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