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- Title
Estimates of micro-, nano-, and picoplankton contributions to particle export in the northeast Pacific.
- Authors
Mackinson, B. L.; Moran, S. B.; Lomas, M. W.; Stewart, G. M.; Kelly, R. P.
- Abstract
The contributions of micro-, nano-, and picoplankton to particle export were estimated from measurements of size-fractionated particulate 234Th, organic carbon, and phytoplankton indicator pigments obtained during five cruises between 2010 and 2012 along Line P in the subarctic northeast Pacific Ocean. Sinking fluxes of particulate organic carbon (POC) and indicator pigments were calculated from 234Th-238U disequilibria and, during two cruises, measured by a sediment trap at Ocean Station Papa. POC fluxes at 100 m ranged from 0.65 to 7.95 mmol m-2 d-1, similar in magnitude to previous results at Line P. Microplankton pigments dominate indicator pigment fluxes (averaging 69 ± 19% of total pigment flux), while nanoplankton pigments comprised the majority of pigment standing stocks (averaging 64 ± 23 % of total pigment standing stocks). Indicator pigment loss rates (the ratio of pigment export flux to pigment standing stocks) point to preferential export of larger microplankton relative to smaller nano- and picoplankton. However, indicator pigments do not quantitatively trace particle export resulting from zooplankton grazing, which may be an important pathway for the export of small phyto-plankton. These results have important implications for understanding the magnitude and mechanisms controlling the biological pump at Line P in particular, and more generally in oligotrophic gyres and high-nutrient, low-chlorophyll (HNLC) regions where small phytoplankton represent a major component of the autotrophic community.
- Subjects
PLANKTON; PHYTOPLANKTON; AUTOTROPHIC bacteria; CHLOROPHYLL; ZOOPLANKTON; PACIFIC Street (Seattle, Wash.)
- Publication
Biogeosciences, 2015, Vol 12, Issue 11, p3429
- ISSN
1726-4170
- Publication type
Article
- DOI
10.5194/bg-12-3429-2015