Primary production and sediment trap flux measurements and calculations by the Hawaii Ocean Time-series (HOT) program at Station ALOHA in the North Pacific 100 miles north of Oahu, Hawaii for Cruises HOT1-227 during 1988-2010 (NCEI Accession 0089168)

Methodology:

Primary Production:
Photosynthetic production of organic matter was measured by the 14C tracer method. All incubations from 1990 through mid-2000 were conducted in situ at eight depths (5, 25, 45, 75, 100, 125, 150 & 175m) over one daylight period using a free-drifting array as described by Winn et al. (1991). Starting HOT-119 (October 2000), we collected samples from only the upper six depths & modeled the lower two depths based on the monthly climatology. Some incubations during 1988-1990 were carried out in situ, and some on deck under simulated in situ light and temperature conditions. Integrated carbon assimilation rates were calculated using the trapezoid rule with the shallowest value extended to 0 m and the deepest extrapolated to a value of zero at 200 m.

Particle Flux:
Particle flux was measured at a standard reference depth of 150 m using multiple cylindrical particle interceptor traps deployed on a ree-floating array for approximately 60 h during each cruise. Sediment trap design and collection methods are described in Winn et al. (1991). Samples were analyzed for particulate C, N, P and Si as described in Section 2.5.5 above. Typically six traps are analyzed for PC and PN, three for PP, and another three traps for PSi.