{"555171":{"#nid":"555171","#data":{"type":"news","title":"Before Animals, Evolution Waited Eons to Inhale","body":[{"value":"\u003Cp\u003EA couple of times in four billion years, evolution has slowed to a crawl. And an eon or so has passed before more complex life forms, such as simple animals, could arise.\u003C\/p\u003E\u003Cp\u003EEvolution may have been waiting for a decent breath of oxygen, said researcher Chris Reinhard. And that was hard to come by. His research team is tracking down O\u003Csub\u003E2\u003C\/sub\u003E concentrations in oceans, where earliest animals evolved.\u003C\/p\u003E\u003Cp\u003EBy doing so, they have jumped into the middle of a heated scientific debate on what rising oxygen did, if anything, to charge up evolutionary eras. Reinhard, a geochemist from the Georgia Institute of Technology, is shaking up conventional thinking with the help of computer modeling.\u003C\/p\u003E\u003Ch4\u003ESmash the beaker\u003C\/h4\u003E\u003Cp\u003EThat thinking goes like this: \u201cAtmospheric oxygen had a value of \u2018x\u2019 back then, and so we just assume that the whole ocean is a beaker that equilibrates with that value,\u201d Reinhard said. Then all evolving animals everywhere had the selfsame concentration of oxygen to live on.\u003C\/p\u003E\u003Cp\u003EBut oceans are expansive and asymmetrical; deep here, shallower there, frosty at the poles, soupy at the girth. Turbulences, streams and temperatures distribute sediment, algae, salt -- and gases like oxygen -- into lopsided stores.\u003C\/p\u003E\u003Cp\u003EOceans leave some areas teeming and others vacuous. Then they reshuffle their loads. Even today, concentrations of dissolved oxygen vary widely from ocean region to ocean region.\u003C\/p\u003E\u003Cp\u003EEquating the global ocean to a placid lab beaker? \u201cThis is an okay thought experiment to start with, but I think everybody would acknowledge over a beer that it\u2019s simplistic,\u201d said Reinhard, an \u003Ca href=\u0022http:\/\/www.eas.gatech.edu\/content\/reinhard-dr-chris\u0022 target=\u0022_blank\u0022\u003Eassistant professor at Georgia Tech\u2019s School of Earth and Atmospheric Sciences\u003C\/a\u003E.\u003C\/p\u003E\u003Ch4\u003ECreate a stir\u003C\/h4\u003E\u003Cp\u003ESo, he and his team modelled how oxygen entered oceans from the atmosphere and from aquatic sources, and how oceans might have shuffled it around during the mid to late Proterozoic Eon. That was 0.6 to 1.8 billion years ago, when the Earth\u2019s atmosphere had only fraction of the breathable oxygen it does today.\u003C\/p\u003E\u003Cp\u003EIn the model, the ocean didn\u2019t share and share alike, but instead pushed dissolved O\u003Csub\u003E2\u003C\/sub\u003E into areas of concentration that shifted starkly as corresponding concentrations in the atmosphere rose.\u003C\/p\u003E\u003Cp\u003EThat has implications for the way scientists think about the timeframe for animal evolution on Earth and for future estimates for the probability of complex life on exoplanets.\u003C\/p\u003E\u003Cp\u003EThe results and detailed modeling parameters were published on \u003Ca href=\u0022http:\/\/www.pnas.org\/content\/early\/2016\/07\/20\/1521544113.full\u0022 target=\u0022_blank\u0022\u003EMonday, July 25, 2016, in the Proceedings of the National Academy of Sciences\u003C\/a\u003E. The research was funded by the \u003Ca href=\u0022http:\/\/www.nsf.gov\u0022 target=\u0022_blank\u0022\u003ENational Science Foundation\u003C\/a\u003E and the \u003Ca href=\u0022https:\/\/astrobiology.nasa.gov\/\u0022 target=\u0022_blank\u0022\u003ENASA Astrobiology Institute\u003C\/a\u003E.\u003C\/p\u003E\u003Ch4\u003EBe unreliable\u003C\/h4\u003E\u003Cp\u003EHumans and today\u2019s large animals would quickly suffocate in a Proterozoic-like world. And according to Reinhard\u2019s research, its oceans may not have been as conducive to evolution as previously thought.\u003C\/p\u003E\u003Cp\u003E\u201cWhat really matters for the early evolution of animals is ocean oxygen. To a certain degree, it\u2019s really shallow sea floor oxygen that matters,\u201d Reinhard said.\u003C\/p\u003E\u003Cp\u003EThose ocean shallows are called benthic regions, and in the Proterozoic Eon, they received plenty of sunlight and nutrients key to evolution. Even today, they\u2019re teeming with life, which makes them popular places for snorkeling and fishing.\u003C\/p\u003E\u003Cp\u003EBut the new model shows oxygen levels there may have been unreliable during the mid to late Proterozoic Eon.\u003C\/p\u003E\u003Ch4\u003ERob the rich\u003C\/h4\u003E\u003Cp\u003EEarliest metazoans, the term for multicellular beings that are animals, may have done alright with scarce amounts and survived O\u003Csub\u003E2\u003C\/sub\u003E droughts -- periods of anoxia. But they also evolved into a world of rising breathable oxygen.\u003C\/p\u003E\u003Cp\u003EReinhard\u2019s computational model accounted for scenarios from atmospheric oxygen concentrations of 0.5 to 10 percent of today\u2019s levels.\u003C\/p\u003E\u003Cp\u003EAt low concentrations, the simulation showed oceanic oxygen building up around the equator, where hot spots in the water produced higher amounts of it. Then -- as the atmosphere began filling with oxygen -- in the oceans, it shifted toward the poles, where cold water was able to hold on to more of it.\u003C\/p\u003E\u003Cp\u003EFormerly oxygen-rich regions were robbed of conditions friendly to animal evolution.\u003C\/p\u003E\u003Cp\u003EIn the beaker way of thinking, higher atmospheric oxygen should have meant evenly rising levels of oceanic oxygen for animals evolving everywhere, even in those depleted regions. \u201cIn reality, the ecology they would have been facing would have been pretty severe,\u201d Reinhart said.\u003C\/p\u003E\u003Ch4\u003EFollow dead animals\u003C\/h4\u003E\u003Cp\u003EReinhard\u2019s team could have framed the study around other organisms but chose metazoans. \u201cWe focused on animals principally because that\u2019s where we have the best empirical constraints for the oxygen levels that the organisms need,\u201d he said.\u003C\/p\u003E\u003Cp\u003ETheir evolution also left behind a calendar convenient to scientific study \u2013 a progressive fossil record that became more complex as oxygen levels rose.\u003C\/p\u003E\u003Cp\u003EIn Earth\u2019s roughly 3.7-billion-year history of life, animals turned up in about the most recent third. Furry, feathery and even scaly animals have only appeared in the last few hundred million years.\u003C\/p\u003E\u003Cp\u003EAs oxygen became plentiful, critters got bigger, smarter, faster, and became predators and prey. Pursuit and flight accelerated as gasping lungs and gills pulled in more of the powerful oxidant to exponentially boost metabolism.\u003C\/p\u003E\u003Cp\u003EEvolution went into overdrive, diversifying the fossil record over time. But dive back down into it a billion or so years, to the mid to late Proterozoic, and animal fossils get smaller and simpler. You find little, squishy sponges and jellyfish.\u003C\/p\u003E\u003Ch4\u003EThink (eco)logically\u003C\/h4\u003E\u003Cp\u003ETheir stony imprints mark the beginnings of that very complex evolution, and they may point to oxygen concentrations at the time.\u003C\/p\u003E\u003Cp\u003E\u201cWe were focusing on changes in atmospheric oxygen during the time period in which animals appear in the fossil record and trying to link that quantitatively to the oxygen levels early animals would have needed,\u201d Reinhard said.\u003C\/p\u003E\u003Cp\u003EHis computational oxygen distribution model was based on the current constellation of Earth\u2019s continents \u2013 vastly different from that of the Proterozoic Eon.\u003C\/p\u003E\u003Cp\u003EBut Reinhard said that difference would not change the conclusions. And the concepts they support should also apply to predictions about life on exoplanets with differing continental structures.\u003C\/p\u003E\u003Cp\u003E\u201cThe basic take-home -- that we need to be thinking ecologically rather than just in terms of a single oxygen level -- is going to prove to be pretty robust,\u201d he said.\u003C\/p\u003E\u003Cp\u003EThat beaker? May have just flown out the window.\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003ENoah Planavsky from Yale University, Stephanie Olson and Timothy Lyons from the University of California Riverside and Douglas Erwin from the National Museum of Natural History coauthored the paper.\u0026nbsp; Research was funded by a National Science Foundation Sedimentary Geology and Paleobiology grant (number 1338290) and NASA Astrobiology Institute (grant number NNA15BB03A).\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003E\u003Ca href=\u0022http:\/\/www.rh.gatech.edu\/features\/what-came-chicken-or-egg\u0022 target=\u0022_blank\u0022\u003EREAD MORE: Research Horizons special on chemical evolution.\u003C\/a\u003E\u003Cbr \/\u003E\u003C\/em\u003E\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":[{"value":"Animal evolution may have sputtered in uneven ocean oxygen; model useful when considering life on exoplanets"}],"field_summary":[{"value":"\u003Cp\u003EEvolutionary timelines beware. Calculating ocean oxygen to calibrate the appearance of new life can be tricky. Oceans are deeper here, shallower there, turbulent and calm, hot and cold all at once. They distribute oxygen unevenly, then they rob O\u003Csub\u003E2\u003C\/sub\u003E rich areas and push the oxygen to the ends of the globe, as this new computational model framed in the Proterozoic Eon shows.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Animal evolution may have sputtered in sparse, uneven ocean oxygen. New model offers insights for probability of complex life on exoplanets."}],"uid":"31759","created_gmt":"2016-07-25 15:14:05","changed_gmt":"2016-10-08 03:22:08","author":"Ben Brumfield","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2016-07-25T00:00:00-04:00","iso_date":"2016-07-25T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"555151":{"id":"555151","type":"image","title":"Exoplanets NASA depictions","body":null,"created":"1469472913","gmt_created":"2016-07-25 18:55:13","changed":"1504298027","gmt_changed":"2017-09-01 20:33:47","alt":"","file":{"fid":"218215","name":"nasa.earthlikeexoplanets.jpg","image_path":"\/sites\/default\/files\/images\/nasa.earthlikeexoplanets.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/nasa.earthlikeexoplanets.jpg","mime":"image\/jpeg","size":487983,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/nasa.earthlikeexoplanets.jpg?itok=Ckjf0AeQ"}},"555111":{"id":"555111","type":"image","title":"Pteridinium fossil oxygen level evolution","body":null,"created":"1469472089","gmt_created":"2016-07-25 18:41:29","changed":"1475895353","gmt_changed":"2016-10-08 02:55:53","alt":"Pteridinium fossil oxygen level evolution","file":{"fid":"218212","name":"reinhard.fossil.smithsonian.sized_.jpg","image_path":"\/sites\/default\/files\/images\/reinhard.fossil.smithsonian.sized_.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/reinhard.fossil.smithsonian.sized_.jpg","mime":"image\/jpeg","size":4474835,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/reinhard.fossil.smithsonian.sized_.jpg?itok=9qVZfDLN"}},"555131":{"id":"555131","type":"image","title":"Chris Reinhard oxygen level evolution","body":null,"created":"1469472354","gmt_created":"2016-07-25 18:45:54","changed":"1475895353","gmt_changed":"2016-10-08 02:55:53","alt":"Chris Reinhard oxygen level evolution","file":{"fid":"218213","name":"chris_reinhard_georgia_tech.jpg","image_path":"\/sites\/default\/files\/images\/chris_reinhard_georgia_tech.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/chris_reinhard_georgia_tech.jpg","mime":"image\/jpeg","size":1537733,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/chris_reinhard_georgia_tech.jpg?itok=WJOy1Eza"}},"555141":{"id":"555141","type":"image","title":"Oceanic oxygen model Proterozoic Eon","body":null,"created":"1469472716","gmt_created":"2016-07-25 18:51:56","changed":"1475895353","gmt_changed":"2016-10-08 02:55:53","alt":"Oceanic oxygen model Proterozoic Eon","file":{"fid":"218214","name":"oxygen_model_proterozoic_georgia_tech.jpg","image_path":"\/sites\/default\/files\/images\/oxygen_model_proterozoic_georgia_tech.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/oxygen_model_proterozoic_georgia_tech.jpg","mime":"image\/jpeg","size":433067,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/oxygen_model_proterozoic_georgia_tech.jpg?itok=GSaht-Ad"}}},"media_ids":["555151","555111","555131","555141"],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"154","name":"Environment"},{"id":"146","name":"Life Sciences and Biology"},{"id":"135","name":"Research"}],"keywords":[{"id":"170499","name":"animal"},{"id":"39591","name":"computational modeling"},{"id":"3028","name":"evolution"},{"id":"170501","name":"metazoan"},{"id":"1383","name":"model"},{"id":"4649","name":"Ocean"},{"id":"1657","name":"oxygen"},{"id":"170507","name":"Proterozoic Eon"},{"id":"167040","name":"science"},{"id":"167045","name":"simulation"}],"core_research_areas":[{"id":"39441","name":"Bioengineering and Bioscience"},{"id":"39431","name":"Data Engineering and Science"}],"news_room_topics":[{"id":"71911","name":"Earth and Environment"},{"id":"71881","name":"Science and Technology"}],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EBen Brumfield\u003C\/p\u003E\u003Cp\u003EResearch News\u003C\/p\u003E\u003Cp\u003E(404) 660-1408\u003C\/p\u003E","format":"limited_html"}],"email":["ben.brumfield@comm.gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}