No abstract

The GEOTRACES Intermediate Data Product 2014 (IDP2014) is the first publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2013. It consists of two parts: (1) a compilation of digital data for more than 200 trace elements and isotopes (TEls) as well as classical hydrographic parameters, and (2) the eGEOTRACES Electronic Atlas providing a strongly inter-linked on-line atlas including more than 300 section plots and 90 animated 3D scenes. The IDP2014 covers the Atlantic, Arctic, and Indian oceans, exhibiting highest data density in the Atlantic. The TEI data in the IDP2014 are quality controlled by careful assessment of intercalibration results and multi-laboratory data comparisons at cross-over stations. The digital data are provided in several formats, including ASCII spreadsheet, Excel spreadsheet, netCDF, and Ocean Data View collection. In addition to the actual data values the IDP2014 also contains data quality flags and 1-sigma data error values where available. Quality flags and error values are useful for data filtering. Metadata about data originators, analytical methods and original publications related to the data are linked to the data in an easily accessible way. The eGEOTRACES Electronic Atlas is the visual representation of the IDP2014 data providing section plots and a new kind of animated 3D scenes. The basin-wide 3D scenes allow for viewing of data from many cruises at the same time, thereby providing quick overviews of large-scale tracer distributions. In addition, the 3D scenes provide geographical and bathymetric context that is crucial for the interpretation and assessment of observed tracer plumes, as well as for making inferences about controlling processes. (C) 2015 The Authors. Published by Elsevier B.V

[1] Neodymium isotopic compositions (e Nd ) and rare earth element (REE) concentrations were measured for filtered surface to deep waters (112 samples) in the Southern Tropical Pacific. The relatively detailed picture of these tracer distributions allowed us to refine the areas where oceanic e Nd variations occur. e Nd values increase for most of the water masses flowing from Samoa to the Solomon Sea and in the Papua New Guinea (PNG) area, as already observed. Furthermore, water masses arriving from the eastern equatorial Pacific (200-550 m depth) also revealed radiogenic values, possibly acquired in the vicinity of the South American coasts and Galapagos Islands. These e Nd variations affect the whole water column. The most likely process causing such variations is "boundary exchange" between the numerous radiogenic slopes/margins located in this area and seawater flowing past. Dissolution of atmospheric deposition and/or diffuse streaming of volcanic ash are also suggested to explain the radiogenic e Nd observed at the surface in the PNG area. Interestingly, a positive europium (Eu) anomaly characterizes the normalized REE patterns of most of the studied water masses. This anomaly is consistent with the REE patterns of sediment and rock samples that are potential sources for the local waters. Such consistency reinforces the hypothesis that lithogenic sources play a major role in the oceanic REE budget, thanks to "boundary exchange." The data set presented here is a good basis for further sampling that will be realized in the framework of the ongoing GEOTRACES program (www.geotraces.org).