Short-term climate dynamics and biogeochemical processes in the Gulf of Taranto: From regional proxy variations to climate records

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The overall goal of the proposed project is to reconstruct records of climate and related biogeochemical cycles in the Gulf of Taranto (southern Italy) for the past few centuries and the late Holocene. We expect that these records will not only yield local information but will also record the effect of large-scale climate modes like the North Atlantic Oscillation. This goal necessitates the development of novel transfer functions to derive environmental information from sediment archives. Traditionally, transfer functions are defined by evaluating the relationships between proxy data and environmental parameters in the spatial domain. Here, we propose an alternative approach, in which we derive a transfer function that examines both the variability of the spatial and temporal domains, thus being a more direct approach to the reconstruction of temporal climate variations from proxy records. In order to achieve our goal, we will apply a high-resolution physical and biogeochemical ocean model for the period 1958-2013, including simulations of synthetic sediment cores with the targeted proxy variables. For this time period, high-quality reanalysis data are available to force the model. The modeled time series will be then compared with high-resolution proxy records generated from available surface sediments and sediment cores. The Gulf of Taranto is an ideal region for this research because the marine environments are closely linked to climate changes on land and sediments accumulate in deposition centers at high rates permitting the reconstruction of environmental variability at a sub-decadal resolution. Our new spatio-temporal transfer function will then be applied for the reconstruction of the regional climate and biogeochemical variability for the instrumental period (since at least 1850, individual records even longer), which allows an assessment of the quality of the reconstruction. Subsequently, we will extend the reconstruction to the full length of the available proxy records (approximately 5000 years). We plan to study the sensitivity of Mediterranean marine environments to large-scale climate patterns of the Northern hemisphere such as the North Atlantic Oscillation and the Atlantic Multidecadal Oscillation during the late Holocene. Additionally, the anthropogenic contribution to the changes found in the proxy records will be quantified.