Late Quaternary Glacial Interglacial Cyclicity Models of the

Late Quaternary Glacial / Interglacial Cyclicity Models of the Red Sea Amani Badawi National Institute of Oceanography and Fisheries, Alexandria, Egypt amani_badawi@yahoo. com Fig. 1: Map of the Red Sea and investigated core positions. Geo. TüKL 23 recovered during Meteor cruise M 31/2 at 702 m water depth, with a core recovery of 22. 1 m, and Geo. Tü Kl 42 during the Sonne cruise 121, at 958 m water depth, with a core recovery of 10. 4 m. Four distinct glacial / interglacial cycle during the last 380 Kyr have been recognized in the Red Sea. The identified four cycles reveal deviation in deep-sea ecosystem between the northern and southern Red Sea. In the northern Red Sea salinity fluctuations, productivity and deep-water ventilation and formation had the major impact on benthic foraminiferal pattern corresponding to glacial/interglacial cycles and glacio-eustatic sea level changes coupled with the impact of Mediterranean climate regime. While in the southern Red Sea region the oscillation trend of benthic foraminiferal pattern within the glacials and interglacials stages, indicating a high frequency environmental alternation. This alternation is consistent with the extent of NE monsoonal wind that controls the intensity and extension of the productivity, which in turn determine organic matter fluxes and oxygen level at the sea floor. The benthic foraminiferal faunas from samples of two piston cores retrieved along a North–South transect in the Red Sea were studied. Benthic foraminiferal faunas from both sites exhibit large variability with respect to density, diversity, species composition and assemblages combined with stable oxygen and carbon isotope records of planktic and benthic foraminifera. One hundered thirty benthic foraminiferal species were identified in the investigated cores. The faunal data set of the northern core was reduced to five assemblages (factors) while the southern one was reduced to four assemblages. All assemblages were ranked according to their ecological significance. Besides, Relative abundance of major benthic foraminiferal suborders (Textulariina (agglutinating foraminifera), Miliolina, and Rotaliina), in addition to infaunal/epifaunal relative abundance were used as paleoenvironmental proxies allowing the reconstruction of past changes in deep-water salinity, ventilation, and organic carbon fluxes at the sea-floor. PC 1 d 18 O (‰ PDB) Geo. Tü KL 42 Geo. Tü KL 23 0 4 2 0 -2 d 13 C (‰ PDB) Geo. Tü KL 42 Geo. Tü KL 23 -2 0 2 -2 0 Geo. Tü KL 23 BFN (Ind. /g) 0 2 200 4 00 Gyroidina soldanii Geo. Tü KL 42 Diversity H (S) 0 1 2 3 BFN (Ind. /g) 0 50 100 Diversity H (S) 0 1 2 3 0 1 2 0. 8 PC 4 0. 8 0. 4 0. 8 PC 3 PC 2 PC 3 Bulimina Loxostomina Chilostomella marginata africana oolina MIS 0. 8 0. 4 0. 8 PC 1 Anomalinoides sp. 0. 4 0. 8 0. 4 PC 4 Hanzawaia sp. A PC 2 Uvigerina auberiana 0. 8 0. 4 0 Textulariina Miliolina Rotaliina (%) (%) 20 40 60 80 0 20 Marine Isotope Stage (MIS) 0 20 In fa u n a l / E p ifa u n a l (% 0 40 80 ) MIS Miliolina (%) 20 0 7 Rotaliina (%) 20 20 40 60 80 10 9 8 11 0 200 400 600 800 1000 1200 1400 Geo. Tü KL 23 1600 Geo. Tü KL 42 1800 2000 2200 2400 0 50 100 150 200 250 300 350 400 Age (Kyr) Fig. 3: Age model of the northern and southern Red Sea core. In fa u n a l / E p if a u n a l ( % ) 0 40 80 0 0 Geo. Tü KL 42 Trophic Level Indicators (%) 20 4 0 6 0 8 0 Relative Sea Level (m) -150 -100 -50 0 50 Sea Level H ig h 0 Trophic Level Indicators (%) Summer insolatiom At 65 °N (Wm-2) MIS 450 20 40 60 80 500 550 1 2 3 Low 3 50 50 4 6 5 1 2 A 50 4 Geo. Tü KL 23 Textulariina 0 3 1 2 Geo. Tü KL 42 Geo. Tü KL 23 2 3 50 0. 4 PC 5 Anomalinoides Cibicides sp. mabahethi National Institute of Oceanography and Fisheries Red Sea Depth (cm bsf) Vienna | Austria | 12 – 17 April 2015 4 4 4 H ig h 100 5 100 150 6 Age (kyr) 100 200 5 2 00 250 3 00 300 9 High 9 9 3 50 10 350 10 11 (e) (f) (g) 4 00 (h) 400 (a ) H ig h (b ) (c ) 11 (d ) 400 Oxygenation Fig. 4: a) Graphical correlation of global standard isotope curve (Imbrie et al. , 1984) (gray line) with stable oxygen isotope curve of planktic foraminifera G. ruber (black line) and benthic foraminifera C. mabahethi (stippled line). b) Graphical correlation of global standard isotope curve (Imbrie et al. , 1984) (gray line) with oxygen isotope curve of planktic foraminifera G. ruber. c) Stable carbon isotope curve of planktic foraminifera G. ruber (black line), and benthic foraminifera C. mabahethi (stippled line). d) Stable carbon isotope curve of planktic foraminifera G. ruber. Benthic foraminiferal number (BFN) and benthic foraminiferal diversity of cores Geo. Tu¨ KL 23 and Geo. Tu¨ KL 42 (e, f, g and h). 10 Low 10 350 11 (d) 8 8 300 (c) 7 Low 8 8 (b) High 2 50 250 (a) 6 7 250 400 Low 6 7 350 5 Low High 1 50 150 6 1 00 Fig. 6: Environmental proxies in the northern and southern Red Sea core against age. Fig. 5: Benthic foraminiferal assemblages (Principal component analysis) of the northern and southern Red Sea core Geo. Tü KL 23 and Geo. Tü KL 42, respectively, against age. Significat factor loadings (> 0. 4). Organic Matter NE Monsoon SW Monsoon Fig. 7 : Climatic parameters influencing the Red Sea during the Late Quaternary. a) and c) Infaunal (shallow and deep) relative abundance of total fauna of Geo. Tü KL 23 and Geo. Tü KL 42. b) Sea level changes (Waelbroeck et al. , 2002), stipped line represent recent sea level (137 m). d) Summer insolation values at 65ºN (Berger and Loutre, 1991). Humid & Warm Cool & Arid Deep-sea ecosystem variability of the Red Sea is strongly linked with global sea level history and regional climate changes during the past four glacial–interglacial cycles. Productivity and related organic matter fluxes are controlled by regional climate and oceanographic processes. In the northern Red Sea, surface water mixing and fertilization of the northern Red Sea is influenced by the Mediterranean climate. Stronger winds, enhanced dust flux and hence surface water productivity are reconstructed for glacial periods and more oligotrophic conditions for interglacial periods as reflected by the proportion of infaunal taxa and the benthic foraminiferal number. Trophic conditions of the Southern Red Sea are related to the inflow of nutrient-rich surface water masses from the Gulf of Aden (GASW) driven by SSE winds during the winter season. Increase of GASW inflow was likely enhanced during glacials due to a generally stronger NE winter monsoon and a more negative water budget (higher evaporation rates) of the Red Sea under glacial boundary conditions. At minimum sea level, however, GASW inflow may have been at a minimum due to the shallow and narrow strait at Bab el Mandeb. Enhanced glacial organic matter fluxes in the northern and southern Red Sea associated with increased oxygen consumption in the water column, consequently, vertical expansion of the OMZ. Deep water formation of the Red Sea seems to have been primarily influenced by changes in surface water salinity and basin morphology that in turn are controlled by global sea level. Vertical mixing and deep water formation should have been generally enhanced during glacials with additional deep water formation sites in the southern Red Sea. However, emerged shelf areas of the Gulf of Suez during times of lowest sea level, in particular during late MIS 6 and MIS 2, likely resulted in a drop of formation of dense deep waters in the northern Red Sea. At least some deep water formation persisted throughout glacial intervals, presumably originating from the Gulf of Aqaba, resulted in hypersaline glacial deep waters with salinity values comparable to those of surface waters. Rain fall Dominant NE Monsoon Dominant SW Monsoon Med. Winds ~ 112 m ~ 20 -22 ºN ~ 82 m Evaporation ~ 36 ‰ ~ 37 ‰ (3) Gulf of Suez (1) Bab el Mandeb (2) ~ 40 ‰ Gulf of Aden Gulf of Ade Stage 8 ~ 303 -245 Kyr BP Stage 7 ~ 245 -186 Kyr BP (a) (b) Humid & Warm Arid & Cold Enhanced SW Monsoon Dominant NE Monsoon Med. Winds Evaporation ~ 18 ºN ~ 122 m ~ 47 m Gulf of Suez Bab el Mandeb (4) Gulf of Aden Stage 6 ~ 186 -128 Kyr BP Stage 5 ~ 128 -71 Kyr BP (c) (d) Humid & Rainy Rainfall Dry & Cold Enhanced SW Monsoon Enhanced NE Monsoon ~77 m Med. Winds Evaporation ~ 67 m Gulf of Suez Bab el Mandeb OMZ Gulf of Aden Stage 4 ~ 71 -59 Kyr BP Gulf of Aden Stage 3 ~ 59 -24 Kyr BP (e) (f) Arid & Cold Arid Climate Dominant NE Monsoon Med. Winds Enhanced NE Monsoon Med. Winds Evaporation Deep Sea Variability ~17 m Evaporation ~ 55 ‰ ~137 m ~ 37 ‰ ~ 38 ‰ ~ 49 ‰ Gulf of Suez Southern Red Sea Northern Red Sea Bab el Mandeb ~ 57 ‰ OMZ ~41 ‰ Gulf of Aden LGM ~ 24 -12 Kyr BP Influenced By Gulf of Aden (g) Recent (h) Fig. 8: Schematic models of the Late Quaternary Red Sea modified after the Recent circulation pattern (h) of Cember (1988). (1) Vertical mixing, (2) deep water formation, (3) organic matter fluxes, (4) convection cell. Salinity fluctuations Deep-water formation Trophic magnitude Oxygen level References: Badawi, A. , (2015). Late quaternary glacial/interglacial cyclicity models of the Red Sea. Environmental Earth Sciences, 73 (3): 961 -977. Controlled By Glacial/ interglacial Mediterranean climate 1 Badawi, A. , Schmiedl, G. , Hemleben, C. , (2005). Impact of late Quaternary environmental changes on deep-sea benthic foraminiferal faunas of the Red Sea. Mar. Micropaleontol. , 58 (1): 13– 30. Berger, A. , Loutre, M. F. , 1991. Insolation Values for the Climate of the Last 10 Million Years. Quaternary Science Reviews 10, 297– 317. Monsoonal changes Birch, H. , Coxall , H. , Pearson, P. , Kroon, D. , O'Regan, M. , 2013. Planktonic foraminifera stable isotopes and water column structure: Disentangling ecological signals. Mar. Micropaleontol. In Press: 1 -19 Bower, A. S. , Furey, H. H. , 2012. Mesoscale eddies in the Gulf of Aden and their impact on the spreading of Red Sea Outflow Water. Progress in Oceanography, 96. Forced by 3 Eccentricity Precession Edelman-Fürstenberg, Y. , Almogi-Labin, A. , and Hemleben, Ch. , (2009). Palae-oceanographic evolution of the central Red Sea during the late Holocene. The Holocene, 19 (1): 117– 127. Fleitmann, D. , 2007. Holocene ITCZ and Indian monsoon dynamics recorded in stalagmites from Oman and Yemen (Socotra). Quaternary Sc. Rev. , 26: 170– 188. Hemleben, Ch. , Meischner, D. , Zahn, R. , Almogi-Labin, A. , Erlenkeuser, H. and Hiller, B. , 1996. Three hundred eighty thousand year long stable isotope and faunal record from the Red Sea: Influence of global sea level change on hydrography. Paleoceanography 11(2), 147 -156. Acknowledgements Dr. M. Segl is acknowledged for performing the stable isotope measurements at the Department of Geosciences, Bremen University. Appreciations are to Dr. Ch. Hemleben for his critical discussions and support. Thanks are due to the ship crews and scientists of R/V Meteor and R/V Sonne for good collaboration during cruises. Prell, W. L. , Imbrie, J. , Martinson, D. G. , Morley, J. J. , Pisias, N. G. , Shackleton, N. J. , Streeter, H. F. , 1986. Graphic correlation of oxygen isotope stratigraphy application to the Late Quaternary Paleoceanography. American Geophysical Union 1: 22, 137 -162. Siccha, M. , Trommer, G. , Schulz, H. , Hemleben, Ch. , i t r y and Kucera, M. , 2009. Factors controlling the distribution of planktonic foraminifera in the Red Sea and. implications for the development of transfer functions. Mar. Micropaleontol. , 72: 146– 156 °°