SEA BIRD MORTALITY AT CABO SAN LUCAS, MEXICO:EVIDENCE THAT TOXIC DIATOM BLOOMSARE SPREADING

Presented to fullfill assignment of Marine Microbiology, Vrije University of Brussels, April 2009

Written by:A. SIERRA BELTRAN, 1 M. PALAFOX-URIBE, 2J. GRAJALES-MONTIEL, 3 A. CRUZ-VILLACORTA ~ and J. L. OCHOA I

Lay Out of presentation

• Introduction• Objective• Materials and Methods• Results and Discussions• Conclusion and Recommendation

• Death of Sea Birds cases:- Monterey Bay in 1991 (Work et al i,1991, 1993)

- Santa Cruz, California, U.S.A. 1992 (Work et al., 1993)

- Ensenada BC, Mexico in 1992- Baja California peninsula, January 1996

Introduction

Introduction

Causes of the death

Domoic acid (DA) toxin

Objective

• To explain the death of the sea birds by determining the presence of such toxic microorganisms and/or DA in the stomach content of both mackerel and pelicans

Materials and Methods

Stomach content were observed by light microscopy ( × 400 and x 1000) and extracted, to obtain digestive tract (DT) and liver (L) extracts

Extract from the viscera of the dead pelicans were made and injected to the mice and observed for 48 hour

DA analysis was carried out by high-performance liquid chromatography (HPLC) using the method described by Quilliam et al. (1995) and IOC (1994)

HPLC apparatus

(1) Solvent reservoirs, (2) Solvent degasser, (3) Gradient valve, (4) Mixing vessel for delivery of the mobile phase, (5) High-pressure pump, (6) Switching valve in "inject position", (6') Switching valve in "load position“ (7) Sample injection loop, (8) Pre-column, (9) Analytical column, (10) Detector (i.e. IR, UV), (11) Data acquisition, (12) Waste or fraction collector.

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Results & Discussions

The samples of Cabo San Lucas pelicans and mackerel showed some structures resembling empty frustules corresponding to the diatom Pseudonitzschia

Results & Discussions

Most of seabirds extracts injected into mice indicated very low amounts of DA

Results & Discussions

Results & Discussions

40 min

139 min

DA intoxication such as akinesia, postration and scratching

All the animals had diarrhea

18 hr 1st animals dead, others showed convulsions, loss of lateral movement and motor incoordination

20 hr Dead

48 hr Survive mice: slight intoxication, e.g. akinesia, scratching and lack of motor coordination

The level action for DA in shellfish is 40 µg/g wet weight The upper limit allowed for human consumption of shellfish is 20 µg/g

Results & Discussions

DA was first isolated from Chondria armata ("doumoi" or "hanayanagi“), in Japan

DA can bioaccumulate in marine organisms such as shellfish, anchovies, and sardines

DA acts as an agonist to glutamate receptors which open Na+ ion channels in the pstsynaptic membrane, inducing depolarization (increasing Ca)

Chondria armatawww.algabase.org

Results & Discussions

Is there any correlation between species of Pseudonitschia to the production DA?- Blooming of P. Pungens No DA production- Blooming of P. Pungens + P. Australis YES

• Is it possible to predict HAB

Conclussions & Recommendations

• Pseudonitzschia sp. was identified as the source of the birds death intoxication by DA• Diatom blooms have been observed mostly during active upwelling• DA is difficult to detect unless a mouse bioassay is conducted• A monitoring program is recommended• New tools should be developed to make economically feasible a permanent monitoring program

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• Chromatography is the term used to describe a separation technique in which a mobile phase carrying a mixture is caused to move in contact with a selectively absorbent stationary phase. Different components of the sample are carried forward at different rates by the moving liquid phase, due to their differing interactions with the stationary and mobile phases.

• In HPLC: The Mobile Phase is a solvent. This solvent is pumped under high pressure through a column.

• The Stationary Phase is a finely divided solid held inside the column.• HPLC:It's used to find the amount of a chemical compound within a mixture of

other chemicals