Blanchet C Tjallingii Rik rik.tjallingii@gfz-potsdam.de 0000-0002-9723-3622 Schleicher Anja Maria 0000-0003-4052-8654 Schouten Stefan Stefan.Schouten@nioz.nl Frank Martin mfrank@geomar.de https://www.geomar.de/mfrank/ 0000-0002-8606-4421 Brauer Achim achim.brauer@gfz-potsdam.de 0000-0002-6655-9451 2021 XRF elemental contents of sediment core POS362-2_33 dataset https://doi.org/10.1594/PANGAEA.930758 2021-04-26T06:21:18 https://doi.org/10.1594/PANGAEA.930796 Ocean deoxygenation is a rising threat to marine ecosystems and food resources under present climate warming conditions. Organic-rich sapropel layers deposited in the Mediterranean Sea provide a natural laboratory to study the processes that have controlled the changes in seawater oxygen levels in the recent geological past. Our study is based on three sediment cores spanning the last 10 thousand years (10 kyr BP) and located on a bathymetric transect offshore the western distributaries of the Nile delta. These cores are partly to continuously laminated in the sections recording sapropel S1, which is indicative of bottom-water anoxia above the western Nile deep-sea fan. We used a combination of microfacies analyses and inorganic and organic geochemical measurements to reconstruct changes in oxygenation conditions at seasonal to millennial time-scales. The regular alternations of detrital, biogenic and chemogenic sublayers in the laminated sequences are interpreted in terms of seasonal changes. Our microfacies analyses reveal distinct summer floods and subsequent plankton blooms preceding the deposition of inorganic carbonates formed in the water-column during spring-early summer. The isotopic signature of these carbonates suggests year-round anoxic to euxinic bottom waters resulting in high levels of anaerobic remineralisation of organic matter and highlights their potential to reconstruct seawater chemistry at times when benthic fauna was absent. Synchronous changes in terrigenous input, primary productivity and past oxygenation dynamics on millennial time-scales obtained by our multi-proxy study show that runoff-driven eutrophication played a central role in driving rapid changes in oxygenation state of the entire Levantine Basin. Rapid fluctuations of oxygenation conditions in the upper 700 m water depth occurred above the Nile deep-sea fan between 10 and 6.5 ka BP while deeper cores recorded more stable anoxic conditions. These findings are further supported by other regional records and reveal time-transgressive changes in oxygenation state driven by rapid changes in primary productivity during a period of long-term deep-water stagnation. Blanchet Cécile L cblanchet@geomar.de 0000-0002-7146-705X Tjallingii Rik rik.tjallingii@gfz-potsdam.de 0000-0002-9723-3622 Schleicher Anja Maria 0000-0003-4052-8654 Schouten Stefan Stefan.Schouten@nioz.nl Frank Martin mfrank@geomar.de https://www.geomar.de/mfrank/ 0000-0002-8606-4421 Brauer Achim achim.brauer@gfz-potsdam.de 0000-0002-6655-9451 accepted Deoxygenation dynamics above the western Nile deep-sea fan during sapropel S1 at seasonal to millenial time-scales journal article Climate of the Past https://doi.org/10.5194/cp-2020-114 29.75083 29.75083 31.69317 31.69317 29.75083 31.69317 2008-02-16T00:00:00 2008-02-16T00:00:00 0.01 5.58 not specified POS362-2_33 31.69317 29.75083 Mediterranean Sea -738.0 2008-02-16T00:00:00 POS362/2 POS362/2 2008-02-09T00:00:00 2008-02-09 2008-02-24T00:00:00 2008-02-24 Poseidon https://www2.bsh.de/aktdat/dod/fahrtplanung/Poseidon.htm DBKV 7427518 Feseker, Tomas Feseker, Tomas doi:10.3289/ifm-geomar_rep_15_2008 Poseidon https://www2.bsh.de/aktdat/dod/fahrtplanung/Poseidon.htm DBKV 7427518 Gravity corer GC 1575 CC-BY-4.0 Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/ DEPTH, sediment/rock Depth sed m depth http://purl.obolibrary.org/obo/PATO_0001595 sediment http://purl.obolibrary.org/obo/ENVO_00002007 rock Length L http://dbpedia.org/resource/Length Blanchet C Depth sed [m] AGE Age ka BP http://en.wikipedia.org/wiki/Kyr age http://purl.obolibrary.org/obo/PATO_0000011 Time T http://dbpedia.org/resource/Time Blanchet C Age [ka BP] Age, error Age e ± age http://purl.obolibrary.org/obo/PATO_0000011 Blanchet C 2s Age e [±] (2s) log-ratio log-ratio Blanchet C Log ratio of sulfur over chlorine log-ratio (Log ratio of sulfur over chlo...) log-ratio log-ratio Blanchet C Log ratio of potassium over titanium log-ratio (Log ratio of potassium over t...) log-ratio log-ratio Blanchet C Log ratio of titanium over calcium log-ratio (Log ratio of titanium over ca...) Score Score Blanchet C Z-scored Log ratio of titanium over calcium Score (Z-scored Log ratio of titaniu...) CurationLevelC Enhanced curation https://wiki.pangaea.de/wiki/Curation_levels citable Deoxygenation Geochemistry Nile River Sapropel S1 geomar author10279 author26503 author28103 author30350 author34918 author36485 author448 basis11 campaign3397510 campaign34816 curlevel30 event2716745 geocode1 geocode1599 geocode1600 geocode1601 geocode2205 geocode8128 journal3567 license21 method11107 param170288 param8097 param83159 pi34918 ref108164 term1073131 term1073135 term20609 term242 term267 term2687806 term38263 term41056 term43863 term43975 term60425 term67687 topotype1