Presentation Abstract

Water column respiration is a key driver of carbon cycling, ocean acidification, and oxygen dynamics in marine ecosystems. However, empirical estimates of the range and variability of respiration and its relative contribution to ocean acidification are seldom measured. In 2014, we began measuring respiration rates at multiple sites in the central Salish Sea (San Juan Islands, Bellingham Bay) and then initiated routine monitoring of water column respiration at multiple sites in Padilla Bay National Estuarine Research Reserve (NERR). Measurements in Padilla Bay were integrated into the well-established NERR System Wide Monitoring Program (SWMP). Our investigation revealed that 1) rates of respiration vary seasonally and appear to be associated with changes in organic matter supply and, to a lesser extent, temperature, and 2) incoming deeper waters of marine origin are characterized by relatively low rates of respiration (i.e. ~5ugO2/L/h). To further explore underlying mechanisms, we conducted a series of manipulative experiments to investigate the direct effect of increasing ocean temperature and organic matter supply on rates of respiration. These experiments revealed that respiration can more than triple in response to increases in organic carbon supply and that this response may be influenced by seasonal changes in the export of organic matter and detritus from the extensive eelgrass meadows of Padilla Bay. Our field sampling and manipulative experiments have produced empirical estimates of respiration that can be included in models and projections of water quality and ocean acidification for the Puget Sound, and provide insight into the response of inland marine waters of the Pacific Northwest to a warmer, more acidified ocean.

Session Title

Response of Water-Column Processes and Pelagic Organisms to Long-term Change

Keywords

Ocean acidification, Respiration, Salish Sea model

Conference Track

SSE16: Long-Term Monitoring of Salish Sea Ecosystems

Conference Name

Salish Sea Ecosystem Conference (Seattle, WA : 2018)

Document Type

Event

SSEC Identifier

SSE16-178

Start Date

5-4-2018 3:30 PM

End Date

5-4-2018 3:45 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, 3:30 PM Apr 5th, 3:45 PM

Variability in water column respiration in Salish Sea waters and implications for coastal and ocean acidification

Water column respiration is a key driver of carbon cycling, ocean acidification, and oxygen dynamics in marine ecosystems. However, empirical estimates of the range and variability of respiration and its relative contribution to ocean acidification are seldom measured. In 2014, we began measuring respiration rates at multiple sites in the central Salish Sea (San Juan Islands, Bellingham Bay) and then initiated routine monitoring of water column respiration at multiple sites in Padilla Bay National Estuarine Research Reserve (NERR). Measurements in Padilla Bay were integrated into the well-established NERR System Wide Monitoring Program (SWMP). Our investigation revealed that 1) rates of respiration vary seasonally and appear to be associated with changes in organic matter supply and, to a lesser extent, temperature, and 2) incoming deeper waters of marine origin are characterized by relatively low rates of respiration (i.e. ~5ugO2/L/h). To further explore underlying mechanisms, we conducted a series of manipulative experiments to investigate the direct effect of increasing ocean temperature and organic matter supply on rates of respiration. These experiments revealed that respiration can more than triple in response to increases in organic carbon supply and that this response may be influenced by seasonal changes in the export of organic matter and detritus from the extensive eelgrass meadows of Padilla Bay. Our field sampling and manipulative experiments have produced empirical estimates of respiration that can be included in models and projections of water quality and ocean acidification for the Puget Sound, and provide insight into the response of inland marine waters of the Pacific Northwest to a warmer, more acidified ocean.