Mark Brush CHRP-EPA Jul 2015 Workshop

Motivation As part of a NOAA Coastal Hypoxia Research Program project: Apply a novel, reduced complexity, parsimonious ecological model to predict hypoxia in Narragansett Bay Implement within a fast running, coarse boxed scheme linked to a fine resolution hydrodynamic model allowing for annual updates (JV) and with an Officer box model allowing >10 years of runs (MB) Simulate responses to nutrient reductions and climate change Make the model available for direct use by managers.

COMPARISON OF THE MODELS EcoGEMEcoOBM Nearly Identical, Simplified Ecology  Officer approach to exchanges using river flow and salinity (fast running, online)  Exchanges capture effects of tides, winds, & river flow through ROMS  Daily temporal resolution (captures events)  (so far)  Adding additional years or flow scenarios requires additional ROMS runs  ROMS dye-tracking approach to exchanges (most defensible hydrodynamics possible)  Daily temporal resolution although driven by 10-day moving-average flows  No explicit winds or tides (although exchanges implicitly include these effects through forced salinity)  (additional years in progress)  Adding additional years only requires new data, but flow scenarios still require a linkage between flow and changes in salinity  Concept: EcoGEM includes the most rigorous simulation of hydrodynamics so should be used as the primary management tool; EcoOBM provides a semi-independent, longer-term confirmation.

Narragansett Bay EcoOBM: Ecology * * *

Phytoplankton NPP: Carbon Flux to Sediments: Denitrification: Empirical Formulation of Key Rate Processes: Plankton Community Respiration: Narragansett Bay EcoOBM: Ecology

EcoOBM: Sensitivity

Officer Box Model: exchanges = f (freshwater, salinity) Fast run times Exchanges independent of ROMS; constrained by salinity Enables long term runs: e.g., (through 2013/14 coming)

Freshwater Inputs 7 gauged rivers: Blackstone Moshassuk Woonasquatucket Ten Mile Pawtuxet Taunton Hunt Gauged flow extrapolated to the entire watershed; Hunt R. used in other ungauged areas WWTFs: Fields Point Bucklin Point East Providence Fall River PPT (TF Green – NOAA) Evaporation (computed)

InsomniacsNuShuttle + Buoys + Box Model: Exchanges = f (freshwater, salinity) We now have a continuous daily record of T and S in each model element, plus T, S, DO, and Chl in RIS.

Nutrient InputsRIS Boundary T, S, O 2, Chl-a, DIN, DIP Watershed: Mean river concentrations (DIN, DIP, TOC) computed from Nixon et al. (1995); multiplied by daily flows WWTFs: DIN, DIP (estimated) & BOD from plants multiplied by flows Atmosphere (dry + wet): DIN, DON: Fraher (1991); Nowicki & Oviatt (1990) DIP, DOP: Nowicki & Oviatt (1990) Meteorology (precip, wind, Ta, Td) – TF Green (NOAA) PAR – Eppley Lab  NOAA Kingston Other Forcing Data NuShuttle

EcoOBM: Exchanges Compared to ROMS Rogers (2008) vs. 3D ROMS 2D box model Destination Box Fraction of Water Box Model ROMS Source Box 2006 ROMS output from D. Ullman; Comparison by J. Vaudrey

EcoOBM: Calibration Data Stocks: Chl-a: Smith & Oviatt Buoys GSO dock [NBC] DIN/DIP: NuShuttle GSO dock [NBC] O 2 : Insomniacs Buoys NuShuttle Rates: Prim Prod: Smith & Oviatt Resp (water): Smith & Oviatt Resp (sed): Fulweiler DNF: Fulweiler Oviatt buoy P & R  open water [not yet included]

EcoOBM: Surface Layer Chl-a Green: Smith & Oviatt Grey: buoys Box 13: MERL GSO dock mg m -3

EcoOBM: Surface DIN Red: NuShuttle/CHRP Box 13: MERL GSO dock MM

EcoOBM: Phyto NPP Green: Smith & Oviatt g C m -2 d -1

EcoOBM: Water Column Resp Green: Smith & Oviatt g C m -2 d -1

EcoOBM: Sediment Resp Points: Fulweiler g C m -2 d -1

EcoOBM: Surface DO Points: Insomniacs Red: NuShuttle Grey: buoys mg l -1

EcoOBM: Bottom DO Points: Insomniacs Red: NuShuttle Grey: buoys mg l -1

EcoOBM: Bottom DO Points: Insomniacs Red: NuShuttle Grey: buoys mg l -1

EcoOBM: Annual Hypoxia Index

Model predicts daily mean DO But state criteria are for: instantaneous minimum DO time with DO below 2.9 mg/l time with DO below 1.4 mg/l Empirical Linkages to Assess State Criteria: Temporal Variability 15 minute buoy data

Model predicts daily mean DO within each box Empirical Linkages to Assess State Criteria: Spatial Variability Insomniacs YSI profiles

Publications & Products Publications: Brush et al – MEPS (BZI formulation) Brush & Brawley 2009 – J Mar Sys (BZI depth correction) Brush & Harris 2010 – Ecol Model special issue (guest editors & introduction) Brush & Nixon 2010 – Ecol Model (macroalgae model with DO effects) Kremer et al – Ecol Model (EcoGEM approach) Lake & Brush 2011 – Est Coast Shelf Sci (benthic microalgae in Narragansett Bay) Harris & Brush 2012 – Ecol Model (BZI temperature correction) Lake & Brush 2015 – Estuaries & Coasts (EcoOBM in the York River, VA) Brush & Harris in press – Encyclopedia of Estuaries (modeling entry) Ganju et al. in press – Estuaries & Coasts (model review paper) Lake & Brush in review – MEPS (EcoOBM in the York River, VA – climate) Brush & Nixon in review – Springer hypoxia book (EcoOBM in Greenwich Bay, RI) Products: Online EcoOBM Brush, M.J Narragansett Bay EcoOBM v1a. Online CHRP models.

Online EcoOBM bio/programs/semp/models/index.php

Online EcoOBM

Output also available for chl-a, DIN, and DIP

CHRP II Scenario Runs

Nutrient Load Scenarios

Effect of Timing

Climate Scenarios

Interactive Effects of Nutrients and Warming

Empirically-Varying Salinities Insomniacs data, : Flow into Box 1

Empirically-Varying Salinities x = 10-day moving average FW input to Box 1, m 3 d -1 y = mean layer salinity from Insomniacs cruises,

Wider Applicability of the Model

Cross-System Comparisons