RED TIDES
By Stella Angeli
Back ground taken from: http://biology.unm.edu/ccouncil/Biology_203/Images/Protists/dino1.gif
What is red tides?
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Red tide is a common name for a
phenomenon known as algal bloom, that
occurs when toxic, microscopic algae in sea
water proliferate to higher than normal
concentration often discoloring the water
red, brown, green or yellow.
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World distribution: Mexico, Texas, Florida,
South and North Carolina and others.
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Most blooms last three to five months and
may affect hundreds of square miles.
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As the bloom increases the density of red
tide organisms increase to several million
cells in each liter of sea water, creating
visible patches near the water’s surface.
Picture taken from: www.whoi.edu/redtide/
Causes of red tides
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The causes of red tides are unclear but experienced scientists have arrived at the
conclusion that some specific factors might have caused the phenomenon:
Result of human activities
Coastal upwelling, a natural result of the movement of certain ocean currents
Coastal water pollution
Systematic increase in sea water temperature
Iron-rich dust influx from large desert areas such as the Saharan desert
El Niño events (ocean-atmosphere phenomenon)
Background taken from: http://www.hkredtide.org/eng/images/Figure_1AlgalGrowthfactor.jpg
Effects
• Kills fish, invertebrates such as certain clams and oysters, other marine
mammals such as dolphins, and water fowl and other birds.
• On humans
health problems
 Tingling in lips, tongue and throat
 Diarrhea, vomiting
 Asthmatic symptoms
 Temperature ́reversals΄: cold feels hot and vice versa
Background taken from: http://bp2.blogger.com/_QCWLAhyamfg/SDdrNx9eEpI/AAAAAAAAEc4/zj533-WqzLk/s1600-h/dead+fish.jpg
Elimination and treatment in humans
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Researchers at Florida International University in Miami are experimenting with
using 640-kilohertz ultrasound waves that create micropressure zones as hot as
3,700 °C. This breaks some water molecules into reactive fragments that can kill
algae.
Treatment in humans
Filter
masks(asthmatic
symptoms)
Antiemetics
Asthma Medications :
Albuterol,
Dipheniramine,
Cromolyn, Prednisone,
Brevenal,bronchodilators
Intravenous
fluids
Which organism causes the red tides?
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The organism that causes the red tides is a microscopic alga called Karenia brevis,
which produces strong chemical brevetoxins that can harm manatees and many
other species of aquatic life.
Initiation and Transport
The initiation of Karenia brevis happens in four stages:
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Karenia brevis population is first introduced into an area
Growth, during which the population steadily increases
Maintenance, during which the bloom may be maintained in a circulation feature
offshore or moved inshore by wind and currents
Dissipation/termination. Mechanisms that contribute to this stage, such as winds
and currents, may disperse the cells, introduce new water masses, or move the
bloom to a different area.
Background taken from: http://www.marine.usf.edu/microbiology/images/k-brevis-scan.jpg
Karenia brevis
Classification
Kingdom: Alveolata
Phylum: Dinophyta
Class: Dinophyceae
Order: Gymnodiniales
Background taken from: www.whoi.edu/redtide
Shared defining characters
Flagella
Kingdom: Protista
Chloroplasts
Nucleus
Single cells
Chloroplasts
Spiraling swimming motion
Phylum:
Dinophyta
2 flagella
Nucleus
Theca
Grooves
Picture taken from: http://dinos.anesc.u-tokyo.ac.jp/plankton/figure/Karenia_brevis.jpg
Shared defining characters
Apical plate
Sulcus
Class: Dinophyta
Thecal surface
Chloroplasts
Oval shape
Ridges
Sulcus located in the intermediate
region of the cingulum
Order:Gymnodiales
Apical grooves
Chloroplasts
Fucoxanthin
Cingulum
Nucleus
Picture taken from: http://dinos.anesc.u-tokyo.ac.jp/plankton/figure/Karenia_brevis.jpg
Features
• Karenia brevis is a photosynthetic dinoflagellate.
• Cells are squarish in outline and are strongly dorsoventrally flattened. The girdle is not or only slightly
displaced.
• Length: 23-24µm
• Width: 24-36µm
• Depth: 10 to 15 µm
Background taken from: http://www.liv.ac.uk/hab/Data%20sheets/k_brev/fig4.htm
Features (2)
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Apical groove- at the anterior part of the cell
extending on both the ventral and dorsal sides.
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Chloroplast-contains chlorophyll
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Cingulum (girdle) -A furrow encircling the cell
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Cingular ridges-Longitudinal ridges in the
cingulum
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Fucoxanthin-A brownish accessory pigment used
in capturing energy.
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Longitudinal and transverse flagellum-like a
rudder, steers the cell-when beating propels the
cell.
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Nucleus
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Sulcus-The longitudinal area on the ventral surface
of the cell
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Theca (also called cell covering or cell wall)Multiple membrane layers contains vesicles,
bladderlike cavities
Picture taken from: http://www.floridamarine.org/images/articles/17864/17864_3359.jpg
Karenia brevis detector
Picture taken from: http://coolgate.mote.org/socool/images/BreveBuster.jpg
“Breve Busters optically detect Karenia brevis blooms by comparing light absorption by
particles in ambient water to the light absorption fingerprint that is characteristic of K.
brevis. That comparison yields a Similarity Index (SI) which is related to the fraction of
phytoplankton community biomass contributed by K. brevis. Values of SI below 0.5
indicate less than 10% K. brevis, values over 0.8 indicate greater than 90% K. brevis.”
(Sarasota Operations Coastal Ocean Observation Lab)
Background is taken from: Dr. Barbara’s Kirkpatrick lecture( START Board Member)
Programs associated with red tides
- Study what causes HABs and how they can be predicted and
prevented
• NOS Programs
• NOAA Marine Biotoxins Program
• IOC Harmful Algal Bloom Programme
• ECOHAB program- Florida etc.
References
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Article from: Environmental health ,Harmful algal bloom, 2008
Article from: Fish and Wildlife Research Institute, Red Tides in Florida
Article from: Laurin Publishing, 'FlowCytobot' Detects Blooms, 2008
Article from: Roth P. 2005. The microbial community associated with the Florida red
tide dinoflagellate Karenia brevis: algicidal and antagonistic interactions. MS thesis.
The College of Charleston, Charleston, South Carolina.
Article from: Anderson, D.M. 1995. ECOHAB: the ecology and oceanography of
harmful algal blooms: A national research agenda. Woods Hole Oceanographic
Institute.
Article from: Hansen et Moestrup, 1989,Karenia brevis (Davis)
Article from: Earth Observatory,NASA Satellites Detect “Glow” of Plankton in Black
Waters,2004
Article from: National Ocean Service, Harmful Algal Blooms,2007
Article from: Ocean World ,Red Tides,2004
Article from : Shifting Baselines Blog, Can Red Tide Make You Sick?,2005
Article from: National Centers for Coastal Ocean Science, Silver Spring,2008, MD.,
USA
Article from: Journey North, What is red tide?, 2003