Investigating livestock management in the early Neolithic archaeological site of Cabecicos Negros (Almería, Spain) from the organic residue analysis in pottery.

This paper seeks to reconstruct the management of food resources in the early Neolithic site of Cabecicos Negros in southeastern Spain. For this purpose, we have studied 29 potsherds from Cabecicos Negros (Andalusia, Spain). Applying the methods of gas chromatography and mass spectrometry we were able to recompose the daily use of the sherds related to the consumption and storage of food products. Among the results obtained in this work, we were able to show new evidence of the exploitation of dairy products in the south of the Iberian Peninsula, as well as provide information on the exploitation and management of the early domestic animals herds. To improve the archaeological results obtained, isotopic results were compared with a modern reference of 53 fat samples from the adipose tissue of domestic pigs and wild boars.

Quantitative Link Between Sedimentary Chlorin and Sea-Surface Chlorophyll-a.

Primary productivity in the ocean plays a major role in the global carbon cycle. To estimate its changes through geological time, different sedimentary proxies are used. However, the relative weights of the various processes driving the sedimentary accumulation of organic matter are not fully constrained or represent the flux of specific algal classes. Here, we compare sea-surface chlorophyll-a (SSchla) abundance estimated from remote sensing data over the last 20 years with the sedimentary concentration of its derivatives (i.e., chlorin) on a suite of 140 core-top sediments from different biogeochemical regions. We estimate with field data that only 0.33% of SSchla in tropical and subtropical regions is transferred to surface sediments in the form of chlorin. Despite the small fraction of chlorin that arrive to the sea-floor, the sedimentary spatial distribution of chlorin is driven primarily by SSchla concentration in high and moderate productivity locations (SSchla > 0.20 mg·m-3). Our calibration paves the way for the use of chlorin as quantitative proxies of primary productivity in paleoreconstructions and cautions on their use in low primary productivity settings.

Upwelling intensification as part of the Pliocene-Pleistocene climate transition.

A deep-sea sediment core underlying the Benguela upwelling system off southwest Africa provides a continuous time series of sea surface temperature (SST) for the past 4.5 million years. Our results indicate that temperatures in the region have declined by about 10 degrees C since 3.2 million years ago. Records of paleoproductivity suggest that this cooling was associated with an increase in wind-driven upwelling tied to a shift from relatively stable global warmth during the mid-Pliocene to the high-amplitude glacial-interglacial cycles of the late Quaternary. These observations imply that Atlantic Ocean surface water circulation was radically different during the mid-Pliocene.

High-performance liquid chromatography-mass spectrometry of porphyrins by using an atmospheric pressure interface.

A method is described for the high-performance liquid chromatography (HPLC) mass spectrometry analysis of porphyrin mixtures by using an atmospheric pressure interface, which can operate in two modes: pneumatically assisted elecrrospray and atmospheric pressure chemical ionization (APCI). Optimization of the conditions and evaluation of spectral information has been carried out by using direct injection of free-base and metallo porphyrin standards. The most effective results were obtained using APCI. HPLC-APCI mass spectrometry analysis of the demetallated vanadyl porphyrin fraction from the Triassic Serpiano oil shale has allowed rapid characterization of the distribution; more than 50 significant components are present. The presence of trace amounts of high molecular weight (>C33) cycloalkano porphyrins indicates the occurrence of photic zone anoxia in the ancient water column. This example illustrates the potential of the approach for studies of porphyrin mixtures of environmental or biological significance, which should be applicable to other types of metallo and free-base components that can be separated by HPLC under normal or reversed-phase conditions.