Description: Concentrations of dissolved Cd, Cu, and Zn, and Cu-binding organic ligands in the waters of the Kuroshio region in the East China Sea were presented in this dataset. The samples were collected as part of the GEOTRACES-Japan project during KH-15-3 cruise (Principal Investigator: Jing Zhang, Toyama University, Japan) onboard R/V Hakuho Maru in October 2015 to understand trace element distributions and behaviors in the highly dynamic East China Sea. All sampling followed trace-metal clean techniques as stated in the GEOTRACES cookbook. Seawater samples were filtered through 0.2 μm filter and acidified for dissolved trace metal analysis or frozen for organic ligand analysis. Trace metal concentrations were measured using ICP-MS following pre-concentration by NOBIAS PA-1 chelating resin column, while the chemical speciation parameters of Cu were determined using competitive ligand exchange adsorptive cathodic stripping voltammetry with salicylaldoxime as the competing ligand. These data reveal the unique interaction between the continental shelf waters and Kuroshio waters in the East China Sea.

Description: Data archived here are the external iron input data and model output data discussed in a paper entitled "Slowly sinking particles underlie dissolved iron transport across the Pacific Ocean" submitted to Global Biogeochemical Cycles. The model used in this study was developed by coupling Regional Ocean Modeling System (Shchepetkin and McWilliams, 2005) and Biogeochemical Elemental Cycling model (Moore et al., 2013). The model covers the whole North Pacific Ocean. The model horizontal resolution was set to 1/4° mesh. The external iron input data are iron fluxes due to atmospheric deposition and dissolution from seabed sediments. The model output data are dissolved iron concentrations simulated by the model and were only presented for the data in the intermediate layer (26.6-27.4 sigma-theta divided by 0.02 sigma-theta). The simulated data were regridded 1° mesh to reduce the size of the data. The model was calculated for 100 years and the simulated dissolved iron concentration are in quasi-steady state. For more details about the individual archived data, please refer to README.pdf included in the data. Reference Shchepetkin, A. F., & McWilliams, J. C. (2005). The regional oceanic modeling system (ROMS): A split-explicit, free-surface, topography-following-coordinate oceanic model. Ocean Modelling, 9(4), 347-404. Moore, J. K., Lindsay, K., Doney, S. C., Long, M. C., & Misumi, K. (2013). Marine ecosystem dynamics and biogeochemical cycling in the Community Earth System Model (CESM1-BGC). Journal of Climate, 26, 9291-9312.

Description: This study presents a new set of paired d18Osw and salinity data (n = 83) from a large region of the western Pacific (mainly the western south Pacific) collected during the 2014–2015 El Niño period. We determined regional salinity–d18Osw relationships for three ocean regions (40º–20ºN, 20ºN–30ºS, and 30º–66ºS) and found that all three regions exhibited highly linear relationships between d18Osw and salinity. The 40º–20ºN and 20ºN–30ºS regions had relatively low slopes (0.33 and 0.37 ‰ psu-1, respectively), while the 30º–66ºS region had a relatively high slope (0.54 ‰ psu-1). Each regional regression was statistically different from those of the GEOSECS (1973–1974 La Niña) data, indicating that inter-annual ENSO variability has an impact on salinity–d18Osw relationships over a wide area of the western Pacific.

Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Philosophical Transactions of the Royal Society A 374 (2016): 20160035, doi:10.1098/rsta.2016.0035.

Description: Hydrothermal activity occurs in all ocean basins, releasing high concentrations of key trace elements and isotopes (TEIs) into the oceans. Importantly, the calculated rate of entrainment of the entire ocean volume through turbulently mixing buoyant hydrothermal plumes is so vigorous as to be comparable to that of deep-ocean thermohaline circulation. Consequently, biogeochemical processes active within deep-ocean hydrothermal plumes have long been known to have the potential to impact global-scale biogeochemical cycles. More recently, new results from GEOTRACES have revealed that plumes rich in dissolved Fe, an important micronutrient that is limiting to productivity in some areas, are widespread above mid-ocean ridges and extend out into the deep-ocean interior. While Fe is only one element among the full suite of TEIs of interest to GEOTRACES, these preliminary results are important because they illustrate how inputs from seafloor venting might impact the global biogeochemical budgets of many other TEIs. To determine the global impact of seafloor venting, however, requires two key questions to be addressed: (i) What processes are active close to vent sites that regulate the initial high-temperature hydrothermal fluxes for the full suite of TEIs that are dispersed through non-buoyant hydrothermal plumes? (ii) How do those processes vary, globally, in response to changing geologic settings at the seafloor and/or the geochemistry of the overlying ocean water? In this paper, we review key findings from recent work in this realm, highlight a series of key hypotheses arising from that research and propose a series of new GEOTRACES modelling, section and process studies that could be implemented, nationally and internationally, to address these issues.

Description: his paper represents the outcomes from a series of break-out group discussions held at Chicheley Hall, UK, on 9 and 10 December 2015, as part of a Quantifying Fluxes and Processes in Trace-Metal Cycling in the Oceans science meeting sponsored by the Royal Society. C.R.G. also acknowledges further support from NSF grant OCE-1130870.