Neuston C and N isotope ratios along the Malaspina 2010 Expedition

Raw isotopic data of carbon and nitrogen ratios of neustonic samples collected during the Malaspina Expedition. Samples were collected along the Malaspina 2010 Expedition, which circumnavigated the globe and was carried out between December 2010 and July 2011 between 35° N and 40° S. Specifically, the neuston samples reported here included 10 oceanic Longhurst provinces (Longhurst, 2007). Four provinces in the Atlantic (Northeast Atlantic subtropical gyral – NASE; North Atlantic tropical gyral – NATR; Western tropical Atlantic – WTRA; South Atlantic gyral - SATL), 4 in the Pacific (South Pacific gyre – SPSG; Pacific equatorial divergence – PEQD; North Pacific tropical gyre – NPTG; North Pacific equatorial counter current – PNEC), and 2 in the Indian Ocean (Indian South subtropical gyre – ISSG; South subtropical convergence – SSTC). Samples were collected twice a day at 12 pm and 4 am, by towing a neuston sampler, with a mouth opening of 80 x 30 cm and a mesh size of 200 µm, at 2-3 knots for 10-15 minutes, which sampled the first 15 cm of the water at a distance of 5 m from the starboard of the vessel. The content of each sample was stored in 4% formaldehyde until analysis. The most abundant and representative taxa selected for SIA were copepods of the families Acartiidae, Calanidae, Corycaeidae, Oncaeidae, and Pontellidae, and Phylum Chaetognatha. Four functional groups (FG) were considered and taxa assigned as follow: FG1 = detritivores (Oncaeidae); FG2 = herbivores/omnivores (Acartiidae and Calanidae); FG3 = carnivores (Corycaeidae and Pontellidae) and FG4 = predators (Chaetognatha). All specimens selected for analysis were adults according to their morphological aspect under the microscope. Dried samples (~1 mg) were packed into tin capsules and measured in an elemental analyzer (Carlo Erba CHNSO 1108) coupled to an isotope-ratio mass spectrometer (Finnigan Matt Delta Plus).