NEW PRODUCTION AT THE VERTEX TIME-SERIES SITE

Particulat organic carbon and nitrogen fluxes measured with free-floating seediment traps deployed six times over an 18-month period were combined with 14C primary production and 15N uptake measurements in order to obtain annual estimates of new production (NP) and associted f-ratios at the VERTEX time-series site. The site, located in the northeast Pacific Ocean at 33°N, 139°W, was occuped at trimonthly intervals to conduct water column studies and to recover/redeploy the sediment traps. The upper 250m of the VERTEX site exhibited considerable variability in some biological properties over seasonal time scales. While integrated photoautotrophic biomass remained relatively constant (0.57 ± 0.1 g C m-2) during the 18-month period, both integrated primary production and particulate ATP varied approximately 2.5-fold, ranging from 220 to 550 mg C m-2d-1 and 0.6-1.5 g C m-2, respectively. There was also considerable variation in both NP and f-ratios over the 18-month sampling period, although most of the NP variability was associated with short-term (i.e <72 h) estimates. Despite the relatively large range in NP values derived from 72 h sediment trap deployments and the 15N tracer work (18-179 mg C m-2d-1), no clear relationship between NP and primary productivity was found. However, the f-ratio appeared to be inversely related to primary production, with lowest estimates obtained during the period of highest productivity. Values of annual NP derived from various estimates were remarkably similar ranging from 13-17 g C m-2y-1. The average annual f-ratio ranged from 0.11 to 0.14. © 1990.