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Iron, nutrient, and phytoplankton distributions in Oregon coastal waters
Citation
Chase, Z and van Geen, A and Kosro, PM and Marra, J and Wheeler, PA, Iron, nutrient, and phytoplankton distributions in Oregon coastal waters, Journal of Geophysical Research: Oceans, 107, (C10) pp. 38.1-37.17. ISSN 2169-9275 (2002) [Refereed Article]
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Copyright Statement
Copyright 2002 by the American Geophysical Union
Abstract
The relationship between iron and nitrate concentrations was examined off the coast of Oregon during the upwelling season. Surface Fe and N (nitrate + nitrite) concentrations measured underway by flow injection analysis ranged from <0.3 to 20 nmol L−1 and <0.1 to 30 μmol L−1, respectively. Total dissolvable Fe concentrations, measured in unfiltered, acidified samples in surface waters and in vertical profiles, ranged from <0.3 to 300 nmol L−1. Surface water Fe and N concentrations were highly variable and uncoupled. Our observations indicate two dominant sources of Fe to Oregon coastal waters: Slope or shelf sediments and the Columbia River. Sedimentary iron, probably largely in the particulate form, appears to be added to surface waters through wind-induced vertical mixing during strong winds, through thickening of the bottom mixed layer during relaxation or downwelling favorable wind conditions, and through outcropping of shelf bottom waters during upwelling events. The existence of multiple iron sources and the generally high iron concentrations may explain why the distribution of phytoplankton, measured both remotely (by Sea-viewing Wide Field-of-view Sensor) and underway (by in vivo fluorescence), appeared to be driven primarily by physical dynamics and was not strongly linked to the distribution of iron. Nevertheless, at some offshore stations where underway Fe concentrations were <0.3 nmol L−1, underway measurements of the physiological state of phytoplankton by fast repetition rate fluorometry were consistent with mild iron stress, and cross-shelf nutrient distributions were consistent with iron regulation of the magnitude of phytoplankton blooms.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | iron, Oregon, upwelling, nutrients, coastal, chlorophyll |
| Research Division: | Earth Sciences |
| Research Group: | Oceanography |
| Research Field: | Chemical oceanography |
| Objective Division: | Expanding Knowledge |
| Objective Group: | Expanding knowledge |
| Objective Field: | Expanding knowledge in the earth sciences |
| UTAS Author: | Chase, Z (Professor Zanna Chase) |
| ID Code: | 101497 |
| Year Published: | 2002 |
| Web of Science® Times Cited: | 29 |
| Deposited By: | IMAS Research and Education Centre |
| Deposited On: | 2015-06-25 |
| Last Modified: | 2015-08-20 |
| Downloads: | 308 View Download Statistics |
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