emily sekula-wood, claudia...

Clarissa AndersonUniversity of South Carolina & UC Santa Cruz

Emily Sekula-Wood, Claudia Benitez-Nelson,Christopher Burrell, Steve Morton, Robert Thunell

University of South CarolinaSteve Bograd

NOAA-SWFSC/PFEL

Dave Siegel, Mark Brzezinski, Libe WashburnUC Santa Barbara

Raphe Kudela, Jenny LaneUC Santa Cruz

Trainer et al 2000, Hickey and Banas 2003, in Kudela 2005

DA events are now a seasonal stressto the coastal California ecosystem

1998 DOMOIC ACID EVENT

The Santa Barbara Channel has been a recurring hotspot

Santa Barbara Channel Oceanographic Monitoring

-121 -120.8 -120.6 -120.4 -120.2 -120 -119.8 -119.6 -119.4 -119.2 -11933.8

34

34.2

34.4

34.6

34.8

Longitude (°W)

Latit

ude

(°N

)

Pt. Conception

5354

23

RBCOP

San Miguel

Santa RosaSanta Cruz

Anacapa

1

2

3

4

5

6

7

89

10

11

12

1314

15

1617

18

1920

212223

2425

• SBC LTER – 2000-2006, seasonal grid• Plumes and Blooms – 1996+ monthly• CODAR HF Radar (&SCCOOS)• SBB Sediment Traps & Cores• CalCOFI 82.47 –1984 – 2008, seasonal

SSD

020406080

100120140160180200220240260280

Pseudo-nitzschia spp. Abundance(x 103 cell L-1)Cellular Domoic Acid(pg cell-1)

Nov Dec Mar Apr May Jun Aug Sep Oct Nov Nov Jan Mar Mar Apr May Jun2004 2005 2006

Mon

thly

Mea

n A

cros

s S

tatio

nsPlumes and Blooms Time Series:

Pseudo-nitzschia and DA, 2004-2006

June 2005

Aug 2005May 2006

June 2006

Cyclonic Eddies –offshore retention?

0

500

1000

1500

2000

2500

3000

3500

4000

090320 090421 090728 90827 90925 91030 91120 100226 100324 100721

PN Avg

pDA Avg

Pseudo-nitzschia spp. Abundance(x 102 celsl L-1)Particulate Domoic Acid (ng L-1)

Plumes & Blooms Transect: Pseudo-nitzschia and DA 2009-2010

El Niño YearLate Fall Events w/ eddies

High DA!!!

Mea

n A

cros

s S

tatio

ns

Mar Apr Jul Aug Sep Oct Nov

NSF Project: Benitez-Nelson, Anderson, Sekula-Wood, Burrell

Feb Mar Jul2009 2010

data gapMay-June

data gapDec-Jan

No Pseudo-Ncell counts yet!

Significant PredictorsFULL

MODELS

Significant PredictorsRS parameters only

MODELS

Pseudo-nitzschia

Abundance

-Rrs(510/555)-Si:N

-Month-Si:P

-Rrs(510)

-Rrs(510/555)-Month

-Rrs(490/555)

ParticulateDA

+Chl-Si:N

-Nitrite-Temp

+Salinity

+Chl+Salinity-Rrs(555)

PLUMES & BLOOMS: 2004-2006 & 2009-2010Empirical HAB Models

Anderson et al. 2009 Harmful Algae

A

B

Sediment trap study to examine vertical flux of Pseudo-nitzschia and DA toxin

C. Benitez-Nelson, E. Sekula-Wood, C. Anderson, R. ThunellUniversity of South Carolina

Good coherence between surface samples (from P&B line) and trap fluxes

Sekula-Wood et al. 2009, Nature Geoscience

Domoic Acid

Pseudo-nitzschia

r2 = 0.66

r2 = 0.50

past events ?

P-nConc.

P-nFlux

Flux(zoom)

From Barron et al. (2009), P-nincreases to 15% relative

abundance in 2000-2001 in SBB core

SBB Sediment Trap Time Series1993 - 1999

E. Sekula-Wood, dissertation

No data

DA FluxP-n Flux

SBB Sediment Trap Time Series2000 - 2008

E. Sekula-Wood, dissertation

P-n FluxDA Flux

Why this apparent jump in DA production after 2000?

Upwelling – 20° C isotherm < 20 m

Pseudo-nitzschia Flux to 540 m Trap

more prolonged upwelling after 1998?

Pseudo-nitzschia Flux to 540 m Trap

OCEANIC NINO INDEX

DA events not highly correlated with either ENSO phase

Pseudo-nitzschia Flux to 540 m Trap

PACIFIC DECADAL OSCILLATION

Shifts in 2000, but not a smoking gun.

0 20 40 60 80 100 120 140 160 18-3

-2

-1

0

1

2

3

NORTH PACIFIC GYRE OSCILLATION (NPGO)

Pseudo-nitzschia Flux to 540 m Trap

Maybe, but drops in 2005

0 20 40 60 80 100 120 140 160 18-3

-2

-1

0

1

2

3

Domoic Acid Flux to 540 m Trap

NORTH PACIFIC GYRE OSCILLATION (NPGO)

NORTH PACIFIC GYRE OSCILLATION

Large DA events in traps generally correspond with positive NPGO

If NPGO is involved, what is the mechanism leading to more DA production and/or more blooms in the last decade?

•When positive, the NPGO represents an intensification of the geostrophic circulation, that is a strengthening of the NPC, and (in contrast to the PDO) an increase in the transport of both the Alaskan Coastal Current and California Current circulation…

• In the California Current System (CCS) the NPGO reflects changes in wind stress, in particular the winds that force coastal upwelling..When positive, the associated changes in wind forcing create upwelling-favorable conditions in the CCS and Alaskan Gyre … only south of 38N.

[The 2nd EOF mode of SSHa], the NPGO mode in its positive phase shows a pair of counterrotating gyres that reflect the gyre-scale mean geostrophic circulationinferred from satellite.

Di Lorenzo et al. 2008, GRL

California Undercurrent

o 1984-2008o Quarterly Surveyso consistent samplingo 66 stationso 0-500 mo >100 Occupations

CalCOFI Hydrographic Data

Station 82.47:Santa Barbara Basin

Station 93.30:California Undercurrent

CalCOFI Station 82.47

+

Increasing Anoxia in SBB?• near-surface warming• less dense waters at

western sill• fewer basin flushing events• lower oxygen content

O2

NO3

PO4

SiO4

S

σθ

θ

CalCOFI, Anoxia in the Santa Barbara Basin

Deepest Sample, 1986-2006

O2 ~ NO3 ~ 0

Steve Bograd, SWFC/PFEL

Line 93 Mean Autumn Spiciness

25.6

26.4CUC

600km 400 200 0

400

200

0 m

CalCOFI, California Undercurrent Property Trends:inorganic nutrients, nutrient ratios

Steve Bograd, SWFC/PFEL

1984-2008

CalCOFI, Long-Term Trends in Inorganic Nutrients:magnitude of change, 1984-2008

Nitrate

Silicate

Oxygen

Phosphate

N:P S:N

σθ = 26.5 (CUC core)

Strongest trends at 100-300m offshore; shallower for NO3

Strong deep silicate decline in coastal waters of Bight

Plumes & Blooms Data, Santa Barbara Channelnutrients and nutrient ratios (anomalies)

Nitrate

Silicate

Si:N

mid-channel station, Surface

mid-channel station, 50m

Nitrate ?

Silicate

Si:N

Plumes & Blooms Data, Santa Barbara Channel• deeper Si anomalies more like CUC core data

• Observed rise in toxic diatom blooms in SBC results from

changes in local to regional oceanography, possibly modulated by

climate variability (NPGO).

• Modulation of CUC transport into the SBB by NPGO could

explain the timing of the increase in DA events post-97/98 ENSO.

• Increased blooms related to a change in the biogeochemistry of

upwelled sourcewaters – e.g. the CUC (possibly in turn driven by

changes in its source waters from the eq. Pacific)

SUMMARY: Working Hypotheses

REGIONAL DOWNSCALING and REMOTE SENSING

MODIS-Aqua 1km Chl, Rrs(λ)

Toxic Bloom Nowcasts/Hindcasts

SST, Salinity

Ocean Color

SBC ROMS

BIOGEOCHEMICALBEC MODEL

Embedded in ROMSCOMING SOON!

Statistical HAB Models

Predicted Probability of High Cellular DA

THANK YOU

SBC-LTER (NSF)UCSB Plumes & Blooms (NASA)NASA ESS Graduate Fellowship

NRC Postdoctoral FellowshipNOAA MERHAB Program/Cal PRe-EMPT

NSF Chemical OceanographyCA Sea Grant – OPC

ISSHA Travel Award 2010