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

responsive to N reductions field data responsive to N reductions hypoxia map: W. Prell, D. Murray, C. Deacutis Brown U. - http://www.geo.brown.edu/georesearch/insomniacs/index.html

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

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

(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)

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

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

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)