposed is kind of an off-the-cuff comment that I into a paper written by a postdoc at the time of mine Andy Kurtz now at Boston Boston University that may be the this was an episode of widespread Pete and coal oxidation because the Paleo seen the event the the epic prior to this event is known for widespread calls especially in the western United States but also in South America widespread Pete Meyers of the late paleocene now there’s still Cole remaining from that time but but but that seemed to us to be a large reservoir of easily oxidized carbon that might have been involved in this and it has a more intermediate carbonized topic composition so so the battle still rages as to which of these sources of carbon might have been it one of the things to emphasize is that the the peat fires the the methane hydrate destabilization those are responses little parts of a positive feedback to some initial trigger of the warming and there’s been a suggestion of course like for most major Vincent Earth history that maybe it was a cometary impact very little evidence in support of that but the volcanism itself can be thought of as potentially the triggers so I think the prevailing view at the moment is that there was widespread volcanic eruption