Logo Universitat Bremen


since 2015:

Fischer, G., Romero, O., Toby, E., Iversen, M., Donner, B., Mollenhauer, G., Nowald, N. Ruhland, G., Klann, M. Hamady, B.and Wefer, G. (2019). Changes in the dust-influenced biological carbon pump in the Canary Current System: implications from a coastal and an offshore sediment trap record off Cape Blanc, Mauritania. Global Biogeochemical Cycles, subm.

Markussen, T.M., C. Konrad, C. Waldmann, M. Becker, G. Fischer and MH. Iversen (2019). Tracks in the snow – combining optical methods to unravel marine aggregate dynamic, Frontiers, Special Issue, in review.

Park, E., Hefter J., Fischer, G., Iversen, M.H., Ramondenc, S., Nöthig, E.-M. and Mollenhauer, G. (2019) Seasonality of archaeal lipid flux and GDGT-based thermometry in sinking particles of high latitude oceans: Fram Strait (79° N) and Antarctic Polar Front (50° S). Biogeosciences, bg-2019-34, in press.

Park, E., J. Hefter, G. Fischer and G. Mollenhauer (2018). TEX86 in sinking particles in three eastern Atlantic upwelling regimes. Organic Geochemistry, 124, 151-163, doi.org/10.1016/j.orggeochem.2018.07.015

Van der Jagt, H., Friese, C., Stuut, J.-B., Fischer, G. and Iversen, M. (2018). The ballasting effect of Saharan dust deposition on aggregate dynamics and carbon export: Aggregation, settling and scavenging potential of marine snow, Limnology and Oceanography, 8, doi:10.1002/lno.10779.

Vorrath, E., N. Lahajnar, Fischer, V.M. Libuku,  M. Schmidt and K.-C. Emeis (2018). Spatiotemporal variation of vertical particle fluxes and modelled chlorophyll a standing stocks in the Benguela Upwelling System, Journal of Marine Systems, 180, 59-75, https://doi.org/10.1016/j.jmarsys.2017.12.002.

Gray, W.R., Weldeab, S., Lea, D.W., Rosenthal, Y., Gruber, N., B., Donner, B. and G. Fischer (2018). The effects of temperature, salinity, and the carbonate system on Mg/Ca in Globigerinoides ruber (white): a global sediment trap calibration and new SST estimates for the LGM, Earth and Planetary Science Letters, 482, 607-622. doi.org/10.1016/j.epsl.2017.11.026.

Guerreiro, C., -H. Baumann, G.-J. Brummer, G. Fischer, L.F. Korte, U. Merkel, C. Sa, H. de  Stigter and J.-B. Stuut (2017). Coccolithophore fluxes in the open tropical North Atlantic: influence of the thermocline depth, Amazon water, and of Saharan dust deposition. Biogeosciences, 14, 4577-4599.

Romero, O. and G. Fischer (2017). Shift in the species composition of the diatom community in the eutrophic Mauritanian coastal upwelling: Results from a multi-year sediment trap experiment (2003 – 2010). Prog. Oceanogr., 159, 31-44.

Friese, C.A., H. van Hateren, C. Vogt, G. Fischer, Jan-Berend W. Stuut (2017). Seasonal provenance changes of present-day Saharan dust collected on- and offshore Mauritania. Atmospheric Chemistry and Physics, Special Issue, 17, 1-31

Friese, C., van der Does, M., Iversen, M., Merkel, U., Fischer, G., and J.-B. Stuut (2016). Environmental factors controlling the seasonal variation in particle size of modern Saharan dust deposited offshore Cape Blanc. Aeolian Res., 22, 165-179.

Romero, O.E., Fischer, G. Karstensen, J. and Cermeño, P. (2016). Eddies as trigger for diatom productivity in the open-ocean NE Atlantic, Prog Oceanogr, 147, 38-48.

Wefer, G., Fischer, G. and M. Iversen (2016). Export Production. Encyclopedia of Marine Geosciences. J. Harff, M. Meschede, S. Petersen, J. Thiede (Eds.), Springer, 1st ed. 2016, XXXIII, 961 p. 458, doi 10.1007/978:94-007-6644-0_59-1.

Neuer, S., Iversen, M. and G. Fischer (2016). Featured L&O E-lecture: The Ocean’s Biological Carbon Pump as part of the Global Carbon Cycle. Limnol. Oceanogr. Bull., 25 (1), 22-23.

Koebrich, M.I., Baumann, K.-H. and G. Fischer (2016). Seasonal and inter-annual dynamics of coccolithophore fluxes from the upwelling region off Cape Blanc, NW Africa. Journal of Micropaleontolgy, doi:10.1144/jmpaleo2014-024.

Fischer, G., Romero, O., Merkel, U., Donner, B., Iversen, M., Nowald, N., Ratmeyer, V., Ruhland, G., Klann, M. and G. Wefer (2016). Deep ocean particle flux in the coastal upwelling off Mauritania from 1988 to 2012: variability on seasonal to decadal timescales. Biogeosciences, 13, 3071-3090.

Fischer,G., J. Karstensen, O. Romero, K.-H. Baumann, B. Donner, J. Hefter, G. Mollenhauer, M. Iversen, B. Fiedler , I. Monteiro and A. Körtzinger (2016). Bathypelagic particle flux signatures from a suboxic eddy in the oligotrophic tropical North Atlantic: production, sedimentation and preservation. Biogeosciences, Special Issue 'Hydrography, biogeochemistry, and biology of "dead-zone eddies" in the eastern tropical North Atlantic', Biogeosciences, 13, 3203–3223.



Karstensen, J., B. Fiedler, F. Schütte, P. Brandt, A. Körtzinger, G. Fischer, R. Zantopp, J. Hahn, M. Visbeck, and D. Wallace (2015). Open ocean dead-zone in the tropical North Atlantic Ocean. Biogeosciences, 12, 2597–2605.

Nowald, N., M. H. Iversen, G. Fischer, V. Ratmeyer and G. Wefer (2015). Time series of in-situ particle properties and sediment trap fluxes in the coastal upwelling filament off Cape Blanc, Mauritania. Prog Oceanogr., http://dx.doi.org/10.1016/j.pocean.2014.12.015

Mollenhauer, G., Basse, A., Kim, J.-H., Sinninghe Damsté, J.S. and G. Fischer (2015). A four-year record of UK37 - and TEX86-derived sea surface temperature estimates from sinking particles in the filamentous upwelling region off Cape Blanc, Mauritania. Deep-Sea Research I, 97, 67-79.

Neuer, S., Iversen, M. and G. Fischer (2014). The Ocean’s Biological Carbon Pump as part of the Global Carbon Cycle". Limnol. Oceanogr. e-Lectures, doi:10.4319/lol.2014.sneuer.miversen.gfischer.9. http://onlinelibrary.wiley.com/doi/10.1002/loe2.v4.4/issuetoc

Basse, A., Zhu, C., Versteegh, G.M., Fischer, G., Hinrichs, K.-U. and G. Mollenhauer (2014) Distribution of intact and core tetraether lipids in water column profiles of suspended particulate matter off Cape Blanc, NW Africa. Organic Geochemistry, 72, 1-13.

Romero, O.E., Leduc, G., Vidal, L. and Fischer, G. (2011) Millenial variability and long-term changes of the diatom production in the eastern Equatorial Pacific during the last glacial cycle. Paleoceanography, doi:10.1029/2010PA002099.


2005-2010 (selected):

Iversen, M. H., Nowald, N., Ploug, H., Jackson, G. A. and Fischer, G. (2010) High resolution profiles of vertical particulate organic matter export off Cape Blanc, Mauritania: Degradation processes and ballasting effects. Deep-Sea Res., doi:10.1016/j.dsr.2010.03.007.

Fischer, G., S. Neuer, R. Davenport, O. Romero, V. Ratmeyer, B. Donner, T. Freudenthal, H. Meggers and G. Wefer (2010) The Northwest African Margin. In: Liu, K .K., Atkinson, L., Quinones, R., Talaue-McManaus, L. (Editors), Carbon and Nutrient Fluxes in Continental Margins: A Global Synthesis, IGBP Book Series, Springer, Berlin, pp. 77-103.

Zonneveld, K.A.F., Susek, E. and Fischer, G. (2010) Seasonal variability of the organic-walled dinoflagellate cyst production in the coastal upwelling region off Cape Blanc (Mauritania): A five-year survey. Journal of Phycology 46,1: 202 - 215.

Nowald, N., Fischer, G., Ratmeyer, V., Iversen, M., Reuter, C. and Wefer, G. (2009) In-situ sinking speed measurements of marine snow aggregates acquired with a settling chamber mounted to the Cherokee ROV. Oceans 2009, Bremen.

Karakas, G., Nowald, N., Schäfer-Neth, C., Iversen, M., Barkmann, W., Fischer, G., Marchesiello, P. and Schlitzer, R. (2009) Impact of particle aggregation on fluxes of organic matter. Progress in Oceanography, 83, 331-341.

Fischer, G., G. Karakas, M. Blaas, V. Ratmeyer, N. Nowald, R. Schlitzer, P. Helmke, R. Davenport, B. Donner, S. Neuer and G. Wefer (2009a) Mineral ballast and particle settling rates in the coastal upwelling system off NW Africa and the South Atlantic. Int., J. Earth Sci., Special Volume. doi 10.1007/s00531-007-0234-7.

Fischer, G., Reuter, C., Karakas, G., Nowald, N. and Wefer. G.(2009b) Offshore advection of particles within the Cape Blanc filament, Mauritania: results from observational and modelling studies. Progress in Oceanography, 83, 322-330.

Fischer, G. and G. Karakas (2009). Sinking rates and ballast composition of particles in the Atlantic Ocean: implications for the organic carbon fluxes to the deep ocean. Biogeosciences, 6, 85-102.

Ploug, H., M. Iversen and G. Fischer (2008) Ballast, sinking velocity, and apparent diffusivity within marine snow and fecal pellets: Implications for substrate turnover by attached bacteria. Limnology and Oceanography, 53 (5), 1878-1886.

Nowald, N., G. Karakas, V. Ratmeyer, G. Fischer, R. Schlitzer, R. Davenport and G. Wefer (2006) Distribution and transport processes of marine particulate matter off Cape Blanc (NW-Africa): results from vertical camera profiles, Ocean Science Discussions, Vol. 3, pp 903-938, 25-7-2006.

Garrity C., R.O. Ramseier, R. Peinert, S. Kern and G. Fischer (2005) Water column particulate organic carbon modeled in the ice-frequented Southern Ocean. Journal of Marine Systems, 56, 133-149.

Susek E, K.A.F. Zonneveld, G. Fischer, G.J.M. Versteegh and H. Willems (2005) Organic walled dinoflagelate cysts production in relation to upwelling intensity and lithogenic influx in the Cape Blanc region (off north-west Africa). Phycological Research, 53 (2), doi:10.1111/j.1440-183.2005.00377.x.

Zaric S., B. Donner, G. Fischer, S. Mulitza and G. Wefer (2005) Sensitivity of planktonic foraminifera to sea surface temperature and export production as derived from sediment trap data. Marine Micropaleontology., 55, 75-105.

Helmke, P., O. Romero and G. Fischer (2005) Northwest African upwelling and its effect on off-shore organic carbon export to the deep sea. Global Biogeochemical Cycles, 19, doi: 10.1029/2004/GB00265, 2005.


2003-2000 (selected):

Usbeck, R., R. Schlitzer, G. Fischer and G. Wefer (2003) Particle fluxes in the ocean: comparison of sediment trap data with results from inverse modelling. Journal of Marine Systems, 39, 176-183.

Schneider, B., R. Schlitzer, G. Fischer and E.-M. Noethig (2003) Depth-dependent elemental compositions of particulate organic matter (POM) in the ocean. Global Biogeochemical Cycles, 17 (2), 1032, doi:10.029/2002GB001871.

Fischer, G., G. Wefer, O. Romero, N. Dittert, V. Ratmeyer and B. Donner (2003) Transfer of particles into the deep Atlantic and the global Ocean: control of nutrient supply and ballast production. In: The South Atlantic in the Late Quaternary: Reconstruction of material budget and current systems, Wefer, G., S. Mulitza and V. Ratmeyer (Eds.), Springer, Berlin, Heidelberg, New York, pp. 21-46.

Holmes, M.E., G. Lavik, G. Fischer and G. Wefer (2003) Nitrogen isotopes in sinking particles and surface sediments in the Central and Southern Atlantic. In: The South Atlantic in the Late Quaternary: Reconstruction of material budget and current systems, Wefer, G., S. Mulitza and V. Ratmeyer (Eds.), Springer, Berlin, Heidelberg, New York, pp. 143-165.

Mulitza, S., B. Donner, G. Fischer, A. Paul, J. Pätzold, C. Rühlemann and M. Segl (2003) The South Atlantic oxygen isotope record of planktic foraminifera. In: The South Atlantic in the Late Quaternary: Reconstruction of material budget and current systems, Wefer, G., S. Mulitza and V. Ratmeyer (Eds.), Springer, Berlin, Heidelberg, New York, pp. 121-142..

Müller, P.J. and G. Fischer (2003) C37-alkenones as paleotemperature tool: fundamentals based on sediment traps and surface sediments from the South Atlantic Ocean. In: The South Atlantic in the Late Quaternary: Reconstruction of material budget and current systems, Wefer, G., S. Mulitza and V. Ratmeyer (Eds.), Springer, Berlin, Heidelberg, New York, pp. 167-193.

Schlitzer, R., R. Usbeck and G. Fischer (2003) Inverse modeling of particulate organic carbon fluxes in the South Atlantic. In: The South Atlantic in the Late Quaternary: Reconstruction of material budget and current systems, Wefer, G., S. Mulitza and V. Ratmeyer (Eds.), Springer, Berlin, Heidelberg, New York, pp. 1-19.

Holmes, E.M., G. Lavik, G. Fischer, M. Segl, G. Ruhland and G. Wefer (2002) Seasonal variability of 15N in sinking particles in the Benguela upwelling region. Deep-Sea Research I, 49, 377-394.

Fischer, G., R. Gersonde and G. Wefer (2002) Organic carbon, biogenic silica and diatom fluxes in the marginal winter sea ice zone and in the Polar Front Region in the Southern Ocean (Atlantic Sector): interannual variation and changes in composition. Deep-Sea Research II, 49, 1721-1745.

Romero, O, B. Boeckel, B. Donner, G. Lavik, G. Fischer and G. Wefer (2002) Seasonal productivity dynamics in the pelagic central Benguela system inferred from the carbonate and silicate organisms. Journal of Marine Systems 37/4, 259-278.

Walter, H.-J., W. Geibert, M.M. Rutgers van der Loeff, G. Fischer and U. Bathmann (2001). Shallow vs. deep-water scavenging of 231Pa and 230Th in radionuclide enriched waters of the Atlantic Sector of the Southern Ocean. Deep-Sea Research, 48, 471-493.

Müller, P.J. and G. Fischer (2001) A four-year record of alkenones in the filamentous upwelling zone off Cape Blanc, NW Africa and a comparison with distributions in the underlying sediments. Deep Sea Research I, 48 (8), 1877-1903.

Antia, A.A., W. Koeve, G. Fischer, T. Blanz, D. Schulz-Bull, J. Scholten, S. Neuer, K. Kremling, J. Kuss, R. Peinert, D. Hebbeln, U. Bathmann, M. Conte, U. Fehner and B. Zeitzschel (2001) Basin-wide particulate carbon flux in the Atlantic Ocean: Regional export patterns and potential for atmospheric CO2 sequestration. Global Biogeochemical Cycles, 15 (4), 845-862.

Ragueneau, O., P. Tréguer, R.F. Anderson, M.A. Brzezinski, D.J. DeMaster, R.C. Dugdale, J. Dymond, G. Fischer, R. Francois, C. Heinze, A. Leynaert, E. Meier-Reimer, V. Martin-Jézéquel, D.M Nelson and B. Quéguiner (2000). Understanding the Si cycle in the modern ocean, a pre-requisite for the use of biogenic opal as a paleoproductivity proxy. Global Planetary Change, 26, 317-365.

Romero,O., G. Fischer, C.F. Lange and G. Wefer (2000) Siliceous phytoplankton of the western equatorial Atlantic: sediment traps and surface sediments. Deep-Sea Research II, 47, 1939-1959.

Fischer, G., V. Ratmeyer and G. Wefer (2000) Organic carbon fluxes in the Atlantic and the Southern Ocean: relationships to primary production compiled from satellite radiometer data. Deep-Sea Research II, 47, 1961-1997.

Sigman, D.M., M.A. Altabet, D.C. McCorkle, R. Francois and G. Fischer (2000) The ?15N of nitrate in the Southern Ocean: Nitrogen cycling and circulation in the ocean interior. Journal of Geophysical Research, 105 (C8), 19,599-19,614.

Fischer, G. and G. Wefer (1999, Eds.) Use of proxies in paleoceanography - Examples from the South Atlantic. Springer, Berlin, Heidelberg, New York, 735p.

before 2000 (selected):

Fischer, G. and G. Wefer (1999, Eds.) Use of proxies in paleoceanography - Examples from the South Atlantic. Springer, Berlin, Heidelberg, New York, 735p.

Sigman, D. M., M. A. Altabet, D. C. McCorkle, R. Francois, G. Fischer (1999) The d15N of nitrate in the Southern Ocean: Nitrate consumption in surface waters. Global Biogeochemical Cycles, 13, 4, 1149-1166, doi:10.1029/1999GB900038.

Wefer, G., G. Fischer, D.K. Fütterer and R. Gersonde (1988) Seasonal particle flux in the Bransfield Strait, Antarctica. Deep-Sea Research, 35, 891-898.

Fischer, G., D. Fütterer, R. Gersonde, S. Honjo, D. Ostermann and G. Wefer (1988) Seasonal variability of particle flux in the Weddell Sea and its relation to ice cover. Nature, 335, 426-428.

Wiencke, C. and G. Fischer (1990) Growth and carbon isotope composition of cold-water macroalgae in relation to light and temperature. Marine Ecology Progress Series, 65, 283-292.

Bathmann, U., G. Fischer and P.J. Müller (1991) Short-term variations in particulate matter sedimentation off Kapp Norvegia, Antarctica: relation to water mass advection, ice-cover, plankton biomass and feeding activity. Polar Biology, 11, 185-195.

Wefer, G. and G. Fischer (1991) Annual primary production and export flux in the Southern Ocean from sediment trap data. Marine Chemistry, 35, 597-613.

Fischer, G. (1991) Stable carbon isotope ratios of phytoplankton carbon and sinking organic matter from the Atlantic Sector of the Southern Ocean. Marine Chemistry, 35, 581-596.

Fischer, G. and G. Wefer (1991) Sampling, preparation and analysis of marine particulate matter. In: Marine Particles: Analysis and Characterization, Hurd D.C. and D.W. Spencer (Eds.). Geophysical Monograph, 63, pp. 391-397.

Fischer, G. and C. Wiencke (1992) Stable carbon isotope composition, depth distribution and fate of macroalgae from the Antarctic Peninsula region. Polar Biology, 12, 341-348.

Wefer, G. and G. Fischer (1993) Seasonal patterns of vertical particle flux in equatorial and coastal upwelling areas of the Eastern Atlantic. Deep-Sea Research, 40, 1613-1645.

Kalberer, M., G. Fischer, J. Pätzold, B. Donner, M. Segl and G. Wefer (1993) Seasonal sedimentation and stable isotope records of pteropods off Cape Blanc. Marine Geology, 113, 305-320.

Mackensen, A., H.-W. Hubberten, T.Bickert, G. Fischer and D. Fütterer (1993) The 13C in benthic foraminiferal tests of Fontbotia wuellerstorfi (SCHWAGER) relative to the 13C of dissolved inorganic carbon in Southern Ocean deep water: implications for glacial ocean circulation models. Paleoceanography, 8, 587-610.

Lange, C.B., U. Treppke and G. Fischer (1993) Seasonal diatom fluxes in the Guinea Basin and their relationships to trade winds, ITCZ migrations and upwelling events. Deep-Sea Research, 41, 859-878.

Fischer, G., B. Donner, V. Ratmayer, R. Davenpoort and G. Wefer (1996a) Distinct year-to-year flux variations off Cape Blanc during 1988-1991: relation to 18O-deduced sea-surface temperatures and trade winds. Journal of Marine Research, 54, 73-98.

Fischer G., G. Krause, S. Neuer and G. Wefer (1996b) Short-term sedimentation pulses recorded with a chlorophyll sensor and sediment traps in 900 m water depth in the Canary Basin. Limnology and Oceanography, 41, 1354-1359.

Treppke, U.F., C.B. Lange, B. Donner, G. Fischer, G. Ruhland and G. Wefer (1997) Diatom and silicoflagellate fluxes at the Walvis Ridge: an environment controlled by coastal upwelling in the Benguela system. Journal of Marine Research, 54, 991-1016.

Neuer, S., V. Ratmeyer, R. Davenport, G. Fischer, and G. Wefer (1997) Deep water particle flux in the Canary Island region: seasonal trends in relation to long-term satellite derived pigment data and lateral sources. Deep-Sea Research, 44, 1451-1466.

Fischer, G., R. Schneider, P.J. Müller, and G. Wefer (1997) Anthropogenic CO2 in Southern Ocean surface waters: evidence from stable organic carbon isotopes. Terra Nova, 9, 153-157.

Fischer, G., P.J. Müller G. and Wefer (1998) Latitudinal 13Corg variations in sinking matter and sediments from the South Atlantic: effects of anthropogenic CO2 and implications for palaeo-PCO2 reconstructions. Journal of Marine Systems, 17, 471-495.

Ratmeyer, V., G. Fischer and G. Wefer (1999) Lithogenic particle fluxes and grain size distributions in the deep ocean of northwest Africa: Implications for seasonal changes of aeolian dust input and downward transport. Deep-Sea Research, 46, 1289-1337.

Ratmeyer, V., W. Balzer, G. Bergametti, I. Chiapello, G. Fischer and U. Wyputta (1999) Seasonal impact of mineral dust on deep-ocean particle flux in the eastern subtropical Atlantic Ocean. Marine Geology, 159, 241-252.