General Information

Event name: US-99-010
Nature of the harmful event:
Water Discoloration , High Phyto concentration , Other ( Bioluminescence.)
Event directly affected:
Planktonic life
Toxicity detected: No
Associated syndrome:
Unexplained toxicity: No
Species implicated in toxin transmission (transvector):
Report the outcome of a monitoring programme: No
Event occurred before in this location: Yes
Individuals to contact: MONCREIFF, Cynthia A.

Location & Date

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Location: Latitude: 30.254167, Longitude: -88.773056
General location information: ca. 1 mile N of west tip of Horn Island., Gulf of Mexico, Florida.
HAB Area code(s): US-17
Additional location information: Bloom existed in large patches throughout southern Mississippi Sound and south of the barrier islands in coastal Mississippi waters.
Bloom event dates (yyyy/mm/dd): Event Date:1999-07-16
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information: Samples containing species were collected on 15/7/99 through 16/8/99.


Causative organism known: Yes
Causative Species/Genus: Alexandrium monilatum (1,098,000 cells/L)
Discolored water observed on a collecting trip associated with a GCRL Summer Field Program course and on red tide surveys
Co-Ocurring Species/Genus: Dinophysis caudata ( cells/L)
Roughly 4,000 cells/L for each species listed
Prorocentrum scutellum ( cells/L)
Roughly 4,000 cells/L for each species listed
Prorocentrum gracile ( cells/L)
Roughly 4,000 cells/L for each species listed
Chlorophyll concentration, if known: Not performed. µg/l
Additional bloom information: A list of other genera of microalgae (predominantly diatoms) present in association with the bloom is available on request. Cells/L additional species: 12,000. Roughly 4,000 cells per liter for each species listed. Cysts: none observed.
Event-related bibliography: None.

Environmental Conditions

Weather: Warm and sunny. Turbidity (NTU): Wind direction:
Stratified water: Oxygen content (nL/L): Wind velocity:
Temperature (°C): 31 Oxygen saturation %: Current Direction:
Sechhi disk (m): Salinity: 29 Current Velocity:
Nutrient information:
Temperature Range During Event: Max: 31 °C, Min: 30 °C
Salinity Range During Event: Max: 31, Min: 29
Bloom location in the water column:
In situ
Growth Comments Assume advected population with in situ growth. Cell numbers relatively high, suggesting groth of bloom in area.
Additional Environmental information: Wind direction: Variable. Wind velocity: 0 - 5 kt. Current direction and velocity: Not available.

Toxin Assay Information

Species containing the toxin Toxin type Toxin details Max. concentration Assay type
Kit used: Type of kit used:
Additional information:
Economic losses: None reported
Management decision: None taken
Additional harmful effect information: Anecdotal accounts of "dead zones" on bottom observed by divers involved with artificial reef fish program; affected areas appeared to coincide with locations of bloom patches.