Items where Author is "Fischer, Gerhard"

Versteegh, GJM, Zonneveld, KAF, Hefter, J, Romero, OE, Fischer, G and Mollenhauer, G (2022) Performance of temperature and productivity proxies based on long-chain alkane-1, mid-chain diols at test: a 5-year sediment trap record from the Mauritanian upwelling. Biogeosciences, 19(5). 1587-1610. doi:10.5194/bg-19-1587-2022

Romero, OE, Ramondenc, S and Fischer, G (2021) A 2-decade (1988–2009) record of diatom fluxes in the Mauritanian coastal upwelling: impact of low-frequency forcing and a two-step shift in the species composition. Biogeosciences, 18(5). 1873-1891. doi:10.5194/bg-18-1873-2021

Guerreiro, CV, Baumann, KH, Brummer, GJA, Valente, A, Fischer, G, Ziveri, P, Brotas, V and Stuut, JBW (2021) Carbonate fluxes by coccolithophore species between NW Africa and the Caribbean: Implications for the biological carbon pump. Limnology and Oceanography. doi:10.1002/lno.11872

Kiss, P, Jonkers, L, Hudáčková, N, Reuter, RT, Donner, B, Fischer, G and Kucera, M (2021) Determinants of planktonic foraminifera calcite flux: Implications for the prediction of intra‐ and inter‐annual pelagic carbonate budgets. Global Biogeochemical Cycles, 35(9). doi:10.1029/2020GB006748

Fischer, G, Romero, OE, Karstensen, J, Baumann, KH, Moradi, N, Iversen, MH, Ruhland, G, Klann, M and Körtzinger, A (2021) Seasonal flux patterns and carbon transport from low-oxygen eddies at the Cape Verde Ocean Observatory: lessons learned from a time series sediment trap study (2009–2016). Biogeosciences, 18(24). 6479-6500. doi:10.5194/bg-18-6479-2021

Moradi, N, Klawonn, I, Iversen, MH, Wenzhöfer, F, Grossart, HP, Ploug, H, Fischer, G and Khalili, A (2021) A novel measurement-based model for calculating diffusive fluxes across substrate-water interfaces of marine aggregates, sediments and biofilms. Frontiers in Marine Science, 8. doi:10.3389/fmars.2021.689977

Romero, OE, Baumann, KH, Zonneveld, KAF, Donner, B, Hefter, J, Hamady, B, Pospelova, V and Fischer, G (2020) Flux variability of phyto- and zooplankton communities in the Mauritanian coastal upwelling between 2003 and 2008. Biogeosciences, 17(1). 187-214. doi:10.5194/bg-17-187-2020

Fischer, G, Neuer, S, Ramondenc, S, Müller, TJ, Donner, B, Ruhland, G, Ratmeyer, V, Meinecke, G, Nowald, N, Klann, M and Wefer, G (2020) Long-term changes of particle flux in the Canary Basin between 1991 and 2009 and comparison to sediment trap records off Mauritania. Frontiers in Earth Science, 8. doi:10.3389/feart.2020.00280

Markussen, TN, Konrad, C, Waldmann, C, Becker, M, Fischer, G and Iversen, MH (2020) Tracks in the snow – advantage of combining optical methods to characterize marine particles and aggregates. Frontiers in Marine Science, 7. doi:10.3389/fmars.2020.00476

Fischer, G, Romero, OE, Toby, E, Iversen, MH, 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, 33(8). 1100-1128. doi:10.1029/2019GB006194

Vorrath, ME, Lahajnar, N, Fischer, G, Libuku, VM, Schmidt, M and Emeis, KC (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. doi:10.1016/j.jmarsys.2017.12.002

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

Van der Jagt, H, Friese, C, Stuut, JBW, Fischer, G and Iversen, MH (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, 63(3). 1386-1394. doi:10.1002/lno.10779

Gray, WR, Weldeab, S, Lea, DW, Rosenthal, Y, Gruber, N, Donner, B and Fischer, G (2018) The effects of temperature, salinity, and the carbonate system on Mg/Ca in Globigerinoides ruber (white): A global sediment trap calibration. Earth and Planetary Science Letters, 482. 607-620. doi:10.1016/j.epsl.2017.11.026

Guerreiro, CV, Baumann, KH, Brummer, GJA, Fischer, G, Korte, LF, Merkel, U, Sá, C, de Stigter, H and Stuut, JBW (2017) Coccolithophore fluxes in the open tropical North Atlantic: influence of thermocline depth, Amazon water, and Saharan dust. Biogeosciences, 14(20). 4577-4599. doi:10.5194/bg-14-4577-2017

Friese, CA, van Hateren, JA, Vogt, C, Fischer, G and Stuut, JBW (2017) Seasonal provenance changes in present-day Saharan dust collected in and off Mauritania. Atmospheric Chemistry and Physics, 17(16). 10163-10193. doi:10.5194/acp-17-10163-2017

Romero, OE and Fischer, G (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). Progress in Oceanography, 159. 31-44. doi:10.1016/j.pocean.2017.09.010

Fischer, G, Karstensen, J, Romero, OE, Baumann, KH, Donner, B, Hefter, J, Mollenhauer, G, Iversen, MH, Fiedler, B, Monteiro, I and Körtzinger, A (2016) Bathypelagic particle flux signatures from a suboxic eddy in the oligotrophic tropical North Atlantic: production, sedimentation and preservation. Biogeosciences, 13(11). 3203-3223. doi:10.5194/bg-13-3203-2016

Fischer, G, Romero, OE, Merkel, U, Donner, B, Iversen, MH, Nowald, N, Ratmeyer, V, Ruhland, G, Klann, M and Wefer, G (2016) Deep ocean mass fluxes in the coastal upwelling off Mauritania from 1988 to 2012: variability on seasonal to decadal timescales. Biogeosciences, 13(10). 3071-3090. doi:10.5194/bg-13-3071-2016

Romero, OE, Fischer, G, Karstensen, J and Cermeño, P (2016) Eddies as trigger for diatom productivity in the open-ocean Northeast Atlantic. Progress in Oceanography, 147. 38-48. doi:10.1016/j.pocean.2016.07.011

Friese, CA, van der Does, M, Merkel, U, Iversen, MH, Fischer, G and Stuut, JBW (2016) Environmental factors controlling the seasonal variability in particle size distribution of modern Saharan dust deposited off Cape Blanc. Aeolian Research, 22. 165-179. doi:10.1016/j.aeolia.2016.04.005

Fischer, G, Bouskri, G, Dia, A, Flintrop, C, Hüttich, D, Iversen, MH, Klann, M, Konrad, C, Park, E, Ruhland, G and Van der Jagt, H (2016) Report and preliminary results of R/V POSEIDON cruise POS495, Las Palmas (Canary Islands) - Las Palmas (Canary Islands), 18.02.2016 - 02.03.2016. Berichte, MARUM – Zentrum für Marine Umweltwissenschaften, Fachbereich Geowissenschaften, Universität Bremen, 310. 1-29. urn:nbn:de:gbv:46-00105269-12

Wefer, G, Fischer, G and Iversen, MH (2015) Export Production. In: Harff, J, Meschede, M, Petersen, S and Thiede, J (eds.) Encyclopedia of Marine Geosciences. Springer Netherlands, 1-2. doi:10.1007/978-94-007-6644-0_59-1

Karstensen, J, Fiedler, B, Schütte, F, Brandt, P, Körtzinger, A, Fischer, G, Zantopp, R, Hahn, J, Visbeck, M and Wallace, D (2015) Open ocean dead zones in the tropical North Atlantic Ocean. Biogeosciences, 12(8). 2597-2605. doi:10.5194/bg-12-2597-2015

Fischer, G, Dia, A, Klann, M, Nowald, N, Markussen, T, Meckel, S, Ruhland, G, Van der Jagt, H and Waldmann, C (2015) Report and preliminary results of R/V POSEIDON cruise POS481, Las Palmas (Canary Islands) - Las Palmas (Canary Islands), 15.03.2015 - 03.03.2015. Berichte, MARUM – Zentrum für Marine Umweltwissenschaften, Fachbereich Geowissenschaften, Universität Bremen, 307. urn:nbn:de:gbv:46-00104572-13

Koebrich, MI, Baumann, KH and Fischer, G (2015) Seasonal and inter-annual dynamics of coccolithophore fluxes from the upwelling region off Cape Blanc, NW Africa. Journal of Micropalaeontology, 35. 103-116. doi:10.1144/jmpaleo2014-024

Nowald, N, Iversen, MH, Fischer, G, Ratmeyer, V and Wefer, G (2015) Time series of in-situ particle properties and sediment trap fluxes in the coastal upwelling filament off Cape Blanc, Mauritania. Progress in Oceanography, 137. 1-11. doi:10.1016/j.pocean.2014.12.015

Mollenhauer, G, Basse, A, Kim, JH, Sinninghe Damsté, JS and Fischer, G (2015) A four-year record of UK′37- and TEX86-derived sea surface temperature estimates from sinking particles in the filamentous upwelling region off Cape Blanc, Mauritania. Deep Sea Research Part I: Oceanographic Research Papers, 97. 67-79. doi:10.1016/j.dsr.2014.11.015

Basse, A, Zhu, C, Versteegh, GJM, Fischer, G, Hinrichs, KU and Mollenhauer, G (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. doi:10.1016/j.orggeochem.2014.04.007

Neuer, S, Iversen, MH and Fischer, G (2014) The Ocean's Biological Carbon pump as part of the global Carbon Cycle. Limnology and Oceanography e-Lectures. doi:10.4319/lol.2014.sneuer.miversen.gfischer.9

Fischer, G, Dehning, K, Dia, A, Füssel, J, Hefter, J, Iversen, MH, Klann, M, Nowald, N, Olbrich, M and Ruhland, G (2014) Report and preliminary results of R/V POSEIDON cruise POS464, Las Palmas (Canary Islands) - Las Palmas (Canary Islands), 03.02.2014 - 18.02.2014. Berichte, MARUM – Zentrum für Marine Umweltwissenschaften, Fachbereich Geowissenschaften, Universität Bremen, 304. urn:nbn:de:gbv:46-00103963-17

Fischer, G, Ba, M, Dehning, K, Hefter, J, Iversen, MH, Klann, M, Nowald, N, Ploug, H, Ruhland, G and Witte, Y (2013) Report and preliminary results of R/V POSEIDON cruise POS445. Las Palmas – Las Palmas, 19.01.2013 – 01.02.2013. Berichte, MARUM - Zentrum für Marine Umweltwissenschaften, Fachbereich Geowissenschaften, Universität Bremen, 298. 1-30. urn:nbn:de:gbv:46-00103379-13

Fischer, G (2012) Report and preliminary results of RV POSEIDON Cruise P425. Las Palmas - Las Palmas, 16.01.2012 - 30.01.2012. Berichte aus dem Fachbereich Geowissenschaften der Universität Bremen, 287. Department of Geosciences, Bremen University. urn:nbn:de:gbv:46-00102708-17

Romero, OE, Leduc, G, Vidal, L and Fischer, G (2011) Millennial variability and long-term changes of the diatom production in the eastern equatorial Pacific during the last glacial cycle. Paleoceanography, 26. PA2212. doi:10.1029/2010PA002099

Fischer, G and cruise participants (2011) Report and preliminary results of RV POSEIDON Cruise POS 396, Las Palmas - Las Palmas (Spain), 24 February - 8 March 2010. Berichte aus dem Fachbereich Geowissenschaften der Universität Bremen, 277. Department of Geosciences, Bremen University. urn:nbn:de:gbv:46-00101866-18

Iversen, MH, Nowald, N, Ploug, H, Jackson, GA and Fischer, G (2010) High resolution profiles of vertical particulate organic matter export off Cape Blanc, Mauritania: Degradation processes and ballasting effects. Deep Sea Research Part I: Oceanographic Research Papers, 57(6). 771-784. doi:10.1016/j.dsr.2010.03.007

Fischer, G, Neuer, S, Davenport, B, Helmke, P, Schlitzer, R, Romero, OE, Ratmeyer, V, Donner, B, Freudenthal, T, Meggers, H and Wefer, G (2010) The Northwest African Margin. In: Liu, KK, Atkinson, L, Quiñones, R and Talaue-McManus, L (eds.) Carbon and Nutrient Fluxes in Continental Margins: A Global Synthesis. The IGBP Series. Springer, Berlin, Heidelberg, 78-102.

Zonneveld, KAF, 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. doi:10.1111/j.1529-8817.2009.00799.x

Karakas, G, Nowald, N, Schäfer-Neth, C, Iversen, MH, 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. doi:10.1016/j.pocean.2009.07.047

Nowald, N, Fischer, G, Ratmeyer, V, Iversen, MH, Reuter, C and Wefer, G (2009) In-situ sinking speed measurements of marine snow aggregates aquired with a settling chamber mounted to the Cherokee ROV. OCEANS 2009 - EUROPE (OCEANS-IEEE Series). 1-6. doi:10.1109/OCEANSE.2009.5278186

Fischer, G, Karakas, G, Blaas, M, Ratmeyer, V, Nowald, N, Schlitzer, R, Helmke, P, Davenport, R, Donner, B, Neuer, S and Wefer, G (2009) Mineral ballast and particle settling rates in the coastal upwelling system off NW Africa and the South Atlantic. International Journal of Earth Sciences, 98(2). 281-298. doi:10.1007/s00531-007-0234-7

Fischer, G, Reuter, C, Karakas, G, Nowald, N and Wefer, G (2009) Offshore advection of particles within the Cape Blanc filament, Mauritania: Results from observational and modelling studies. In: Freon, P, Barange, M and Aristegui, J (eds.) Eastern Boundary Upwelling Ecosystems: Integrative and Comparitive Approaches. Special Issue, Progress in Oceanography, 83(1-4). Elsevier Ltd., 322-330. doi:10.1016/j.pocean.2009.07.023

Ruhland, G, Fischer, G and cruise participants (2009) Report and preliminary results of R/V POSEIDON Cruise 365 (Leg 1+2). Leg 1: Las Palmas - Las Palmas, 13.4. - 16.4.2008. Leg 2: Las Palmas - Las Palmas, 18.4. - 29.4.2008. Berichte aus dem Fachbereich Geowissenschaften der Universität Bremen, 270. Department of Geosciences, Bremen University. urn:nbn:de:gbv:46-ep000106558

Fischer, G and Karakas, G (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. doi:10.5194/bg-6-85-2009

Ploug, H, Iversen, MH and Fischer, G (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. doi:10.4319/lo.2008.53.5.1878

Fischer, G, Ruhland, G and cruise participants (2008) Report and preliminary results of Poseidon cruise 344, Leg 1 & Leg 2, Las Palmas - Las Palmas, 20.10.2006.-02.11.2006 & 04.11.2006 - 13.11.2006. Berichte aus dem Fachbereich Geowissenschaften der Universität Bremen, 259. Department of Geosciences, Bremen University. urn:nbn:de:gbv:46-ep000106580

Nowald, N, Karakas, G, Ratmeyer, V, Fischer, G, Schlitzer, R, Davenport, R and Wefer, G (2006) Distribution and transport processes of marine particulate matter off Cape Blanc (NW-Africa): results from vertical camera profiles. Ocean Science Discussions, 3. 903-938. doi:10.5194/osd-3-903-2006

Helmke, P, Romero, OE and Fischer, G (2005) Northwest African upwelling and its effect on off-shore organic carbon export to the deep sea. Global Biogeochemical Cycles, 19(4). GB4015. doi:10.1029/2004GB002265

Susek, E, Zonneveld, KAF, Fischer, G, Versteegh, GJM and Willems, H (2005) Organic-walled dinoflagellate cysts production in relation to upwelling intensity and lithogenic influx in the Cape Blanc region (off north-west Africa). Phycological Journal, 53(2). 97-112. doi:10.1111/j.440-183.2005.00377

Zaric, S, Donner, B, Fischer, G, Mulitza, S and Wefer, G (2005) Sensitivity of planktic foraminifera to sea surface temperature and export production as derived from sediment trap data. Marine Micropaleontology, 55(1-2). 75-105. doi:10.1016/j.marmicro.2005.01.002

Garrity, C, Ramseier, RO, Peinert, R, Kern, S and Fischer, G (2005) Water column particulate organic carbon modeled in the ice-frequented Southern Ocean. Journal of Marine Systems, 56. 133-149. doi:10.1016/j.jmarsys.2004.09.009

Holmes, ME, Lavik, G, Fischer, G and Wefer, G (2004) Nitrogen isotopes in sinking particles and surface sediments in the Central and Southern Atlantic. In: Wefer, G, Mulitza, S and Ratmeyer, V (eds.) The South Atlantic in the Late Quaternary: Reconstruction of Material Budgets and Current Systems. Springer, Berlin, Heidelberg, 143-165. doi:10.1007/978-3-642-18917-3_8

Mulitza, S, Donner, B, Fischer, G, Paul, A, Pätzold, J, Rühlemann, C and Segl, M (2004) The South Atlantic oxygen isotope record of planctic foraminifera. In: Wefer, G, Mulitza, S and Ratmeyer, V (eds.) The South Atlantic in the Late Quaternary. Reconstruction of Material Budgets and Current Systems. Springer-Verlag, Berlin Heidelberg, 121-142.

Fischer, G, Wefer, G, Romero, OE, Dittert, N, Ratmeyer, V and Donner, B (2004) Transfer of particles into the deep Atlantic and the global ocean: Control of nutrient supply and ballast production. In: Wefer, G, Mulitza, S and Ratmeyer, V (eds.) The South Atlantic in the Late Quaternary: Reconstruction of Material Budgets and Current Systems. Springer, Berlin, Heidelberg, 21-46.

Schneider, B, Schlitzer, R, Fischer, G and Nöthig, EM (2003) Depth dependent elemental compositions of particle organic matter (POM) in the ocean. Global Biogeochemical Cycles, 17(2). 1032. doi:10.1029/2002GB001871

Schlitzer, R, Usbeck, R and Fischer, G (2003) Inverse Modeling of Particulate Organic Carbon Fluxes in the South Atlantic. In: Wefer, G, Mulitza, S and Ratmeyer, V (eds.) The South Atlantic in the Late Quaternary: Reconstruction of Material Budgets and Current Systems. Springer, Berlin, Heidelberg, New York, 1-19.

Usbeck, R, Schlitzer, R, Fischer, G and Wefer, G (2003) Particle fluxes in the ocean: comparison of sediment trap data with results from inverse modeling. Journal of Marine Systems, 39(3-4). 167-183. doi:10.1016/S0924-7963(03)00029-0

Fischer, G, Gersonde, R and Wefer, G (2002) Organic carbon, biogenic silica and diatom fluxes in the marginal winter sea ice zone and in the Polar Front Region: interannual variation and changes in composition. Deep Sea Research Part II: Topical Studies in Oceanography, 49(9-10). 1721-1745. doi:10.1016/S0967-0645(02)00009-7

Fischer, G and et al (2002) Report and preliminary results of RV Meteor-Cruise M49/4 Salvador da Bahia - Halifax, 4.4.-5.5.2001. Berichte aus dem Fachbereich Geowissenschaften der Universität Bremen, 194. Department of Geosciences, Bremen University. urn:nbn:de:gbv:46-ep000103191

Romero, OE, Boeckel, B, Donner, B, Lavik, G, Fischer, G and Wefer, G (2002) Seasonal productivity dynamics in the pelagic central Benguela System inferred from the flux of carbonate and silicate organisms. Journal of Marine Systems, 37(4). 259-278. doi:10.1016/S0924-7963(02)00189-6

Holmes, ME, Lavik, G, Fischer, G, Segl, M, Ruhland, G and Wefer, G (2002) Seasonal variability of d15N in sinking particles in the Benguela upwelling region. Deep Sea Research Part I: Oceanographic Research Papers, 49(2). 377-394. doi:10.1016/S0967-0637(01)00055-3

Müller, PJ and Fischer, G (2001) A 4-year sediment trap record of alkenones from the filamentous upwelling region off Cape Blanc, NW Africa and a comparison with distributions in underlying sediments. Deep Sea Research Part I: Oceanographic Research Papers, 48(8). 1877-1903. doi:10.1016/S0967-0637(00)00109-6

Antia, AN, Koeve, W, Fischer, G, Blanz, T, Schulz-Bull, D, Scholten, J, Neuer, S, Kremling, K, Kuss, J, Peinert, R, Hebbeln, D, Bathmann, U, Conte, MH, Fehner, U and Zeitzschel, B (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. doi:10.1029/2000GB001376

Fischer, G and et al (1999) Report and preliminary results of METEOR-Cruise M 41/4, Salvador da Bahia - Las Palmas, 18.5.-13.6.1998. Berichte aus dem Fachbereich Geowissenschaften der Universität Bremen, 130. Department of Geosciences, Bremen University. urn:nbn:de:gbv:46-ep000102492

Fischer, G and et al (1997) Report and preliminary results of METEOR-Cruise M 38/1, Las Palmas - Recife, 25.1.-1.3.1997. Berichte aus dem Fachbereich Geowissenschaften der Universität Bremen, 094. Department of Geosciences, Bremen University. urn:nbn:de:gbv:46-ep000102319

Fischer, G and et al (1996) Report and preliminary results of Meteor-Cruise M 34/4, Recife-Bridgetown. Berichte aus dem Fachbereich Geowissenschaften der Universität Bremen, 080. Department of Geosciences, Bremen University. urn:nbn:de:gbv:46-ep000102102

Fischer, G (1989) Stabile Kohlenstoff-Isotope in partikulärer organischer Substanz aus dem Südpolarmeer (Atlantischer Ozean). Berichte aus dem Fachbereich Geowissenschaften der Universität Bremen, 005. Department of Geosciences, Bremen University. urn:nbn:de:gbv:46-ep000101449