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Oxygen in the Columbia Pat Welle River Estuary: Distribution and Dynamics Additional Contributors: Observation ● Prediction ● Analysis ● Collaboration Antonio Baptista1 Yvette Spitz2 Jesse E. Lopez1 G. Curtis Roegner3 Joseph A. Needoba1 Tawnya D. Peterson1 Charles Seaton1 Clara Llebot1 CMOP Astoria Team1

1Oregon Health & Science University 2Oregon State University 3NOAA Northwest Fisheries Science Center

Support: www.stccmop.org 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

Dissolved Oxygen, SATURN-03, July – October 2010 4

4.3 ml/l DO (ml/l) DO 2.1 ml/l

Surface < 2.1 ml/l; hypoxic Mid-Depth (EPA 1986) Bottom < 4.3 ml/l; incipient response (Davis 1975) SATURN-05, June 2010 – May 2011 5

Seasonal freshwater signature

DO (ml/l) DO

07/10 09/10 11/10 01/11 03/11 05/11

Incoming freshwater is consistently well oxygenated DO measured by Phoebe glider on the WA shelf, 2011 6

47.6 180

June 10-July 3, 2009

DO > 1.4 ml/l Latitude

Depth Depth (m) 0.5 ml/l < DO < 1.4 ml/l (mild hypoxia) 46.8 0 Longitude DO < 0.5 ml/l (severe hypoxia) 125.0 124.0

0 Sept 1 – 28, 2011 Jun 20-Jul 16, 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 Wind Stress; SATURN-03, Seasonal DO Variability 8

June 2010 through October 2011 Surface Mid-Depth

Bottom

DO (ml/l) DO

07/10 10/10 01/11 04/11 07/11 10/11

)

2 downwelling

WS (N/m WS upwelling

07/10 10/10 01/11 04/11 07/11 10/11

WS = wind stress SATURN-01 – Salinity, DO, Phycoerythrin; tide-cycle 9

6.5

0 30 0

)

psu

DO (ml/l) DO

Depth Depth (m) Salinity ( Salinity 15 15 1 1 0

0

Flu(RFU)

Depth Depth (m) 15 Phy 15 00:00 13:00 00:00 13:00 Time, Aug 25, 2010 Time, Aug 25, 2010 SATURN-03; Salinity-to-DO, Tidal Day 10

July 18, 2010 August 29, 2010

DO DO (ml/l)

Salinity (psu)

Low biology (chl max <5ug/l) Mod-high biology (chl max 15ug/l) Upwelling Upwelling Neap tide Neap tide Moderate flow (4200m3s-1) Mod-low flow (3000m3s-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 DO Nutrient, Dissolved Oxygen Phytoplankton, & Atmosphere Exchange Zooplankton, Detritus 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) Modeled data preliminary results, SATURN-03 16

Salinity-to-DO, (tidal day); Model vs Observed

July 18, 2010 September 5, 2010

Modeled

Modeled

DO DO (ml/l) Observed Observed

Salinity (psu) Salinity (psu)

Low biology (chl max <5ug/l) High biology (chl max 15ug/l) Upwelling 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 End 18 Modeled Dissolved Oxygen, July 18, 6-hour period 19 DO (ml/l) Estuarine Hypoxia: Mechanisms, Processes 20

Surface Atmosphere CR Estuary Columbia Exchange River Coastal Ocean Atmosphere Exchange Coastal High Normoxic Plankton Nutrients Water Blooms Primary Low DO Production Freshwater Plankton Bottom Org Matter Estuary Hypoxia Blooms Coastal Ocean Remineralization

Coastal Hypoxic Org Matter DOC Low DO Upwelling Water Remineralization

Modified from Needoba, 2011 SELFE skill – estuary grid 21

Scale: 3km down to ~ 100m