Short-term climate dynamics and biogeochemical processes in the Gulf of Taranto: From regional proxy variations to climate records
Final Report Abstract
The simulation covering the entire 20th century with a high-resolution ocean circulation and biogeochemistry model (MPIOM-HAMOCC) for the Mediterranean Sea has been dedicated to obtain a clear understanding of the climate imprint on the sediment. The simulated synthetic sediment core data, e.g. the temperature recorded in sediment flux of detritus, could be directly compared with sediment proxy records, e.g. the alkenone-derived SST. Sensitivity experiments have been conducted to isolate the physical signal transfer. It is found in the simulation that variability in the primary production in the Gulf of Taranto is closely related with the North Ionian Gyre (NIG) upper layer circulation, which is modulated by the Adriatic Dense Water outflow events as a result of the large-scale climate variations. In contrast to the findings from the sediment proxy record analysis, the model simulation doesn’t show a significant influence of the Po river runoff. The high-resolution model results provide a database for a detailed statistical analysis. The temporal correlation analysis shows that the temperatures recorded in sediment flux of detritus mostly record the local temperatures in the upper layer of the water column. In some regions, the sediment tracer is rather recording spring temperatures than annual means, which is in contrast to the standard assumptions used for temperature reconstructions from alkenones. The high correlations indicate a good quality of the SST reconstruction skill by the sediment record in many areas, which can be further used to derive the transfer function. The additional examination of sediment cores from high-accumulation sites of the Gulf of Taranto delivered insights into the regional variability of benthic ecosystems, depositional environments, biogeochemical processes and water mass dynamics on decadal to multi-decadal timescales. The proxy work focused on the last millennium and were used to decipher natural and anthropogenic forcing mechanisms. We found that the marine processes are closely linked to large-scale and regional climate patterns because precipitation changes in the Italian catchment and related fluctuations in riverine runoff drive changes in marine nutrient and suspended sediment load, local phytoplankton blooms and organic matter availability at the sea floor.
Publications
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2016. Late Holocene benthic ecosystem variability and geochemical processes in the Gulf of Taranto (Italy). 12th International Conference on Paleoceanography, Utrecht, P-613
Menke, V., Brzelinski, S., Emeis, K., Schmiedl, G.
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2017. 20th century simulations of the Mediterranean Sea with focus on the climate variability in the Adriatic Sea. In EGU General Assembly Conference Abstracts, Vienna, Vol. 19, P-13051
Liu, F., Mikolajewicz, U., Six, K.D.
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2017. Combined North Atlantic and anthropogenic forcing of changes in the marine environments in the Gulf of Taranto (Italy) during the last millennium. Climate of the Past Discussions
Menke, V., Ehrmann, W., Milker, Y., Brzelinski, S., Möbius, J., Mikolajewicz, U., Zolitschka, B., Zonneveld, K., Emeis, K.C., Schmiedl, G.
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2018. Assessing the interannual climate variability in the Mediterranean Sea during 1901-2010 with a physical-biogeochemical ocean model. In EGU General Assembly Conference Abstracts (Oral), Vienna, Vol. 20, P-13205
Liu, F., Mikolajewicz, U., Six, K.D.
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2018. Cryptotephra from Lipari Volcano in the eastern Gulf of Taranto (Italy) as a time marker for paleoclimatic studies. Quaternary Research, 89, 520-532
Menke, V., Kutterolf, S., Sievers, C., Schindlbeck, J.C., Schmiedl, G.
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2018. Impacts of short-term climate change and anthropogenic activity on marine ecosystem variability and biogeochemical processes in the Gulf of Taranto (central Mediterranean Sea). PhD thesis, University of Hamburg, 141 pp.
Menke, V.
