1 Oxygen in the Columbia River Estuary: Distribution and Dynamics Observation Prediction Analysis Collaboration Pat Welle Additional Contributors: Antonio Baptista 1 Yvette Spitz 2 Jesse E. Lopez 1 G. Curtis Roegner 3 Joseph A. Needoba 1 Tawnya D. Peterson 1 Charles Seaton 1 Clara Llebot 1 CMOP Astoria Team 1 1 Oregon Health & Science University 2 Oregon State University 3 NOAA Northwest Fisheries Science Center www.stccmop.org Support: National Science Foundation
Outline 2 Dissolved Oxygen (DO) in Columbia River estuary (CRE) Freshwater source Coastal source Observations Upwelling forces Biological forces Modeling Management Considerations
Dissolved Oxygen in the CRE 3 Understanding DO is a key piece to understanding the physical and biogeochemical processes in the estuary Oxygen concentrations are critical to: benthic species migrating salmon Important to understanding net ecosystem metabolism
DO (ml/l) Dissolved Oxygen, SATURN-03, July October 2010 4 4.3 ml/l 2.1 ml/l Surface Mid-Depth Bottom < 2.1 ml/l; hypoxic (EPA 1986) < 4.3 ml/l; incipient response (Davis 1975)
DO (ml/l) SATURN-05, June 2010 May 2011 5 Seasonal freshwater signature 07/10 09/10 11/10 01/11 03/11 05/11 Incoming freshwater is consistently well oxygenated
Latitude Depth (m) DO measured by Phoebe glider on the WA shelf, 2011 6 47.6 June 10-July 3, 2009 180 DO > 1.4 ml/l 0.5 ml/l < DO < 1.4 ml/l (mild hypoxia) 46.8 Longitude 125.0 124.0 0 DO < 0.5 ml/l (severe hypoxia) 0 Jun 20-Jul 16, 2011 Sept 1 28, 2011 Depth (m) 200 Time
Coastal Upwelling / Downwelling 7 Increasing occurences of low DO off coast (Grantham et al 2004, Chan et al 2008) Upwelling and downwelling are a response to shelf wind stress 2001; American Meteorological Society
WS (N/m 2 ) DO (ml/l) Wind Stress; SATURN-03, Seasonal DO Variability 8 June 2010 through October 2011 Surface Mid-Depth Bottom 07/10 10/10 01/11 04/11 07/11 10/11 downwelling upwelling 07/10 10/10 01/11 04/11 07/11 10/11 WS = wind stress
Depth (m) Phy Flu (RFU) Depth (m) Salinity (psu) DO (ml/l) SATURN-01 Salinity, DO, Phycoerythrin; tide-cycle 9 0 30 0 6.5 15 1 15 1 0 0 15 15 00:00 Time, Aug 25, 2010 13:00 00:00 Time, Aug 25, 2010 13:00
DO (ml/l) SATURN-03; Salinity-to-DO, Tidal Day 10 July 18, 2010 August 29, 2010 Salinity (psu) Low biology (chl max <5ug/l) Upwelling Neap tide Moderate flow (4200m 3 s -1 ) Mod-high biology (chl max 15ug/l) Upwelling Neap tide Mod-low flow (3000m 3 s -1 )
Model Concept 11 Complicated biology An effective way to tease apart all the contributions to DO distribution is through data-supported modeling Our circulation models address Elevation, velocity, salinity, temperature Adding DO and biology into the model moves toward representing the complex ecosystem functions Model will rely heavily on empirical measurements for parameterization and validation
Model Components 12 CIRCULATION Advection & Diffusion NPZD Nutrient, Phytoplankton, Zooplankton, Detritus DO Dissolved Oxygen & Atmosphere Exchange
Model as Management Tool 13 Quantify and differentiate both the physical and biological forces influencing DO transformations over time and space in estuary Understand where, when, and under what forces low DO and hypoxic concentrations would be expected Leading to predictions of where and length of time at low DO within estuary Look at how these may intersect with potential issues of concern for benthic and migrating species
Modeled Dissolved Oxygen, SATURN Stations 14 July 18 2010 18:00; bottom layer, high tide DO (ml/l)
Modeled Dissolved Oxygen, July 18, 24-hour period 15 DO (ml/l)
DO (ml/l) Modeled data preliminary results, SATURN-03 16 Salinity-to-DO, (tidal day); Model vs Observed July 18, 2010 Modeled September 5, 2010 Modeled Observed Observed Salinity (psu) Low biology (chl max <5ug/l) Upwelling Salinity (psu) High biology (chl max 15ug/l) Upwelling
Summary 17 Coastal upwelling brings low DO into the estuary, a potential water quality problem Sensors provide insight into DO distribution and controls Have limited spatial resolution No predictive ability for changes due to management or climate change Emerging DO model will allow us to better characterize and predict low DO and estuarine hypoxia; suggest mitigation strategies Continuing model development Improve representation of physical processes of DO distribution Refine parameterization, and validation of biological and DO models; sediment, light attenuation and nutrient cycling
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Modeled Dissolved Oxygen, July 18, 6-hour period 19 DO (ml/l)
Estuarine Hypoxia: Mechanisms, Processes 20 Surface Coastal Ocean High Nutrients Low DO Coastal Plankton Blooms Atmosphere Exchange Normoxic Water CR Estuary Atmosphere Exchange Primary Production Columbia River Bottom Coastal Ocean Org Matter Remineralization Estuary Hypoxia Freshwater Plankton Blooms Coastal Upwelling Low DO Hypoxic Water Org Matter Remineralization DOC Modified from Needoba, 2011
SELFE skill estuary grid 21 Scale: 3km down to ~ 100m