Dr Robert Turnewitsch

        Head and shoulder photo of marine geochemist Dr Robert Turnewitsch

Marine Geochemist

I research the interactions between seafloor topography (abyssal hills, seamounts, hadal trenches) and fluid dynamics on the biogeochemistry of ocean waters and sediments.

I am a core member of the Peer Review College at the United Kingdom’s Natural Environment Research Council.

Contact details:

Research interests

The deep sea constitutes one of the main biogeochemical compartments of the Earth system and deep-sea sediments form one of the main archives of environmental change. A wide range of factors controls deep-sea and sediment biogeochemistry. However, so far, the influence of seafloor geometry has received very little attention. This is despite the fact that >60% of the global seafloor are covered by topographic ‘roughness elements’ such as abyssal hills, seamounts and valleys (fracture zones, hadal trenches). This equates to >40% of the Earth surface. The mere presence of these seafloor features introduces environmental heterogeneity, and this ‘patchiness’ is amplified through interactions of different physical-oceanographic flow components with the seafloor features. These interactions can lead to topographically driven ‘granularity’ of depositional patterns that is rarely considered and their impacts on deep-sea biogeochemistry and the formation of sedimentary records of environmental change are virtually unknown.

To pursue this highly interdisciplinary research, I have been enjoying collaborations with physical oceanographers at Princeton University, Stockholm University, IFREMER, Aarhus University, the Meteorological Research Institute of Japan and the University of Tasmania.


Current research projects

HADES-ERC: This project aims to provide the first detailed, combined analysis of benthic diagenesis and microbial ecology of some of the deepest oceanic trenches on Earth. Funded by ERC. 2016-20

Influence of seafloor geometry on sediment biogeochemistry: To investigate the influence of flow-topography interactions on carbon dynamics in hadal trenches (this is a variant of related work on abyssal hills). Funded by MASTS and SAGES. 2017-18

Sediment deposition in the deep sea  -  from seamounts to the hadal trenches. Funded by NERC. 2012-18


Past highlight projects

TopoDeep (Seamount biogeochemistry and biology). Funded by NERC. 2009-13

Impact of fluid dynamics around seamounts on bentho-pelagic coupling. Funded by DFG. 2007-09

OASIS (OceAnic Seamounts: an Integrated Study). Funded by EU FP5. 2002-05

Mogg, A.O.M., Attard, K.M., Stahl, H., Brand, T., Turnewitsch, R. and Sayer, M.D.J. (2017), The influence of coring method on the preservation of sedimentary and biogeochemical features when sampling soft-bottom, shallow coastal environments. Limnol. Oceanogr. Methods. doi:10.1002/lom3.10211

Turnewitsch, R., Dale, A., Lahajnar, N., Lampitt, R.S., Sakamoto, K. (2017). Can neap-spring tidal cycles modulate biogeochemical fluxes in the abyssal near-seafloor water column? Progress in Oceanography 154, 1-24, doi.org/10.1016/j.pocean.2017.04.006

Turnewitsch, R., Dumont, M., Kiriakoulakis, K., Legg, S., Mohn, C., Peine, F., Wolff, G. (2016) Tidal influence of particulate organic carbon export about a tall seamount. Progress in Oceanography 149, 189-213, 10.1016/j.pocean.2016.10.009.

Wenzhöfer, F., Oguri, K., Middelboe, M., Turnewitsch, R., Toyofuku, T., Kitazato, H., Glud, R.N. (2016). Benthic carbon mineralization in hadal trenches: Assessment by in situ O2 microprofile measurements. Deep-Sea Research I 116, 276-286, doi.org/10.1016/j.dsr.2016.08.013.

Turnewitsch, R., Lahajnar, N., Haeckel, M., Christiansen, B. (2015). An abyssal hill fractionates organic and inorganic matter in deep-sea surface sediments. Geophysical Research Letters 42, doi:10.1002/2015GL065658

Turnewitsch, R., Falahat, S., Stehlikova, J., Oguri, K., Glud, R.N., Middelboe, M., Kitazato, H., Wenzhöfer, F., Ando, K., Fujio, S., Yanagimoto, D. (2014). Recent sediment dynamics in hadal trenches: evidence for the influence of higher-frequency (tidal, near-inertial) fluid dynamics. Deep-Sea Research I 90, 125-138, doi:10.1016/j.dsr.2014.05.005.

Watson, C., Chivers, A., Narayanaswamy, B., Lamont, P., Turnewitsch, R. (2014). Chrysopetalidae (Annelida: Phyllodocida) from Senghor Seamount, NE Atlantic: taxa with deep-sea affinities and morphological adaptions. Memoirs of Museum Victoria 71, 311–325.

Turnewitsch, R., Falahat, S., Nycander, J., Dale, A., Scott, R.B., Furnival, D. (2013). Deep-sea fluid and sediment dynamics  -  Influence of hill- to seamount-scale seafloor topography. Earth-Science Reviews 127, 203-241, doi:10.1016/j.earscirev.2013.10.005.

Chivers, A.J., Narayanaswamy, B.E., Lamont, P.A., Dale, A. Turnewitsch, R. (2013). Changes in polychaete standing stock and diversity on the northern side of Senghor Seamount (NE Atlantic). Biogeosciences 10, 3535-3546.

Glud, R.N., Wenzhoefer, F., Middelboe, M., Oguri, K., Turnewitsch, R., Canfield, D.E., Kitazato, H. (2013). High rates of microbial carbon turnover in sediments in the deepest oceanic trench on Earth. Nature Geoscience 6, 284-288. doi:10.1038/NGEO1773.

Mohn, C., Erofeeva, S., Turnewitsch, R., Christiansen, B., White, M., (2013). Tidal and residual currents over abrupt deep-sea topography based on shipboard ADCP data and tidal model solutions for three popular bathymetry grids. Ocean Dynamics 63(2-3), 195-208. doi:10.1007/s10236-013-0597-1.

Maiti, K., Buesseler, K.O., Pike, S.M., Benitez-Nelson, C., Cai, P., Chen, W., Cochran, K., Dai, M., Dehairs, F., Gasser, B., Kelly, R.P., Masque, P., Miller, L., Miquel, J.C., Moran, S.B., Morris, P., Peine, F., Planchon, F., Renfro, A.A., Rutgers van der Loeff, M., Santschi, P., Turnewitsch, R., Waples, J.T., Xu, C. (2012). Intercalibration studies of short lived thorium-234 in the water column and marine particles. Limnology and Oceanography: Methods 10, 631-644.

Turnewitsch, R., Pohl, C. (2010). An estimate of the efficiency of the dissolved inorganic phosphorus trap at an oxic/euxinic water-column redoxcline. Global Biogeochemical Cycles, 24, GB4025, doi:10.1029/2010GB003820.

Peine, F., Turnewitsch, R., Mohn, C., Reichelt, T., Springer, B.M., Kaufmann, M. (2009). The importance of tides for sediment dynamics in the deep sea – Evidence from the particulate-matter tracer 234Th in deep-sea environments with different tidal forcing. Deep-Sea Research I 56, 1182-1202.

Forster, S., Turnewitsch, R., Powilleit, M., Werk, S., Ziervogel, K., Kersten, M. (2009). Thorium-234 derived information on particle residence times and sediment deposition in shallow waters of the south-western Baltic Sea. Journal of Marine Systems 75, 360-370.

Turnewitsch, R., Reyss, J.-L., Nycander, J., Waniek, J, Lampitt, R.S. (2008). Internal tides and sediment dynamics in the deep sea – Evidence from radioactive 234Th/238U disequilibria. Deep-Sea Research I, 55, 1727–1747.

Lampitt, R.S., Boorman, B., Brown, L., Lucas, M., Salter, I., Sanders, R., Saw, K., Seeyave, S., Thomalla, S.J., Turnewitsch, R. (2008). Particle export from the euphotic zone: Estimates using a novel drifting sediment trap, 234Th and new production. Deep-Sea Research I, 55, 1484-1502.

Thomalla, S.J., Poulton, A.J., Sanders, R., Turnewitsch, R., Holligan, P., Lucas, M. (2008). Variable export fluxes and efficiencies for calcite, opal, and organic carbon in the Atlantic Ocean: A ballast effect in action? Global Biogeochemical Cycles 22, GB1010, doi:10.1029/2007GB002982.

Morris, P.J., Sanders, R., Turnewitsch, R., Thomalla, S.J. (2007). 234Th derived particulate organic carbon export compared to new production from an island induced phytoplankton bloom in the Southern Ocean. Deep-Sea Research II 54, 2208–2232.

Turnewitsch, R., Springer, B.M., Kiriakoulakis, K., Vilas Español, J.C., Arístegui, J., Wolff, G., Peine, F., Werk, S., Graf, G., Waniek, J. (2007). Determination of the concentration of particulate organic carbon (POC) in seawater: the relative methodological importance of artificial organic carbon gains and losses in two glass-fiber-filter-based techniques. Marine Chemistry 105, 208-228.

Turnewitsch, R., Domeyer, B., Graf, G. (2007). Experimental evidence for an effect of early-diagenetic interaction between labile and refractory marine sedimentary organic matter on nitrogen dynamics. Journal of Sea Research 57, 270-280.

Thomalla, S., Turnewitsch, R., Lucas, M., Poulton, A. (2006). Particulate organic carbon export from the North and South Atlantic: the 234Th/238U disequilibrium approach. Deep-Sea Research II 53, 1629-1648.

Rutgers van der Loeff, M.M., Sarin, M.M., Baskaran, M., Benitez-Nelson, C., Buesseler, K.O., Charette, M., Dai, M., Gustafsson, Ö., Masque, P., Morris, P., Orlandini, K., Rodriguez y Baena, A., Savoye, N., Schmidt, S., Turnewitsch, R., Vöge, I., Waples, J. (2006). A review of present techniques and methodological advances in analyzing 234Th in aquatic systems. Marine Chemistry 100, 190-212.

Turnewitsch, R., Reyss, J.-L., Chapman, D.C., Thomson, J., Lampitt, R.S. (2004). Evidence for a sedimentary fingerprint of an asymmetric flow field surrounding a short seamount. Earth and Planetary Science Letters (Frontiers Article) 222(3-4), 1023-1036.

Turnewitsch, R., Graf, G. (2003). Variability of particulate seawater properties related to bottom mixed layer-associated internal waves in shallow water on a time scale of hours. Limnology and Oceanography 48(3), 1254-1264.

Turnewitsch, R., Springer, B.M. (2001). Do bottom mixed layers influence 234Th dynamics in the abyssal near-bottom water column? Deep-Sea Research I 48(5), 1279-1307.

Turnewitsch, R., Witte, U., Graf, G. (2000). Bioturbation in the abyssal Arabian Sea: influence of fauna and food supply. Deep-Sea Research II 47(14-16), 2877-2911.

Consultancy and industry experience

I have extensive experience working on the influence of interactions of ocean fluid dynamics with seafloor topography such as abyssal hills, seamounts and trenches on sediment deposition and seafloor chemistry. An understanding of such interactions is of value for the planning and impact mitigation of deep-sea mining operations.


Accessing consultancy services from SAMS

SAMS consultancy work is delivered through its wholly owned commercial subsidiary, SAMS Research Services Ltd. (SRSL). SRSL operates a comprehensive Quality Management System (QMS) that is accredited to ISO9001:2008 standard, guaranteeing that all projects deliver the best possible service to our customers. All SRSL projects are planned by a professional programme manager who oversees a team of dedicated project managers, all of whom are focussed specifically on client delivery, and have scientific experience and technical expertise in fields relevant to their assigned projects.

For further information concerning commercial enterprise opportunities at SAMS, please contact SRSL by email (info@srsl.com) or phone +44 (0) 1631 559 470.


Marine Science BSc: Module leader year 1 'Fundamentals of Marine Chemistry'

Marine Science BSc: Module leader year 3 'Marine Pollution'

Marine Science BSc: Lecturer year 2 'Chemical Oceanography'

Marine Science BSc: Lecturer year 2 'Marine Geology'

Marine Science BSc: Lecturer year 4 'Defining the Marine Carbon Cycle'

Ecosystem-based Management of Marine Systems MSc: NERC proposal writing module


Current research students

Jirina Stehlikova: Sediment deposition in the deep sea  -  from seamounts to the hadal trenches. PhD 2012-18. UHI / University of Aberdeen

Matthew Dumont: Reconstructing the Biological C Pump in the Southern Ocean during the last Deglaciation. PhD 2014-18. University of Edinburgh


Alumni research students

Paul Morris: Carbon export from natural iron fertilisation in the Southern Ocean. PhD. University of Southampton

Sandy Thomalla: Phytoplankton productivity and carbon export in the Atlantic and Southern Oceans. PhD. University of Cape Town / NOC

Adam Chivers: The biodiversity and ecology of Senghor Seamount (NE Atlantic). PhD. University of Aberdeen

Matthew Dumont: 234Th, 238U and the fate of settling particles at Senghor Seamount. MRes. University of St Andrews

Stephan Werk: Laborversuche zum Adsorptionsverhalten von 234Thorium an natürlichen Partikeln. MSc. University of Rostock

Professional activities


Core Member of the Peer Review College of the UK’s Natural Environment Research Council


Member of the Deep-Sea Forum Steering Committee of the Marine Alliance for Science and Technology for Scotland (MASTS)

Reviewer for funding agencies: Natural Environment Research Council (NERC), UK; The Royal Society, UK; British Council, UK; National Oceanic and Atmospheric Administration (NOAA), USA; National Science Foundation (NSF), USA; United States – Israel Binational Science Foundation (BSF)

American Geophysical Union: Member since 1998

Americal Society of Limnology and Oceanography: Member since 2003


Media coverage


The Royal Society of Edinburgh: interview on 'Science at the deep end'


Reporting on the Mariana Trench study

Live radio interview: BBC Radio 4, BBC Radio Scotland, BBC Radio Wales, BBC Radio 5 Live

Pre-recorded radio interview: BBC World Service, The Voice of Russia, the Austrian broadcaster FM4 ORF, PRI's World - Global Perspectives for an American Audience

Employment history

Since 2006 Principal Investigator and Senior Lecturer in Marine Geochemistry. SAMS

2006 Visiting Researcher. Baltic Sea Research Institute Warnemünde (IOW) (Germany)

2002-06 NOC Independent Research Fellow. National Oceanography Centre, Southampton (UK)

2000-01 Postdoc. IOW/Rostock University (Germany)



1999 PhD (Dr rer nat). University of Kiel / GEOMAR (Germany)

1995 MSc (Diplom) with distinction. University of Kiel