Particulate nutrient Sampling:

Total particulate carbon and nitrogen samples (150–250 mL) were filtered at low vacuum onto GF/F filters that had been precombusted at 450oC for 2 h. Filters were then dried at 60oC. Samples were analyzed with a Finnigan Delta Plus mass spectrometer and a Carlo Erba NA1500 elemental analyzer/Conflo II. Elemental compositions were measured using the mass 44 beam intensity (V) on the Delta Plus and calibrated against the mass 44 beam intensity of at least five standards also analyzed during each run of 40 samples. Total particulate phosphorus samples (100–200 mL) were gently filtered onto precombusted GF/F filters and rinsed with 2 ml 0.12 mol L−1 Na2SO4. Filters were placed overnight in precombusted (450oC, overnight) 20mL borosilicate glass scintillation vials with 2mL 0.017 mol L−1 MnSO4. Vials were covered with aluminum foil, dried at 95oC and stored dessicated until analysis. Total particulate phosphorus content was determined as follows: vials and filters were combusted at 450oC for 2 h, cooled, and 5mL 0.2 mol L−1 HCl was added to each vial. Vials were capped and heated to 80oC for 30 min to digest particulate organic phosphorus into inorganic phosphate, and digested samples were analyzed using the standard molybdate colorimetric method (Solorzano and Sharp, 1980). Biogenic silica samples (100–250 mL) were gently filtered onto 0.6μm polycarbonate filters, dried at 60oC and stored at room temperature until analysis. Samples were analyzed according to Brzezinski and Nelson (1995).

References:

Bruland, K.W., E.L. Rue, G.J. Smith, and G.R. DiTullio. 2005. Iron, macronutrients and diatom blooms in the Peru upwelling regime: brown and blue waters of Peru. Marine Chemistry 93: 81-103.
Brzezinski, M.A., and D.M. Nelson. 1995. The annual silica cycle in the Sargasso Sea near Bermuda. Deep-Sea Research I 42: 1215-1237.
Buck, K.N., M.C. Lohan, C.J.M. Berger, and K.W. Bruland. 2007. Dissolved iron speciation in two distinct river plumes and an estuary: implications for riverine iron supply. Limnology and Oceanography 52: 843-855.
Donat, J.R., and K.W. Bruland. 1988. Direct determination of dissolved cobalt and nickel in seawater by differential pulse cathodic stripping voltammetry preceded by adsorptive collection of cyclohexane-1,2,-dione dioxime complexes. Analytical Chemistry 60.
Ellwood, M., and C.M.G. Van den Berg. 2000. Zinc speciation in the Northeastern Atlantic Ocean. Marine Chemistry 68: 295-306.
Solorzano, L., and J.H. Sharp. 1980. Determination of total dissolved phosphorus and particulate phosphorus in natural waters. Limnology and Oceanography 25: 756-760.

nuts_partic_ant1.csv