Event Title

The effect of El Niño on the relationship between surface pH, salinity, and chlorophyll in the possession sound

Presentation Abstract

Possession Sound is located in the northern reaches of the Puget Sound basin and exhibits a significant freshwater influence from the Snohomish River on its eastern boundary. Within an estuarine system such as this, pH levels influence the biological processes of many organisms. This study examines the effect of the El Niño weather pattern on the relationship between surface salinity, pH, chlorophyll, and the plankton genus Pseudo-nitzschia. This investigation utilizes data derived from the Ocean Research College Academy, where students collect longitudinal data as part of a long-term study on the Possession Sound. This study used data from a sample site (BUOY) since 2004 near the Snohomish River. Measurements of surface salinity, pH, temperature, and chlorophyll were taken with YSI probes, while a 20μm plankton net was utilized for plankton collection in order to determine Pseudo-nitzschia density. Measurements and samples were collected monthly at BUOY during the most recent La Nada period (June 2012-September 2014) and El Nino period (December 2014-June 2016). It was hypothesized that salinity, surface pH, and Pseudo-nitzschia populations would be lower during the La Nada period, following seasonal trends of river discharge, but that during the El Niño period, warmer temperatures and an increase in salinity would lead to an increase in surface pH and chlorophyll which would correlate with an increased and longer lasting presence of Pseudo-nitzschia. Results show that surface pH, temperature, and chlorophyll levels were elevated during El Niño, while surface salinity was not. The results suggest that the warmer, more consistent weather observed during El Niño periods creates improved conditions for photosynthesis year-round, thus contributing to the higher, more consistent pH levels. In all years, Pseudo-nitzschia densities spiked during periods of high river discharge in spring and fall, but it exhibited a longer seasonal presence during the El Nino period.

Session Title

Posters: Climate Change: Impacts, Adaptation, & Research

Conference Track

SSE18: Posters

Conference Name

Salish Sea Ecosystem Conference (Seattle, WA : 2018)

Document Type

Event

SSEC Identifier

SSE18-8

Start Date

5-4-2018 11:30 AM

End Date

5-4-2018 1:30 PM

Type of Presentation

Poster

Contributing Repository

Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.

Geographic Coverage

Salish Sea (B.C. and Wash.)

Rights

This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.

Type

text

Language

English

Format

application/pdf

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Apr 5th, 11:30 AM Apr 5th, 1:30 PM

The effect of El Niño on the relationship between surface pH, salinity, and chlorophyll in the possession sound

Possession Sound is located in the northern reaches of the Puget Sound basin and exhibits a significant freshwater influence from the Snohomish River on its eastern boundary. Within an estuarine system such as this, pH levels influence the biological processes of many organisms. This study examines the effect of the El Niño weather pattern on the relationship between surface salinity, pH, chlorophyll, and the plankton genus Pseudo-nitzschia. This investigation utilizes data derived from the Ocean Research College Academy, where students collect longitudinal data as part of a long-term study on the Possession Sound. This study used data from a sample site (BUOY) since 2004 near the Snohomish River. Measurements of surface salinity, pH, temperature, and chlorophyll were taken with YSI probes, while a 20μm plankton net was utilized for plankton collection in order to determine Pseudo-nitzschia density. Measurements and samples were collected monthly at BUOY during the most recent La Nada period (June 2012-September 2014) and El Nino period (December 2014-June 2016). It was hypothesized that salinity, surface pH, and Pseudo-nitzschia populations would be lower during the La Nada period, following seasonal trends of river discharge, but that during the El Niño period, warmer temperatures and an increase in salinity would lead to an increase in surface pH and chlorophyll which would correlate with an increased and longer lasting presence of Pseudo-nitzschia. Results show that surface pH, temperature, and chlorophyll levels were elevated during El Niño, while surface salinity was not. The results suggest that the warmer, more consistent weather observed during El Niño periods creates improved conditions for photosynthesis year-round, thus contributing to the higher, more consistent pH levels. In all years, Pseudo-nitzschia densities spiked during periods of high river discharge in spring and fall, but it exhibited a longer seasonal presence during the El Nino period.