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The time interval from 19 to 9 kyr BP is characterized by pronounced climate variability. Among the climatic setbacks during that time, the most prominent are the Younger Dryas (YD) and the Heinrich event 1 (H1). The impact of these setbacks on the eastern Mediterranean region is still under debate, although analyses from the Holocene indicate that this region is particularly sensitive to climatic change. Recent analyses of terrestrial and marine palynomorphs and foraminifera from marine cores have shown that both events can be traced in the northern Aegean and caused significant declines in precipitation and temperatures. However, the impact of these events on the marine realm is still unsufficiently constrained due to inconsistencies between the signals from different marine proxies (planktic foraminifer assemblages, foraminifer-based ∂18O data, and dinoflagellate cyst assemblages; Kotthoff et al., 2011).

 

Recent biometrical analyses of the dinoflagellate cyst Lingulodinium machaerophorum from the Aegean Sea support older findings that the average process length of this cyst is related to summer salinity and temperature at water depths of ~30 m (Mertens et al., 2009), with longer and fewer processes being related to lower water temperatures and/or higher salinity. Therefore, in combination with other marine proxies, dinocyst process lengths measurements may be a useful tool to reconstruct marine paleotemperatures and -salinity.

 

In light of the above, we show new measurements of L.-machaerophorum- and Operculodinium-centrocarpum-process lengths and compare them to already published foraminifer and palynomorph data derived from marine sediment cores GeoTü SL152 and GeoTü SL148. The new data show that longest processes occur during cold phases, particularly the Last Glacial Maximum, the H1, and the YD, while the interval of Sapropel S1 deposition, with particularly warm sea-surface temperatures and reduced sea-surface salinities is characterized by cysts with particularly short processes. Thus, our data support the potential of biometrical analyses of dinoflagellate cysts to contribute to a more precise view on paleo-sea-surface conditions and on the impact of medium- to short-term climate change on marine systems.

 

Kotthoff, U., Koutsodendris, A., Pross, J., Schmiedl, G., Bornemann, A., Kaul, C., Marino, G., Peyron, O., Schiebel, R. (2011): Impact of late glacial cold events in the Northern Aegean region, reconstructed from integrated marine and terrestrial proxy data. Journal of Quaternary Research 26,86-96.

Mertens, K.N., Ribeiro, S., Bouimetarhan, I., Caner, H., Combourieu-Nebout, N., Dale, B., De Vernal, A., Ellegaard, M., Filipova, M., Godhe, A., Goubert, E., Grøsfjeld, K., Holzwarth, U., Kotthoff, U., Leroy, S.A.G., Londeix, L., Marret, F., Matsuoka, K., Mudie, P.J., Naudts, L., Peña-Manjarrez, J.L., Persson, A., Popescu, S.-M., Pospelova, V., Sangiorgi, F., Van Der Meer, M.T.J., Vink, A., Zonneveld, K.A.F., Vercauteren, D., Vlassenbroeck, J., Louwye, S., (2009). Process length variation in cysts of a dinoflagellate, Lingulodinium machaerophorum, in surface sediments investigating its potential as a salinity proxy. Marine Micropaleontology 70, 54-69.

biometry; dinoflagellate cysts; Aegean Sea; Lateglacial; foraminifera; palynology; early Holocene