{"670731":{"#nid":"670731","#data":{"type":"event","title":"PhD Defense by  Tyler Vollmer","body":[{"value":"\u003Cp\u003E\u003Cspan\u003E\u003Cspan\u003EOSE Ph.D. Defense: Tyler Vollmer\u003C\/span\u003E\u003C\/span\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cspan\u003E\u003Cspan\u003ETitle: Last Glacial Maximum Oxygen and Preformed Phosphate Reconstructions and its Linkage to Atmospheric CO2 Drawdown and Ocean Circulation\u003C\/span\u003E\u003C\/span\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cbr \/\u003E\r\n\u003Cspan\u003E\u003Cspan\u003EDate\/Time: Thursday November 9 @ 2pm\u003C\/span\u003E\u003C\/span\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cspan\u003E\u003Cspan\u003ERoom Number: Ford ES\u0026amp;T 1177\u003C\/span\u003E\u003C\/span\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cspan\u003E\u003Cspan\u003EVirtual Link: \u003Ca href=\u0022https:\/\/gatech.zoom.us\/j\/5365614544?pwd=WXRPc0NUNjM0WGZjNkNJRTlETnBmdz09\u0022\u003Ehttps:\/\/gatech.zoom.us\/j\/5365614544?pwd=WXRPc0NUNjM0WGZjNkNJRTlETnBmdz09\u003C\/a\u003E\u003C\/span\u003E\u003C\/span\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cspan\u003E\u003Cspan\u003EAbstract:\u0026nbsp;\u003C\/span\u003E\u003C\/span\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cspan\u003E\u003Cspan\u003EDuring the Last Glacial Maximum (LGM), atmospheric CO2\u0026nbsp;was significantly lower than the pre-industrial, potentially due to an increase in the biological pump efficiency. Oxygen and preformed phosphate reconstructions can provide insight to changes in the biological pump efficiency.\u0026nbsp;\u003Cspan\u003E\u003Cspan\u003EMany qualitative shallow\/intermediate waters record higher O2\u0026nbsp;during the LGM due to an increase in oxygen solubility\u003C\/span\u003E\u003C\/span\u003E. Contrastingly, the\u0026nbsp;\u003Cspan\u003E\u003Cspan\u003Equalitative oxygen proxies record lower O2\u0026nbsp;in deep waters during the LGM, potentially indicating this increased storage of respired carbon.\u0026nbsp;In chapter 1, we quantified preformed phosphate and preformed\u0026nbsp;\u003C\/span\u003E\u003C\/span\u003E\u03b413C\u003Cspan\u003E\u003Cspan\u003E\u0026nbsp;of LGM bottom waters using a compilation of published paleo-temperatures, nutrient, and oxygen estimates from benthic foraminifera.\u0026nbsp;\u003C\/span\u003E\u003C\/span\u003E\u003Cspan\u003E\u003Cspan\u003EOur results show that preformed phosphate of the Pacific and Indian deep oceans was reduced by about \u22120.53\u0026nbsp;\u00b1\u0026nbsp;0.13\u0026nbsp;\u03bcM and suggest that much (64\u0026nbsp;\u00b1\u0026nbsp;28\u0026nbsp;ppmv) of the Glacial-Interglacial CO\u003C\/span\u003E\u003C\/span\u003E\u003Cspan\u003E2\u0026nbsp;\u003C\/span\u003E\u003Cspan\u003E\u003Cspan\u003Edrawdown resulted from changes in the ocean\u0027s biological pump efficiency. In chapter 2,\u0026nbsp;\u003C\/span\u003E\u003C\/span\u003Ewe updated the first quantitative oxygen proxy, \u0394\u03b413C \u2013 O2, calibration from 6 cores to over 30 cores, providing increase confidence in this proxy. Using this updated calibration, we\u0026nbsp;\u003Cspan\u003E\u003Cspan\u003Egenerated an oxygen, phosphate, and preformed phosphate\u0026nbsp;depth profile in the South Indo-Pacific and Eastern Equatorial Pacific.\u0026nbsp;\u0026nbsp;\u003C\/span\u003E\u003C\/span\u003EFrom the \u0026nbsp;paired oxygen and phosphate reconstructions, we show no significant changes in ocean circulation or productivity in the South Pacific or evidence of other deep water formation sites in the Pacific Ocean during the LGM. \u0026nbsp;Lastly, in chapter 3, we generated an oxygen profile in the Southeast Atlantic, where the Benguela upwelling oxygen minimum zone exist, showing a weakening and a downward shift of the oxygen minimum zone during the LGM.\u0026nbsp;\u003C\/span\u003E\u003C\/span\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cspan\u003E\u003Cspan\u003ECommittee Members:\u003C\/span\u003E\u003C\/span\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cspan\u003E\u003Cspan\u003EJean Lynch-Stieglitz\u003C\/span\u003E\u003C\/span\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cspan\u003E\u003Cspan\u003ETakamitsu Ito\u003C\/span\u003E\u003C\/span\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cspan\u003E\u003Cspan\u003EChristopher Reinhard\u0026nbsp;\u003C\/span\u003E\u003C\/span\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cspan\u003E\u003Cspan\u003EKevin Haas\u0026nbsp;\u003C\/span\u003E\u003C\/span\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cspan\u003E\u003Cspan\u003EJoseph Montoya\u003C\/span\u003E\u003C\/span\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\r\n","summary":"","format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003E\u003Cspan\u003E\u003Cspan\u003ELast Glacial Maximum Oxygen and Preformed Phosphate Reconstructions and its Linkage to Atmospheric CO2 Drawdown and Ocean Circulation\u003C\/span\u003E\u003C\/span\u003E\u003C\/p\u003E\r\n","format":"limited_html"}],"field_summary_sentence":[{"value":"Last Glacial Maximum Oxygen and Preformed Phosphate Reconstructions and its Linkage to Atmospheric CO2 Drawdown and Ocean Circulation"}],"uid":"27707","created_gmt":"2023-10-27 19:24:59","changed_gmt":"2023-11-06 20:28:22","author":"Tatianna Richardson","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2023-11-09T09:00:00-05:00","event_time_end":"2023-11-09T11:00:00-05:00","event_time_end_last":"2023-11-09T11:00:00-05:00","gmt_time_start":"2023-11-09 14:00:00","gmt_time_end":"2023-11-09 16:00:00","gmt_time_end_last":"2023-11-09 16:00:00","rrule":null,"timezone":"America\/New_York"},"location":"Ford ES\u0026T 1177","extras":[],"groups":[{"id":"221981","name":"Graduate Studies"}],"categories":[],"keywords":[{"id":"100811","name":"Phd Defense"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1788","name":"Other\/Miscellaneous"}],"invited_audience":[{"id":"78771","name":"Public"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[],"email":[],"slides":[],"orientation":[],"userdata":""}}}