2009/2010 Water Column Overview, Red Tide Update, and Bay Eutrophication Model 2010 Results. OMSAP Meeting June 30, 2011.

Transcription

1 29/21 Water Column Overview, Red Tide Update, and Bay Eutrophication Model 21 Results OMSAP Meeting June 3, 211 Scott Libby Contributions from D. Anderson, D. Borkman, C.S. Chen, R. Geyer, and C. Oviatt 7/6/211 1

2 29/21 Water Column Overview Nutrient, chlorophyll, and DO results Typical trends generally observed in these parameters Major Events - Variability in bloom frequency and magnitude (Phaeocystis, diatoms, and Alexandrium) Contingency Plan threshold results - 29 Alexandrium exceedance (and 211) - No exceedances in 21 Compare post transfer years and baseline Have nutrients changed near the outfall or in the farfield? Has phytoplankton biomass changed? Has dissolved oxygen changed? Has productivity changed? No Yes Yes, but regionally Yes, decreased 2

3 29/21 WQ Monitoring Program 12 Nearfield surveys/year 6 Farfield surveys/year Suite of oceanographic parameters measured In situ hydrographic parameters Nutrients Dissolved Oxygen Biomass Primary Production Phytoplankton and Zooplankton Community Structure Additional data from Other components of the MWRA HOM program GoMOOS & NOAA buoys 3

4 Nutrients NO NO 3 (µm) 6 NO 3 (µm) Boston Harbor Coastal Nearfield Offshore N. Boundary Cape Cod Baseline Mean Post-Diversion Mean Nearfield NO 3 (µm)

5 Nutrients SiO SiO 4 (µm) 6 SiO 4 (µm) Boston Harbor Coastal Nearfield Offshore N. Boundary Cape Cod Baseline Mean Post Mean Nearfield SiO 4 (µm)

6 Nutrients NH NH 4 (µm) 3 NH 4 (µm) Boston Harbor Coastal Nearfield Offshore N. Boundary Cape Cod NH 4 (µm) Baseline Mean Post-Diversion Mean Boston Harbor NH 4 (µm) Baseline Mean Post-Diversion Mean Nearfield

7 Annual Mean Nutrients NH 4 Post Diversion Large Decrease in Boston Harbor (red) Decrease in Coastal area (green) Initial doubling in nearfield (black) Unchanged elsewhere MB and CCB After 23 Decrease across all areas Current nearfield levels comparable to 9 s NH 4 (µm) Other nutrients more interannual variability and no long-term trends (except for decreases in all nutrients in Boston Harbor) Boston Harbor Coastal Nearfield N. Boundary Cape Cod Bay 7

8 Areal Chlorophyll Areal Chla (mg m -2 ) Areal Chla (mg m -2 ) Boston Harbor Coastal Nearfield Offshore N. Boundary Cape Cod Areal Chla (mg m -2 ) Boston Harbor Baseline Mean Post-Diversion Mean Areal Chla (mg m -2 ) Baseline Mean Post-Diversion Mean Nearfield 25 8

9 Particulate Organic Carbon POC (µm) 3 POC (µm) Boston Harbor Coastal Nearfield Offshore N. Boundary Cape Cod Nearfield Baseline Mean Post-Diversion Mean POC (µm) 3 2 POC (µm) 3 2 Baseline Mean 1 Boston Harbor Post-Diversion Mean

10 Nearfield Phytoplankton Abundance (1 6 cells L -1 ) Nearfield Area Phaeocystis Dinoflagellate Pennate Diatom Centric Diatom Cryptophytes Microflagellate Abundance (1 6 cells L -1 ) 6-Feb 25-Feb 18-Mar 8-Apr 12-May 15-Jun 21-Jul 17-Aug 1-Sep 3-Sep 2-Oct 1-Nov Nearfield Area 6-Feb 25-Feb 18-Mar 8-Apr 12-May 15-Jun 21-Jul 17-Aug 1-Sep 3-Sep 2-Oct 1-Nov 1

11 Abundance (1 6 cells L -1 ) Cape Cod Bay Phytoplankton Cape Cod Bay Areal Chla (mg m -2 ) Areal Chla 6-Feb 25-Feb 18-Mar 8-Apr 12-May 15-Jun 21-Jul 17-Aug 1-Sep 3-Sep 2-Oct 1-Nov Abundance (1 6 cells L -1 ) Cape Cod Bay Areal Chla (mg m -2 ) Feb 25-Feb 18-Mar 8-Apr 12-May 15-Jun 21-Jul 17-Aug 1-Sep 3-Sep 2-Oct 1-Nov Boston Harbor Coastal Nearfield Offshore N. Boundary Cape Cod Phaeocystis Dinoflagellate Pennate Diatom Centric Diatom Cryptophytes Microflagellate 11

12 Abundance (1 6 cells L -1 ) Northern Boundary Phytoplankton N. Boundary Area Areal Chla (mg m -2 ) Areal Chla 6-Feb 25-Feb 18-Mar 8-Apr 12-May 15-Jun 21-Jul 17-Aug 1-Sep 3-Sep 2-Oct 1-Nov 3 N. Boundary Area 3 Abundance (1 6 cells L -1 ) Areal Chla (mg m -2 ) Feb 25-Feb 18-Mar 8-Apr 12-May 15-Jun 21-Jul 17-Aug 1-Sep 3-Sep 2-Oct 1-Nov Boston Harbor Coastal Nearfield Offshore N. Boundary Cape Cod Phaeocystis Dinoflagellate Pennate Diatom Centric Diatom Cryptophytes Microflagellate 12

13 Abundance (1 6 cells L -1 ) Boston Harbor Phytoplankton Boston Harbor POC (µm) POC 6-Feb 25-Feb 18-Mar 8-Apr 12-May 15-Jun 21-Jul 17-Aug 1-Sep 3-Sep 2-Oct 1-Nov Abundance (1 6 cells L -1 ) Boston Harbor POC (µm) Feb 25-Feb 18-Mar 8-Apr 12-May 15-Jun 21-Jul 17-Aug 1-Sep 3-Sep 2-Oct 1-Nov Boston Harbor Coastal Nearfield Offshore N. Boundary Cape Cod Phaeocystis Dinoflagellate Pennate Diatom Centric Diatom Cryptophytes Microflagellate 13

14 Primary Production 4 3 Nearfield Baseline Mean Post-Diversion Mean N4 mg C m -2 d Boston Harbor Baseline Mean Post-Diversion Mean F N18 Baseline Mean Post-Diversion Mean mg C m -2 d -1 2 mg C m -2 d

15 Annual Productivity Harbor and Nearfield Annual Production (gc m -2 y -1 ) Comparison to Baseline Productivity Harbor Annual production decreased by 48% (P<.5) Nearfield station N16/N18 decreased by 3% (P<.5) No change in production at nearfield station N4 Large decrease in annual prod at all 3 stations after 22 N4 N16/N18 Post Diversion decreases in productivity coincident with (driven by?) regional decreases Exploring effects associated with regional forcing factors (i.e. winds and resulting stratification) F23 15

16 Baseline vs. Post-discharge Bottom DO Nearfield & Stellwagen DO (mg L -1 ) Nearf ield DO (mg L -1 ) Stellwagen Basin DO (% saturation) Nearf ield DO (% saturation) Stellwagen Basin 6 6 Baseline Mean Post-Diversion Mean

17 River Discharge 58th percentile 97 th percentile record-max* 28 th 24 th 98 th 58 th record-max* 3 rd 61 st record-min* Two Major Differences 29 very wet summer record high discharge th percentile 97 th percentile record-max* 28 th 66 th 98 th 83 rd record-max* 29 th 24 th Very wet winter record high discharge Very dry summer record low discharge * Conditions in summer 21 led to warmer, more saline waters Contributed to low DO levels in late summer/early fall 17

18 29-21 Summary Nutrients 29 high concentrations in February and March with sharp decline (except for SiO 4 ) coincident with the Phaeocystis bloom in MA Bay in April 21 lower concentrations in February with early diatom and Phaeocystis blooms 29/21 relatively low during summer with increasing concentrations and variability into the fall Chlorophyll Trends dominated by regional phytoplankton trends 29 large April Phaeocystis bloom in offshore MB waters, August diatom bloom observed in coastal, harbor, and CCB areas, and a late fall diatom bloom in MB 21 Phaeocystis dominated bloom in CBB and offshore waters of MB in February, large April diatom bloom in MB, subsequent diatom bloom in Boston Harbor and coastal waters in June, fall blooms of diatoms and dinoflagellates in nearfield waters. Low seasonal and annual chlorophyll vs. thresholds though close to baseline and post-diversion means Dissolved Oxygen Relatively high bottom water DO in 29 with fall minimum of >7 mg/l in nearfield Relatively low bottom water DO in 21 with fall minimum of <6.5 mg/l in nearfield Low bottom water DO levels correlated to warmer, more saline bottom waters consistent with 21 results 18

19 Baseline Comparison Summary Nutrients Increase in nearfield NH 4 in vicinity of the outfall Overall there has been decrease in NH 4 (and NO 3, SiO 4, and PO 4 ) in Boston Harbor and adjacent coastal waters Biomass Chlorophyll and POC Trends in Nearfield compared to baseline - Higher in winter/spring with March/April (Phaeocystis due to diatoms in 21) - Summer levels comparable - Early fall levels have decreased while late fall levels have increased vs. baseline 2-29 spring Phaeocystis blooms were regional events that contributed to a change in trends for winter/spring biomass levels in northern boundary, offshore and nearfield areas (April vs. February/March peak) No change in coastal, CCB or Boston Harbor areas. Productivity Rates have decreased since relocation in the harbor and nearfield Baseline vs. Post-diversion comparisons appear to be influenced by long-term trends that may be related to regional forcing mechanisms 19

20 Threshold Values for Nuisance Species Parameter Phaeocystis pouchetii (cells L -1 ) Pseudonitzschia (cells L -1 ) Alexandrium Time Period Winter/ spring Caution Level ,2, 186,4 269, 482, 2,87, 438,5 383, 2,15, 1,98, 42, 53,3 Summer 357 absent 14,9 1,7 164, , absent absent absent absent Autumn 2,54 absent absent absent absent absent absent absent absent absent absent Winter/ spring 21, 6, absent 77.5 absent absent 61 Summer 43, ,32 absent absent 54 absent 54 Autumn 24,7 6,3 3,21 12, absent 171 1,46 1,16 Any nearfield sample ,831 5, , No Phaeocystis exceedance in 29 & 21 Exceedance of Alexandrium threshold in May 29 2

21 Phaeocystis pouchetii blooms Phaeocystis pouchetti (D. Borkman) Sept 2 Transfer to Bay Outfall 1 6 Cells L Boston Harbor Coastal Nearfield Offshore N. Boundary Cape Cod 21

22 Diatom and Phaeocystis Trends (time series analysis) Nearfield Abundance Trend Thousands of cells per liter Diatom TREND (cells / L) Phaeocystis TREND (cells / L) Year Diatom trend of long-term decline but increasing in 21 Phaeocystis peaking in Inverse correlation (Pearson r = -.47, P<.5) 22

23 Pseudo-nitzschia blooms Sept 2 Transfer to Bay Outfall Cells L Boston Harbor Coastal Nearfield Offshore N. Boundary Cape Cod 23

24 Nearfield Alexandrium Abundance Alexandrium per sample (cells/l +1 ) pre-discharge discharge caution level Minor blooms for both 29 and 21 in Massachusetts Bay Abundances >1 cells/l in 29 (= threshold exceedance) A major bloom had been forecast for 21, but counts <1 cells/l 24

25 Nuisance Species Summary Phaeocystis 29 large bloom in April highest in offshore MB waters 21 present in the bays in February-April, but at low abundances (lowest since 1999 when it was absent) Phaeocystis and diatoms are inversely correlated currently looking at what factor may be contributing to this trend Pseudo-nitzschia continues 1+ year trend of low abundances Alexandrium May/June 29 bloom cell abundance in MB was relatively low, but did exceed the 1 cell/l threshold. Overall a relatively minor bloom, but did result in some PSP toxicity closures in MB Observed early in 21, but only a minor bloom in MB (and Gulf of Maine) and did not result in a threshold exceedance or PSP toxicity in the bay Alexandrium model forecast for a moderate bloom for 29 and a major bloom in 21 25

26 29 ensemble forecast (1997) 26

27 29 Alexandrium Bloom in the Bay May 2 May 27 June 8 Bloom over by June 8 in the bay 27

28 29 Alexandrium Bloom Report of red water off Portsmouth, NH on July 1, 29 WHOI confirms Alexandrium abundances of 25, to nearly 1,8, cells L -1! WHOI survey on July 12 showed elevated abundances off Cape Ann reaching 7,2 cells L -1 offshore Much lower abundances in Massachusetts Bay Overall 29 bloom was minor to moderate in Massachusetts Bay Abundances in 1s cells L -1 PSP closures in the bay July 12 28

29 21 ensemble forecast 29

30 21 Alexandrium Bloom in the Bay May 3 May 11 May 21 Nearfield peak abundance May 3 at N1 79 cells/l Maximum abundance May 11 at AF4 (south shore) 285 cells/l Minor Alexandrium event in Massachusetts Bay and Gulf of Maine No PSP toxicity in MA or NH in 21 3

31 21 Alexandrium Bloom Disconnect between observations and model: - early April (WF14, top) - early May (WHOI, bottom) Source: McGillicuddy et al. submitted 31

32 So what happened? Why was the forecast so wrong? Working hypothesis: A mesoscale Gulf of Maine water mass change occurred that was outside the envelope of observations from the last six years used as the basis of the 21 ensemble forecast. - GOMTOX cruise data are being used to assess this hypothesis and these factors. Alexandrium cysts germinated into conditions not supportive of normal growth (i.e. the endogenous clock that regulates germination was out of synch with the environment in 21). Forecast was for a moderate bloom in 211 Indications that similar water mass conditions are present in

33 211 ensemble forecast 33

34 211 Alexandrium Bloom in the Bay April 4 May 2 May 25 Early presence of Alexandrium in MB in April low abundance Nearfield peak abundance May 2 at N7 2,453 cells/l Relatively high abundances present through late May 34

35 211 Alexandrium Bloom in the Bay June 1 June 8 June 16 Elevated counts (5-18 cells L -1 ) in nearfield and coastal waters in early June Bloom was over by mid-june Overall a Moderate Alexandrium event in Massachusetts Bay Abundances in the 1s cells L -1 PSP toxicity closures from Cape Ann south to Plymouth 35

36 211 Observations vs. Model Good overall concurrence between data and model Captured initial, peak and end of the bloom Some variability, but essentially captured the temporal and spatial trends in the observed data 36

37 Red Tide Summary Moderate blooms in 29 and 211 Higher cell abundances observed in 211 PSP toxicity closures from Cape Ann to along the South Shore Minor bloom in 21 Peaked below 1 cells L -1 No PSP toxicity closures in Massachusetts Bay Model Forecasts Good results forecasting the moderate blooms in 29 and 211 Still a work in progress understanding 21 bloom result Date evaluation and interpretation on 211 bloom ongoing 37

38 MB FVCOM domain:.5-1 km Modeling 21 in Massachusetts Bay Unstructured-grid Bay Eutrophication Model Regional FVCOM domain: up to 2.5 km 38

39 Model-predicted temperature and salinity Temperature Salinity 39

40 21 model results and observations at Station N18 4

41 F26 F27 Observation of DIN in the bottom-layer at stations F26 and F27 Near the northern open boundary 41

42 Multi-year comparison of DIN in the surface layer Black: 28. Blue: 29. Red: 21. Stations: Outfall, N18, N7, F15, F13, F1) 42

43 Multi-year comparison of chlorophyll in the surface layer Black: 28. Blue: 29. Red: 21. Stations: Outfall, N18, N7, F15, F13, F1) 43

44 Multi-year comparison of DO in the bottom layer Black: 28. Blue: 29. Red: 21. Stations: Outfall, N18, N7, F15, F13, F1) 44

45 DIN projection (black: with outfall; red: without outfall) Surface waters Bottom layer 45

46 Do and chlorophyll projection (black: with outfall; red: without outfall) Bottom DO Surface chlorophyll 46

47 Modeling Summary Model with data assimilation is able to capture general trends in observed 21 water quality physical conditions, DIN, and DO. Measured nutrient concentrations in February 21 were significantly lower than previous year. Driven by these lower levels the model failed to capture the spring Chl-a peak. Model-simulated Chl-a concentration is very sensitive to the nutrient flux condition on the northern boundary area Model-based conclusions about the impact of MWRA outfall remains similar to previous years Model showed differences in DIN in nearfield and vicinity No apparent differences in the DO or Chl-a modeled results Agreement between model output and monitoring observations. 47

48 Acknowledgements The data presented are the result of the efforts from many HOM7 & HOM8 team members including: Presenters from the 211 Technical Meeting who provided slides: D. Anderson, D. Borkman, C.S. Chen, R. Geyer, & C. Oviatt Battelle Coastal and Marine Systems field group Battelle, subcontractor, and MWRA labs Matt Fitzpatrick for helping with data analysis & graphics WHOI/Don Anderson s team for Alexandrium information 48

49 49

50 211 Station Maps 5

51 Annual Production Harbor Annual production decreased by 48% Nearfield station N16/N18 decreased by 3% No change in production at station N4 Annual Production 8 6 g C m -2 y F23 N16/N18 N4 51

52 Conceptual Model 25 Bloom Regional blooms initiated in western Gulf of Maine and driven by physical forcing mechanisms Expect these blooms to continue with regularity in GoM and lead to frequent toxicity in Massachusetts Bay 52

53 A Coupled Bio-physical Numeric Model for Alexandrium fundyense Dennis McGillicuddy, Ruoying He, Don Anderson, Bruce A. Keafer and others Cyst Dist. (# / cm^2) Endogenous Clock Multi-nested configuration for the regional GOM circulation and A. fundyense bloom population dynamics modeling. Germ. rate (% / day) Growth (per day) 53

54 21 Forecast Cyst Maps 29 Source: McGillicuddy et al. submitted 54

55 Nested Regional and MB FVCOM System Regional FVCOM domain: up to 2.5 km Driven by five tidal constituents at GOM open boundary (M 2, S 2, N 2, K 1 and O 1 ); 33 rivers; WRF-assimilated meteorological forcing (wind, net heat flux/solar irradiance, and precipitation minus evaporation). - Data assimilation of all available T, S data MB FVCOM domain:.5-1 km Driven by Regional FVCOM fields at the nested boundary and the same meteorological and river discharges (13 rivers). Total vertical layers: 3. 55

56 UG-RCA Simulation UG-RCA Driven by hourly FVCOM physical fields WRF-calculated solar radiation for photosynthesis winds for DO reareation point source loadings non-point source loadings rive discharges (3 rivers) atmospheric loading boundary conditions extrapolated based bio-monthly MWRA observations 56

57 At 4413 In MB Monthly averaged wind Surface net flux River discharges 57