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This dataset contains information about the hydrographic cruises carried out off Cape Silleiro (NW Iberia, Atlantic Ocean) between July 2010 and June 2012. These cruises sampled CALIBERIA station, located at 42º05´ N, 9º23´ W (~350 m depth). A CTD (Seabird 911) equipped with fluorescence and oxygen sensors was used for these hydrographic cruises

Paleodata of environmental responses to climate change from the Last Glacial Maximum (LGM) and the Holocene provide a useful performance test for climate models' sensitivity, contributing to better forecasts. Temporal high resolution data for both periods is important to reduce the uncertainties of models regionally.The Portuguese margin, one of the most productive marine regions of the world and having high sedimentation rates, is considered a key area to reconstruct past climate. This high temporal resolution study contributes with planktonic foraminifera (PF) data (fauna and stable isotopes), temperature and export productivity (Pexp) at two sites under different oceanographic conditions: MD03-2699 – off Estremadura spur and Shak-03-6K - off Sines. Preliminary results show that during the LGM, the average SSTs at the Estremadura was lower than Sines (12.3 °C vs. 19.4 °C) while the Pexp was higher (86.2 gC/m2/yr vs. 60.8 gC/m2/yr). In contrast, during the Mid Holocene (MH), at both sites, the average SSTs were warmer and the Pexp was lower than during the LGM (Estremadura - 18.9 °C, 76.1 gC/m2/yr; Sines - 21.2 °C, 55.2 gC/m2/yr). Subtropical and transitional PF species are abundant during the LGM reflecting warm, stable SSTs at both locations relative to the high mid-latitudinal North Atlantic (NA) sites, whereas higher Pexp was possibly caused by stronger westerly winds that enhanced the upwelling. SSTs at both sites during the MH were interrupted by a cold event (starting at 5.2 ky) coincident with a decrease in Pexp at both sites. This cold event could be related to the freshwater input from the melting Laurentide ice sheet, already observed in the NA. Pexp at the Estremadura was relatively higher than off Sines (~20 gC/m2/yr difference), probably because like today this site is under a stronger influence of upwelling events and riverine nutrient input from the Tagus River

To assess the anthropogenic effect on biodiversity, it is essential to understand the global diversity distribution of the major groups at the base of the food chain, ideally before global warming initiation (1850 Common Era CE). Since organisms in the plankton are highly interconnected and carbonate synthesizing species have a good preservation state in the Atlantic Ocean, the diversity distribution pattern of planktonic foraminifera from 1741 core-top surface sediment samples (expanded ForCenS database) provides a case study to comprehend centennial to decadal time-averaged diversity patterns at pre-1970 CE times, the tempo of the substantial increase in tropospheric warming. In this work, it is hypothesized and tested for the first time, that the large-scale diversity patterns of foraminifera communities are determined by sea surface temperature (SST, representing energy), Chl-a (a surrogate for photosynthetic biomass), and ocean kinetic energy (as EKE). Alpha diversity was estimated using species richness (S), Shannon Wiener index (H), and Simpson evenness (E), and mapped using geostatistical approaches. The three indices are significantly related to SST, Chl-a, and EKE (71-88% of the deviance in the generalized additive mixed model, including a spatial component). Beta diversity was studied through species turnover using gradient forest analysis (59% of the variation). The primary community thresholds of foraminifera species turnover were associated with 5-10 °C and 22-28 °C SST, 0.05-0.15 mg m-3 Chl-a, and 1.2-2.0 cm2 s-2 log10 EKE energy, respectively. Six of the most important foraminifera species identified for the environmental thresholds of beta diversity are also fundamental in transfer functions, further reinforcing the approaches used. The geographic location of the transition between the four main biogeographic zones was redefined based on the results of beta diversity analysis and incorporating the new datasets, identifying the major marine latitudin

The Sines Contourite Drift (SCD), located in the Alentejo margin, southwest Iberian continental margin, has been through many depositional phases in result of climatic variations and bottom current oscillations, which determined a variable depositional pattern and an irregular sedimentary evolution since the Late Pleistocene. The SCD, being in the main path of the Mediterranean Outflow Water (MOW), which greatly constrains the sedimentary building of this drift, constitutes the distal part of the Gulf of Cadiz Contourite Depositional System and its sedimentary evolution therefore reflects the history of MOW variations. In order to investigate this, we report on a multiproxy analysis of grain-size, carbon content and physical, geochemical, and environmental-magnetic properties on the AMS 14C dated 350-cm long gravity core CO14-GC-07, retrieved in the SCD, at 1425 meters water depth (mwd). The main objective is to reconstruct the evolution of the sedimentary package of the SCD from >43 cal kyr BP to Present and bring new insights about the impact of bottom currents' activity on the morphosedimentary evolution of the margin. Results show the existence of four distinct depositional phases in response to climate variations and bottom current oscillations during the Late Pleistocene-Holocene. Phase 1 (350–322 cm: >42.9 cal kyr BP) occurred in Marine Isotope Stage (MIS) 3 and presents silty-muddy sediments with presence of shell fragments and moderate bioturbation. Phase 2 (322–176 cm: >42.9–~30.5 cal kyr BP), which lasted from middle MIS 3 to the onset of MIS 2, reveals sediment coarsening towards the top limit, suggesting climate cooling and strong bottom current winnowing. Phase 3 (176–144 cm: ~30.5–17.1 cal kyr BP) covers most of MIS 2 prior to the last deglaciation and shows the sharpest variations on all sediment properties and the coarsest sediment facies, with Fe-rich layers associated with the increase of terrigenous input and sea-level regression that coincide wi

The interplay between the Mediterranean Outflow Water (MOW) and irregular seafloor morphology in the Alentejo Margin promotes the formation of downslope and alongslope morphosedimentary features, essentially materialized by both sedimentary gravitational instabilities and deposition of the Sines contourite drift (SCD). In order to better understand the interaction between both processes, a gravity core was retrieved in the most unstable area of the Sines Drift located at 1425 mwd, in the transition between middle and lower continental slope. Its multi-analysis provides valuable information about the evolution of the sedimentary conditions through the most recent time. The 350-cm long core CO14-GC-07 was studied, through a 5-cm sampling step, using different analyses to assess both their grain size and carbonate content. Physical properties - magnetic susceptibility, P-wave velocity, gamma-ray density, and resistivity - have been determined through multi-sensor core logger (MSCL). X-ray fluorescence (XRF) was used to determine geochemical properties as the Fe, Si, Ti, Ca, K contents, through an ITRAX XRF-core scanner. For magnetic fabric and environ-magnetic fabric analyses were collected cubic samples (8 cm3) each three centimetres. Preliminary results of sedimentological analysis point to granulometric variations, mainly occurring between 100 and 200 cm depth with successions of fine- and coarse-grained layers. The sediments consist of alternating layers of muddy-silt, silt and silty-sand. Carbonate-content (calcimetry) analysis indicates predominance of inorganic material over organic, suggesting the presence of terrigenous material. Preliminary results of magnetic susceptibility show an overall increase in depth, whereas density follows the general pattern of grain size, being denser in the coarser layers and lighter in the finer ones. Resistivity is constantly decreasing with major falls between ~150 and 200 cm. P-wave velocity data show variations along the cor

A systematic investigation of the spatial and temporal variability in coccolithophore abundance and distribution through the water column of the NW Iberian coastal upwelling system was performed. From July 2011 to June 2012, monthly sampling at various water depths was conducted at two parallel stations located at 42 N. Total coccosphere abundance was higher at the outer-shelf station, where warmer, nutrient-depleted waters favoured coccolithophore rather than phytoplanktonic diatom blooms, which are known to dominate the inner-shelf location. In seasonal terms, higher coccosphere and coccolith abundances were registered at both stations during upwelling seasons, coinciding with high irradiance levels. This was typically in conjunction with stratified, nutrient-poor conditions (i.e. relaxing upwelling conditions). However, it also occurred during some upwelling events of colder, nutrient-rich subsurface waters onto the continental shelf. Minimum abundances were generally found during downwelling periods, with unexpectedly high coccolith abundance registered in subsurface waters at the inner-shelf station. This finding can only be explained if strong storms during these downwelling periods favoured resuspension processes, thus remobilizing deposited coccoliths from surface sediments, and hence hampering the identification of autochthonous coccolithophore community structure., At both locations, the major coccolithophore assemblages were dominated by Emiliania huxleyi, small Gephyrocapsa group, Gephyrocapsa oceanica, Florisphaera profunda, Syracosphaera spp., Coronosphaera mediterranea, and Calcidiscus leptoporus. Ecological preferences of the different taxa were assessed by exploring the relationships between environmental conditions and temporal and vertical variability in coccosphere abundance. These findings provide relevant information for the use of fossil coccolith assemblages in marine sediment records, in order to infer past environmental conditions, of particular importance for Paleoceanography. Both E. huxleyi and the small Gephyrocapsa group are proposed as proxies for the upwelling regime with a distinct affinity for different stages of the upwelling event: E. huxleyi was associated with warmer, nutrient-poor and more stable water column (i.e. upwelling relaxation stage) while the small Gephyrocapsa group was linked to colder waters and higher nutrient availability (i.e. early stages of the upwelling event), similarly to G. oceanica. Conversely, F. profunda is suggested as a proxy for the downwelling regime and low-productivity conditions. The assemblage composed by Syracosphaera pulchra, Coronosphaera mediterranea, and Rhabdosphaera clavigera may be a useful indicator of the presence of subtropical waters conveyed northward by the Iberian Poleward Current. Finally, C. leptoporus is proposed as an indicator of warmer, saltier, and oligotrophic waters during the downwelling/winter regime.

The Mediterranean region is a climate hot spot, sensitive not only to global warming but also to water availability. In this work we document major temperature and precipitation changes in the Iberian Peninsula and margin during the last 2000 years and propose an interplay of the North Atlantic internal variability with the three atmospheric circulation modes (ACMs), (North Atlantic Oscillation (NAO), east atlantic (EA) and Scandinavia (SCAND)) to explain the detected climate variability. We present reconstructions of sea surface temperature (SST derived from alkenones) and on-land precipitation (estimated from higher plant n-alkanes and pollen data) in sedimentary sequences recovered along the Iberian Margin between the south of Portugal (Algarve) and the northwest of Spain (Galiza) (36 to 42 degrees N). A clear long-term cooling trend, from 0 CE to the beginning of the 20th century, emerges in all SST records and is considered to be a reflection of the decrease in the Northern Hemisphere summer insolation that began after the Holocene optimum. Multi-decadal/centennial SST variability follows other records from Spain, Europe and the Northern Hemisphere. Warm SSTs throughout the first 1300 years encompass the Roman period (RP), the Dark Ages (DA) and the Medieval Climate Anomaly (MCA). A cooling initiated at 1300 CE leads to 4 centuries of colder SSTs contemporary with the Little Ice Age (LIA), while a climate warming at 1800 CE marks the beginning of the modern/Industrial Era. Novel results include two distinct phases in the MCA: an early period (900-1100 years) characterized by intense precipitation/flooding and warm winters but a cooler spring-fall season attributed to the interplay of internal oceanic variability with a positive phase in the three modes of atmospheric circulation (NAO, EA and SCAND). The late MCA is marked by cooler and relatively drier winters and a warmer spring-fall season consistent with a shift to a negative mode of the SCAND. The Industria

The objective of the current work is to improve our understanding of how water column diatom's abundance and assemblage composition is seasonally transferred from the photic zone to seafloor sediments. To address this, we used a dataset derived from water column, sediment trap and surface sediment samples recovered in the NW Iberian coastal upwelling system. Diatom fluxes (2.2 (+/- 5.6) 10(6) valves m(-2) d(-1)) represented the majority of the siliceous microorganisms sinking out from the photic zone during all studied years and showed seasonal variability. Contrasting results between water column and sediment trap diatom abundances were found during downwelling periods, as shown by the unexpectedly high diatom export signals when diatom- derived primary production achieved their minimum levels. They were principally related to surface sediment remobilization and intense Minho and Douro river discharge that constitute an additional source of particulate matter to the inner continental shelf. In fact, contributions of allochthonous particles to the sinking material were confirmed by the significant increase of both benthic and freshwater diatoms in the sediment trap assemblage. In contrast, we found that most of the living diatom species blooming during highly productive upwelling periods were dissolved during sinking, and only those resistant to dissolution and the Chaetoceros and Leptocylindrus spp. resting spores were susceptible to being exported and buried. Fur-thermore, Chaetoceros spp. dominate during spring-early summer, when persistent northerly winds lead to the upwelling of nutrient-rich waters on the shelf, while Leptocylindrus spp. appear associated with late-summer upwelling relaxation, characterized by water column stratification and nutrient depletion. These findings evidence that the contributions of these diatom genera to the sediment's total marine diatom assemblage should allow for the reconstruction of different past upwelling regimes.

To better understand sources and transport of particulate material in the NW Iberian coastal upwelling system, a mooring line dotted with an automated PPS 4/3 sediment trap was deployed off Cape Silleiro at the base of the photic zone. The samples were collected from November 2008 through June 2012 over sampling periods of 4-12 days. Our study represents the first automated sediment trap database for the NW Iberian margin. The magnitude and composition of the settling material showed strong seasonal variability with the highest fluxes during the poleward and winter mixing periods (averages of 12.9±9.6 g m−2 d−1 and 5.6±5.6 g m−2 d−1 respectively), and comparatively lower fluxes (3.6±4.1 g m−2 d−1) for the upwelling season. Intensive deposition events registered during poleward and winter mixing periods were dominated by the lithogenic fraction (80±3%). They were associated to high energy wave-driven resuspension processes, due to the occurrence of south-westerly storms, and intense riverine inputs of terrestrial material from Minho and Douro rivers. On the other hand, during the spring - summer upwelling season, the share of biogenic compounds (organic matter, calcium carbonate (CaCO3), biogenic silica (bSiO2)) to downward fluxes was higher, reflecting an increase in pelagic sedimentation due to the seasonal intensification of primary production and negligible river inputs and wave-driven resuspended material. Otherwise, the large variations of biogenic settling particles were mainly modulated by upwelling intensity, which by means of upwelling filaments ultimately controlled the offshore transport of the organic carbon fixed by primary producers towards the adjacent ocean. Based on the average downward flux of organic carbon (212 mg C m−2 d−1) and considering an average primary production of 1013 mg C m−2 d−1 from literature, we estimated that about 21% of the fixed carbon is vertically exported during the upwelling season

Marine sediments, mainly the ones from coastal upwelling areas, are valuable archives for past reconstructions, including climate changes, global and regional oceanography, and the cycles of biochemical components in the ocean. However, the regional calibrations of the sediment properties (“proxy” data) to the present-day oceanographic and biological conditions are necessary for interpretation of high-resolution sediment-derived information. Many works have contributed directly or indirectly to improving proxy calibrations related to upwelling and nutrient cycling parameters, but there are few studies with a multi-proxy approach for the same region. Along NW Iberian margin, little work has been done regarding with calibration of proxy data. Thus, we lack understanding on (1) how the seasonally variable hydrography affects the various plankton groups and (2) how much of the water column signal is preserved in the sediments and available for paleo-reconstructions. In order to minimize this lack of information from the upper water column temperature point of view, we investigate trace element and stable isotopes from planktonic foraminifera, and alkenone Uk’37 index from a large set of core-top sediment samples from the NW Iberian margin (41.5-42.5ºN; 9-10ºW). Sediment data are compared with present-day water column data (CTD, stable isotopes, satellite measurements) and to “global” calibration data sets of the proxies with sea surface temperature. We explore reconstructing upper water column structure using three species (G. bulloides, N. pachyderma dextral, and G. inflata) with different depth habitats, different seasonal abundances, and linked to specific hydrographic conditions in this region. Preliminary results show that Mg/Ca and 18O temperatures of all species are consistent with seasonal temperatures observed in present-day water column data. In addition G. bulloides and N. pachyderma dextral appears with temperatures related with subtropical and subpolar East

New data and a review of historiographic information from Neolithic sites of the Malaga and Algarve coasts (southern Iberian Peninsula) and from the Maghreb (North Africa) reveal the existence of a Neolithic settlement at least from 7.5 cal ka BP. The agricultural and pastoralist food producing economy of that population rapidly replaced the coastal economies of the Mesolithic populations. The timing of this population and economic turnover coincided withmajor changes in the continental and marine ecosystems, including upwelling intensity, sea-level changes and increased aridity in the Sahara and along the Iberian coast. These changes likely impacted the subsistence strategies of the Mesolithic populations along the Iberian seascapes and resulted in abandonments manifested as sedimentary hiatuses in some areas during the Mesolithic-Neolithic transition. The rapid expansion and area of dispersal of the early Neolithic traits suggest the use of marine technology. Different evidences for a Maghrebian origin for the first colonists have been summarized. The recognition of an early North-African Neolithic influence in Southern Iberia and the Maghreb is vital for understanding the appearance and development of the Neolithic in Western Europe. Our review suggests links between climate change, resource allocation, and population turnover.