Update on the Ecological Model: Box Model Version Mark Brush (VIMS) CHRP October 8, 2009

Officer Box Model

Current Activities Expanding from 2001 – 2008 Improved salinity functions around the bay: NuShuttle data Alternate S functions: - Cosine functions - Insomniacs + NuShuttle - Supplement with buoy data when available

Relating Model Daily Average Results to Management Criteria Mark Brush (VIMS) CHRP October 8, 2009

One potential problem re: management use of the model: RI O 2 criteria focus on instantaneous values Our eco model simulates daily mean O 2 Models can simulate diel O 2 variations, but …

Rhode Island DO criteria: Surface Waters (and waters without a pycnocline): “Waters with a DO concentration above an instantaneous value of 4.8 mg/l shall be considered protective of Aquatic Life Uses.” Bottom Waters (waters with a pycnocline): As above, plus … “When instantaneous DO values fall below 4.8 mg/l, the waters shall not be: 1. Less than 2.9 mg/l for more than 24 consecutive hours during the recruitment season; nor 2. Less than 1.4 mg/l for more than 1 hour more than twice during the recruitment season; nor 3. Shall they exceed the cumulative DO exposure presented in Table 3.A.”

Concept for GEMBox / GEM-OBM: daily mean DO instantaneous minimum DO time with DO below 2.9 mg/l time with DO below 1.4 mg/l Use buoy O 2 data to look for relationships between: DO mean DO NCPCR ? 2.9 DO Inst. min t 2.9 t 1.4

Test sites: North Prudence Conimicut Point Bullocks Reach Greenwich Bay 2003,

Test sites: North Prudence 2003 SURFACE BOTTOM

Test sites: Conimicut Point 2003 SURFACE BOTTOM

Test sites: Bullocks Reach 2003 SURFACE BOTTOM

Test sites: Greenwich Bay 2003 SURFACE BOTTOM Need a change-point regression?

All years together … 2003,

Test sites: North Prudence 2003, SURFACE BOTTOM

Test sites: Conimicut Point 2003, SURFACE BOTTOM

Test sites: Bullocks Reach 2003, SURFACE BOTTOM

Test sites: Greenwich Bay 2003, SURFACE BOTTOM

All sites & years together …

Test sites: All Sites 2003, SURFACE BOTTOM

Predicting DO Criteria Attainment: Inst. min. DO and time below DO thresholds appears predictable directly from daily mean DO Addition of terms for metabolism does not appear to help Fit is especially good in bottom waters, which is good news Relationship appears robust across years, and to a lesser degree across sites PROPOSAL: fit statistical distribution functions by site (years aggregated) with all available buoys to predict criteria attainment/violation from modeled daily mean DO