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Dr. Mahyar Mohtadi

Research Staff

Group: 

Marine Sedimentology

Phone: 

+49 421 218-65660

Fax:

+49 421 218-65653

Email:

Room: 

MARUM II, Room 3170

Mahyar Mohtadi

Research Statement

The body of my research activities is devoted to the long-term evolution of, and the interaction between, the coupled land-ocean-atmosphere climate phenomena such as the Australasian monsoon systems, the Indian Ocean Dipole, and El Niño-Southern Oscillation. To this end, I make use of various proxies and models, together with my partners, to reconstruct and to simulate past changes of the hydrological cycle: ocean circulation and thermal structure of the water column, salinity, terrestrial vegetation, rainfall, and runoff, as well as atmospheric zonal and meridional circulations.

Completed projects:

BMBF: PUCK (2001-2003); PABESIA (2005-2007), SUMATRA (2006-2008), ChiMeBo (2010-2012); TransGeoBiOc (2012), CAFINDO (SPICE III, 2012-2015), CARIMA (2012-2015), INVERS (2012-2013), EISPAC (2013-2015),

DFG: HE 3412/15-1 (2009-2013), MARUM-Excellence cluster (2011-2018).

Running:

CAHOL (2016-2019), TACTEAC (2017-2019), MARUM-Excellence cluster (2019-2025)

Pending:

MOST proposal in cooperation with Taiwanese partners (Indonesia), NSFC with Chinese partners (W Pacific)

Publications

  1. Groeneveld J., Ho S.L., Mackensen A., Mohtadi M., Laepple T. (accepted). Deciphering the variability in Mg/Ca and stable oxygen isotopes of individual foraminifera. Paleoceanography and paleoclimatology.
  2. Karami M.P., Mohtadi M., Zhang Q., Koenigk K. (accepted). West Asian Climate during the last millennium according to EC-Earth model. Canadian Journal of Earth Sciences.
  3. Cheng Z., Weng C., Steinke S., Mohtadi M. (2018). Anthropogenic modification of vegetated landscapes in southern China from 6,000 years ago. Nature Geoscience, doi:10.1038/s41561-018-0250-1.
  4. Hollstein M., Mohtadi M., Rosenthal Y., Prange M., Oppo D.W., Martinez-Mendez G., Tachikawa K., Moffa Sanchez P., Steinke S., Hebbeln D. (2018). Variations in Western Pacific Warm Pool surface and thermocline conditions over the past 110,000 years: Forcing mechanisms and implications for the glacial Walker circulation. Quaternary Science Reviews 201, 429-445.
  5. Wang X., Jian Z., Lückge A., Wang Y., Dang H., Mohtadi M. (2018). Precession-paced thermocline water temperature changes in response to upwelling conditions off southern Sumatra over the past 300,000 years. Quaternary Science Reviews 192, 123-134.
  6. Huang E., Chen Y., Schefuß E., Steinke S., Liu J., Tian J., Martínez-Méndez G., Mohtadi M. (2018). Precession and glacial-cycle controls of monsoon precipitation isotope changes over East Asia during the Pleistocene. Earth and Planetary Science Letters 494, 1-11.
  7. Lehmann N., Granger J., Kienast M., Brown K.S., Rafter P.A., Martínez-Méndez G., Mohtadi M. (2018). Isotopic Evidence for the Evolution of Subsurface Nitrate in the Western Equatorial Pacific. Journal of Geophysical Research Oceans 123, doi:10.1002/2017JC013527.
  8. Mohtadi M., Prange M., Schefuß E., Jennerjahn T.C., 2017. Late Holocene Slowdown of the Indian Ocean Walker circulation. Nature Communications 8, doi:10.1038/s41467-017-00855-3.
  9. Panmei C., Naidu D.P., Mohtadi M., 2017. Bay of Bengal Exhibits Warming Trend During the Younger Dryas: Implications of AMOC. Geochemistry, Geophysics, Geosystems 18, 4317-4325, doi:10.1002/2017GC007075.
  10. Hollstein M., Moh­ta­di M., Ro­sen­thal Y., Moffa San­chez P., Oppo D., Mar­tí­nez Mén­dez G., Stein­ke S., Heb­beln D., 2017. Sta­ble oxy­gen iso­topes and Mg/​Ca in plank­tic fo­ra­mi­ni­fe­ra from mo­dern sur­face se­di­ments of the Wes­tern Pa­ci­fic Warm Pool: Im­pli­ca­ti­ons for ther­mo­cli­ne re­con­struc­tions. Paleoceanography 32, doi:10.1002/​2017PA003122.
  11. Wittmann H., von Blanckenburg F., Mohtadi M., Christl M., Bernhardt A., 2017. The competition between coastal trace metal fluxes and oceanic mixing from the 10Be/9Be ratio: implications for sedimentary records. Geophysical Research Letters 44, doi:10.1002/2017GL074259.
  12. Mohtadi M., Prange M., Steinke S., 2016. Palaeoclimatic insights into forcing and response of monsoon rainfall. Nature 533, 191-199, doi:10.1038/nature17450.
  13. Liu J., Steinke S., Vogt C., Mohtadi M., De Pol-Holz R., Hebbeln D., 2017. Temporal and spatial patterns of sediment deposition in the northern South China Sea over the last 50,000 years. Palaeogeography, Palaeoclimatology, Palaeoecology 465, 212-224.
  14. Johnstone H.J.H., Steinke S., Kuhnert H., Bickert T., Pälike H., Mohtadi M., 2016. Automated cleaning of foraminifera shells before Mg/Ca analysis using a pipette robot. Geochemistry Geophysics Geosystems 17, doi:10.1002/2016GC006422.
  15. Chen W., Mohtadi M., Schefuß E., Mollenhauer G., 2016. Concentrations and abundance ratios of long-chain alkenones and glycerol dialkyl glycerol tetraethers in sinking particles south off Java. Deep Sea Research I 112, 14-24.
  16. Setiawan R.Y., Mohtadi M., Southon J., Groeneveld J., Steinke S., Hebbeln D., 2015. The consequences of opening the Sunda Strait on the hydrography of the eastern tropical Indian Ocean. Paleoceanography 30, 1358-1372.
  17. Kwiatkowski C., Prange M., Varma V., Steinke S., Hebbeln D., Mohtadi M., 2015. Holocene variations of thermocline conditions in the eastern tropical Indian Ocean. Quaternary Science Reviews 114, 33-42.
  18. Mohtadi M., Prange M., Oppo D.W., De Pol-Holz R., Merkel U., Zhang X., Steinke S., Lückge A., 2014. North Atlantic forcing of tropical Indian Ocean climate. Nature 509, 76-80.
  19. Steinke S., Prange M., Feist C., Groeneveld J., Mohtadi M., 2014. Upwelling variability off southern Indonesia over the past two millennia. Geophysical Research Letters 41, doi:10.1002/2014GL061450.
  20. Niedermeyer E.M., Sessions A.L., Feakins S.J., Mohtadi M., 2014. Hydroclimate of the western Indo-Pacific Warm Pool during the past 24,000 years. Proceedings of the National Academy of Science 111, 9402-9406.
  21. Dubois N., Oppo D.W., Galy V., Mohtadi M., van der Kaars S., Tierney J., Rosenthal Y., Eglinton T., Lückge A., Linsley B., 2014. Indonesian vegetation response to changes in rainfall seasonality over the past 25,000 years. Nature Geoscience 7, 513-517.
  22. Kuhnert H., Kuhlmann H., Mohtadi M., Meggers H., Baumann K.H., Pätzold J., 2014. Holocene tropical western Indian Ocean sea surface temperatures in covariation with climatic changes in the Indonesian region. Paleoceanography 29, 423-437.
  23. Steinke S., Mohtadi M., Prange M., Varma V., Pittauerova D., Fischer H.W., 2014. Mid- to Late-Holocene Australian-Indonesian summer monsoon variability. Quaternary Science Reviews 93, 142-154.
  24. Chen W., Mohtadi M., Schefuß E., Mollenhauer G., 2014. Organic-geochemical proxies of sea surface temperature in surface sediments of the tropical Eastern Indian Ocean. Deep-Sea Research I 88, 17-29.
  25. Gibbons F., Oppo D.W., Mohtadi M., Rosenthal Y., Cheng J, Liu Z, Linsley B.K., 2014. Deglacial δ18O and hydrologic variability in the tropical Pacific and Indian Oceans. Earth and Planetary Science Letters 387, 240-251.
  26. Martínez-Méndez G., Hebbeln D., Mohtadi M., Lamy F., De Pol-Holz R., Reyes-Macaya D., Freudenthal T., 2013. Changes in the advection of Antarctic Intermediate Water to the northern Chilean coast during the last 970 kyr. Paleoceanography 28, doi:10.1002/palo.20047.
  27. Southon J., Mohtadi M., De Pol-Holz R., 2013. Planktonic foram dates from the Indonesian Arc: marine 14C reservoir ages and a mythical 535 AD eruption of Krakatau. Radiocarbon 55, 1164-1172.
  28. Hessler I., Young M., Holzwarth U., Mohtadi M., Lückge A., Behling H., 2013. Imprint of eastern Indian Ocean surface oceanography on modern organic-walled dinoflagellate cyst assemblages. Marine Micropaleontology 101, 89-105.
  29. Ho S.L., Mollenhauer G., Lamy F., Martínez-Garcia A., Mohtadi M., Gersonde R., Hebbeln D., Nuñez-Ricardo S., Rosell-Melé A., Tiedemann R., 2012. Sea surface temperature variability in the Pacific sector of the Southern Ocean over the past 700 kyr. Paleoceanography 27, PA4202, doi:10.1029/2012PA002317.
  30. Yu P-S., Kienast M., Chen M-T., Cacho I., Flores J.A., Mohtadi M., Mix A., 2012. Influences of extra-tropical water masses on equatorial Pacific cold tongue during the past 160 kyr as revealed by faunal evidence of planktic foraminifers. Journal of Quaternary Science 27, 921-931.
  31. Romero O.E., Mohtadi M., Helmke P., Hebbeln D., 2012. High Interglacial Diatom Paleoproductivity in the Westernmost Indo-Pacific Warm Pool During the Past 130,000 yr. Paleoceanography 27, PA3209, doi:10.1029/2012PA002299.
  32. Mohtadi M., Oppo D.W., Steinke S., Stuut J-B W., De Pol-Holz R., Hebbeln D., Lückge A., 2011. Glacial to Holocene swings of the Australian-Indonesian monsoon. Nature Geoscience 4, 540-544.
  33. Steinke S., Glatz C., Mohtadi M., Groeneveld J., Li Q., Jian Z., 2011. Past dynamics of the East Asian monsoon: No inverse behaviour between the summer and winter monsoon during the Holocene. Global and Planetary Change 78, 170-177.
  34. Mohtadi M., Oppo DW, Lückge A, De Pol-Holz R, Steinke S, Groeneveld J, Hemme N, Hebbeln D, 2011. Reconstructing the thermal structure of the upper ocean: insights from planktic foraminifera shell chemistry and alkenones in modern sediments of the tropical eastern Indian Ocean. Paleoceanography 26, PA3219, doi:10.1029/2011PA002132.
  35. Haarmann T., Hathorne E.C., Mohtadi M., Groeneveld J., Kölling M., Bickert T., 2011. Mg/Ca ratios of single planktonic foraminifer shells and the potential to reconstruct the thermal seasonality of the water column. Paleoceanography 26, PA3218, doi:10.1029/2010PA002091.
  36. Steinke S., Mohtadi M., Groeneveld J., Lin L-C., Löwemark L., Chen M-T., Rendle-Bühring R., 2010. Reconstructing the southern South China Sea upper water-column structure since the Last Glacial Maximum (LGM): Implications for the East Asian winter monsoon development. Paleoceanography 25, PA2219, doi:10.1029/2009PA001850.
  37. Mohtadi M., Steinke S., Lückge A., Groeneveld J., Hathorne E.C., 2010. Glacial to Holocene surface hydrography of the tropical eastern Indian Ocean. Earth and Planetary Science Letters 292, 89-97.
  38. Baumgart A., Jennerjahn T., Mohtadi M., Hebbeln D., 2010. Distribution and burial of organic carbon in sediments from the Indian Ocean upwelling region off Java and Sumatra, Indonesia. Deep Sea Research I 57, 458-467.
  39. Mohtadi M., Lückge A., Steinke S., Groeneveld J., Hebbeln D., Westphal N., 2010. Late Pleistocene surface and thermocline conditions of the eastern tropical Indian Ocean. Quaternary Science Reviews 29, 887-896.
  40. De Pol-Holz R., Keigwin L., Southon J., Hebbeln D., Mohtadi M., 2010. No signature of abyssal carbon in intermediate waters off Chile during deglaciation. Nature Geoscience 3, 192-195.
  41. Lückge A., Mohtadi M., Rühlemann C., Scheeder G., Vink A., Reinhardt L., Wiedicke-Hombach M., 2009. Monsoon versus ocean circulation controls on paleoenvironmental conditions off southern Sumatra during the past 300,000 years. Paleoceanography 24, PA1208, doi:10.1029/2008PA001627.
  42. Mohtadi M., Steinke S., Groeneveld J., Fink H.G., Rixen T., Hebbeln D., Donner B., Herunadi B., 2009. Low-latitude control on seasonal and inter-annual changes in planktonic foraminiferal flux and shell geochemistry off south Java: a sediment trap study. Paleoceanography 24, PA1201, doi:10.1029/2008PA001636.
  43. Kaiser J., Schefuß E., Lamy F., Mohtadi M., Hebbeln D., 2008. Glacial to Holocene changes in sea surface temperature and coastal vegetation in north central Chile: high versus low latitude forcing. Quaternary Science Reviews 27, 2064-2075.
  44. Mohtadi M., Rossel P., Lange C.B., Pantoja S., Böning P., Repeta D.J., Grunwald M., Lamy F., Hebbeln D., Brumsack H-J., 2008. Deglacial pattern of circulation and marine productivity in the upwelling region off central-south Chile. Earth and Planetary Science Letters 272, 221-230.
  45. Mohtadi M., Max L., Hebbeln D., Baumgart A., Krück N., Jennerjahn T., 2007. Modern environmental conditions recorded in surface sediment samples off W and SW Indonesia: planktonic foraminifera and biogenic compounds analyses. Marine Micropaleontology 65, 96-112.
  46. Mohtadi M., Romero O.E., Kaiser J., Hebbeln D., 2007. Cooling of the southern high latitudes during the Medieval Period and its effect on ENSO. Quaternary Science Reviews 26, 1055-1066.
  47. Hebbeln D., Lamy F., Mohtadi M., Echtler H., 2007. Tracing the impact of glacial-interglacial climate variability on erosion of the southern Andes. Geology 35, 131-134.
  48. Marchant M., Cecioni A., Figueroa S., Gonzales H., Giglio S., Hebbeln D., Kaiser J., Lamy F., Mohtadi M., Pineda V., Romero O.E., 2007. Marine geology, oceanography and climate. In: Moreno, T. & Gibbons, W. (Eds.), The Geology of Chile. The Geological Society, London, 289-309.
  49. Stuut J-B W., Marchant M., Kaiser J., Lamy F., Mohtadi M., Romero O.E., Hebbeln D., 2006. The Late Quaternary paleoenvironment of Chile as seen from marine archives. Geographica Helvetica 61, 135-151.
  50. Mohtadi M., Hebbeln D., Nuñez-Ricardo S., Lange C.B., 2006. El Niño-like pattern in the Pacific during Marine Isotope Stages (MIS) 13 and 11? Paleoceanography 21, PA1015, doi:10.1029/2005PA001190.
  51. Mohtadi M., Hebbeln D., Marchant M., 2005. Upwelling and productivity along the Peru-Chile Current derived from faunal and isotopic compositions of planktic foraminifera in surface sediments. Marine Geology 216, 107-126.
  52. Mohtadi M., Hebbeln D., 2004. Mechanisms and variations of paleoproductivity off northern Chile (24°S-33°S) during the last 40,000 years. Paleoceanography 19, PA 2023, doi:10.1029/2004PA001003.
  53. Mohtadi M., Romero O.E., Hebbeln D., 2004. Changing marine productivity off northern Chile during the past 19,000 years: a multi-variable approach. Journal of Quaternary Science 19, 347-360.

Sea-going expeditions

Mahyar
Monsoon rain on RV Sonne, Hong Kong
MeBo
MeBo on deck

Talks (selection)

  • 4th Xiamen Symposium on Marine Environmental Sciences, Xiamen, China, 2019 (invited)
  • ICTP 2nd Meeting on Monsoons and Tropical Rain, Trieste, Italy, 2018 (keynote)
  • EGU Annual Meeting, Vienna, Austria, 2018 (invited)
  • AGU Fall Meeting, New Orleans, USA, 2017 (invited)
  • 12th International Conference on Paleoceanography, Utrecht, the Netherlands, 2016 (invited)
  • Annual Meeting of the Japanese Quaternary Society, Chiba, Japan, 2016 (keynote)
  • AGU Chapman Conference on the evolution of the Asian Monsoon, Hong Kong, China, 2015
  • AGU Fall Meeting, San Francisco, USA, 2014 (invited)
  • SAGE Workshop Ocean Gateways, Berlin, Germany, 2013 (keynote)
  • IMAGES/PAGES WPP III Workshop, Kaohsiung, Taiwan, 2013 (keynote)
  • AOGS-AGU (WPGM) Meeting, Singapore, 2012 (invited)
  • 7th ICAMG Meeting, Goa, India, 2011
  • IMAGES WPP II Workshop, Keelung, Taiwan, 2011 (keynote)
  • AGU Fall Meeting, San Francisco, USA, 2009 (invited)
  • AGU Chapman Conference on Abrupt Climate Change, Columbus, USA, 2009
 

Editor

  • Quaternary Science Reviews: 2019-2021
  • Quaternary International: 2016-2019
  • Climate of the Past (Guest Editor): 2014-2015
 

Referee

  • Nature, Science, Nature Communications, Nature Geoscience, Nature Climate Change, Nature Scientific Reports, Geology, Earth and Planetary Science Letters, Paleoceanography, Quaternary Science Reviews, Geophysical Research Letters, Climate of the Past, Quaternary Research, Geochem., Geophys., Geosys., Palaeogeogr. Palaeoclim. Palaeoecol., Quaternary International, Marine Micropaleontology, Marine Geology, Journal of Foraminiferal Research, Deep-Sea Research I and II, The Geological Society (GSL), National Science Foundation (NSF), Deutsche Forschungsgemeinschaft (DFG), American Petroleum Institute (API), ...