Reconciling dinoflagellate cyst Mg/Ca records as tools for temperature, salinity and productivity reconstructions during the last 40,000 years in the Southern Gulf of Cádiz
Mertens, K.N.; Groeneveld, J.C.; Van Kerckhoven, L.; Wienberg, C.; Hebbeln, D.; Verleye, T.J.; Louwye, S. (2009). Reconciling dinoflagellate cyst Mg/Ca records as tools for temperature, salinity and productivity reconstructions during the last 40,000 years in the Southern Gulf of Cádiz, in: Mertens, K.N. Tracing hydrological millennial-scale cycles in the Late Quaternary of the Cariaco Basin and the southern Gulf of Cádiz using coccoliths and dinoflagellate cycts = Opsporing van hydrologische cycli op millenium-schaal in het late Quartair van het Cariaco Bekken en de zuidelijke Golf van Cádiz met behulp van coccolieten en dinoflagellatencysten. pp. 119-134 In: Mertens, K.N. (2009). Tracing hydrological millennial-scale cycles in the Late Quaternary of the Cariaco Basin and the southern Gulf of Cádiz using coccoliths and dinoflagellate cycts = Opsporing van hydrologische cycli op millenium-schaal in het late Quartair van het Cariaco Bekken en de zuidelijke Golf van Cádiz met behulp van coccolieten en dinoflagellatencysten. PhD Thesis. Department of Biology/Ghent University, Department of Geology and Soil Science: Gent. 205 pp., more |
| Authors | | Top | - Mertens, K.N., more
- Groeneveld, J.C.
- Van Kerckhoven, L.
- Wienberg, C.
| - Hebbeln, D.
- Verleye, T.J., more
- Louwye, S., more
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| Abstract | The southern Gulf of Cadiz is a particularly climatologically sensitive region, acting as a natural laboratory to record variations of the North Atlantic Oscillation (NAO). Past variations triggered assemblage and morphological changes of dinoflagellate cysts and other palynomorphs, analysed from core GeoB9064-l. The recovered dinoflagellate cyst assemblages are dominated by abundances of Lingulodinium machaerophorum, which are determined by enhanced fluvial supply during negative NAO phases, pronounced during precession minima. This enhanced fluvial supply causes transport and enhanced preservation via mineral ballasting of Lingulodinium machaerophorum cysts and other organic components. Positive NAO phases can be related to higher upwelling conditions during HEs, and are mirrored in cooler Mg/Ca SSTs, W/C ratios, "Bitectatodinium tepikiense-Nematosphaeropsis labyrinthus events" and bisaccate pollen. Despite a short lag, Lingulodinium machaerophorum average process lengths and paired Mg/Ca – d180 deduced salinities reflect enhanced precipitation conditions during the Bølling/Allerød and middle Holocene over the Mediterranean area. These salinity changes are in sync with temperature differences between Mg/Ca and alkenone derived SSTs, which can be related to lateral advection of alkenones, which thus exhibit a salinity influence. |
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