Record Details
The Secret Life of Estuaries: Phytoplankton-determined Seasonality of Particulate Organic Carbon in Cathlamet Bay and the Columbia River Estuary
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | The Secret Life of Estuaries: Phytoplankton-determined Seasonality of Particulate Organic Carbon in Cathlamet Bay and the Columbia River Estuary |
| Names |
Shumway, David O.
(creator) Prahl, Fredrick G. (advisor) |
| Date Issued | 2014-12-02 (iso8601) |
| Note | Carotenoid pigment analysis used as a means of population/species composition survey in a lateral bay in the Columbia River estuary |
| Abstract | This study investigated the composition and character of organic matter on suspended particulate material (SPM) in the Columbia River estuary system to determine the contribution of biological activity in lateral bays to the greater nutrient cycle of the river. Water samples were collected during neap and spring tidal forcing (25 hourly sampling periods each) encountered under high (May – June 2012: 11,000 m³/s) and low (September 2012: 4,500 m³/s, August 2013: 5,000 m³/s) river flow conditions. The samples were analyzed for SPM concentration (mg/L) as well as chemical composition (weight percentage organic carbon {%POC}, phytoplankton pigments {chlorophyll a and carotenoids}) Combined POC and chlorophyll analysis suggests phytoplankton are the main source of organic matter associated with SPM at the sampling site and shows clear, but distinct “mixing lines” for the relationship between %POC vs. [SPM ]⁻¹ under the high and low river flow conditions. Chemotaxonomic analysis of carotenoids suggests that changing phytoplankton ecology drives the seasonal variation in weight percentage organic carbon content on the SPM. The dominance of diatoms in the phytoplankton community in the Spring flow yields a steeper POC vs. [SPM ]⁻¹ slope; increasing abundance of non- diatom populations in the Fall leads to a reduction of the POC vs. [SPM ]⁻¹ slope. Comparison with earlier work in the Columbia River estuary, focused on the estuarine turbidity maximum, shows that the seasonality in the relationship between %POC vs. [SPM ]⁻¹ is widely expressed in this system and that changing phytoplankton ecology is the best explanation of this trend. Evidence for unique biogeochemical activity in Cathlamet Bay is also discussed. |
| Genre | Thesis |
| Access Condition | http://creativecommons.org/licenses/by-nd/3.0/us/ |
| Topic | phytoplankton |
| Identifier | http://hdl.handle.net/1957/54569 |
