Climate of the Past www.clim-past.net 1814-9324 1814-9332 4 2 2008 10.5194/cp-4-107-2008 http://www.clim-past.net/4/107/2008/ http://www.clim-past.net/4/107/2008/cp-4-107-2008.html http://www.clim-past.net/4/107/2008/cp-4-107-2008.pdf 107 124 2008-06-10 Thirty thousand years of vegetation development and climate change in Angola (Ocean Drilling Program Site 1078) L. M. Dupont H. Behling J.-H. Kim MARUM – Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany Palynology and Climate Dynamics, Albrecht-von-Haller-Inst. for Plant Sciences, Univ. of Göttingen, Göttingen, Germany NIOZ, Texel, The Netherlands ODP Site 1078 situated under the coast of Angola provides the first record of the vegetation history for Angola. The upper 11 m of the core covers the past 30 thousand years, which has been analysed palynologically in decadal to centennial resolution. Alkenone sea surface temperature estimates were analysed in centennial resolution. We studied sea surface temperatures and vegetation development during full glacial, deglacial, and interglacial conditions. During the glacial the vegetation in Angola was very open consisting of grass and heath lands, deserts and semi-deserts, which suggests a cool and dry climate. A change to warmer and more humid conditions is indicated by forest expansion starting in step with the earliest temperature rise in Antarctica, 22 thousand years ago. We infer that around the period of Heinrich Event 1, a northward excursion of the Angola Benguela Front and the Congo Air Boundary resulted in cool sea surface temperatures but rain forest remained present in the northern lowlands of Angola. Rain forest and dry forest area increase 15 thousand years ago. During the Holocene, dry forests and Miombo woodlands expanded. Also in Angola globally recognised climate changes at 8 thousand and 4 thousand years ago had an impact on the vegetation. During the past 2 thousand years, savannah vegetation became dominant. Adegbie, A. T., Schneider, R. R., Röhl, U., and Wefer, G.: Glacial millennial-scale fluctuations in central African precipitation recorded in terrigenous sediment supply and freshwater signals offshore Cameroon, Palaeogeogr. Palaeocl., 197, 323–333, 2003. Adkins, J., DeMenocal, P., and Eshel, G.: The "African humid period" and the record of marine upwelling from excess $^230$Th in Ocean Drilling Program Hole 658C, Paleoceanography, 21(PA4203), 1–14, 2006. Barker, P., Talbot, M. R., Street-Perrot, F. A., Marret, F., Scourse, J., and Odada, E.: Late Quaternary climatic variability in intertropical Africa, in: Past Climate Variability through Europe and Africa, Springer, Dordrecht, The Netherlands, 118–138, 2004. Bartholome, E., Belward, A. S., Achard, F., Bartalev, S., Carmona-Moreno, C., Eva, H., Fritz, S., Gregoire, J.-M., Mayaux, P., and Stibig H.-J.: GLC2000: Global Land Cover mapping for the year 2000, http://www-gem.jrc.it/glc2000/, European Commission, 2002. Beentje, H.: Kenya trees, shrubs and lianas, National Museum of Kenya, Nairobi, Kenya, 1994. Bonnefille, R. and Chalié, F.: Pollen-inferred precipitation time-series from equatorial mountains, Africa, the last 40 kyr BP, Global Planet. Change, 26, 25–50, 2000. Bonnefille, R. and Riollet, G.: Pollens des savanes d'Afrique orientale, Éditions du Centre National de la Recherche Scientifique, Paris, France, 1980. Bonnefille, R. and Riollet, G.: The Kashiru pollen sequence (Burundi). Palaeoclimatic implications for the last 40,000 yr. B.P. in tropical Africa, Quaternary Res., 30, 19–35, 1988. Bostoen, K.: Pots, words and the Bantu problem: on lexical reconstructionand early African history, J. Afr. Hist., 48, 173–199, 2007. Butzin, M., Prange, M., and, Lohmann, G.: Radiocarbon simulations for the glacial ocean: the effects of wind stress, Southern Ocean sea ice and Heinrich events, Earth Planet. Sci. Lett., 235, 45–61, 2005. Coetzee, J. A.: Pollen analytical studies in east and southern Africa, Palaeoecol. Afr., 3, 1–146, 1967. DeMenocal, P. B., Ortiz, J., Guilderson, T., and Sarnthein, M.: Coherent high- and low-latitude climate variability during the Holocene warm period, Science, 288, 2198–2202, 2000. Dupont, L. M. and Behling, H.: Land-sea linkages during deglaciation: High-resolution records from the eastern Atlantic off the coast of Namibia and Angola (ODP site 1078), Quatern. Int., 148, 19–28, 2006. Dupont, L. M. and Wyputta, U.: Reconstructing pathways of aeolian pollen transport to the marine sediments along the coastline of SW Africa, Quaternary Sci. Rev., 22, 157–174, 2003. Dupont, L. M., Shi, N., Jahns, S., and Marret, F.: Podocarpus in West Africa during the Late Pleistocene, Palaeoecol. Afr., 24, 85–101, 1996. Dupont, L. M., Behling, H., Jahns, S., Marret, F., and Kim, J.-H.: Variability in glacial and Holocene marine pollen records offshore from west southern Africa, Veg. Hist. Archaeobot., 16, 87–100, 2007. Elenga, H., Schwartz, D., and Vincens, A.: Pollen evidence of late Quaternary vegetation and inferred climate changes in Congo, Palaeogeogr. Palaeocl., 109, 345–356, 1994. Elenga, H., Maley, J., Vincens, A., and Farrera, I.: Palaeoenvironments, palaeoclimates and landscape development in Atlantic Equatorial Africa: a review of key sites covering the last 25 kyrs, Past Climate Variability through Europe and Africa, Springer, Dordrecht, The Netherlands, 181–198, 2004. Fairbanks, R. G.: A 17,000-year glacio-eustatic sea level record: influence of glacial melting dates on the Younger Dryas event and deep ocean circulation, Nature, 342, 215–230, 1989. Fairbanks, R. G., Mortlock, R. A., Chiu, T.-C., Cao, L., Kaplan, A., Guilderson, T. P., Fairbanks, T. W., Bloom, A. L., Grootes, P. M., and Nadeau, M.-J.: Radiocarbon calibration curve spanning 0 to 50,000 years BP based on paired $^230$Th/$^234$U/$^238$U and $^14$C dates on pristine corals, Quaternary Sci. Rev., 24, 1781–1796, 2005. Fleming, K., Johnston, P., Zwartz, D., Yokoyama, Y., Lambeck, K., and Chappell, J.: Refining the eustatic sea-level curve since the Last Glacial Maximum using far- and intermediate-field sites, Earth Planet. Sci. Lett., 163, 327–342, 1998. Gasse, F.: Hydrological changes in the African tropics since the Last Glacial Maximum, Quaternary Sci. Rev., 19, 189–211, 2000. Gasse, F. and Van Campo, E.: Late Quaternary environmental changes from a pollen and diatom record in the southern tropics (Lake Tritrivakely, Madagascar), Palaeogeogr. Palaeocl., 167, 287–308, 2001. Hanebuth, T., Stattegger, K., and Grootes, P. M.: Rapid flooding of the Sunda shelf: A Late-Glacial sea level record, Science, 288, 1033–1035, 2000. Hastings, D. A. and Dunbar, P. K.: Development & assessment of the Global Land One-km Base Elevation digital elevation model (GLOBE), ISPRS Archives, 32, 218–221, 1998. Hoelzmann, P., Gasse, F., Dupont, L.M., Salzmann, U., Staubwasser, M., Leuschner, D. C., and Sirocko, F.: Palaeoenvironmental changes in the arid and sub arid belt (Sahara-Sahel-Arabian Peninsula) from 150 kyr to present, Past Climate Variability through Europe and Africa, Springer, Dordrecht, The Netherlands, 219–256, 2004. Hughen, K. A., Baillie, M. G. L., Bard, E., Bayliss, A., Beck, J. W., Bertrand, C., Blackwell, P. G., Buck, C. E., Burr, G., Cutler, K. B., Damon, P. E., Edwards, R. L., Fairbanks, R. G., Friedrich, M., Guilderson, T. P., Kromer, B., McCormac, F. G., Manning, S., Bronk Ramsey, C., Reimer, P. J., Reimer, R. W., Remmele, S., Southon, J. R., Stuiver, M., Talamo, S., Taylor, F. W., Van Der Plicht, J., and Weyhenmeyer, C. E.: Marine04 Marine radiocarbon age calibration, 26–0 ka BP, Radiocarbon, 46, 1059–1086, 2004. Johnson, T. C., Brown, E. T., and McManus, J.: Diatom productivity in Northern Lake Malawi during the past 25 000 years: implications for the position of the Intertropical Convergence Zone at millennial and shorter time scales, Past Climate Variability through Europe and Africa, Springer, Dordrecht, The Netherlands, 93–116, 2004. Jolly, D. and Haxeltine, A.: Effect of low glacial atmospheric CO₂ on tropical African montane vegetation, Science, 276, 786–788, 1997. Kim, J.-H., Schneider, R. R., Müller, P. J., and Wefer, G: Interhemispheric comparison of deglacial sea-surface temperature patterns in Atlantic eastern boundary currents, Earth Planet. Sci. Lett., 194, 383–393, 2002. Kim, J.-H., Schneider, R. R., Mulitza, S., and Müller, P. J.: Reconstruction of SE trade-wind intensity based on sea-surface temperature gradients in the Southeast Atlantic over the last 25 kyr, Geophys. Res. Lett., 30, 2144–2147, 2003. Kim, J.-H., Dupont, L. M., Behling, H., and Versteegh, G. J. M.: Impacts of rapid sea-level rise on mangrove deposit erosion: application of taraxerol and Rhizophora records, J. Quaternary Sci., 20, 221–225, 2005. Kiruki, H. and Njung'e, J.: Population density, structure and early growth characteristics of Tarchonanthus camphoratus ina woodland at Naivashe, Kenya, Afr. J. Ecol., 45, 31–40, 2007. Köhler, E. and Brückner, P.: Die Pollenmorphologie der afrikanischen \textitBuxus- und \textitNotobuxus-Arten (Buxaceae) und ihre systematische Bedeutung, Grana, 21, 71–82, 1982. Lanfranchi, R. and Clist, B. (Eds.): Aux origines de l'Afrique centrale, Sepia, Paris, 1991. Leroux, M.: Le climat de L'Afrique tropicale (Texte and atlas), Champion, Paris, France, 1983. Lezine, A.-M. and Cazet, J.-P.: High-resolution pollen record from core KW31, Gulf of Guinea, documents the history of the lowland forests of West Equatorial Africa since 40 000 yr ago, Quaternary Res., 64, 432–443, 2005. Maley, J. and Brenac, P.: Vegetation dynamics, palaeoenvironments and climatic changes in the forests of western Cameroon during the last 28 000 years B.P., Rev. Palaeobot. Palyno., 99, 157–187, 1998. Marchant, R. and Hooghiemstra, H.: Rapid environmental change in African and South American tropics around 4000 years before present: a review, Earth-Sci. Rev., 66, 217–260, 2004. Marret, F., Scourse, J., Versteegh, G., Jansen, J. H. F., and Schneider, R.: Integrated marine and terrestrial evidence for abrupt Congo River palaeodischarge fluctuations during the last deglaciation, J. Quaternary Sci., 16, 761–766, 2001. Monnin, E., Indermühle, A., Dällenbach, A., Flückiger, J., Stauffer, B., Stocker, T. F., Raynaud, D., and Barnola, J.-M.: Atmospheric CO₂ concentrations over the last glacial termination, Science, 291, 112–114, 2001. Müller, J. P., Kirst, G., Ruhland, G., Von Storch, I., Rosell-Melé, T.: Calibration of the alkenone paleotemperature index $U_37^K' $ based on core-tops from the eastern South Atlantic and the global ocean (60° N–60° S), Geochim. Cosmochim. Ac., 62, 1757–1772, 1998. Nicholson, S. E.: The nature of rainfall variability over Africa on time scales of decades to millennia, Global Planet. Change, 26, 137–158, 2000. Niebler, H. S., Arz, H. W., Donner, B., Mulitza, S., Pätzold, J., and Wefer, G.: Sea surface temperatures in the equatorial and South Atlantic Ocean during the Last Glacial Maximum (23–19 ka), Paleoceanography, 18, 1069–1080, 2003. Palgrave, K. C.: Trees of Southern Africa, 3rd Ed., revised and updated, Struik, Cape Town, South Africa, 2002. Peltier, W. R. and Fairbanks, R. G.: Global glacial ice volume and Last Glacial Maximum duration from an extended Barbados sea level record, Quaternary Sci. Rev., 25, 3322–3337, 2006. Peterson, R. G. and Stramma, L.: Upper-level circulation in the South Atlantic Ocean, Prog. Oceanogr., 26, 1–73, 1991. Prahl, F. G. and Wakeham, S. G.: Calibration of unsaturation patterns in long-chain ketone compositions for paleotemperature assessment, Nature, 330, 367–369, 1987. Prahl, F. G., Muehlhausen, L. A., and Zahnle, D. L.: Further evaluation of long-chain alkenones as indicators of paleoceanographic conditions, Geochim. Cosmochim. Ac., 5, 2303–2310, 1988. Rommerskirchen, R., Eglinton, G., Dupont, L., Güntner, U., Wenzel, C., and Rullkötter, J.: A North to South Transect of Holocene Southeast Atlantic Continental Margin Sediments: Relationship between Aerosol Transport and Compound-Specific $\delta ^13$C Land Plant Biomarker and Pollen Records, Geochem. Geophy. Geosy., 4, 1101–1129, 2003. Rühlemann, C., Mulitza, S., Lohmann, G., Paul, A., Prange, M., and Wefer, G.: Intermediate-depth warming in the tropical Atlantic related to weakened thermohaline circulation: Combining paleoclimate and modeling results for the last deglaciation, Paleoceanography, 19, PA1025, 1–10, 2004. Schefuss, E., Schouten, S., and Schneider, R. R.: Climate controls on central African hydrology during the past 20 000 years, Nature, 437, 1003–1006, 2005. Schelpe, E. A. C. L. E.: Flora Zambesiaca, Pteridophyta, Royal Botanical Gardens, Kew, UK, 1970. Schneider, R. R., Müller, P. J., and Ruhland, G.: Late Quaternary surface circulation in the east equatorial South Atlantic: Evidence from alkenone sea surface temperatures, Paleoceanography, 10, 197–219, 1995. Schneider, R. R., Price, B., Müller, P.J, Kroon, D., and Alexander, I.: Monsoon related variations in Zaire (Congo) sediments load and influence of fluvial silicate supply on marine productivity in the east equatorial Atlantic, Paleoceanography, 12, 463–481, 1997. Scott, L.: Late Quaternary fossil pollen grains from the Transvaal, South Africa, Rev. Palaeobot. Palyno., 36, 241–278, 1982a. Scott, L.: A late Quaternary pollen record fromTransvaal bushveld, South Africa, Quaternary Res., 17, 339–370, 1982b. Scott, L. and Tee-Thorp, J. A.: Holocene climatic trends and rythms in southern Africa, Past Climate Variability through Europe and Africa, Springer, Dordrecht, The Netherlands, 69–91, 2004. Scott, L., Steenkamp, M., and Beaumont, P. B.: Palaeoenvironmental conditions in South Africa at the Pleistocene-Holocene transition, Quaternary Sci. Rev., 14, 937–947, 1995. Shannon, V. and Nelson, G.: The Benguela: Large scale features and processes and system variability, The South Atlantic: Present and Past Circulation, Springer, Berlin, Germany, 163–210, 1996. Shi, N. and Dupont, L. M.: Vegetation and climate history of SW Africa: a marine palynological record of the last 300 000 years, Veg. Hist. Archaeobot., 6, 117–131, 1997. Shi, N., Dupont, L. M., Beug, H.-J., and Schneider, R.: Correlation between vegetation in southwestern Africa and oceanic upwelling in the past 21 000 years, Quaternary Res., 54, 72–80, 2000. Sowunmi, M. A.: Pollen grains of Nigerian plants I, Woody species, Grana, 13, 145–186, 1973. Sowunmi, M. A.: Pollen of Nigerian plants II, Woody species, Grana, 34, 39–44, 1995. Spalding, M., Blasco, F., and Field, C.: World mangrove Atlas, The International Society for mangrove Ecosystems (ISME), Smith Settle, Otley, UK, 1997. Stuiver, M. and Reimer, P. J.: Extended 14C database and revised CALIB 3.0 14C age calibration program, Radiocarbon, 35, 215–230, 1993. Tyson, P. D.: Climate Change and Variability in Southern Africa, Oxford University Press, Cape Town, South Africa, 1986. Vincens, A., Schwartz, D., Elenga, H., Reynaud-Farrera, I., Alexandre, A., Bertaux, J., Mariotti, A., Martin, L., Meunier, J. D., Nguetsop, F., Servant, M., Servant-Vildary, S., and Wirrmann, D., Forest response to climate changes in Atlantic Equatorial Africa during the last 4000 years BP and inheritance on the modern landscape, J. Biogeogr., 26, 879–885, 1999. Vincens, A., Buchet, G., Williamson, D., and Taieb, M.: A 23 000 yr pollen record from Lake Rukwa (8° S, SW Tanzania): New data on vegetation dynamics and climate in Central Eastern Africa, Rev. Palaeobot. Palyno., 137, 147–162, 2005. Vincens, A., Garcin, Y., and Buchet, G.: Influence of rainfall seasonality on African lowland vegetation during the Late Quaternary: pollen evidence from Lake Masoko, Tanzania, J. Biogeogr., 34, 1274–1288, 2007. Weldeab, S., Lea, D. W., Schneider, R. R. and Andersen, N.: 155 000 Years of West African Monsoon and Ocean Thermal Evolution, Science, 316, 1303–1307, 2007. Weldeab, S., Lea, D. W., Schneider, R. R., and Andersen, N.: Centennial scale climate instabilities in a wet early Holocene West African monsoon, Geophys. Res. Lett., 34, L24702, 1–6, 2007. Wefer, G., Berger, W. H., Richter, C., and Shipboard Scientific Party: Proceedings Ocean Drilling Program, Initial Reports, 175, Ocean Drilling Program, College Station TX, 1998. White, F.: The vegetation of Africa, Natural Resourses Research, 20, UNESCO, Paris, France, 1983. Wotzka, H.-P.: Studien zur Archäologie des zentral-afrikanischen Regenwaldes, Africa Praehistorica, 6, Heinrich Barth Institut, Köln, 1995. Ybert, J.-P.: Atlas de pollens de Cote d'Ivoire, ORSTOM, Paris, France, 1979.