Record Details
El Nino related variations in nutrient and chlorophyll distributions off Oregon
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | El Nino related variations in nutrient and chlorophyll distributions off Oregon |
| Names |
Corwith, Holly L.
(creator) Wheeler, Pat (advisor) |
| Date Issued | 2000-08-24 (iso8601) |
| Internet Media Type | application/pdf |
| Note | Graduation date: 2001 |
| Abstract | The Oregon continental shelf waters are typically characterized by four to five major upwelling events that occur between May and October. The upwelled water is rich in nutrients, which fuels an increase in phytoplankton biomass. The onset of El Nino, however, can disrupt the normal physical processes along the Oregon coastline by decreasing upwelling, thereby potentially changing the distribution of nutrients and chlorophyll in this region. As part of the Eastern North Pacific GLOBEC program, we have examined the direct effect of El Nino on nutrient and chlorophyll distributions along the Oregon coast. We sampled chlorophyll and nutrients (phosphate, silicate, nitrate, nitrite, and ammonium) from September 1997 through July 1999 along 4 lines from 40°52.0' to 44°39.1'. Results showed that the shelf was nitrate limited, and chlorophyll concentrations were significantly lower off Newport during the El Nino summer. The percentage of large sized cells (> 10 gm) was decreased to 23% of the total population, as compared to 92% found during the more typical upwelling conditions in August. 1998, which indicates a species composition change occurred during the El Nino period. The slope and offshore waters were less affected by the El Nino conditions during the upwelling season. |
| Genre | Thesis |
| Topic | Upwelling (Oceanography) -- Oregon |
| Identifier | http://hdl.handle.net/1957/7139 |
