Does Elevated Ammonia-N Negatively Impact Phytoplankton Biomass and - PowerPoint PPT Presentation

Does Elevated Ammonia-N Negatively Impact Phytoplankton Biomass and Community Composition in Freshwater or Brackish Water? Mary Lou Esparza, Ann Farrell, Doug Craig, Curt Swanson and Bhupinder Dhaliwal March 8, 2013

Background Background General Concensus General Concensus • Phytoplankton biomass, Chl(a), in the SFE has • Phytoplankton biomass, Chl(a), in the SFE has significantly dropped from the late 1970 ’ s. significantly dropped from the late 1970 ’ s. • Diatom abundance in the SFE has significantly • Diatom abundance in the SFE has significantly dropped from the late 1970 ’ s. dropped from the late 1970 ’ s. • Cyanobacteria and flagellates abundance has • Cyanobacteria and flagellates abundance has generally increased from the late 1970 ’ s. generally increased from the late 1970 ’ s. Baxter et al. (2010); Solger-Muller et al. (2002); Jassby (2008)

Background Background Potential causes of the change: Potential causes of the change: • Salinity • Salinity • Freshwater flows • Freshwater flows • Turbidity/irradiance • Turbidity/irradiance • Temperature • Temperature • Grazing pressures (clams) • Grazing pressures (clams) • Inhibitory contaminants (Herbicides) • Inhibitory contaminants (Herbicides) • Nutrients • Nutrients • Other unknown factors • Other unknown factors Baxter et al. (2010); Cloren and Jassby (2012)

Background Background Nutrients Nutrients Hypotheses: Hypotheses: • Elevated NH 4 (>4 µmol) suppresses phytoplankton • Elevated NH 4 (>4 µmol) suppresses phytoplankton NO 3 and/or NH 4 uptake – eliminating NO 3 and/or NH 4 uptake – eliminating phytoplankton blooms that were regular in the phytoplankton blooms that were regular in the 1970 ’ s 1970 ’ s Dugdale et al. (2007) Dugdale et al. (2007) Parker et al. (2012a) Parker et al. (2012a) Parker et al. (2012b) Parker et al. (2012b) • Increased N:P and NH 4 :NO 3 ratios have shifted • Increased N:P and NH 4 :NO 3 ratios have shifted phytoplankton composition from diatoms to phytoplankton composition from diatoms to cynobacteria/flagellates dominance cynobacteria/flagellates dominance Glibert (2010) Glibert (2010) Glibert et al. (2011) Glibert et al. (2011)

Background Background Caution Flags Caution Flags 1. 1. Elevated NH 4 (>4 µm) does not always inhibit Elevated NH 4 (>4 µm) does not always inhibit phytoplankton blooms. phytoplankton blooms. • • From 1968 – 1979, phytoplankton blooms regularly From 1968 – 1979, phytoplankton blooms regularly occurred in the SFE at NH 4 concentrations >4 µmol occurred in the SFE at NH 4 concentrations >4 µmol Ball & Arthur (1979) Ball & Arthur (1979) • • In Delaware Estuary, generally more phytoplankton In Delaware Estuary, generally more phytoplankton biomass, Chl(a), occurs at relatively high NH 4 levels biomass, Chl(a), occurs at relatively high NH 4 levels compared to SFE compared to SFE Yoshiyama & Sharp (2006) Yoshiyama & Sharp (2006)

Background Background Caution Flags Caution Flags 2. 2. Reduced NH 4 , <4 µmol, offer no reasonable Reduced NH 4 , <4 µmol, offer no reasonable assurance that phytoplankton blooms will occur, assurance that phytoplankton blooms will occur, even though NO 3 is plentiful. even though NO 3 is plentiful. • • In 2010, field sampling blooms occurred only on four In 2010, field sampling blooms occurred only on four sampling events out of 30 when NH 4 was <4 µmol in sampling events out of 30 when NH 4 was <4 µmol in the SFE the SFE Dugdale et al. (2012) Dugdale et al. (2012) “ At low ammonium concentrations, while some “ At low ammonium concentrations, while some • • nitrate uptake rates are high, most are quite low, nitrate uptake rates are high, most are quite low, implying that other factors besides external NH 4 …. ” implying that other factors besides external NH 4 …. ” Dortch, Q. (1990) Dortch, Q. (1990)

Background Background Caution Flags Caution Flags 3. 3. Increased N:P and NH 4 :NO 3 ratios do not always Increased N:P and NH 4 :NO 3 ratios do not always mean reduced abundance of diatoms and mean reduced abundance of diatoms and increased abundance of dinoflagellates and increased abundance of dinoflagellates and cyanobacteria cyanobacteria McCarthy et al. (2009) McCarthy et al. (2009)

Chlorophyll (a) and NH 4 concentrations in Chlorophyll (a) and NH 4 concentrations in Delaware Estuary vs. SFE Delaware Estuary vs. SFE Delaware SFE 2 Estuary* 1 NH 4 , µmol 11 6 Chl(a), µg/L 14 4** 1 – 26 year average 2 – 29 year average *Yoshiyama and Sharp (2006) Table 1 **Jassby (2008) Table 5

Dr. Richard Dugdale et. al. Source: River flow and Ammonium discharge determine spring phytoplankton blooms in an urbanized estuary. Revised manuscript for submission to Estuarine, Coastal and Shelf Science August 6, 2012

CCCSD Field Experiment CCCSD Field Experiment Test the Nutrient Hypotheses Test the Nutrient Hypotheses • Nutrient rich effluent diverted to holding • Nutrient rich effluent diverted to holding basin basin • After about two days in the basin, the • After about two days in the basin, the effluent overflowed into Pacheco Slough effluent overflowed into Pacheco Slough • Samples collected from the overflow, • Samples collected from the overflow, Pacheco Slough upstream and downstream Pacheco Slough upstream and downstream of the overflow of the overflow

Water Quality Characteristics Water Quality Characteristics Concentrations, Concentrations, Characteristics Mean ± sd Mean, Range n=9 Dissolved oxygen, mg/L 7.5 ± 1.7 ph, units 7.6 ± 0.2 Turbidity, NTU 5.4 ± 1.6 Salinity, ppt 0.5 ± 0 Temperature, ° C 23.0 ± 2.3 TSS, ug/L 8 (3 - 17) 14 ± 8 BOD, mg/L 6 (2 - 23) 8 ± 5 Soluable COD, mg/L 45 ± 13 NH 4 -N, mg/L 26.2 (14 - 30.5) 26.7 ± 1.1 NO 3 -N, mg/L 0.78 (0.3 - 1.9) 0.28 ± 1.1 NO 2 -N, mg/L 0.34 (0.4 - 1.4) 0.27 ± 0.19 Total-P, mg/L 1.13 (0.7 - 1.8) 1.14 ± 0.27

Ammonia-N and Chl(a) in Freshwater in relation to NO 3 and NH 4 uptake Ammonia-N and Chl(a) in Freshwater in relation to NO 3 and NH 4 uptake inhibitory thresholds and Chl(a) levels considered healthy and blooming. inhibitory thresholds and Chl(a) levels considered healthy and blooming. (August 2 – October 11, 2012) (August 2 – October 11, 2012) 420 410 400 380 360 336 340 318 320 300 280 260 226 240 220 200 178 180 148 160 140 116 120 102 85 100 71 80 60 42 21.7 25.6 25.9 23.4 26.5 24.6 18.9 16.5 16.5 27.0 27.3 40 20 0 8/2/12 8/23/12 9/5/12 9/11/12 9/14/12 9/18/12 9/27/12 10/3/12 10/5/12 10/9/12 10/11/12 (11:20) (10:32) (12:15) (12:49) (14:14) (11:59) (10:29) (11:20) (11:58) (16:09) (12:42) Sampling Dates & Times Ammonia's NO 3 uptake inhibitory concentration = 0.056 mg/L Ammonia's NH 4 uptake inhibitory concentration = ~0.14 mg/L Healthy Chlorophyll level = (~10 ug/L) Chl-a (ug/L) Ammonia-N (mg/L) Chlorophyll bloom = (>30 ug/L)

Ammonia-N and Chl(a) in Brackish Water in relation to NO 3 and NH 4 Ammonia-N and Chl(a) in Brackish Water in relation to NO 3 and NH 4 uptake inhibitory thresholds and Chl(a) levels considered healthy and uptake inhibitory thresholds and Chl(a) levels considered healthy and blooming. blooming. (August 2 – October 11, 2012) (August 2 – October 11, 2012) 123 111 110.0 102.0 100.0 88.0 90.0 80.0 69.0 70.0 61.0 58.0 60.0 51.0 49.0 50.0 40.0 31.0 30.0 18.8 19.6 18.9 17.8 16.5 16.5 16.0 15.1 20.0 14.6 14.6 10.0 3.6 0.8 1.3 2.9 2.8 2.8 2.6 1.5 1.2 0.8 0.0 8/23/2012 9/5/2012 9/14/2012 9/14/12 9/18/12 9/21/12 9/27/12 ( 10/3/12 10/5/12 10/9/12 (10:32) (12:15) (08:30) (09:47) (11:59) (13:39) 07:57) (10:45) (11:23) (16:09) Ammonia inhibitory concentration = 0.056 mg/L Healthy Chlorophyll level (~10 ug/L) Chlorophyll bloom (>30ug/L) Chlorophyll (a), ug/L Ammonia-N, mg/L Salinity, ppt

Summary Freshwater and brackish water Chl(a) data shows that Freshwater and brackish water Chl(a) data shows that elevated NH 4 is not inhibitory to phytoplankton blooms elevated NH 4 is not inhibitory to phytoplankton blooms as has been suggested by Dugdale et al. (2007), as has been suggested by Dugdale et al. (2007), Dugdale et al. (2012) and Parker et al. (2012a), Dugdale et al. (2012) and Parker et al. (2012a), (2012b). (2012b).

Does elevated NH 4 reduce the diatom Does elevated NH 4 reduce the diatom abundance in brackish water? abundance in brackish water?

Phytoplankton Composition of Brackish Water Downstream of Basin Overflow (August 2 – October 11, 2012) 70% Diatom 13% Cryptophytes Chlorophytes Euglanophytes Cyanobacteria 13% 3% 1% Average total cell count/mL = 11,700

Phytoplankton Biomass and Composition in Relation to Ammonia Phytoplankton Biomass and Composition in Relation to Ammonia Loads in the Bay-Delta System Loads in the Bay-Delta System 2001 - 2010 2001 - 2010 Chlorophyll-a 1 Diatoms 2 Ammonia Loads 3 Year ug/L % tons/month 2001-02 4.7 60 460 2003 4.3 43 ― 2004 4.1 51 ― 2005 3.5 40 550 2006 3.5 39 ― 2007 3.9 52 ― 2008 5.2 22 ― 2009 4.4 68 ― 2010 3.8 73 555 1 - Average for all IEP stations except San Pablo Bay 2 - Average for all IEP stations 3 - Sacramento and Central San loads