Vertical distribution of total and particulate 234Th, particulate organic carbon (POC) and nutrients with their physical forcings (temperature, salinity, fluorescence-based Chl a)

Particulate 234Th and POC were filterd by quartz microfiber (QMA) filters (25 mm diameter, 1.0 μm pore size) as particulate samples following method described in the JGOFS cookbook (Knap et al., 1996); the activity of 234Th was determined by a gas-flow proportional low-level RISØ beta counter (Model GM-25-5).

Precipitation efficiency was determined by ICP-MS. Nutrients were analysed onboard using a Four-channel Continuous Flow Technicon AA3 Auto-Analyzer (Bran-Lube GmbH). The detection limits for both N+N (nitrate plus nitrite, termed as dissolved inorganic nitrogen, DIN) and SRP (soluble reactive phosphate) were 0.03 μmol L-1.