Ship-based hydrography remains the only method for obtaining high-quality, high spatial and vertical resolution measurements of a suite of physical, chemical, and biological parameters over the full water column on a global scale. Only ship-based hydrography can document ocean changes throughout the water column, including the deep ocean below 2 km (52% of global ocean volume not sampled by profiling floats). This is especially true for carbon-cycle parameters which are not routinely sampled on profiling floats due to instrumental obstacles that still need to be overcome. In 2007 the IOCCP and CLIVAR communities established the Global Ocean Ship-based Hydrographic Investigations Program (GO-SHIP) to develop a strategy and establish a set of criteria for a globally coordinated network of repeat coast-to-coast hydrographic sections.

Biogeochemical-Argo aims at developing a global network of biogeochemical sensors on Argo profiling floats. The concept of global robotic biogeochemical measurements was articulated in a Community White Paper (Gruber et al., 2007) that was supported by IOCCP and the US Ocean Carbon and Biogeochemistry Program (US-OCB). Through the work of subsequent scoping workshops, working groups and resulting white papers, recommendations for implementation of integrated deployments of larger numbers of profiling floats with biogeochemical sensors were put forward. Biogeochemical-Argo is poised to address a number of grand challenges in ocean science and in the management of ocean and global resources. Its development, as described in the Implementation Plan, will compliment ship-based observations and further our capacity to study biogeochemical phenomena related to ocean carbon uptake, oxygen minimum zones, inorganic nutrient cycling, ocean acidification and export fluxes.

www.go-ship.org	www.biogeochemical-argo.org