Presentation Title

Linking seasonal trends of light and temperature conditions to eelgrass plant performance at Dumas Bay, Washington.

Session Title

The Role of Eelgrass Ecosystems in the Salish Sea

Conference Track

Habitat

Conference Name

Salish Sea Ecosystem Conference (2016 : Vancouver, B.C.)

Contributing Repository

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

Type of Presentation

Poster

Abstract

SeagrassNet is a global seagrass monitoring program that is now established in 33 countries with 132 monitoring sites world-wide. Standardized protocols for scientific monitoring have been developed and are successfully implemented by trained teams of local scientists and managers. Quarterly fixed-transect sampling is carried out at sites for seagrass species composition including: cover, density, biomass, and canopy height, as well as temperature, salinity, and light. A monitoring team at each site sends data via the internet to an online database and archive at www.SeagrassNet.org.

In 2008, the Washington State Department of Natural Resources’ Nearshore Habitat Program established a SeagrassNet site at Dumas Bay. Eight years of sampling show, cumulatively, seagrass is declining at the site and particularly at transects located at the highest and lowest tidal elevations (+1 m and -1.6 m, respectively). Causal factors of decline have not been explicitly identified but we hypothesize change is related to environmental stressors such as temperature and reduced water clarity. Light data collected across the site varied consistently by season over time and data confirm there is adequate light to support eelgrass growth at all transect elevations monitored (>3 mol/day). Temperature measurements and ambient mean daily PAR were above seasonal averages throughout 2013. Z. marina responded differently than expected to increased light, with no clear response in plant morphology detected in subsequent sample events. Meanwhile, increased shoot density and canopy height in the non-native seagrass, Z. japonica was observed at the highest transect elevation. Above average light conditions were not observed at depth in 2013, indicating reduced light availability. Though not directly measured, reduced water clarity due to algal blooms noted could be a major driver of observed seagrass decline at the site.

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.

Language

English

Format

application/pdf

Type

Text

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Linking seasonal trends of light and temperature conditions to eelgrass plant performance at Dumas Bay, Washington.

2016SSEC

SeagrassNet is a global seagrass monitoring program that is now established in 33 countries with 132 monitoring sites world-wide. Standardized protocols for scientific monitoring have been developed and are successfully implemented by trained teams of local scientists and managers. Quarterly fixed-transect sampling is carried out at sites for seagrass species composition including: cover, density, biomass, and canopy height, as well as temperature, salinity, and light. A monitoring team at each site sends data via the internet to an online database and archive at www.SeagrassNet.org.

In 2008, the Washington State Department of Natural Resources’ Nearshore Habitat Program established a SeagrassNet site at Dumas Bay. Eight years of sampling show, cumulatively, seagrass is declining at the site and particularly at transects located at the highest and lowest tidal elevations (+1 m and -1.6 m, respectively). Causal factors of decline have not been explicitly identified but we hypothesize change is related to environmental stressors such as temperature and reduced water clarity. Light data collected across the site varied consistently by season over time and data confirm there is adequate light to support eelgrass growth at all transect elevations monitored (>3 mol/day). Temperature measurements and ambient mean daily PAR were above seasonal averages throughout 2013. Z. marina responded differently than expected to increased light, with no clear response in plant morphology detected in subsequent sample events. Meanwhile, increased shoot density and canopy height in the non-native seagrass, Z. japonica was observed at the highest transect elevation. Above average light conditions were not observed at depth in 2013, indicating reduced light availability. Though not directly measured, reduced water clarity due to algal blooms noted could be a major driver of observed seagrass decline at the site.