1. EcoGEM – modeling hypoxia in Narragansett Bay, RI
Jamie Vaudrey, University of Connecticut
excerpts from a presentation given on November 21, 2014 – LISS STAC meeting
funded by NOAA’s Coastal Hypoxia Research Program
collaborators
Christelle Balt
Deanna Bergondo, PI
Mark Brush, PI
Daniel Codiga, lead-PI
Christopher Deacutis, PI
Wally Fulweiler
Sue Kiernan, PI
Chris Kincaid, PI
Candace Oviatt, PI
Anna Pfeiffer-Herbert
Warren Prell, PI
Edwin Requintina Sr.
Leslie Smith
Heather Stoffel
David Ullman, PI
Jamie Vaudrey, PI
James Kremer, PI
Jason Krumholz
Nicole LaSota
Conor McManus
David Murray, PI
Scott Nixon, PI

2. responsive to N reductions
field data
responsive to N reductions
hypoxia map: W. Prell, D. Murray, C. Deacutis
Brown U. -

3. Phyto – 10% to 15% reduction Oxygen – no change Nitrogen – reduction
surface – 2006 N input
surface – 50% WWTF DIN
bottom – 2006 N input
bottom – 50% WWTF DIN
1 gC m-3 = 24 ug / L
Phyto –
10% to 15% reduction
Oxygen –
no change
Nitrogen – reduction

4. Model predictions match field data collected after the 50% reduction was achieved in spring of 2013.
Candace Oviatt1, Leslie Smith2, Jason Krumholz3, Catherine Coupland1, Heather Stoffel1, Aimee Keller4, M. Conor McManus1, and Laura Reed1
(submitted)
Managed Nutrient Reduction Impacts on Nutrient Standing Stock Concentrations, Metabolism and Hypoxia in Narragansett Bay

5. (this slide not presented to LISS STAC)
No “legacy effect”
ran the model for 50 years, using output on Dec 31st as input on Jan 1st for following year
no effect on hypoxic area or duration
indicates no carry-over of C, N, or P from previous year
assumes model accurately reflects NB capacity for storage
(this slide not presented to LISS STAC)

6. N reduction can come from other sources, not just WWTF
surface – 2006 N input
surface – 75% WWTF DIN
N reduction can come from other sources, not just WWTF
bottom – 2006 N input
bottom – 75% WWTF DIN
1 gC m-3 = 24 ug / L
Phyto –
15% to 30% reduction
Oxygen –
alleviation
of hypoxia
Nitrogen – reduction

7. Model suggests…
Larger N reductions needed before alleviation of hypoxia.
Oxygen in the model is sensitive to N input.

8. Time Line
Dec 19th – chapter to Dave and Mark for review, sending for external review in January (OBM / GEM comparison)
Vaudrey, J.M.P., M.J. Brush, D. Ullman; Chapter 5: Modeling estuarine hypoxia in Narragansett Bay, R.I. with an intermediate-complexity approach. in: Modeling Coastal Hypoxia: Numerical Simulations of Patterns, Controls and Effects of Dissolved Oxygen Dynamics, eds: J. Dubravko, K.A. Rose, R.D. Hetland, K. Fennel. Springer Publishing.
mid January – 1st model paper to co-authors, submission by early February (model description, skill assessment)
end of February – 2nd model paper to co-authors, submission by end of March (model scenarios)
March – work with Jason on N-budget paper
mid February – meeting to review model interface, model scenarios to run
1 or 2 meetings? Angelo, Sue & Heidi? Or everyone invited?
April – incorporate new exchange coefficients, assess skill of model
May – final report, model documentation revision
June – draft paper using new exchanges (submission by end of July)