Do we run the west coast offense?

Transcription

1 Observations and modeling of Narragansett Bay nutrient dynamics: Do we run the west coast offense? Presenters: Chris Kincaid & Kevin Rosa, Graduate School of Oceanography, University of Rhode Island Colleagues: Scott Nixon, David Ullman, Steve Granger, URI-GSO R. Wally Fulweiler, Boston University Anna Pfeiffer-Herbert, Richard Stockton University

2 Rhode Island Coastal Waters: Narragansett Bay & Rhode Island Sound East Coast Offense: Nutrients from watershed Urbanized Higher runoff Providence Narragansett Bay West Coast Offense: Nutrients from shelf Lower runoff L. I. Sound Rhode Island Sound (RIS) Inner shelf Buzzards Bay Marthas Vineyard Block Is.

3 Focus on Watershed Nutrients to Narragansett Bay Estuary Providence Providence River Blackstone River nutrients: Northern Blackstone River Pawtuxet River Woonasquatucket/Moshas. Eastern Taunton River Greenwich Bay Mt. Hope Bay Fall River KEY PT. SOURCES: WWTFs or waste-water treatment facilities West Passage Fields Pt. & Bucklin Pt. (NBC)

4 Connecting Circulation > Nutrients > Water Quality Providence Blackstone Chronic Low Oxygen Regions Red = hypoxia Providence River Seekonk R. Edgewood Shoal Greenwich Bay Mt. Hope Bay Fall River Greenwich Bay West Passage

5 Laboratory Utilize a 3-legged stool approach to Tilt Current Meters Coastal circulation e.g. Edgewood Shoals Region ROMS Numerical Model Regional Ocean Modeling System Scaled Physical Model Spatial-Temporal Observations FULLBAY ROMS

6 Tilt Current Meters Circulation Data Lagrangian Drifters Bottom-mounted ADCP Ship-mounted ADCP

7 20 Years of Bay Data: Circles=BM-ADCPs Lines=Shipmounted-ADCPs Yellow regions = TCMS 20 Years of Bay Data: Counterclockwise residual flow Up east, Out west Impacted embayments Retention gyres Reduced flushing

8 METHOD 3: Computer Models

9 Input Forcing: Tides Runoff Winds Air Temperature Water Density (Salt, Temp.) ROMS Model Solves Equations: Conserve Mass Momentum Conserve Energy / Salt ROMS 3. Output: 4-D Flow & Salt/Temp. Transport Todays talk (a) Chemical Dyes (b) Ecosystem Processes

10 ROMS Cases. Terrestrial (East-coast) nutrient dynamics Case 1 Case 2 (1) Nutrients as passive chemical dye advection/diffusion only Dye sources supplying low-do areas? (2) ROMS NPZD Model N=nutrients, P=phytoplankton, Z=zooplankton, D=detritus Factors controlling phytoplankton biomass? Forcing files detail -January September River discharge (USGS), Winds (PORTS), Tides (ADCIRC), Atmospheric (reanalysis-narr), rain (TF Green). -Blackstone River nutrients (Pt. & Non-Pt.) UMass Blackstone River Water Quality Model ( P. Rees, Mass Water Resourses Res. Center). -Pawtuxet River nutrients - NBC data. -Other rivers: empirical flow vs. nutrients model (from UMass model). -WWTF nutrients (data from plant managers and hypothetical levels)

11 Case 1 16 Distinct Dyes 9 Rivers 7 WWTFs 1) How each dye through system? 2) Flushing vs. accumulation? 3) Cost/benefit of WWTF (nutrient) reduction strategies? Mosh/Woon Fields Pt. WWTF 2 Greenwich Bay Rivers Pawtuxet GB WWTF Hunt Blackstone (Pt. vs. Non Pt.) Bucklin Pt. WWTF 10-Mile EP-WWTF Taunton Palmer WWTF Fall River WWTF

12 Chemical Dye from Fields Pt. WWTF: Focus on upper Providence River Shoal Red = Dimensionless Concentration of 1 Channel

13 Dye from Fields Point WWTF: Transport examples Plume in outflow jet Plume entrained in shoal gyre Plume flushed

14 (near-surface) Blackstone River Dye: Repeatable Mid-Bay Transport Paths 1. West Passage: Weak wind SW-ward wind 2. Greenwich Bay Intrusion: Seabreeze NW-ward wind 3. East Passage Strong NE-ward wind

15 Greenwich Bay? Nitrogen Contributors to Greenwich Bay: SPRING HIGH FLOW (+30days) 1) Blackstone, 2) Pawtuxet, 3) Fields Pt, 4) Taunton, 5) Internal From north From east Late Summer August, 2010 Greenwich Bay 2. Greenwich Bay Blackstone 41% Pawtuxet 20% 24%

16 Greenwich Bay? Nitrogen to Greenwich Bay Late Summer 2010: 1) Internal, 2) Blackstone, 3) Fields Pt, 4) Pawtuxet Variable with season, runoff, wind Late Summer August, % 2. Greenwich Bay Greenwich 41% 20% Bay

17 Conclusions: Dye Transport Patterns Complex. Northern sources variable down-bay paths. Accumulations in impacted areas vary seasonally (winds, runoff) Counterclockwise residual flow & layered estuarine flow: eastern & southern dyes to impacted northern areas. Near-bottom Taunton Dye in Providence River Taunton Dye Edgewood Shoals Bottom Water

18 Second set of ROMS Models: ROMS NPZD Ecosystem Model Nitrogen not a conservative dye. P=phytoplankton Uptake rate Z=zooplankton Also Detritus Equation N= Total nitrogen Light penetration term Multiple runs: Uptake rate, light extinction, grazing, mortality, WWTF levels

19 Transport oscillations: Northern nutrients 1) down East Passage, 2) down West Passage. 3) pumped into Greenwich Bay Start with focus on bay-wide bloom, June, 2010 Total Nitrogen: Surface Reference case: Vm2.5, KL0.75, ZG1.0. Contours in milli-mole/m^3 (divide by 75 to get to mg/l). 50 mm/m^3 Wind, tide, runoff controls

20 Transport oscillations: Northern nutrients 1) down East Passage, 2) down West Passage. 3) pumped into Greenwich Bay Total Nitrogen Contours: (near-surface, summer 2010) Mid-Bay Transport Paths Similar to Dye Wind, tide, runoff controls a)

21 Total Nitrogen Seekonk River Fundamental observation in Bay: TN reduction from Seekonk to Mouth of Providence River All runs (pre-bloom) have TN match basic observation: 1. 40% reduction Head of Prov. River to Mouth 2. Seekonk 50% higher than upper Prov. River Providence River N. Prudence S. Prudence Lower Bay Latitude

22 Phytoplankton Contours: (early summer bloom 2010) Day 165 (June 14) Initiate Mid-bay and migrate northward SURFACE BOTTOM RED= 20 mm m -3

23 Surface Phytoplankton Contours: (early summer bloom 2010) Movie: Bloom starts mid-bay Moves northward Day 165 (June 14) RED= 20 milli-m m -3

24 Modeled bloom matches a) nutrient magnitudes, b) mid-bay start, c) timing of northward march Phillipsdale Fast uptake rate, less light Slow uptake rate, more light Large uptake rate, more light Greenwich Bay DATA

25 Phytoplankton bloom intensity vs. parameters: 1. ecosystem parameters (uptake, light, death) 2. environmental factors 3. different WWTF releases levels Phytoplankton Conc., mm/m Plots from mid-bay: North Prudence 5, 3 & 0 mg/ml

26 Difference in Total Bloom Magnitude Use differential-integrated phytoplankton bloom index to quantify relative sizes of a) environmental factors and b) managed nutrient changes c) NPZD parameters (uptake, light, grazing) Variations In Wind Eliminate Greenwich Bay Change Light Extinction Changing Growth Rate ROMS Case A ROMS Case B Difference in = - Integrated Bloom Magnitude over 10 days Absolute value

27 Difference in Total Bloom Magnitude Use differential-integrated phytoplankton bloom index to quantify relative sizes of a) environmental factors and b) managed nutrient changes c) NPZD parameters (uptake, light, grazing) Variations In Wind Changing Growth Rate Change If big difference Eliminate Light then blooms Greenwich Extinction very to sensitive Bay to this parameter ROMS Case A ROMS Case B Difference in = - Integrated Bloom Magnitude over 10 days Absolute value

28 3 vs. 0 Difference in Total Bloom Concentration Use differential-integrated phytoplankton bloom index to quantify relative sizes of a) environmental factors and b) managed nutrient changes c) NPZD parameters (uptake, light, grazing) Variations In Wind Eliminate Greenwich Bay Change Light Extinction Changing Growth Rate WWTFs nutrient release levels at 0 mg/l versus 3 mg/l

29 0 vs 3 3 vs 5 5 vs 15 Difference in Total Bloom Concentration Variations In Wind Eliminate Greenwich Bay Change Light Extinction Changing Growth Rate Bigger difference 5 mg/l vs. 15 mg/l WWTF releases, factor of 10

30 3 to 0 5 to 3 15 to 5 3 to 0 5 to 3 15 to 5 Difference in Total Bloom Concentration Changing WWTF Nutrient Outputs Medium Growth Rate Higher Growth Rate Variations In Wind Eliminate Greenwich Bay Change Light Extinction Changing Growth Rate Higher phytoplankton uptake rate, 15 to 5 mg/l change in WWTF release, bigger impact

31 3 to 0 5 to 3 15 to 5 3 to 0 5 to 3 15 to 5 Southeastward Northwestward Northeastward Southwestward Difference in Total Bloom Concentration Compare changes in applied prevailing wind to a reference case of no-wind. Natural effect of wind changes has similar impact as 15 to 5 mg/l WWTF change Medium Growth Rate Changing WWTF Nutrient Outputs High Growth Rate Variations In Wind Eliminate Greenwich Bay Change Light Extinction Changing Growth Rate

32 3 to 0 5 to 3 15 to 5 3 to 0 5 to 3 15 to 5 Southeastward Northwestward Northeastward Southwestward Medium to High Low to Medium Difference in Total Bloom Concentration Changes in light penetration parameter larger impact on integrated total bloom than managed (e.g. 5mg/l to 3/mg/l) nutrient reductions from WWTFs. Changing WWTF Nutrient Outputs Variations In Wind Change Light Extinction Changing Growth Rate Medium Growth Rate High Growth Rate

33 3 to 0 5 to 3 15 to 5 3 to 0 5 to 3 15 to 5 Southeastward Northwestward Northeastward Southwestward Medium to High Low to Medium Low to Medium Medium to High Difference in Total Bloom Concentration Phytoplankton uptake rate key parameter for integrated total bloom Changing WWTF Nutrient Outputs Variations In Wind Change Light Extinction Changing Phytoplankton Uptake Rate Medium Growth Rate High Growth Rate

34 Conclusions: Order of factors controlling bloom size 1) Ecosystem parameters (growth, light, etc) 2a) Environmental parameters (winds) 2b) 15 to 5 mg/l drop in WWTF releases Providence Narragansett Bay 3) 5 to 3 mg/l drop in WWTF releases Relative importance of shelf (RIS) nutrients for Bay ecosystem? Scott Nixon, first week of work, let s test how DIN from shelf gets into Bay L. I. Sound Block Is. Rhode Island Sound (RIS) Inner shelf Buzzards Bay Marthas Vineyard

35 Building RIS Data Sets / Models RISG, Endeavor Prog. 1) led by Scott Nixon 2) Recent 2005, , 2016 Coastal Current BM-ADCPS Drifter Study (x3) Bathymetry (m) Strong in summer Into RIS from SE, exit to SW Weak interior flow Ship-Mounted ADCP Summer stratification RIS to Bay Intrusions!!

36 Drifter Patch: In ~ 5/23/2016 midnight. Plot 6/5 noon. 3. Drifters ride coastal current to Bay 13 Days 2. Drifters Retained in Vineyard Sound June 3 4. Whats up, central RIS? May Colors show 3 deployment sites: Solid line=3m; Dashed=6m

37 Providence River Greenwich Bay Mid-Bay High Production Zone Mt. Hope Bay Nixon, Granger, Fulweiler and others Series of intensive cruises (RISG) Narragansett Bay to RIS (99-01) BAY Temperature, salinity, nutrient surveys North BAY Average Summer Conditions Temperature RIS T=16 South Interface DIN T=10 a) RIS BAY? 1 mg/l RIS DIN: 7 mg/l

38 Depth, m Providence River Greenwich Bay BAY Mid-Bay High Production Zone Mt. Hope Bay Nixon: Is deep RIS DIN an important source for Bay? : 17 Full tide cycle ship-mounted ADCP cruises Mouth-interface region of Bay RIS Winter/summer residual (or subtidal) exchange similar East Passage TRANSECT West Side East Passage ADCP Sub-tidal flow OUTFLOW INFLOW East Side a) RIS 35m Looking north 1300 meters 3800 meters

39 Subtidal Flow, cm/s Lower East Pass., 2000 ADCP Shows Wind-driven Intrusion Northward Inflow 18 Northward wind Southwestward wind Bottom 0 Mean Mid Surface : 3 moored ADCPs. East Passage, West Passage, RIS a) RIS 2007: 3 BM-ADCPs East/West Pass. 2008: 2 BM ADCPs RIS Days since wind event, 5/20/2000

40 Two Modes of RIS to Bay Flow (Pfeiffer-Herbert et al, 2015) 1) Mean residual (non-tidal) inflow to East Passage (3-5 cm/s) 2) 5-15 Wind-driven intrusions per summer Wind-driven intrusion

41 Mode 1: Steady inflow 1000 CMS 200K Moles DIN per day a) HIGH DIN RIS DEEP >1000 CMS 200,000 M of DIN per day Coastal Current Moored ADCP Data Underway ADCP Estimates Nixon Data Subtidal flow x Height x Width x DIN = Intrusion # Mode 2: Large wind-driven inflow >7000 CMS 7 million b) Moles DIN/event Mixed-up RIS DIN? Pump station

42 3 Hose intakes Pump station & ADCPs. Firm up Volume flux & Chemical flux vs. time West Side Lower East Passage In-line sensors, pumps, controls EPSCOR Funding RISG Funding East 30 m? mg/l? East Side 7 mg/l? 50 m Moored ADCPs West Side Lower East Passage ADCP Sub-tidal flow OUTFLOW INFLOW East Side Looking north

43 ROSA: Ongoing work, ROMS Modeling & Analysis of existing data sets Supply pathways RIS water/nutrients to Narragansett Bay. Background/steady intrusions Wind-induced, large scale intrusions High energy exchange events (Floyd).

44 Shelf Intrusions Persistent trickle from Periphery Current 2-7 day wind events Quick, Extreme events

45 Hurricane Floyd 1. ADCP under the Newport Bridge during the storm a. This is a good test of model performance: captured both the bottom temperature and the vertical structure of the currents. H = 40 m z = 2 m Bridge_-_01-700x501.jpg T ADCP

46 The ROMS model

47 The ROMS model RIVERS HEAT, FRESHWATER WIND

48 Bottom temperature time series 4 C drop Storm landfall

49 Bottom temperature time series Cool, high-din shelf-water?

50 Bottom temperature: data vs. model

51 Quantifying post-storm intrusion: data only ADCP Observations Assessing model skill

52 Quantifying post-storm intrusion: data vs. models ADCP Observations ROMS No Stratification Assessing model skill

53 Quantifying post-storm intrusion: data vs. models ADCP Observations ROMS WITH STRATIFICATION ROMS No Stratification Assessing model skill

54 Quantifying post-storm intrusion: data vs. models The barotropic (constant-density) model does not predict the strong shelf-water inflow Assessing model skill

55 Drifter movie 2: Effects of Stratification

56 Density cross-sections

57 Drifter movie 3: Storm vs. No Storm

58 Estimated Input Volume for the 4 days following Floyd: East Passage: Rivers: 5 x 10 7 m 3 5 x 10 8 m 3 (USGS Data) (ROMS model)

59 Storm landfall Bottom temperature time series

60 ADCIRC operational model: Forecasting inundation from Irma

61 ADCIRC operational model: Forecasting inundation from Irma This ocean model is invaluable for informing evacuations but its simplified physics can t predict nutrient transports or ecosystem impacts.

62 Hurricanes: After the storm surge 1. Hazardous Chemical spills a. Extent of oil spills from Hurricanes Katrina and Rita is still being assessed

63 Hurricanes: After the storm surge 1. Chemical spills a. Extent of oil spills from Hurricanes Katrina and Rita is still being assessed rivatives/display_600/image.jpg om_2005_hurricanes_is_still_being_assessed.html 2. Nutrient intrusions, plankton blooms, hypoxia a. Roman et al. (2006) Chesapeake Bay Plankton and Fish Abundance Enhanced by Hurricane Isabel Hurricane b. Li et al. (2006) Hurricane-induced storm surges, currents and destratification in a semi-enclosed bay

64 <<TAKE-AWAYS>> 1. Goal: modeling storm events as realistically as possible. 2. Presenting results from a regional 3D baroclinic modeling that is forced by a 2D storm surge model. a. Find that even under strong winds, baroclinic (stratification-driven) effects are critical. 3. Argue that this model is well-suited for studying water mass exchanges. a. Volume of shelf-water input on order 10x greater than sum of all rivers.

65 Hurricane Floyd 1. Catastrophic flooding in eastern US, particularly North Carolina a. 15 storm surge in Long Beach, NC of rain in parts on New England 3. RI experienced increased river flows but minimal storm surge and only about 3 of rain.

66 Shouldn t vertical mixing lead to warmer bottom water? Wind Wind Wind Wind Wind Wind Warm Partially Stratified z y Intermediate Well- Mixed Cool Intermediate

67 Assessing model skill Sea surface height and northward deep velocity