harmful algae and phycotoxins in san francisco bay ... · – large phytoplankton blooms and low do...
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Harmful Algae and Phycotoxins in San Francisco Bay:Assessing condition and exploring controlling factors
Contributors to this Work:
SFEI: Z Sylvester, M McKibben, T Winchell, E King, A Malkassian, P Trowbridge, D Senn
USGS: J Cloern, T Schraga, C Martin, E Nejad
UCSC: R Kudela, M Peacock, K Hayashi
Funding:
- SFB Nutrient Management Strategy
- SFB Regional Monitoring Program
- USGS in-kind support
NOAA Climate/NOAA View
Summer 2015Domoic Acid
(Amnesic Shellfish Poisoning)
Pseudo-nitzchia
• Domoic Acid in mussels
harvested from Central Bay
• Apr-Sep 2015
• Modest increase, but well-
below concerning levels for
human health
Peacock et al 2018
Bay-wide Loads
N: 50,000 kg d-1
P: 5,000kg d-1
65% WWTP
20% Delta/Ag
15% Stormwater
Delta/Ag
• N and P loads place SFB in upper ~90%ile
of estuaries worldwide (g m-2 d-1)Cloern et al., in prep
• N Concentrations throughout SFB exceed
those in recently upwelled coastal water.
• What nutrient loads can SFB (subembayments) assimilate without adverse impacts?
• What management actions would be effective at achieving protective nutrient loads or concentrations?
NMS Overarching Management Questions
1. Water Quality / Habitat Quality: Substantial HABs // phycotoxin threat ?
a. Sensitive population(s): Biota? Humans?
b. Current vs. Future Conditions? 𝚫 Physical forcings → 𝚫 HA+phycotoxin severity?
HABs and PhycoToxins in SFB: Science/Management Questions
HABs and PhycoToxins in SFB: Science/Management Questions
1. Water Quality / Habitat Quality: Substantial HABs // phycotoxin threat ?
a. Sensitive population(s): Biota? Humans?
b. Current vs. Future Conditions? 𝚫 Physical forcings → 𝚫 HA+phycotoxin severity?
2. What factors regulate HA abundance and toxicity in SFB? transport, in situ production
3. Role of SFB nutrients: N,P → frequency or severity of HA events?
4. Protective nutrient loads, with respect to HAs and phycotoxins?
San Francisco Bay
?
Delta
Marine
Lakes, Creeks,
Urban runoff
Restored Salt
Ponds
- Light availability
- Temperature
- Salinity
- Mixing
- Nutrients
Alexandrium spp.
Saxitoxin(Paralytic Shellfish Poisoning)
Microcystis spp.
Microcystin toxins(hepatotoxin)When are toxins produced?
When they are stressed…e.g.,
• Salinity, Temperature
• Nutrients (e.g., ± P, - Si, ±N)
• Light conditions
Pseudo-nitzschia spp.
Domoic Acid (Amnesic Shellfish Poisoning)
Example Harmful Algal Bloom (HAB) forming species and toxins
NMS Observation and Forecasting Program
What data and tools do we need to inform management decisions?
NMS Observation and Forecasting ProgramShip-based monitoring, with USGS
R/V Peterson
NMS Observation and Forecasting ProgramShip-based monitoring, with USGS
Mussels
Phytoplankton: Microscopy, Sequencing (qPCR)
Algal toxin measurements
- Naturally occurring mussels
- Floating docks, readily-accessible
- Bi-weekly sampling (Sep 2015-present)
- Domoic Acid, Saxitoxin, MicrocystinCollaborators: J Cloern (USGS),
R Kudela (UCSC), T Otten (Bend Genetics)
Mussel Toxin concentrations, 9/2015-3/2018 Lighter color, [tox] < LOQ
Grey = [tox] < LOD
Saxitoxin (ppb) (800ppb)
2016 2017 2018
1000
100
10
Domoic Acid (20,000ppb)
2016 2017 2018
1000
100
10
1
Microcystin (10ppb)
2016 2017 2018
10
1
0.1
0.01
• Multiple phycotoxins regularly detected in biota – Domoic Acid Low– Microcystin Moderate/Elevated– Saxitoxin Low/Moderate/Elevated– Okadaic Acid Moderate/Elevated
• Regularly detect phycotoxins in water (particulate, dissolved)
• Regularly detect multiple HA taxa
What can we learn, mechanistically, about HAs in SFB using long-term data?
- source?
- internal growth?
- resident population(s)?
- Predictors?
Sutula et al 2017
Density
(cells/mL)
Example Harmful Algae Detections (SFB)
Karlodinium
Karenia
Dinophysis
Pseudo-nitzschia
Alexandrium
Frequency or
abundance of HA
Central
LSB
Suisun
DeltaH0
C
A
B
Develop and ‘Test’ conceptual models
H0
indicator(s) of favorable
growth conditions
H0
time
Factor 2
Factor 1
cells
/mL
A
B
C
time
Dates/Locations of Phytoplankton Taxonomy
Karenia
Heterosigma
Dinophysis
Noctiluca
Karlodinium
Gonyaulax
Pseudo-nitzchia
Alexandrium
Prorocentrum
Heterocapsa
Alexandrium
Prorocentrum
Heterocapsa
Alexandrium
Prorocentrum
HeterocapsaDensities (cells/mL)
Alexandrium
Prorocentrum
HeterocapsaDensities (cells/mL)
Alexandrium
Prorocentrum
Heterocapsa
Change in taxonomist
Amplicon Sequencing Pilot Project
30%
80%
75%
75%
50%
90%
What can we learn, mechanistically, about HAs in SFB using long-term data?
- source?
- internal growth?
- resident population(s)?
- Predictors?
Frequency or
abundance of HA
Central
LSB
Suisun
DeltaH0
C
A
B
Develop and ‘Test’ conceptual models
Sutula et al 2017
Density
(cells/mL)
Example Harmful Algae Detections (SFB)
Karlodinium
Karenia
Dinophysis
Pseudo-nitzschia
Alexandrium
H0
indicator(s) of favorable
growth conditions
H0
time
Factor 2
Factor 1
cells
/mL
A
B
C
time
How do HA detections and abundances vary relative to ‘bloom’ and. ‘non-bloom’ conditions?
How do HA detections and abundances vary relative to ‘bloom’ and. ‘non-bloom’ conditions?
Dissolved
Oxygen
(%saturation)
Thalassiosira – a healthy diatom
Upper 25%ile abundance
Detect
nonDetect
Alexandrium
Karlodinium
Pseudo-nitzchia
Dinophysis
What can we learn, mechanistically, about HAs in SFB using long-term data?
- source?
- internal growth?
- resident population(s)?
- Predictors?
Frequency or
abundance of HA
Central
LSB
Suisun
DeltaH0
C
A
B
Develop and ‘Test’ conceptual models
Sutula et al 2017
Density
(cells/mL)
Example Harmful Algae Detections (SFB)
Karlodinium
Karenia
Dinophysis
Pseudo-nitzschia
Alexandrium
H0
indicator(s) of favorable
growth conditions
H0
time
Factor 2
Factor 1
cells
/mL
A
B
C
time
HA detection Frequency: Informative Spatial Patterns
Frequency Detected (%)
Karlodinium KareniaPseudo-nitzschia AlexandriumDinophysis Thalassiosira
Healthy diatom...
Alexandrium:
Frequency of Detection: Seasonally x Spatially
Summary• SFB Nutrient concentrations are sufficiently high that adverse
impacts could occur -- if a larger proportion of the nutrients were utilized. – Large phytoplankton blooms and low DO
– Large-scale HAB events
• NMS is targeting highest priority science needs to inform management decisions
• HAB-forming species are commonly detected throughout the Bay. Multiple HAB-toxins have been regularly detected in water and biota.
• Challenging issues, but highly relevant to management decisions:– Sources of HAs and toxin– In situ growth vs. transport, and role of SFB nutrients– Identifying protective nutrient– Evaluating risks of “events” – present, future