Presentation Abstract

In nearshore, soft-sediment habitats of the Salish Sea, eelgrass (Zostera marina L.) meadows have been identified as potential mitigators of ocean acidification (OA) because their photosynthetic activity can decrease pCO2, increase pH and provide refuge for organisms sensitive to OA. The diurnal light cycle controls photosynthetic production of eelgrass and therefore, along with tidal cycles, exerts strong controls on variations in pCO2 in nearshore environment. In this study, we investigate the carbon uptake rates for eelgrass under varying light, ambient pCO2 conditions and eelgrass densities (leaf area index). The magnitude of changes predicted based on experimentally derived photosynthetic rates, measured light and water depth in Padilla Bay, WA compare well with observed variability in the field. The ambient pCO2 conditions we tested, however, did not appear to be a major control in carbon uptake rates for eelgrass. Combining lab, model, and field results will strengthen our understanding of the variability of OA in the nearshore environment and help shellfish managers understand the drivers of that variability and inform further studies of its effects, such as potential OA refuge for shellfish and other sensitive organisms.

Session Title

Ocean Acidification: Effects and Interactions with Organisms

Keywords

Ocean acidification, Eelgrass, Leaf area index, PCO2

Conference Track

SSE5: Climate Change: Impacts, Adaptation, and Research

Conference Name

Salish Sea Ecosystem Conference (Seattle, WA : 2018)

Document Type

Event

SSEC Identifier

SSE5-107

Start Date

5-4-2018 3:45 PM

End Date

5-4-2018 4:00 PM

Type of Presentation

Oral

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, 3:45 PM Apr 5th, 4:00 PM

Ameliorating ocean acidification: towards a model relating pCO2, irradiance and leaf area index of Zostera marina (eelgrass) in Padilla Bay, WA

In nearshore, soft-sediment habitats of the Salish Sea, eelgrass (Zostera marina L.) meadows have been identified as potential mitigators of ocean acidification (OA) because their photosynthetic activity can decrease pCO2, increase pH and provide refuge for organisms sensitive to OA. The diurnal light cycle controls photosynthetic production of eelgrass and therefore, along with tidal cycles, exerts strong controls on variations in pCO2 in nearshore environment. In this study, we investigate the carbon uptake rates for eelgrass under varying light, ambient pCO2 conditions and eelgrass densities (leaf area index). The magnitude of changes predicted based on experimentally derived photosynthetic rates, measured light and water depth in Padilla Bay, WA compare well with observed variability in the field. The ambient pCO2 conditions we tested, however, did not appear to be a major control in carbon uptake rates for eelgrass. Combining lab, model, and field results will strengthen our understanding of the variability of OA in the nearshore environment and help shellfish managers understand the drivers of that variability and inform further studies of its effects, such as potential OA refuge for shellfish and other sensitive organisms.