COUPLED PHYSICAL BIOGEOCHEMICAL MODELS

COUPLED PHYSICAL BIOGEOCHEMICAL MODELS

Upwelling CONCEPTUAL MODEL OF EUTROPHICATION IN THE COASTAL OCEAN Nutrient/ Acid Deposition Local Emissions HABs! Phytoplankton Blooms Senesce and Settling Respiration: Hypoxia & Acidification Outfall Pipe Nutrients High p(co 2 ) Low O 2 Low ph U Symptoms of Eutrophication: Chlorophyll a/ Primary Production Harmful Algal Blooms/Toxins Dissolved Oxygen Carbonate Chemistry/ ph

ARE ANTHROPOGENIC NUTRIENTS IMPORTANT IN AN UPWELLING DOMINATED REGION? California coastal waters are dominated by upwelling, therefore anthropogenic nutrients are not a primary driver Local anthropogenic inputs can exacerbate global drivers, potentially pushing DO and ph to ecological tipping-points

OCEAN NUTRIENTS PROGRAM: KEY RESEARCH QUESTION What are the relative contributions of three major drivers of symptoms of eutrophication and acidification/hypoxia in the SCB and beyond: 1. Anthropogenic inputs 2. Natural climate variability 3. Anthropogenically induced climate change First step, Bight 8 Nutrient Source Comparison

RELATIVE CONTRIBUTION OF ANTHROPOGENIC NUTRIENTS VARIES BY SCALE! BIGHT-WIDE SCALE Upwelling is the largest source LOCAL SCALE Nitrogen loads are equivalent

WHAT IS THE FATE OF ANTHROPOGENIC NUTRIENTS? NITROGEN FORM MATTERS Sources have equal magnitudes but the form of nitrogen is different: Upwelled nitrogen is 9% nitrate Effluent nitrogen is 8-9% ammonia Nitrate is primary form of inorganic N in the watercolumn Where did the ammonium go? Dissolved Inorganic Nitrogen (um) 25 2 15 1 5 S Nitrate Ammonia S = Surface D = Below CHL max S D S D S D S D 222 223 225 227 228

OCSD DIVERSION: NITROGEN FORMS ARE ELEVATED AROUND OCEAN OUTFALLS NO 3 Depth (m) 3 6 9 222 1 3 5 223 7 1 3 5 72 11 9 4 13 15 91113 2 15 17 6 17 4 19 224 225 226 NH 4 Depth (m) 3 6 9 9/2/212 1 1 2 3 2 1 3 2 4 2 4 1 6 4 DON Depth (m) 222 223 224 225 226 227 228 227 228 NH 4 Depth (m) 3 6 9 DON 222 1 1 1 2 3 23 4 3 5 1 3 5 2 4 7 1 7 2 9 6 9 11 4 13 223 Depth (m) 224 225 226 227 228 DON 9/2/212.51.5 1 2 1.3 2 2. 1.5 4 2.5 3.5 3. 1 3 4. 2 4.5 1 2 6 4 222 223 224 225 226 DON 227 228 Ammonia Nitrate Before Diversion During Diversion NH 4 Depth (m) 3 6 9 9/2/212 Concentrations in mm 9/2/212

Station WASTEWATER AMMONIUM IS RAPIDLY S228 NITRIFIED S222 S227 S225 S223 9/2/212 While forms of nitrogen are initially different, rapid nitrification means the dominant form of inorganic N will be nitrate Station S222 S228 228 S227 S226 227 S225 225 S223 223 9/6/212 1/3/212 S222 Isotopic evidence that effluent nitrate is incorporated into algal biomass Station S228 S227 225 S225 223 S223 222 S222 2 4 5 1 S226 1/3/212 15 2 Nitrification Rate (nmol L -1 d -1 ) S225 1/17/212 9/2/212 Surface Subeuphotic

Upwelling CONCEPTUAL MODEL OF EUTROPHICATION IN THE COASTAL OCEAN Nutrient/ Acid Deposition Local Emissions Phytoplankton Blooms Nutrients High p(co 2 ) Low O 2 Low ph Senesce and Settling How big is the Respiration: Hypoxia & Acidification effect??? Outfall Pipe Take U away: Nearshore, anthropogenic nutrients and upwelling are equivalent Effluent ammonium is nitrified rapidly, so N looks just like upwelling Incorporated into biomass

MODELING PROGRAM GOALS ADDRESS OUR KEY RESEARCH QUESTION Develop OAH model of California Current System (CCS), with regional downscaling So. California Bight, Central Coast, and the Oregon Coast Use the model to understand the relative contributions of : Natural climate variability Anthropogenically-induced climate change Anthropogenic inputs Transmit these findings to coastal zone water quality and marine resource managers

MODELING APPROACH Enhance existing models Validate the models and quantify uncertainty Run climate change and management scenarios Outreach to inform management actions

ENHANCE EXISTING MODELS Physical model: Downscale to smaller spatial scales and move the model closer to shore Biogeochemistry: Improve the carbonate chemistry and develop important feedback loops with zooplankton (pteropods) Inputs: Customize the model to conditions in each of the intensification zones

Availability of local data for validation is key to reducing model uncertainty Biogeochemical Model Phytoplankton Zooplankton Good Data is Rare and Patchy: DO and ph Nutrients Detritus Biogeochemical Processes Data on ph and saturation Temperature and Salinity Patterns Turbulent Mixing and Eddy formation Physical Model Current Speed and Direction Density Variations Wind Speed and Direction Good Data is Relatively Abundant: CTD Data Mooring Data Glider Data Upwelling and Downwelling

VALIDATE MODEL USING BOTH STATE DATA AND RATE/PROCESS DATA Bight 13 Process Studies Compare sources and fate of nitrogen in effluent impacted regions to minimallyimpacted regions

RUN CLIMATE CHANGE AND MANAGEMENT SCENARIOS Current day with and without anthropogenic nutrient reductions Future climate change (IPCC 25-27), with and without anthropogenic nutrient reductions Additional modeling scenarios will be informed through discussion with managers The details are important and we need your input!

LEVEL OF INTERACTION WITH MANAGEMENT AUDIENCES WILL VARY BY SCALE West Coast Wide: Will coordinate through the West Coast Governor s Alliance Will use OAH expert panel for high level technical review SCB Downscaled Region: Will develop stakeholder advisory committee This committee will provide both technical and management feedback throughout the project Will probably meet once or twice a year for three years

CONSENSUS NEEDED ON ENDPOINTS OF CONCERN TO INTERPRET MODEL OUTPUT What are the appropriate indicators and endpoints? Are Ocean Plan standards relevant? How much is too much? What is the duration and extent that is significant enough to warrant regulation? Don t want the modelers to make that call for you you want to define this for them to interpret model output. First stakeholder meeting targeted for May 216.