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Dr. Alice Lefebvre

Telefon: 

+49 421 218-65680

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Raum: 

GEO, 3330

Alice Lefebvre

I am currently a scientist in the Cluster of Excellence ›The Ocean Floor – Earth’s Uncharted Interface‹, in the Research Theme RECEIVER, and part of the Sedimentology Working Group from Prof Elda Miramontes.

If you want to know more about me, you can read my interview to "Wissenschaft persönlich" in German or in English.

I am one of MARUM women's representatives. Feel very welcome to get in touch for any matter related to equal opportunities.

Underwater dunes

Research interests

I am particularly interested in the interaction of geomorphology, hydrodynamics and sediment dynamics. During my PhD, I worked on characterising small-scale roughness and the influence of seagrass meadows on the flow. At MARUM, I have been investigating the complex interaction between large bedform fields and flows. My research interests are now expending to geomorphology and sediment transport in deeper water.

Bedforms (ripples and dunes) are ubiquitous features in rivers, coastal and deep-sea environ­ments, where they reflect the strength and pathways of sediment transport, strongly influence the overlying flow and have a major socio-economic relevance. In rivers, estuaries and shallow tidal seas, large bedform fields develop due to the strong hydrodynamics and high availability of sandy sediment.

In collaboration with the coastal dynamics group of Christian Winter (previously leader of the coastal dynamics group at MARUM, now professor at CAU Kiel), I have worked on field data collected during cruises in tidal inlets during which current velocities and seabed morphology were measured during a whole tidal cycle. This work showed that the roughness associated with compound bedforms varies during a tidal cycle due to the variation of bedform geometry compared to flow direc­tion.
Using numerical modelling, I showed the detailed movement of water above bedforms with idealised and realistic shapes, in two and three dimensions, and driven by unidirectional and tidal flows. This allowed me to identify the presence and size of flow separation and turbulent wake in the lee of bedforms, depending on the lee slope shape. I could also quantify the vari­ation of bedform roughness with lee side angle.
More recently, I have been analysing long timeseries of bedform morphology in the Weser Estuary. I observed that the bedform shape changes spatially along the estuary but also in time due to variations of river discharge.

My current project deals with the transport and deposition of sediment and biogenic particles along and across continental margins. In this project, we are interested in the transport of sediment and biogenic particles by oceanographic processes along and across continental margins, their deposition on the shelves and slopes, and the interaction between biogeochemical cycles and sediment properties. A multidisciplinary approach combining the analysis of measurements from oceanographic processes in the water column, geophysical and sedimentological properties of the seafloor and biogeochemical cycling and activity at the water-sediment interface will allow to further advance the quantification of fluxes of car­bon and other elements from the coast to the deep ocean. To do so, measurements will be ac­quired during research cruises of the Excellence Cluster on the continental margin offshore NW Ireland and complemented by numerical modelling. A specific focus of the project will be to study the interaction between sediment dynamics and biochemical processes in bedform fields.

Please get in touch if you would like to know more or check out my publications.

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Short CV

01/2021 - Present

Scientist, Cluster of Excellence ›The Ocean Floor – Earth’s Uncharted Interface‹, Research Theme RECEIVER, MARUM, University of Bremen, Germany

10/2017 - 12/2020

Own DFG-funded position, MARUM, University of Bremen, Germany

09/2012 - 10/2017

Associate Scientist within GLOMAR, MARUM, University of Bremen, Germany

10/2009 - 08/2012

Post-Doctoral researcher, MARUM, University of Bremen, Germany and Senckenberg Institute, Wilhelmshaven, Germany

09/2009

Participation to the BATHYLUCK cruise onboard the Pourquoi Pas?

10/2005 – 07/2009

PhD candidate. National Oceanography Centre (NOC), University of Southampton, Southampton, UK.
“Bed roughness over vegetated beds: sonar imaging techniques and effect on unidirectional currents”
Supervisors: Prof C.L. Amos, Dr C.E.L. Thompson and Prof R.J. Nicholls.

2003 – 2005

Master ENVOLH (MSc of environment, and coastal and deep sea oceanography). University Bordeaux 1, Bordeaux, France.
first year at the University Bordeaux 1, second year as an ERASMUS student at the NOC, Southampton, UK.

2000-2003

BSc in Earth Sciences (DEUG and Licence Sciences de la Terre). University Bordeaux 1, France.

2000

Scientifique Baccalauréat, Spécialité Mathématiques, Lycée Michel de Montaigne, Bordeaux, France.

 

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Publications

ORCID

ResearchID

Pangaea

 

PEER-REVIEWED PUBLICATIONS:

Lefebvre, A, Herrling, Zorndt, A, G, Becker, M, Krämer, K, Winter, C, 2021. Morphology of estuarine bedforms, Weser Estuary, Germany. Earth Surface Processes and Landforms https://doi.org/10.1002/esp.5243

Herrling, G, Becker, M, Lefebvre, A, Zorndt, A, Krämer, K, Winter, C, 2021. The effect of asymmetric dune roughness on tidal asymmetry in the Weser estuary. Earth Surface Processes and Landforms 46, 2211– 2228. https://doi.org/10.1002/esp.5170

Lefebvre, A, Winter, C, 2021. Special issue: Marine and river bedforms dynamics, MARID VI. Earth Surface Processes and Landforms 46, 1646– 1651. https://doi.org/10.1002/esp.5091

Gutierrez, RR, Lefebvre, A, Núñez‐González, F, Avila, H, 2020. Towards adopting open and data‐driven science practices in bed form dynamics research, and some steps to this end. Earth Surface Processes and Landforms 46, 47– 54. https://doi.org/10.1002/esp.4811


Lefebvre, A
, 2019. Three‐dimensional flow above river bedforms: Insights from numerical modeling of a natural dune field (Río Paraná, Argentina). Journal of Geophysical Research: Earth Surface, 124. https://doi.org/10.1029/2018JF004928


Lefebvre, A, Paarlberg, AJ, Winter, C, 2016. Characterising natural bedform morphology and its influence on flow. Geo-marine Letters 36, 379–393. https://doi.org/10.1007/s00367-016-0455-5

Lefebvre, A, and Winter, C, 2016. Predicting bed form roughness: the influence of lee side angle. Geo-Marine Letters 36:121-133. https://doi.org/10.1007/s00367-016-0436-8

Winter, C, Lefebvre, A, Benninghoff, M and Ernstsen, VB, 2015. Die Verteilung und Eigenschaften von Bodenformen in der Deutschen Bucht, eine Rekonstruktion der Karten von Ulrich (1973). Die Küste, 83, 65-76. In German, Abstract in English.

Chirol, C, Amos, CL, Kassem, H, Lefebvre, A, Umgiesser, G and Cucco, A, 2015. The Influence of Bed Roughness on Turbulence: Cabras Lagoon, Sardinia, Italy. Journal of Marine Science and Engineering 3, 935-956. https://doi.org/10.3390/jmse3030935

Lefebvre, A, Paarlberg, AJ, Ernstsen, VB and Winter, C, 2014. Flow separation and roughness lengths over large bedforms in a tidal environment: A numerical investigation. Continental Shelf Research, 91, 57-69. https://doi.org/10.1016/j.csr.2014.09.001

Lefebvre, A, Paarlberg, AJ and Winter, C, 2014. Flow separation and shear stress over angle-of-repose bed forms: A numerical investigation. Water Resources Research, 50, 986–1005. https://doi.org/10.1002/2013WR014587

Lefebvre, A, Ernstsen, VB and Winter, C, 2013. Estimation of roughness lengths and flow separation over compound bedforms in a natural-tidal inlet. Continental Shelf Research, 61-62. 98-111. https://doi.org/10.1016/j.csr.2013.04.030

Ernstsen, VB, Lefebvre, A, Kroon, A and Niemann, SL, 2013. Oblique second-order sand transport patterns on an intertidal sand flat in a natural tidal inlet system. Journal of Coastal Research, SI65, 1122-1127.

Lefebvre, A, Ernstsen, VB and Winter, C, 2011. Influence of compound bedforms on hydraulic roughness in a tidal environment. Ocean Dynamics, 61(12). 2201-2210. https://doi.org/10.1007/s10236-011-0476-6

Lefebvre, A, Ernstsen, VB and Winter, C, 2011. Bedform characterization through 2D spectral analysis. Journal of Coastal Research SI64, 781-785.

Ernstsen, VB, Lefebvre, A, Bartholdy, J, Bartholomä, A and Winter, C, 2011. Spatiotemporal height variations of large-scale bedforms in the Grådyb tidal inlet channel (Denmark): a case study on coastal system impact. Journal of Coastal Research SI64, 746-750.

Paul, M, Lefebvre, A, Manca, E and Amos CL, 2011. An acoustic method for the remote measurement of seagrass metrics. Estuarine, Coastal and Shelf Science 93, 68-79.

Stark, N, Hanff, H, Svenson, C, Ernstsen, VB, Lefebvre, A, Winter, C and Kopf, AJ, 2011. Coupled penetrometer, MBES and ADCP assessments of tidal variations in surface sediment layer characteristics along active subaqueous dunes, Danish Wadden Sea. Geo-Marine Letters, 31(4). 249-258. https://doi.org/10.1007/s00367-011-0230-6

Garel, E and Lefebvre, A, 2010. Wave-induced Sand re-Suspension at Dredged Gravel Pits based upon Hydrodynamic Measurements (Tromper Wiek, Baltic Sea). Journal of Coastal Research SI51, 195-204.

Lefebvre, A, Thompson, CEL and Amos, CL, 2010. Influence of Zostera marina canopies on unidirectional flow, hydraulic roughness and sediment movement. Continental Shelf Research 30, 1783-1794.

Lefebvre, A, Thompson, CEL, Collins, K and Amos, CL, 2009. Use of a high-resolution profiling sonar and a towed video camera to map a Zostera marina bed, Solent, UK. Estuarine, Coastal and Shelf Science 82, pp. 323-334.

 

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Responsabilities

MARUM women's representatives (January 2019 - present)

Organiser of MARID VI - Marine and River Dune Dynamics 2019, 1-3 April 2019, Bremen, Germany

Administrator of marid.net

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Teaching

Ongoing teaching activities
> 05-MAG-AS1-1, “River and Coastal Management”, Master Applied Geosciences, University of Bremen (Winter Semester 2021/2022)
> GLOMAR course, "Introduction to Matlab" (March 2021)

Past teaching
> 05-GEO-2-K13-1, “Coastal Processes and Engineering”, Masterstudium Geowis­senschaften, University of Bremen (April - Mai 2018-2021)
> One week intensive course: “Introduction to coastal geomorphology and processes” for the ISATEC master, University of Bremen (May 2011-2020)
> GLOMAR Monthly Research Seminars
> GLOMAR thesis workshops
> GLOMAR Introductory Course to Natural Sciences in the Marine Realm
> Onboard teaching: “SOES 2010: Physical Oceanography II” (February-March 2007, 2008)
> Onboard teaching: “SOES 3040: Fieldwork for exchange student” (July 2006-2008)
> Teaching: “SOES 1003: IT, Communication, Field and Laboratory Skills” (March 2006-2008)

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Outreach

Part of the MARUM brochure

Part of the video join us for the MARUM experience

Participation in the University of Bremen Open Doors at MARUM booth (21/07/2013).

Alice Lefebvre. A bord du Pourquoi Pas ? La vie dans les abysses (Onboard the Pourqupoi Pas? Life in the abyss). Aquaforum (talks about the ocean for the general public), Bègles (France), 3rd March 2011.

Interview by BBC Radio 4 for the program “Science in the Making” during fieldwork on the RV Callista (6/06/2008).

Organisation and presentation of 2 stands for the coastal group participation during the open day, NOC (14/03/2009, 15/03/2008, 17/03/2007, 18/03/2006).

Alice Lefebvre. MOSE sauvera-t-il Venise et sa lagune? (Will MOSE save Venice and its lagoon?) (talk). Aquaforum (talks about the ocean for the general public), Bègles (France), 21st December 2006.