Abstract
A high-resolution study (centennial scale) has been performed on the calcareous plankton assemblage of the Holocene portion of the Ocean Drilling Program Site 976 (Alboran Sea) with the aim to identify the main changes in the surface water dynamic. The dataset also provided a seasonal foraminiferal sea surface water temperatures (SSTs), estimated using the modern analog technique SIMMAX 28, and it was compared with available geochemical and pollen data at the site. Three main climate shifts were identified as (1) the increase in abundance of Syracosphaera spp. and Turborotalita quinqueloba marks the early Holocene humid phase, during maximum summer insolation and enhanced river runoff. It is concomitant with the expansion of Quercus, supporting high humidity on land. It ends at 8.2 ka, registering a sudden temperature and humidity reduction; (2) the rise in the abundances of Florisphaera profunda and Globorotalia inflata, at ca. 8 ka, indicates the development of the modern geostrophic front, gyre circulation, and of a deep nutricline following the sea-level rise; and (3) the increase of small Gephyrocapsa and Globigerina bulloides at 5.3 ka suggests enhanced nutrient availability in surface waters, related to more persistent wind-induced upwelling conditions. Relatively higher winter SST in the last 3.5 ka favored the increase of Trilobatus sacculifer, likely connected to more stable surface water conditions. Over the main trends, a short-term cyclicity is registered in coccolithophore productivity during the last 8 ka. Short periods of increased productivity are in phase with Atlantic waters inflow, and more arid intervals on land. This cyclicity has been related with periods of positive North Atlantic Oscillation (NAO) circulations. Spectral analysis on coccolithophore productivity confirms the occurrence of millennial-scale cyclicity, suggesting an external (i.e. solar) and an internal (i.e. atmospheric/oceanic) forcing.
Highlights
An increasing number of climate records reveals that the Holocene has experienced a pervasive millennial- and centennial-scale climate variability (e.g. Jalut et al, 2009; Magny et al, 2013; Mayewski et al, 2004; Walker et al, 2012; Wanner et al, 2015), well-documented in both the NorthAtlantic (e.g. Bond et al, 2001; Repschläger et al, 2017; Thornalley et al, 2009) and westernMediterranean (e.g. Ausín et al, 2015a; Cacho et al, 2001; Català et al, 2018; Frigola et al, 2007; Jalali et al, 2017, 2016; Nieto-Moreno et al, 2015; Rodrigo-Gámiz et al, 2011)
The calcareous plankton assemblage of the Ocean Drilling Program (ODP) Site 976 from the Alboran Sea has been studied at a centennial-scale resolution, to investigate the climate variability and the forcing mechanisms affecting the western Mediterranean basin during the last 12.5 ka
Coccolithophore and planktonic foraminifera dataset is integrated with pollen and geochemical data available at the site
Summary
An increasing number of climate records reveals that the Holocene has experienced a pervasive millennial- and centennial-scale climate variability (e.g. Jalut et al, 2009; Magny et al, 2013; Mayewski et al, 2004; Walker et al, 2012; Wanner et al, 2015), well-documented in both the NorthAtlantic (e.g. Bond et al, 2001; Repschläger et al, 2017; Thornalley et al, 2009) and westernMediterranean (e.g. Ausín et al, 2015a; Cacho et al, 2001; Català et al, 2018; Frigola et al, 2007; Jalali et al, 2017, 2016; Nieto-Moreno et al, 2015; Rodrigo-Gámiz et al, 2011). Mediterranean Sea is extremely sensitive to the changes experienced in the North Atlantic and is an ideal location for high-frequency climatic investigations, because water mass properties changes and oceanographic and atmospheric circulation oscillations are usually amplified During the Holocene, the Alboran Sea experienced relevant oceanographic perturbations, the most important of which was the instauration of the modern geostrophic front and establishment of gyre anticyclonic circulation dynamics, following sea level rising after the last deglaciation (Ausín et al, 2015b; Català et al, 2018; Colmenero-Hidalgo et al, 2004; Heburn and La Violette, 1990; Rohling et al, 1995; Weaver and Pujol, 1988). Targeting the high frequency oscillations experienced during the Holocene, a growing attention has been focused on the impact of the North
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
